Another...How To FIX COMPRESSIONS In Any Rotary Engine with ATF
 

IN the 1970's and 80's our Mazda Service Manger would personally fix Bad Compressions in 10A, 12A and 13B Rotaries with Upper Cylinder Lubrication and or mostly ATF (Automatic Transmission Fluid).

After performing a Mazda Compression Test most of the time he would diagnose sticking or stuck IN Rotor Tips APEX SEALS resulting in extreme Blow back and Poor Compressions, some symptoms would be NO Firing of Engines at all.

After the ATF method and a good on road Test Drive / THRASHING many of these engines were given a new life.

I found the same treatment on the web 30 years later.

While the SEAFOAM procedure is good for removing Carbon perhaps you could try the ATF one first and then follow it up with Seafoam.

http://www.mazspeed.com/atf.htm

ATF Treatment By BOBRx-7

Restoring Compression � The ATF Treatment

One of the more common reasons for failure of rotary engines is actually very preventable and in many cases reversible. This entry will cover just how it's done and why it works 95% of the time.

Rotor Seal Design

The rotary engine is among the simplest in overall design. No valves, cams, heads or any of the parts commonly associated with piston engines. This makes them extremely reliable with one major exception. . . the apex seals.

To seal the three tips of each rotor, a groove is machined to accept a long thin cast iron (in stock engines) insert. This is the apex seal. A spring, located behind the seal, applies the force needed to hold the seal in contact with the rotor housing wall as it passes around the inside housing wall. As the apex seals pass the narrow points in the housing, they are compressed against the springs and then move back outward in the wider parts of the housing. A corner seal at each end of the apex seal is also spring loaded to prevent combustion gasses from leaking around the ends of the rotor tip. Additional seals on the sides of the rotor complete the set to form a relatively leak-free chamber.

Over time, carbon, ash and oil sludge deposits will accumulate in the machined groove in the rotor tip. If allowed to remain, the apex seals will eventually begin to bind in the grooves and will not move outward completely during the combustion cycle or intake cycle. This allows gasses to escape into the next chamber, reducing compression. In the extreme, the apex seals will stick in the compressed position to the extent that virtually all compression is lost. At this point, the engine will likely refuse to run at all.

Dirty oil and general lack of maintenance is the most common cause of compression loss. The oil injection system on the rotary is designed to feed oil in to the chamber to keep both the housing walls and the apex and corner seals lubricated and clean. Dirty oil will simply throw grit, sludge and other combustion debris back into the chamber. Result, thousands of perfectly good 12A and 13B engines, or complete cars, rotting in the junk yard, for no good reason!!!!

Preventive Care

The obvious solution here is consistent oil changes. Never more than 3000 miles between changes and good (spelled Castrol GTX 20W50) oil with a new filter. By the way, the puny little factory filter is COMPLETELY inadequate. A remote filter setup that will allow the use of a 1 qt. filter is much better. At the very least, use a K&N or WIX filter in the stock location. These will filter particles down to 10 microns. A better oil cooler on those 83-85 12A engines is also an excellent idea.

The Fix

So what if your engine is already suffering from the dreaded sticking/seized apex seals, you ask?? Never fear. An old mechanics trick used to free up sticking valves and lifters works WONDERS on your rotary. The procedure works a little differently for carbureted engines that the EGI models, but accomplishes the same results.

1.

Disable the ignition primary circuit by disconnecting the igniters or the negative lead on each ignition coil.

2.

Remove the air cleaner lid on carbureted engines, or pull the Leading (lower) plugs on 13B EGI engines.

3.

For carbureted engines, pour 2 oz. (60 mil) Automatic Transmission Fluid (ATF) (the cheap stuff is fine) down each primary bore (the small ones) of the carb, while an assistant cranks the engine for 5 seconds or so. On EGI engines, use an oil squirt can and pump two or three shots into leach leading spark plug hole. Have an assistant lightly bump the starter two or three times, squirt in more oil, bump the starter, squirt, bump, squirt, bump. . . you get the idea. You want to get ATF in all chambers and thoroughly distributed. Reinstall the spark plugs on EGI engines.

4.

Allow the engine to sit in the ATF stew for AT LEAST 24 hours. Don't be tempted to rush the process. This takes time. The detergents in the fluid, used to keep the small polished valves in an auto trans valve body free, will soften the carbon and sludge deposits.

5.

