Oil & Lubrication

Last updated: February 8, 2003

Engine Oil

The RX-7's rotary engine injects oil into the combustion chamber as a part of normal operation, for lubrication purposes. As a result of this, synthetic oils should not be used. When they burn, they give off more ash than conventional oils, clogging the cats, causing buildup, etc. Also, additives such as Slick 50 are not advised. Any good quality oil that meets the manufacturer's recommendations should do.

Check out the Mazdatrix FAQ on the use of synthetic oil in rotary engines.

Personally, I prefer Valvoline, for the simple reason that I put about 60,000 hard miles on a '69 Firebird (mostly a quarter mile at a time), and did not have a single problem with the car related to oil. In fact, when I opened up the engine to do a valve job, it looked like the day I bolted it together.

Valvoline has a good Web site - SAE acronym definitions, ASE information, etc.

Pennzoil has a nice site with more info on choosing oils.

Check out the other resources on the 'net:

Date: Tue, 18 Nov 97 08:57:32 -0500
From: "Linthicum, Sandy"

> I'm still confused about one point. The "Street" mix
> was 320 parts gas to 1 part oil (20 Gallons to 4 Ounces),
> while the suggested "Race" mix was 80 parts gas to 1 part oil.
> Wouldn't this decrease performance and increase plug fouling?
> This guy is a racer, so I know better, I just don't understand!

1. It will NOT foul plugs. Use a high quality synthetic 2 cycle premix oil (like for motorcycles) like Pettit Racing's, Amsoil, etc. This ensures the seals always have lubrication. Put it in before you put in the gas so it will be mixed. You will use more like 4oz per 12-15 gallons unless you intend to run out of gas before filling. I double or triple this to 8- 12 oz per tank when at the track (drivers schools) and have never had any trouble with the plugs, even thought I run 9's all arround (colder than the stock setup).

2. The oil injection/meter pump takes a while to get going, leaving the apex seals marginally lubes (or unlubed) on initial startup. This is particularly bad if you do not defeat the fast rpm idle on startup (just start the car in gear to defeat this, starting it in neutral will cause fast idle). Look on Pettit racings web site www.pettitracing.com for more info.


Date: Tue, 18 Nov 1997 10:45:50 -0500
From: "Robinette, Maj Robbie D."

The "street mix" the previous owner suggested is for use with the stock oil injection system functioning. He was adding a little oil to be safe. The "race mix" on the bottle refers to the mixture needed when all the oil for the engine comes in the gas (standard on 2 stroke engines).

Date: Sun, 31 Aug 1997 00:41:08 -0400 (EDT)
From: AutoArt22@aol.com

Thanks to all who responded to my poll concerning what type of oil/filter were being used in your RX7's. I have compiled the results as follows:

Total Responses - 47

Dino Juice - 90%
Synthetic - 10%

Castrol GTX - 50%
Valvoline - 25%
Other - 15%
Mobil - 10%

10/30 - 75% of responses
20/50 - 10%
Combination of 20/50 Summer & 10/30 Winter - 15% 

Mazda Filter - 80%
Fram Filter - 16%
Other - 4%

3000 Miles - 33%
2500 Miles - 33%
2000 Miles - 29%
Less Than 2000 Miles - 5%

Thanks Again for your help. I hope this info can help others.

Date: Sun, 7 Dec 1997 20:14:57 EST
From: SLNIX (Steve Nix)

Cameron Worth, President and Racer-Tuner of Pettit Racing and Excellence PerformanceCorp. suggested that I use Valvoline 20-50 Motor Oil in the engine, and add 4 oz. of Protek Fuel Lubricant to each tank of gas (His own private label - I don't know who makes it for him). He also suggested using Amsoil Synthetic Gear Lube in the differential, and Redline MTL Synthetic in the manual transmission. As for gas, the BEST HI-OCTANE (Preferably 93 Octane for the street) you can find (For Turbo applications).

When he is racing his car, he does use synthetic oil in the engine, with an even higher Protek Fuel Lubricant ratio. In his catalog, it states "We have experienced NO oil related mechanical failures to date". His company has been repairing, racing and tuning rotary engines for the past 20 years!


Date: Sat, 26 Jul 1997 10:54:06 -0700
From: Scott Bell

"Motor Oils" Copyright 1996 by Consumers union of U.S., Inc., Yonkers, NY 10703-1057. Reprinted and electronically posted to this mailing list ONLY by permission from CONSUMER REPORTS, July 1996. Further distribution of this article, via print or electronic means, is strictly prohibited.

The Surprising Truth About Motor Oils

A Mobil commercial claims its oil "has been in more Indy 500 winners than any other oil." Quaker State shows an engine with a terminally corroded inside ---- what they imply could happen when you use another oil. Exxon's commercial for its Superflo oil urges motorists to "rely on the tiger."

Oil companies spend millions of advertising dollars each year to convince you that their oil can make your car's engine perform better and last longer. And purveyors of motor oil and engine "treatments" assert that their products offer engine protection that oil alone can't provide. In our most ambitious test project ever, we set out to discover whether such claims are fact or fancy.

One way to gauge the performance of motor oils is to test them on the road. We did just that, using a fleet of 75 New York City taxicabs. Indeed, the oil industry itself tests its oils in New York City taxis.

For 22 months, we tested the performance of 20 popular motor oils. Each of those oils met the industry's latest standards, as certified by a starburst symbol on the container. (See "It's not just oil," page 14.) We also tested Slick 50 Engine Treatment and STP Engine and Oil Treatments.

In addition to the taxicab tests, we had the oils' chemical and physical properties analyzed by an independent lab. We also surveyed our subscribers about their oil changing experiences and preferences, and we sent shoppers to quick lube centers across the country to assess the service (see page 17.) Finally, because changing the oil is just one part of car care, we've reviewed some other ways you can help keep your car running longer. That report begins on page 18.

Testing the oils

We put identical rebuilt engines with precisely measured parts into the cabs at the beginning of the test, and we changed their oil every 6000 miles. That's about twice as long as the automakers recommend for the severe service that taxicabs see, but we chose that interval to accelerate the test results and provide worst-case conditions. After 60,000 miles, we disassembled each engine and checked for wear and harmful deposits.

Our test conditions were grueling, to say the least. The typical Big Apple cab is driven day and night, in traffic that is legendary for its perversity, by cabbies who are just as legendary for their driving abandon.

When the cabs aren't on the go, they're typically standing at curbside with the engine idling ---- far tougher on motor oil than highway driving. What's more, the cabs accumulate lots of miles very quickly making them ideal for our purposes. Big-city cabs don't see many cold start-ups or long periods of highspeed driving in extreme heat. But our test results relate to the most common type of severe service ---- stop-and-go city driving.

Each of the 20 oils we studied was tested in three cabs to provide meaningful test results even if a few cabs fell out with mechanical problems or because of accidents. (Six of the 75 engines did, in fact, have problems, none apparently related to the oil's performance.) For a detailed description of our test procedures, see "Testing in the Big Apple," page 12.

Our shoppers all across the country bought hundreds of quart containers of oil. Some brands had slightly different formulations in different areas, but all the oils included a full package of additives.

The independent lab helped us identify the most representative formulations of each brand. Our engineers transferred containers of that oil to coded 55-gallon drums and hauled them to the fleet garage for testing.

Ideally, oil should be thin enough to flow easily when the engine is cold and remain thick enough to protect the engine when it's hot. The lab analyses of each oil's viscosity characteristics ---- its ability to flow ---- indicate that motor oils have improved since 1987, when we last tested them. This time, far fewer test samples failed to meet the viscosity standards for their grade ---- and those were typically outside the limits by only a slight amount. No brand stood out as having a significant problem.

We tested oils of the two most commonly recommended viscosity grades - ---- 10W-30 and 5W-30. Automakers specify grades according to the temperature range expected over the oil-change period. The lower the number, the thinner the oil and the more easily it flows.

In 5W-30 oil, for example, the two numbers mean it's a "multiviscosity" or "multigrade" oil that's effective over a range of temperatures. The first number, 5, is an index that refers to how the oil flows at low temperatures. The second number, 30, refers to how it flows at high temperatures. The W designation means the oil can be used in winter.

A popular belief is that 5W-30 oils, despite their designation, are too thin to protect vital engine parts when they get hot. However, one of our laboratory tests measured the viscosity of oils under high-temperature, high-stress conditions and found essentially no difference between 5W-30 oils and their 10W-30 brand mates. But at low temperatures, the 5W-30 oil flowed more easily.

Viscosity grade is important, so be careful. Recommendations vary with the make, engine, and model year of the car, so check your owner's manual and ask the mechanic for the proper grade of oil.

Of the 20 oils we tested, nine were conventional 10W-30 oils, and eight were 5W-30. We also tested two synthetic oils, Mobil 1 and Pennzoil Performax, and one synthetic-and-conventional blend, Valvoline Dura-Blend; all three were 10W-30 oils.

No Brand Performed Best

If you've been loyal to one brand, you may be surprised to learn that every oil we tested was good at doing what motor oil is supposed to do. More extensive tests, under other driving conditions, might have revealed minor differences. But thorough statistical analysis of our data showed no brand ---- not even the expensive synthetics ---- to be meaningfully better or worse in our tests.

After each engine ran about 60,000 miles (and through 10 months of seasonal changes), we disassembled it and measured the wear on the camshaft, valvefters, and connecting-rod bearings. We used a tool precise to within 0.00001 inch to measure wear on the key surfaces of the camshaft, and a tool precise to within 0.0001 inch on the valve lifters. The combined wear for both parts averaged only 0.0026 inch, about the thickness of this page. Generally, we noted as much variation between engines using the same oil as between those using different oils. Even the engines with the most wear didn't reach a level where we could detect operational problems.

We measured wear on connectingrod bearings by weighing them to the nearest 0.0001 gram. Wear on the key surface of each bearing averaged 0.240 gram ---- about the weight of seven staples. Again, all the tested oils provided adequate protection.

Our engineers also used industry methods to evaluate sludge and varnish deposits in the engine. Sludge is a mucky sediment that can prevent oil from circulating freely and make the engine run hotter. Varnish is a hard deposit that would remain on engine parts if you wiped off the sludge. It can make moving parts stick.

All the oils proved excellent at preventing sludge. At least part of the reason may be that sludge is more apt to form during cold startups and short trips, and the cabs were rarely out of service long enough for their engine to get cold. Even so, the accumulations in our engines were so light that we wouldn't expect sludge to be a problem with any of these oils under most conditions.

Variations in the buildup of varnish may have been due to differences in operating temperature and not to the oils. Some varnish deposits were heavy enough to lead to problems eventually, but no brand consistently produced more varnish than any other.

The bottom line. In our tests, brand didn't matter much as long as the oil carried the industry's starburst symbol (see "It's not just oil," page 14.) Beware of oils without the starburst; they may lack the full complement of additives needed to keep modern engines running reliably.

One distinction: According to the laboratory tests, Mobil 1 and Pennzoil Performax synthetics flow exceptionally easily at low temperatures ---- a condition our taxi tests didn't simulate effectively. They also had the highest viscosity under high-temperature, high-stress conditions, when a thick oil protects the engine. Thus, these oils may be a good choice for hard driving in extreme temperatures.

Note, too, that a few automakers recommend specific brands of motor oil in the owner's manual. You may need to follow those recommendations to keep a new car in warranty.

Oil changes: How often?

The long-time mantra of auto mechanics has been to change your oil every 3000 miles. Most automakers recommend an oil change every 7500 miles (and a specific time interval) for "normal" driving, and every 3000 miles for "severe" driving ---- frequent trips of less than four or five miles, stop-and-go traffic, extended idling, towing a trailer, or dusty or extremely cold conditions. Many motorists' driving falls into one or more of those "severe" categories.

In our survey, almost two-thirds of our readers said they had their oil changed every 3000 miles or less. They may be following the thinking expressed by one of our staffers: "I have my oil changed every 3000 miles because that's what my father did, and all his cars lasted for many years."

To determine whether frequent oil changes really help, we changed the oil in three cabs every 3000 miles, using Pennzoil 10W-30. After 60,000 miles, we compared those engines with the engines from our base tests of the same oil, changed every 6000 miles. We saw no meaningful differences.

When Mobil 1 synthetic oil came out, Mobil presented it as an oil that, while expensive, could go 25,000 miles between changes. That claim is no longer being made. But Mobil 1 is still on the market, selling at a premium (along with pricey synthetic competitors from several other companies). And synthetic oil's residual reputation as a long-lasting product may still prompt some people to stretch their oil changes longer than the automaker recommends.

Determining whether synthetic oils last longer than conventional ones would require a separate test project. To try to get some indication, we put Mobil 1 synthetic into three cabs and changed their oil every 12,000 miles. We intended to compare the results of these tests with those from the three taxicabs whose Mobil 1 was changed at our normal interval, every 6000 miles. Unfortunately, two of the three engines using the 12,000-mile interval developed problems. (We couldn't attribute those problems to the oil.) The third engine fared no worse than the three whose oil had been changed at 6000-mile intervals.

The bottom line. Modern motor oils needn't be changed as often as oils did years ago. More frequent oil changes won't hurt your car, but you could be spending money unnecessarily and adding to the nation's energy and oil-disposal problems.

Even in the severe driving conditions that a New York City taxi endures, we noted no benefit from changing the oil every 3000 miles rather than eve

Determining whether synthetic oils last longer than conventional ones would require a separate test project. To try to get some indication, we put Mobil 1 synthetic into three cabs and changed their oil every 12,000 miles. We intended to compare the results of these tests with those from the three taxicabs whose Mobil 1 was changed at our normal interval, every 6000 miles. Unfortunately, two of the three engines using the 12,000-mile interval developed problems. (We couldn't attribute those problems to the oil.) The third engine fared no worse than the three whose oil had been changed at 6000-mile intervals.

The bottom line. Modern motor oils needn't be changed as often as oils did years ago. More frequent oil changes won't hurt your car, but you could be spending money unnecessarily and adding to the nation's energy and oil-disposal problems.

Even in the severe driving conditions that a New York City taxi endures, we noted no benefit from changing the oil every 3000 miles rather than f your driving falls into the "normal" service category, changing the oil every 7500 miles (or at the automaker's suggested intervals) should certainly provide adequate protection. (We recommend changing the oil filter with each oil change.)

We don't recommend leaving any oil, synthetic or regular, in an engine for 12,000 miles, because accumulating contaminants ---- solids, acids, fuel, and water ---- could eventually harm the engine. What's more, stretching the oil-change interval may void the warranty on most new cars.

Testing Slick 50 and STP

We also tested Slick 50 and STP Engine Treatments and STP Oil Treatment, each in three cabs. (Slick 50 costs $17.79 per container; STP Engine Treatment has been discontinued.) All three boast that they reduce engine friction and wear.

The engine treatments are added with the oil (we used Pennzoil 10W-30). They claim they bond to engine parts and provide protection for 25,000 miles or more. We used each according to instructions.

The STP Oil Treatment is supposed to be added with each oil change. It comes in one formulation (black bottle, $4.32) for cars with up to 36,000 miles, another (blue bottle, $3.17) for cars that have more than 36,000 miles or are more than four years old. We used the first version for the first 36,000 miles, the second for the rest of the test ---- again, with Pennzoil 10W-30.

When we disassembled the engines and checked for wear and deposits, we found no discernible benefits from any of these products.

The bottom line: We see little reason why anyone using one of today's high-quality motor oils would need these engine/oil treatments. One notable effect of STP Oil Treatment was an increase in oil viscosity; it made our 10W-30 oil act more like a 15W-40, a grade not often recommended. In very cold weather, that might pose a risk of engine damage.


None of the tested oils proved better than the others in our tests. There may be small differences that our tests didn't reveal, but unless you typically drive under more severe conditions than a New York cab does, you won't go wrong if you shop strictly by price or availability. Buy the viscosity grade recommended in your owner's manual, and look for the starburst emblem. Even the expensive synthetics (typically, $3 or $4 a quart) worked no better than conventional motor oils in our taxi tests, but they're worth considering for extreme driving conditions ---- high ambient temperatures and high engine load or very cold temperatures.