PLEASE. . . Make sure the car is outside for this step. You'll see why. Reconnect the ignition system, hold the throttle open way on carbureted engine and start it up. Allow to idle. The neighbors will now think that Mt. St. Helens has erupted in you driveway or a massive brush fire has broken out. It will take about 5 minutes for the smoke to clear completely, since some of the ATF has worked it's way into the exhaust pipe and must be burned off.

6.

Install a new set of plugs. The ATF will foul the old ones and may cause hi-speed misfire. Take the car out on the free-way and THRASH IT for a few miles to completely clear the chambers. 6 to 10 redline runs will do it.

At this point, the apex and corner seals can move freely again. In extreme cases, you may want to repeat the treatment after a week or so of driving. If so, hang on to the old plugs to use again for the second treatment.

If you were to perform a before and after compression test, you could potentially see an increase of 20 psi or more and will feel a whole lot of power that wasn't there before. I have revived engines that would not start and know of a couple ITA drivers running junk yard engines brought back to life this way.

IT'S CHEAP. . . IT WORKS. . . And you can end up with a nearly new engine for $2. You've gotta love it!!

HAPPY ROTORING!!

Bobrx7

NOTE: This will not FIX Compressions IF your Engine's Apex Seals are badly worn (common in high mileage Series I RENESIS because of poor OMP Lubrication).

Concaved Apex Seals in Early RENESIS's will not be fixed using this method of lubricating or cleaning, only a rebuild will rectify compressions if you have this problem.

Another reason WHY Pre-Mixing is a MUST in ALL Rotary Engines.

Hmmm. Good read. So is it worth it to premix a motor with 68k on it?

no offense but you guys really need to learn more about your motors, the "ATF Trick" is a commonly used "trick" by pre-rx8 owners. Been around forever. Take the time out and go over the info out there on other rotary forums we've got all kinds of tricks.

kevin.

^Thats the point of ASH posting this Kevin. For the one that don't move from site to site to read pm and ask questions about stuff :)
Thanks for the good read.
All this stuff should be in a "n0ob" section.

yea i understand the point of posting it to get the knowledge out there, which I commend but saying Bobrx7 created the method is wrong.

kevin.

True dat. His site will come up on google over a thread on a forum.

Just for your info - ATF has minimal, if any, detergent in it's formula.

I don't know where this myth of it's incredible solvent properties came from, but it just plain ain't true.......

"The More You Know! "

I think its more like ATF will "Stick" with the "bad stuff" so it could be burned.

And on this note I call for a thread lock!

YEP, Kevin is right here again...that is why I said at the thread beginning we were doing this ATF trick 35 years ago at my work, a Mazda Dealership in South Australia.

When it comes to the basics in Rotaries, Carbon build up and sticking Seals/Springs is not new, nothing has really changed much in all that time.

I cant see where he says "Incredible Solvent Properties", he says "the detergents in the fluid"....

Whatever you wish to believe, please do, but this ATF method is really for Lubricating Sticking seals and springs, not really for "Cleaning Off Large Volumes Of Carbon Deposits".

That was it's purpose then and still is now, lubricating, that is why I suggested if you wanted to do a "Factory" carbon clean do so with Seafoam.

As Kevin say ( I consider an expert guy working at a Mazda Dealer Today) this method is well recognised and an old one.

And there is NO reason for a "thread lock" to stop debate.

Ash..

Kevin, I did not get the impression that BOBrx7 "created' this procedure. ;)

I actually have a bookmark linked to RR's water cleaning method ...

Just that never tried it on mine.

Hey that one guy that rebuild our Motors said after they use some ATF. Rotaryresurrection what like WTF? then he said its what Mazda tells them to use.

Yeah sleepy z said he didn't know why they do it, but they do use ATF on their rebuilds. Because Mazda said so. Damn Gil you have the memory of an elephant.

I can recall a lot. I mean a lot. Just can spell that good. Oh well.

Engine oil only in my engine, transmission fluid only in my transmission.

http://www.bobistheoilguy.com/forums...690#Post863690

If you do this for some reason prepare your self for the biggest cloud of white smoke you will ever see,. Your neighbors might call the fire dept thinking your house is on fire.

has anybody actually done this in an rx8? I will be giving it a try since I have terribly low compression and nothing to lose.

Atf has been used for years. It doesnt hurt anything really

Try it and let us know if it works for you

I'm curious as to your outcome. Go for it!

I would like to know the outcome as well if your compression gets better, and you get some power back let us know.

Just so u know if your engine has worn housings/seals and or springs, no oil can save you