On the basis of our test results, we think that the commonly recommended 3000-mile oil-change interval is conservative. For "normal" service, 7500-mile intervals (or the recommendation in your owner's manual) should be fine. Change the oil at least that often to protect your engine and maintain your warranty. Even for the severe service experiened by the taxis in our tests, a 6000-mile interval was adequate. But some severe service ---- frequent cold starts and short trips, dusty conditions, trailer towing ---- may require a shorter interval. Note, too, that special engines such as diesels and turbos, which we didn't test, may need more frequent oil changes.

We don't recommend stretching the change interval beyond the automaker's recommendations, no matter what oil you use. Engine combustion contaminants could eventually build up and harm engine parts.

As for STP Oil Treatment, STP Engine Treatment, and Slick 50 Engine Treatment, our advice is simple: If you use an oil with the starburst symbol, you don't need them.

(End - Ed.)

(reference to 'description of test procedures on page 12' shown below - Ed.)

Testing in the Big Apple

New York City taxicabs played a key role in our massive test project to evaluate motor oils. For consistency, we used only 1992-93 Chevrolet Caprice cabs. Each received a precisely rebuilt 4.3-liter V6 at the beginning of its 60,000-mile test. We started with six rebuilt engines; after each engine was installed in a cab, the six engines that were removed were rebuilt and installed in six other cabs ---- and so on. Using that rotation, we monitored 75 cabs over 4.5 million miles of driving in New York City and its environs. Each oil was tested in three engines.

A local shop completely machined each engine block and crankshaft, rebuilt the cylinder heads, and installed new bearings, pistons, rings, seals, gaskets, and oil pump. Though the engines originally had roller lifters and camshafts, a design that reduces friction, we installed conventional sliding lifters and camshafts to accelerate wear.

Before the engines were assembled, we measured or weighed the parts most likely to show wear if the oil wasn't doing its job ---- the camshafts, valve lifters, and connecting-rod bearings. Each cab went through a break-in procedure before hitting the road. During testing, two engine timers measured the time the engine was running and the time it was in gear.

Over the next 22 months, our engineers paid more than 100 calls ---- usually without notice ---- on the fleet garage. They dropped off test oil and picked up used-oil samples for ongoing analysis. They also made sure that oil was being added to the engines when necessary and changed as scheduled.

After each 60,000-mile test, we remeasured the key engine parts. We also examined combustion-chamber deposits, the color of the valves, scoring of cylinder walls, and valvedeck deposits for any sign of engine problems.

(reference to 'description of standards and symbols on page 14' shown below - Ed.)

It's not just oil

Certainly, motor oil is slippery. That's what helps protect an engine's moving parts. But motor oil does much more than lubricate. It helps cool the engine, keep it clean, prevent corrosion, and reduce friction to improve fuel economy To do all that refiners blend in various additives, which account for 10 to 25 percent of the product you buy.

The oil industry has devised a starburst symbol to certify that a particular motor oil meets the latest industry requirements for protection against deposits, wear, oxidation, and corrosion. The starburst on the label means the oil meets API (American Petroleum Institute) Service SH requirements-the latest most advanced formulation. (Service SH supplants SG the previous top category.) The CD designation on most of the oils we tested refers to diesel performance. The starburst also indicates that the oil passes ILSAC/GF-1 standards developed by the International Lubricant Standardization and Approval Committee, a U.S.-Japanese group. And it means the oil meets Energy Conserving II requirements---- it improves fuel economy by reducing engine friction. All the oils we tested carry the starburst-and all performed well in our test. But note that oils without that symbol may not perform as well.

(Below -Ed.) are some of the additives found in modern oils.

Viscosity-index improvers modify the oil so its viscosity is more consistent over a wide temperature range.

Antioxidants prevent the oil from thickening when it runs hot for extended periods.

Dispersants keep contaminants suspended so they don't form deposits in engine.

Detergents help prevent varnish and sludge on engine parts and neutralize acid formed in engine.

Rust and corrosion inhibitors protect metal parts from acids and water formed in engine.

Pour-point depressants help the oil flow in a cold engine, especially in cold weather.

Friction modifiers strengthen the oil film and prevent unlubricated contact between moving parts.

Foam inhibitors collapse the bubbles churned up by engine crankshaft. (Foam reduces lubricating effectiveness.)

Antiwear agents provide lubrication when oil is squeezed out from between moving engine parts.

Ratings & Recommendations

Shopping strategy

Discount stores are generally the least expensive place to buy oil. Look for sales and buy by price ---- but make sure the container has the starburst symbol.

Details (listed alphabetically)

All the tested oils performed well in our tests, and all claim to meet the latest (API-SH and ILSAC/GF-1) industry standards (see "It's not just oil," (above - Ed.)). Prices are the average for one quart, based on a national survey of discount stores.

5W-30 oils

Castrol GTX $1.21
Appears to use same formulation in all areas sampled. Graduated container.

Exxon Superflo
Price not available; not widely found in discount stores. Appears to use same formulation in all areas sampled. Graduated container with window.

Fire & Ice All-Season (Shell) * $0.93
Different formulations in Florida and New York. Graduated container with window.

Havoline Formula 3 (Texaco) $1.11
Appears to use same formulation in all areas sampled. Graduated container with window.

Mobil * $0.95 Appears to use same formulation in all areas sampled. Graduated container with window.

Pennzoil $1.16
Appears to use same formulation in all areas sampled. Graduated container.

Quaker State Deluxe * $1.20
Appears to use same formulation in all areas sampled. Graduated container with window. 10W-30 is called Super Blend.

Valvoline All-Climate $1.14
Different formulations in California and Texas. Graduated container with window.

10W-30 oils

Castol GTX $1.18
Appears to use same formulation in all areas sampled. Graduated container.

Exxon Superflo $1.13
Different formulation in Florida. Graduated container with window.

Fire & Ice All-Season (Shell) * $0.99
Appears to use same formulation in all areas sampled. Graduated container with window.

Havoline Formula 3 (Texaco) * $1.13
Different formulations in Illinois and Texas. Graduated container with window.

Kendall Superb 100 * $1.23
Different formulation in Florida. 5W-30 version not tested.

Mobil 1 synthetic $3.76
Low-temperature flow characteristics were better than most. Appears to use same formulation in all areas sampled. 5W-30 version not tested. Graduated container with window.

Mobil $0.95
Different formulation in New York. Graduated container with window.

Pennzoil $1.16
Appears to use same formulation in all areas sampled. Graduated container.

Pennzoil Performax synthetic $2.97
Low-temperature flow characteristics were better than most. No 5W-30 version. Appears to use the same formulation in all areas sampled.

Quaker State Super Blend * $1.20
Appears to use same formulation in all areas sampled. Graduated container with window. 5W-30 is called Deluxe.

Valvoline All-Climate $1.13
Different formulation in California. Graduated container with window.

Valvoline Semi-Synthetic DuraBlend conventionl/synthetic blend * $2.12
Appears to use same formulation in all areas sampled. Graduated container with window. No 5W-30 version. Flow characteristics were more like those of a conventional oil than those of a synthetic.

* - One or more samples differed from viscosity-grade requirement by a small amount.

Oil Additives

Date: Wed, 01 Oct 1997 19:13:16 -0700
From: Scott Bell

The following report was published in the October 1997 issue of Consumer Reports magazine. It is a quick follow up to the full report on engine oils and additives they gave in July 1996.


Slick 50 stops making slippery claims

Anyone using one of today's high-quality motor oils shouldn't need an additional engine or oil treatment. We reached that conclusion in our July 1996 report on motor oils after we tested Slick 50 Engine Formula and STP Oil Treatment in New York City taxis. The same month that we published our report, the Federal Trade Commission issued a complaint charging that Slick 50 ads claiming improved engine performance and reduced engine wear were deceptive. The FTC alleged that Slick 50 test data don't prove that the product reduces engine wear at start-up, that it reduces engine wear by 50 percent, or that one treatment reduces engine wear for 50,000 miles. In fact, most car engines are adequately protected from wear at start-up when they use motor oil as recommended in the car owner's manual.

This summer, the companies that manufacture and market Slick 50 settled with the FTC, agreeing to stop saying that engines lack protection from wear at start-up unless they have been treated with Slick 50, that engines commonly experience premature failure caused by wear unless they are treated with Slick 50, and that Slick 50 coats engine parts with a layer of polytetrafluoroethylene (PTFE). The agreement bars claims about the performance, benefits, or attributes of engine lubricants without "competent and reliable evidence."

This is not the first time a motor-oil-additive maker has come under FTC scrutiny. A 1976 FTC order prohibited STP Corp. from making unsubstantiated claims about its motor-oil additives. STP violated the order twice, in 1978 and 1995, and had to pay civil penalties that were among the largest sums the FTC has ever obtained for a consumer-protection-order violation.


Date: Tue, 07 Apr 1998 13:19:13 -0400
From: Tom Knott

Quoted from http://home.earthlink.net/~jamesdavis/TIP043.html :In a statement issued about ten years ago, DuPont's Fluoropolymers Division Product Specialist, J.F. Imbalzano said,

"Teflon is not useful as an ingredient in oil additives or oils used for internal combustion engines."

They went on and REFUSED to sell PTFE to anyone that intended to do so!

Naturally, they were sued by, guess who, on grounds of 'restraint of trade'. DuPont lost and have changed their position as follows: DuPont now states that though they sell PTFE to oil additive producers, they have "no proof of the validity of the additive makers' claims." They further state that they have "no knowledge of any advantage gained through the use of PTFE in engine oil."

NASA Lewis Research also ran tests on PTFE additives and they concluded that:

"In the types of bearing surface contact we have looked at, we have seen no benefit. In some cases we have seen detrimental effect. The solids in the oil tend to accumulate at inlets and act as a dam, which simply blocks the oil from entering. Instead of helping, it is actually depriving parts of lubricant."

Chief Chemist of Redline Synthetic Oil Company, Roy Howell, says:

"... to plate Teflon on a metal needs an absolutely clean, high temperature surface, in a vacuum. Therefore, it is highly unlikely that the Teflon in Slick 50 actually plates the metal surface. In addition the Cf (Coefficient of friction) of Teflon is actually greater than the Cf of an Oil Film on Steel. Also, if the Teflon did fill in 'craters' in the steel, than it would fill in the honing of the cylinder, and the oil would not seal the piston rings."


Date: Tue, 07 Apr 1998 13:26:47 -0400
From: Tom Knott

See this.

Oil Filters

For a complete rundown on filters, see the Filter Study. --Steve


Date: Sun, 19 Apr 1998 22:55:44 EDT

Standard Fram, Purolator, and other mass marketed filters generally do not have the "anti-drainback" valve that the Mazda OE filter has.

However, Purolator has recently introduced a line of filters called "Pure One" which does have the anti-drainback feature. Pep Boys has them for around $6 ea. That's just about what I was paying for the Mazda filter. Also, the Pure One line supposedly has more filter media in it than most other filters.

Oil Catch Can

>I am running a great deal of oil from the oil filler pipe down into the
>compressor of the primary. Have any of you put in a catch can that drains back
>into the oil pan? I know Cam Worth has made that modification. I am looking for
>any help on fittings to the oil return pipe or other pieces of the learning
>curve on this modification that you can provide. TIA


Date: Sun, 17 Oct 1999 21:25:35 +0000
From: wael el-dasher (wael.el-dasher@efini.net)

Cork Sport got me a CUSCO catch tank kit for the FD3S, I haven't recieved it yet, but I will let you know how it works.


Date: Sun, 17 Oct 1999 09:10:44 -0400
From: "AL Beder" (albeder@earthlink.net)

I have a catch can setup (that was recommended by Cam). It has two lines one that comes from the side port on the oil filler tube and another from the oil return line for the lst turbo. The port to the PCV valve (the valve is trashed) is plugged as is the original return line to the intake before the turbo. You must make sure the catch can is vented as this is now your engine ventilation system. Once the oil is in the catch can it will not drain back although I suppose you could have a return line. The idea with the current setup is that oil that goes up into the lines (before the catch can) will drain back into the sump.

Even with this setup I run 1/2 quart low otherwise I will get the oil back in the catch can. At most tracks I will see very little oil in the catch can. It's important that the can is as high as possible and not to have the lines level or pointing down to the can to prevent a siphoning effect.


Date: Sun, 17 Oct 1999 15:39:51 -0400
From: "kevin kelleher" (kellehkj@earthlink.net)

I simply added an oil separator to the vapor return line from the filler neck. It is compact, and must be emptied after each 20 min track session.

Bought a purolator F54498 fuel filter, cut it above the lower nipple, gutted the filter out, and jointed back together with both nipples in the same direction. For the joint, used a metal ring (a piece of 1-3/4 exhaust pipe adaptor?) that pressed in on the inside, and a band segment of mountain bike tube on the outside, with hose clamp around the rubber. Could use the same technique to expand the capacity. Used clear hose pieces, and mounted it hanging off the left strut brace anchor. Easy to pull and empty.

Only shows oil when at the track, near the limit at high rpm. Took some kadiddeling, but works for me. I have most stock stuff still uner hood, and little room for a normal catch tank. I put mine together when they were clear, but now it seems they are a white plastic.


Date: Sun, 17 Oct 1999 09:44:22 -0400
From: "Rob Robinette" (robinette2@home.com)

You could also splice a non-vented catch can into the vent line that runs from the oil filler pipe to the primary turbo inlet. Attach the bottom of the can to the filler pipe side of the vacuum line and the top of the can to the turbo inlet side. Then remove the PCV valve and plug it's vacuum line nipples.

With this setup you would still have positive ventilation of the crankcase and you wouldn't be venting oily crankcase gasses in the engine compartment. You would have to disconnect the lower vacuum hose to drain the can. A better setup would be a three outlet can, out on top, in in the middle, and the drain on the bottom. Most catch cans use NPT threaded hose connections so it's easy to install vacuum hose nipples that fit the PCV line.


Date: Sun, 17 Oct 1999 13:10:03 -0400
From: "John Levy" (mazdarx7@ziplink.net)

It seems to me the correct setup that would eliminate having to drain the catch can would be running a line from the oil filler tube to a vented catch can where a second hose runs from the catch can drain to join the oil return line that runs from the 1st turbo into the oil pan. What do you think?


From: Sandro LaRosa" (Sandro.LaRosa@tcgny.com)
Date: 10/04/2002 09:39 AM

Please see my correspondence with the SCCA (below) regarding the PCV routing in stock class. As I am planning to install a sealed catch can (not a breather) in between the oil filler neck and the return to the intake, I asked if I could eliminate the return line to the intake manifold (and the PVC check valve) and make my '93 design current with the '95 on - see Rob Robinettte's site for details. Howard reply is basically that this can only be done if there is a Service Bulletin issued by Mazda which would allow a dealer to address this issue retroactively for '93 model cars. The issue being that if the PVC check valve fails while the turbos are on, air is lost from the intake manifold and recirculated through the intercooler. Are you aware of the existence of such a Service Bulletin or do you know how to check this with Mazda?

(here is Sandro's original message, as well as the SCCA's response)

> Section 13.10 G states:  "The installation of oil catch tanks 
> is allowed provided the PCV system is not altered."
> Background
> This is for a 93 Mazda RX-7
> Problem no. 1 - The 93 RX-7 has two paths for blow-by gasses, 
> one from the oil filler neck through a Positive Crankcase 
> Ventilation (PCV) valve - a one-way (check) - into the 
> manifold, and one from the oil filler neck to the inlet side 
> of the primary turbo (which is always under suction).  When 
> the manifold is pressurized (under boost) the PCV valve 
> prevents pressurized air from flowing into the crankcase. A 
> problem that has manifested with this arrangement is that if 
> the PCV valve sticks open you will loose some boost. This 
> design flaw was corrected starting with the 95 RX-7 model.  
> Mazda eliminated the direct path to the manifold, including 
> the PCV valve, and retained the oil filler neck to turbo 
> inlet path for crankcase ventilation.   By doing so Mazda 
> maintained the functionality of the PCV system as the direct 
> path to the manifold was indeed redundant - since all the air 
> from the turbo inlet, including the air from the crankcase 
> would eventually be directed into the manifold. 
> Problem no. 2 - Another design problem that has manifested in 
> the 93 Rx7 model is that under hard prolonged right hand 
> cornering oil shifts to the left side of the oil pan. With 
> all the oil shifted in the pan the propensity for oil to be 
> drawn up the oil filler neck exists. Under such circumstance, 
> oil is sucked from the two PCV taps into the intake system. 
> Oil will then make its way into the intake system with the 
> propensity to gum up solenoids and other sensors that are 
> sensitive to mediums other than air for which they were not designed. 
> Proposed modification
> I am planning on attempting to minimize Problem no. 2 in my 
> 93 Rx-7 by installing an inline oil catch tank.  The inlet of 
> the catch tank will be connected to the oil filler neck, the 
> outlet will then be routed to the air intake in order to 
> prevent release of gases to the atmosphere.  My preference 
> would be to direct it to the turbo inlet connection only and 
> to eliminate the path to the manifold - as done by Mazda 
> starting starting with the 95 model -  in order to prevent 
> Problem no. 1 from happening. 
> Question
> Would my proposed modification be allowed under the current 
> rules, or should I retain the direct path to the manifold as well?

From: Howard Duncan [xxxxxxxx@scca.org]
Sent: Wednesday, October 02, 2002 6:34 PM
To: Sandro LaRosa
Cc: Guy Ankeny (E-mail)
Subject: RE: Solo II rules interpretation - Section 13.10 G


The only way around Section 13.10.g that I can see is if Mazda issued a Service Bulletin which would allow a dealer to address this issue retroactively for 93 model cars. Otherwise what you are suggesting would seem to violate the requirement of the PCV staying in place. By way of background, this rule was put into place well over ten years before your RX7 was built, and therefore the rule was originally addressing issues of cars from the sixties and seventies.

I have copied Guy Ankeny of the SEB on this reply to see if he has any other thoughts about this. Guy has a lot of experience with Mazda turbos.

From: Guy Ankeny [xxxxxxx@firstautogroup.com]
To: Howard Duncan Sent: Thursday, October 03, 2002 9:38 AM

I talked with Craig Nagler (ed.'s note: Guy used to work for Craig at Tri-Point Engr.) re: the PCV system. He isn't aware of any update in PCV system, for any 3rd gen RX7's. Craig stated this "problem" generally is caused by running the oil too high, and also when the apex and side seals on the engine rotors, become warn. Just like piston rings being warn-blowby increases. On the RX7, in stock class, this pressure is routed to the front of the turbo. This pressure (oil vapor) is then blown all through the intercooler, vacuum hoses--making a big mess. Thanks-Guy

From: Sandro LaRosa" (Sandro.LaRosa@tcgny.com)
Date: 10/04/2002 04:08 PM

Guy, Thank you for forwarding your message to Howard. However, as I already indicated to Howard, there seems to be a misunderstanding in interpreting my original questions. There are two issues.

1. The first, which does not appear to be mentioned in your conversation with Craig, is that under prolonged hard right-hand cornering liquid oil can reach the oil filler neck and eventually get sucked into the turbo compressor inlet. Big white smoke and big mess... I have experienced this personally and I know many other people who have experienced this problem as well. In order to minimize/solve this, I intend to install a sealed catch can (not a breather) and, possibly, an inline oil trap/filter. The catch can/oil trap to be installed between the oil filler neck and the return to the turbo inlet and (if so dictated by the rules - see next issue below) to the intake manifold as well. This would in no way impair the operation of the PVC system. As I read Section 13.10 G, it appears that installation of an oil catch can (and trap/filter?) is legal in Stock Class, provided that the PVC is maintained operable. Still, I would appreciate it receiving a confirmation from either you or Howard that this is indeed the case.

2. Historically, in normally aspirated cars, the PVC system is routed to the engine intake manifold. When Mazda initially designed the 3rd gen Rx7, they did so but also realized they needed to interrupt this path when the turbos were on, as the intake would become pressurized and - through this path - the crankcase as well. They inserted a check valve, which would close on delta pressure between the intake manifold and the oil filler neck and added a new path to vent the oil vapor to the turbo compressor inlet. Therefore, in the '93 cars there are two lines running out of the oil filler neck: one to the intake manifold - with an inline check valve - and one to the turbos inlet. At low rpm the manifold is under vacuum (like in normally aspirated engines), the check valve is open and the oil vapors are sucked into the manifold. When the turbos kick in, the manifold is pressurized, the check valve closes, and the oil vapor is pushed into the turbo inlet and mixes with the air compressed by the turbos. With the '95 model, Mazda simplified the design and eliminated the path from the oil filler neck to the intake manifold. The oil vapor gets pushed now to the turbo intake all the time. Why did they make this change? Because, if the check valve may fails to close when the turbos are on and the manifold is pressurized, air would be recirculated from the intake manifold back to the crankcase and the turbo inlet. Therefore, my second question. Could I make my 93 car current with the 95 design and eliminate the path to the intake manifold. Again, there is no attempt to defeat the PVC operation here but just the desire to eliminate a potential cause of PVC system failure.

Please refer to this link for a more comprehensive explanation of the proposed modification, including a diagram. http://www.rx7turboturbo.com/robrobinette/pcv.htm

Once again, thank you and Howard for your continuous attention. I am looking forward for your definitive answers to my questions 1. and 2. above.

Changing Oil

Date: Mon, 1 Dec 1997 12:42:15 -0600
From: "O'Dell, Mark"

> The total oil capacity for a dry engine is 5.7 qts for an R1 and
> 5.2 for the standard cars. The oil pan is 4.1 qts. According to my
> 93 owners manual the change vol with filter is 3.7 qts. So it looks
> like without taking a lot of things apart we will always have around
> two quarts of oil left behind for an R1 and about 1.5 qts for non
> R1s.

The retained oil is due mostly to the oil coolers. Each oil cooler holds about 0.5 Qts of oil, which doesn't drain out when the car is turned off. Also, the oil lines to the oil coolers and between the oil coolers themselves also retain oil. The R1/R2 models have two coolers versus 1 cooler for all other models, hence they retain more oil.

The only way to drain this oil is to remove the plastic covers under each oil cooler, and disconnect the oil lines where they connect to the oil cooler. I don't recommend this however - the C-Clips that connect the oil lines are not meant to be re-used. And they are relatively expensive to replace each time (sigh). All-in-all, it's a pain in the butt!

Because of the volume of oil left in the engine/oil coolers, I have decided to now change my oil every 1000 miles (filter every 3000 miles). Also, the fuel dilution thing scares me a bit - assuming that the dilution is cumulative, changing every 1000 miles should keep the dilution low. Perhaps this fuel dilution *might be* causing apex seals to wear faster. Hence all the low compression problems and blown motors... (no flames please - I admit that this is pure speculation on my part with no scientific evidence to back it up).

It's really quite easy to just drain the 4 qts. of oil (that you can get out of it) and refill it every 1000 miles - it only takes a few minutes and only costs $4-$5 if you do it yourself. And you don't need to replace the oil filter every time, so you save time there. Sounds like cheap insurance to me!


I would imagine that you could disconnect the lines going into the oil coolers and add a drain fitting of some sort in-line. This would provide an easy means of draining the coolers every oil change. I have not gotten under the car and looked at it yet, however. --Steve


Date: Mon, 01 Dec 1997 15:29:17 -0600
From: David Liberman

There are pre-oilers that are essentially a pump in-line with the oil system. Some of these advertise "one minute oil changes". I imagine they would do a pretty good job at pumping out hard-to-reach oil.


Date: Tue, 02 Dec 1997 09:14:04 -0600
From: David Liberman

From the Summit Racing Catalog:

"Double the life of your engine"

80% of your engine's wear and tear occurs at startup. With the Pre-Luber from Sales Professional, Inc. you can eliminate that wear - and double the life of your engine. The Pre-Luber sends a fresh flow of oil into the engine before startup, giving moving parts a protective coat of oil. At shutdown, the Pre-Luber turns on again, circulating oil up to five minutes to prevent oil coking and reducing heat. The Pre-Luber also has a quick-disconnect that attaches to the pump outlet, allowing you to pump out the oil for one minute oil changes.

The Pre-Luber is ideal for engines up to 549 c.i.d. It includes the pump, electronic control module, hose, fittings, and instructions.

LRI-2000 ..... $419.99 each

If you look past the sales claims, this device just might actually be worth something (but $419?). It looks like a big windshield washer pump, with a couple of oil hoses, a bunch of fittings, and the "electronic control module".

If you're interested in more info, call Summit at 800-230-3030.


Dave has some info on a device that will suck the oil out through the dipstick tube, but this might not pull oil from the coolers. I am not sure about this since the take off points for the lines to the coolers may be higher than the point at which the device sucks from. But here it is. --Steve

Date: Mon, 1 Dec 1997 22:03:00 +0000
From: "David Lane"

Regarding a device for sucking oil out through the dip stick hole:

I do it two to three times a year....on the sail boat.

Since you can't lift the engine to drain the oil from the bottom of many sailboat auxiliary engines, dip stick sucking is the only choice.

Here is the procedure:

  1. Go to a boat supply store and buy a Par Utility Pump. This thing is about 12 inches long, with a handle on the top, and a brass body. It comes with a small hose for the bottom--to stick in the dip stick hole, and a large one for the top end--to go into your used oil container.
  2. Run the engine until the oil is hot enough to scald your hands. This will make it easier for it to flow through the little tube, and it will also make you wish you had gloves--since the brass is an excellent conductor of heat.
  3. Try to find some place to balance your used oil container so that it doesn't fall over as you pull on the pump handle. Expect to wait about 15 seconds between the time the handle is fully extended and the time the brass body of the pump fills. This will build your triceps, and will give the oil plenty of time to burn your hands. Alternate hands so the burning effect is even. Expect the job to take about 5 minutes of pumping.
  4. When the pump starts drawing air, remove the small tube from the dip stick hole. Watch it sling oil all over you and your nice clean engine since it tends to whip around like a wet noodle. If you grab the end to keep it still, you will get hot oil on your fingers.
  5. Remove the other hose from your used oil container, noting that it is full of hot oil, and the outside of the hose (having been near the bottom of the container) now has a nice coating of hot sludge on it. You can wipe the outside off, but oil will continue to drip from the inside. If you turn it upside down so that the inside oil runs back into the tube, the other tube--which by now has started dripping again-- will start to whip around. See #4.
  6. In a very quick and graceful move, grab some paper towels and try to catch the oil that is dripping from both tubes at the same time. Of course, you will have to let go of the pump to do this, and at least one of the tubes will come out at the pump end, giving you yet another dripping tube end to control, plus, of course, the open hole in the pump itself. In your effort to do three things with two hands, you will almost certainly find yourself knocking over the used oil container, dumping at least half of the oil on your engine, and into the bilge of......er......onto your garage floor.
  7. Grab the handle of the used oil container and try to minimize spillage. In doing so, you will certainly sling about a cup of hot oil out of the spout, and it will certainly land somewhere where a.) you can't get a rag in to clean it up or b.) there is exposed skin.
  8. In total frustration, grab the Par Utility Pump and hurl it as far from the car as possible. Avoid living things.
  9. Finish the job, clean up the floor. Wash your engine. Take a shower. Apply burn dressing. Treat yourself to some ice cream. In several days, the splotchy marks created by the hot oil on your skin will make you suspect you have skin cancer. The doctor will ask you if you own a sailboat. Tell him you were trying to suck the oil from the dip stick hole of your RX-7. Don't laugh when he asks to inspect your throat.

When you are done, call Victoria British, Ltd., and order one of their nifty little lever spigots to replace the drain plug on your oil tank. Next time, just jack the damn car up, loosen the oil filler cap and flip the lever.

Oil Consumption

The RX-7's rotary engine injects oil into the combustion chamber as a part of normal operation, for lubrication purposes. So some consumption is normal. Some people have noticed a gasoline smell in the oil when they changed it. No official explanation, but Kevin speculated that it was caused as a result of the higher temps in the rotary. Carl conducted a poll on it, results below. --Steve

Date: Sun, 09 Nov 97 12:34:00 EST
From: "Houseman, Carl W. x1323"

There were a total of 15 responses which answered at least the question about how strong the gas smell was and what oil consumption was. I feel these may be the two most important questions.

Granted, the smell business is very subjective. But I find the following meaningful correlations in the data:

1. Everyone with "no oil usage" or "level increases" reported either a "noticeable" or "strong" gasoline smell in the oil. (8 responses)

2. Everyone with "strong" gasoline smell reported "no oil usage" or "level increases". (3 responses)

3. Everyone with "slight" gasoline smell reported measurable oil consumption ranging from 1500 to 9000 miles per quart.(3 responses).

There was exactly one exception report of "noticeable" gasoline smell with relatively high oil consumption (1000 miles/quart).

There were only two reports of strange noises at startup which weren't easily explained (and one of pffft at shutdown).

There were only 8 responses to the "long" survey, which wasn't enough data to come up with a correlation between gasoline smell/oil consumption with driving style, oil weight, or trip length.

Question of the day: What is it about some of these 3rd gens that they don't use oil? Is it really gasoline dilution, or something else?

Here's the survey questions again in case you missed them.

1. Classify the smell of gasoline on your dipstick - none/slight, noticeable, or strong.
2. What is your oil consumption? Miles per quart, none, or level increases?
3. What kind of oil do you use - weight especially - brand also.
4. Miles since your last oil change?
5. What kind of driving - short, medium, or long trips?
6. What driving style? Easy, Hard, Mix of easy/hard, Track?
7. Year and mileage on your car (optional)


Date: Mon, 10 Nov 97 11:39:00 EST
From: "Houseman, Carl W. x1323"


Since posting my survey results I've gotten about 10 more responses. Some of those run counter to the previous trend (it figures - post a hypothesis and people will to disprove it). I'll re-summarize when I reach about 30 total responses, or next weekend, whichever is later.

Also in the same counter-to-previous-trend feeling, this morning I finally did a _comparison_ sniff test. I have a 92 Mazda B2600 pickup and it, too, NEVER uses any oil. I figured it's just a very tight engine. Anyway both were run yesterday and both were stone cold this morning I did the sniff test and they smelled EXACTLY THE SAME. I would have only characterized the smell as "slight" this morning. I'll do a warm-engine sniff comparison next. Stay tuned.

And if all this wasn't bad enough, I hesitate to point out that if winter fuel formulations have hit the gas pump (I suspect they have), cold weather fuel is more volatile (vaporous) than warm weather fuel.

What a pain. I need to ask my Mazda mechanic (a good one) what he thinks about the situation.

Oil Pressure Low

The oil pressure sensor fails often on the 3rd gens, leading to a low pressure reading. A lot of people have had them fail at 20K miles. Mine started reading low immediately after an oil change (fine on the drive in, low after pulling out of the garage - checked it and it was full). I am going to take it to the dealer and have them replace the sender.

Many people are on their second or third sender.



Date: Sun, 2 Apr 2000 11:24:56 EDT
From: KAWalanski@aol.com

I have a hypothesis. Although very difficult to trace in the Shop Manual because of its small size, the oil-flow diagram seems to show that the oil overpressurization relief valve is at the end of a dead-leg. That is, the oil overpressure relief valve is not in a "loop" as in a 2nd Gen engine; rather it sits at the bottom of a "T" and drains into the oil pan.

My theory is that oil in this dead-leg gets gunked and crudded up with time due to heat, and turns to sludge. With enough time, the oil-relief dead-leg line would presumably become completely plugged and, therefore, nonfunctional. If this is true, the overpressurization you are experiencing would be due to a plugged oil relief line.

I use as evidence for my theory the fact that 3rd Gen oil-pressure-sender switches fail almost universally, and this oil-pressure sender is also on this same dead-leg as the overpressurization relief valve. I think the oil in the "T" which contains the relief valve and the pressure sender switch turns to sludge. Recall that there are 3rd Gen owners who have replaced their oil-pressure senders several time, suggesting that something may be at work besides a faulty sender.

Please trace the oil flow path in the Shop Manual and let me know what you think. If if is indeed is at the end of a dead-end "T", I would consider it a design flaw. This would beg the question: How would one blow out the accumulated sludge in the line?


Date: Sun, 2 Apr 2000 13:21:27 -0400
From: "Alan Beder" (albeder@earthlink.net)

I would agree that the design of the third gen has a much longer path to the pressure regulator than the 2nd. I suppose the other issue is that the 2nd gen valve relief pressure is 71 psi vs 110 for the third so it might not be exercised as often. Although the control valve in the front is the same at 156 psi.

When I had the pan off everything was very clean and visually the regulator relief valve looked good also, but I did not remove it to test it. I've replaced the sender a while back and that passage looked clean as did the tip of the sender. While I agree your theory makes sense I don't ever recall hearing about one of these valves failing. Maybe the people that have overhauled engine might have some direct experience with the sludge built up in the passage and valve.

My guess is that if the passage is plugged it would be necessary to drop the pan remove the valve and clean out the passage from the oil filter housing.

Oil Added to Gas (Premix)

Date: Thu, 10 Sep 98 09:32:37 -0500
From: "Linthicum, Sandy"

One 4oz bottle per fill up (10-16 gallons). Pour oil in tank & then fill, this mixes it. It will not separate unless you let it sit for months. Guarantees seal lubrication at all times since a little oil is always in the gas.


The rotary engine injects oil into the combustion chamber as a normal part operation. Adding it to your gas tank is extra insurance, as Sandy said.

Pettit Racing recommends Protek-R, at the mixture Sandy mentions. Below is an excerpt on Protek-R:

Protek-R is specially designed for use in Rotary Engines. Protek-R is an advanced high performance synthetic lubricity system which contains precision engineered lubricating molecules that help protect Rotary Engines from the damaging effects of molecular shearing and metal to metal contact. Regular use of Protek-R's superior formula has the following advantages:

- Reduced wear on rotor housings and side housings
- Clean Burn Technology reduces carbon and residue build-up
- Ashless, No smoke formula provides cleaner exhaust than 2-stroke oil
- Anti-Oxidation protection against fuel system rust and corrosion
- Low flash point helps stop plug fouling


Add Protek-R to tank before adding fuel using the following formula:

STREET: Minimum of one 4-oz bottle per full 12 gallon tank

RACE: Mix at Ratio 100:1


Doing the math for Pettit, the race mixture is:

There are 128 oz per gallon, so at 100:1, the ratio would be 1.28 oz per gallon of gas. In other words, use one 4 oz bottle per every 3.125 gallons of gas. --Steve

Gas Smell in Oil

Several people have noticed a gasoline smell in their oil. My guess/theory is that a fuel injector may be leaking when the car is off. (See the page on getting injector cleaning for info on how to get the injectors cleaned and checked out.)

Carl took a survey on the gas smell, and posted the results:

Date: Sat, 22 Nov 97 16:38:00 EST
From: "Houseman, Carl W. x1323" (CHOUSEMAN@genicom.com)

Here are the survey results with new responses since the last posting. There were a total of 39 responses to various parts of the survey. Here we go:

Gasoline smell:
Slight/None: 31%
Noticeable: 44%
Strong: 25%

Oil usage, miles/quart, among "Slight/None" gasoline smell:
Less than 1000: 0%
1000-3000: 36%
3001-6000: 27%
More than 6000 or no usage: 27%
Negative consumption: 0%
No answer: 9%

Oil usage, miles/quart, among "Noticeable" gasoline smell:
Less than 1000: 0%
1000-3000 miles: 12%
3001-6000 miles:18%
More than 6000 or no usage: 47%
Negative consumption: 6%
No answer: 18%

Oil usage, miles/quart among "Strong" gasoline smell:
Less than 1000: 10%
1000-3000 miles: 20%
3001-6000 miles: 10%
More than 6000 or no usage: 30%
Negative consumption: 20%
No answer: 10%

Oil usage, miles/quart among "Noticeable" or "Strong" gasoline smell:
Less than 1000: 4%
1000-3000 miles: 15%
3001-6000 miles: 15%
More than 6000 or no usage: 41%
Negative consumption: 11%
No answer: 15%

Gas smell, among those reporting less than 6000 miles/quart consumption:
Slight: 44%
Noticeable: 31%
Strong: 25%

Gas smell, among those reporting 6000+ oil consumption (including   
Slight: 18%
Noticeable: 53%
Strong: 29%

There was still no noticeable pattern as regards miles since last change, oil weight/type, style or length of driving, mileage on the engine, and so forth.

So there is (still) a decent correlation between gasoline smell and lack of oil consumption. But what makes those engines which use oil as expected, different from those that use very little or no oil? Still a mystery.

Also interesting is the fact that 2 of 3 persons reporting negative consumption have had major engine failures (Martin Crane, Dave Roberts). So if you see your oil level going UP, look out!

An Excel spreadsheet with survey results is available to anyone who wishes to look for more patterns. I won't be summarizing any further if more results come in after this but I'll keep the messages and report back if any further trends emerge over time.


See below for getting your oil analyzed. --Steve


Date: Tue, 6 Jun 2000 18:57:43 -0700
From: "les" (lesd@earthlink.net)

>I don't understand why people so often compare the blow by characteristics
>of a rotary to a 2 stroke.  I would expect the blow by contamination to be
>less than that of a 4 stroke.

It might be possible for fuel-air to leak past the side seals of the rotors. That would put that blow by into the oil side of the case.

When I rebuilt and ported one, the side seals reminded me of oil control rings in a piston engine. They are even about the same thickness. But piston engines have two of them, separated by a spacer.


Date: Wed, 07 Jun 2000 00:39:40 -0700
From: Max Cooper (max@maxcooper.com)

There is reasonably clear evidence that some of these cars have a lot of blow-by. The evidence of which I speak is that the oil often smells strongly of gas when changed. And some people even have their oil level INCREASE despite the fact that oil is injected which should cause the level to decrease, which makes me think that a lot of blow-by is going into the oil.

I am by no means an expert on this subject, but there does seem to be a large opportunity for blow-by relative to a piston engine. On a piston engine, gas can blow by the piston rings, which is not a lot of space relative to the combustion chamber size. On a rotary, anything that blows by the side seals would seem to enter the oil. The side seals are long and present a lot of space to blow by relative to the chamber size. Further, the turbo rotary engines we are considering run pretty rich relative to the average piston engine. Also, I think that turbos exacerbate blow-by on any engine. Some combination of these factors (and/or other factors) would seem to explain the experiences that lead me to conclude that the third gen has (or can have) a lot of blow-by.

I have nothing against running synthetic in a rotary. I have run synthetic oil on occasion in both of the rotary cars I have owned. I did this to see if it would last longer and/or to get the increased performance and protection. My oil turned black quickly, as usual. I run synthetic oil exclusively in my piston engines, transmissions, and differentials. I firmly believe that synthetic offers advantages over conventional oil, but not necessarily in this application when cost is considered.

My engine shows no major wear, deposit, or oiling problems (currently being rebuilt at 92K miles for a non-oil related failure). I regularly run 10W-30 mineral oil (since 72K), and the previous owner ran 10W-30 semi-synthetic (a blend of mineral and synthetic oils). The first 52K miles of my car have an unknown oiling history. For my money, I think that I get better protection out of using mineral oil and changing it every 1000-3000 miles depending on how I use the car. It is always thin, black, and has a gas odor when I change it. I doubt it would be significantly better with synthetic. Thus, extending intervals is probably not a good strategy on this particular engine.

By 'better' in the paragraph above, I mean relative to spending the same amount on synthetic oil, which is admittedly a comparison that is not necessarily a good one. My turbo bearings were certainly worn a lot, but the most significant problem with the turbos was that the housings were cracked. This thread has me thinking more about what kind of oil I should run in my new engine, but I am not yet convinced that synthetic is worth the extra cost in this application. My fear is that I would do less frequent changes with the significantly more expensive synthetic oil. And I think frequent changes are of paramount importance for proper oiling on these cars.

Oil Filler Cap Gunk

From Felix Miata's FAQ:

What's that foamy stuff under the oil fill cap & inside the filler tube?

If you look closely, you probably also see water droplets mixed in or nearby the foam. If you find either, there is probably nothing you can do to permanently get rid of them. Luckily, you don't need to. A change in your driving pattern to include more driving under high load and fully warmed, and less driving of short trips or while the engine is cold, might do the job. Enough of such a change will do the job if your car is totally stock.

What you see is an emulsion, oil mixed with water. Your oil includes emulsifiers as part of the additive package. They cause water to actually mix into and "disappear" within the oil. To a point, they do exactly that, preventing small amounts of water from congregating in any one place that might result in oil starvation in a critical location. As long as the amount of water doesn't exceed the ability of the emulsifiers to disperse them, no harm is done.

All engines are subject to condensation from the normal heatup and cooldown processes, the same way dew forms on the grass in the morning. The oil filler tube area is subject to very little oil flow, and very little ventilation flow, while at the same time it is one area highly subject to the forming of condensation. The emulsifier in the little bit of oil in the area forms the foam as its limit to absorb the oil is reached. When the engine gets hot enough, long enough, the water will boil off. Whether this will routinely happen with yours simply depends on your driving patterns.

Oil Analysis

Date: Wed, 12 Nov 1997 13:10:19 PST
From: "Mike Putnam" (mike_putnam@hotmail.com)

With all the questions about oil lately, I though the some on the net would be interested in oil analysis. Most major metropolitan areas have laboratories that will analyze engine oil for a nominal fee. The report usually includes:

        %Water dilution         Total acid number
        %Fuel dilution          Total base number
        % total solids          Particle count
        fuel soot               oxidation
        oxidation               nitration
        % glycol 

Plus about 20 elements such as silicon (dirt), chromium, aluminum, iron, etc. The report I get explains the significance of each of these measurements. The company I use charges $26.35 per sample. You need to send them 2 oz of oil and fill out their Form 50. The best way to collect a representative sample is to wait until you change the oil, remove the drain plug, let the oil drain for a minute, and then collect the sample in a small plastic screw top bottle. Below is the company I use. I have no affiliation with this company I've just used them to analyze my oil.

        Analysts Inc.
        2910 Ford St.
        Oakland, CA 94601
        (800) 424-0099
        FAX (510) 536-5994


Date: Mon, 24 Nov 97 07:49:05 -0500
From: "Linthicum, Sandy" (linthias@sandy-ntws.usps.gov)

I just got my 1st Oil Analysis back (a service provided by Amsoil) and it may be of "extreme" interest to the list that it shows 3% fuel dilution. Oil was changed at 3000 miles, whick included two driver schools (total of about 5 track hours since one school was partially rained out). I usually change oil before every event but didn't this time in order to have a worst case test.

Oil used Amsoil Series 2000 20w50 Racing.

If this is representive of other rotaries, extending oil change intervals beyond 3000 miles would be a big mistake.


Date: Tue, 6 Jun 2000 22:31:38 -0400
From: "kevin kelleher" (kellehkj@earthlink.net)

It is an issue for the 3rd gen turbos. A year or two back, many had the oil tested and most showed higher than normal levels (several % concentrations) at as low as 1000 miles. FD's have more fuel in the compression stroke, brought to higher peak and average pressures, before combustion, vs most NA's. Also known to be set very rich in fuel maps.


Redline MTL or MT-90 in the transmission is said to make it easier to shift (some people have complained about the transmission being difficult to get into certain gears, or it just not being smooth ("notchy")). Redline can be reached at 1-800-624-7958. Racer supply shops such as Racer Wholesale or Pegasus are good places to buy it.


Date: Tue, 4 Nov 1997 17:02:26 -0500
From: "Alan H. Beder"

MTL is also an option. It seems to allow smoother shitfing. I've used it on both my 2nd and 3rd gens. Pettit also uses MTL in their 3rd gens.


Date: Sun, 9 May 1999 10:24:52 -0400
From: "kevin kelleher" (kellehkj@earthlink.net)

The MTL should be OK for stock power levels, and limited use of it, and may be benificial in very cold weather. But...

MTL is 75W-80 GL4 oil, that is actually close to the 70W-85 spec'ns. Mazda calls for 75W-90 oil, and 80W-90 in warm weather. Mazda allows both GL4 and GL5 grades. Most use MT-90, Redline's 75W-90 GL4.

High power cars should use NEO 75W-90 HD, a GL5 extreme service lubricant with better gear and bearing protection at max loads. Wael's car shifted better with this than with MT-90. Redline's Shockproof may be the best high-power track oil.


This is not (I believe) Redline themselves, but someone who distributes Redline. --Steve

From: Red Line Oil Racing - Performance Products (rlracing@sgi.net)
Date: May 3, 1999

Just dropping you a line to let you know that we will be launching our new web page offering red line oil products directly via the internet on May 19th.


Would you please let us know if we could link to your site.

We will offer red line for $7/quart and for group purchases $6.25/ quart. If you have any questions, please feel free to drop me a line.

Thanks in advance for your consideration.

Ron and L.J. Rygelski
Performance Products
Red Line Synthetic Oil


Date: Thu, 4 Jun 1998 19:42:21 -0400
From: "Houseman, Carl W. x1323"

Trans: 2.6 qts
Diff: 1.4 qts


Date: Sun, 28 Mar 1999 10:39:35 -0500
From: Wael El-Dasher

Buy Neo Synthetic HD gear oil, it wil help smooth out those shifts especially when cold. You can but it from Mazdatrix (http://www.mazdatrix.com) or from Neo directly, (http://www.neosyntheticoil.com). I highly recommend it over Redline, just personal experience with my new gearbox.

I highly recommend Neo HD gear oil, save your money and don't buy the Racing HD. Neo didn't recommend it. Call them up and talk to them and they'll tell you what to use for your application.


Date: Fri, 02 Apr 1999 20:31:29 PST
From: "Mike Putnam"

I thought I'd share my experience. I've used Valvoline 75w-90,Redline MT-90 , Redline MTL and Neo 75w-90 HD in my transmission.

With Valvoline in the transmission (and what ever Mazda originally put in there) my car was difficult to quickly shift from 1st to 2nd and to a lesser extent 2nd to 3rd. I would have diagnosed this as bad synchronizers except down shifting from 3rd to 2nd and 4th to 3rd was always as smooth as butter. When the transmission was fully warmed up the notchyness (or crunch) was better but still present.

I next switched to Redline MTL. With MTL the notchyness was almost gone when the transmission was cold and completely gone once warmed up. However, since MTL is a 75w-80 oil and Mazda recommends a 75w-90 I was worried about thinning under hot conditions.

So, I switched to Redline MT-90(which is 75w-90 weight lubricant). MT90 did not reduce the notchyness as well as MTL, although it worked better than Valvoline.

On Wael's suggestion I switched to Neo 75w-90 HD. The Neo oil worked as well as MTL in curing the notchyness and is the correct weight. Since it is a good guess that the transmissions out in net land range from like new to barely serviceable your results will probably vary, but I would recommend you give Neo oil a try. Besides after you change the transmission oil 4 times in 6 months you'll get really good at it. 8)


Date: Thu, 29 Apr 1999 01:54:29 -0400
From: Max Cooper

NEO is based in Signal Hill, CA on Gundry Ave, phone number (800) 959-7757. Their website URL .


Redline 75W90 Gear Oil is used by a lot people on the mailing list in their differentials. It is safe for the Torsen LSD (limited Slip Differential). DO NOT USE the 75W90NS - that is for non-LSD cars. Redline can be reached at 1-800-624-7958. Racer supply shops such as Racer Wholesale or Pegasus are good places to buy it.


Date: Thu, 4 Jun 1998 19:42:21 -0400
From: "Houseman, Carl W. x1323"

Trans: 2.6 qts
Diff: 1.4 qts

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