Rotary Engine Questions

zenjoe · Post by **zenjoe** » Tue Feb 18, 2003 1:48 pm

Apex seals

There are several to choose from depending on what you want to do with the motor. Stock Apex seals seal the very good and give you a good compomise between wear and strength. Stock apex seals are good up to around 18lbs of boost and are relatively cheap ($40 each, need 6)

You can get carbon seals which seal better than stock ones but last half as long. They are more fragile and don't like boost or nitro. These are the best for racing NA style. In case you break an apex with these, they won't destroy your engine.

Ceramic seals ($1000 per set!) handle upwards of 40lbs of boost and nitrous. These are the seals you see the 700hp 13b's running. (yes, 700hp from 1.3 liters!)

All apex seals are durable as long as you keep your ignition timing and air/fuel mixture in check. The One thing that kills these seals is detonation, running lean or too much timing. One hard ping will cause your engine to go byby. Piston engines by design are much more tolerant of crappy tuning. You need to be more precise with a rotary.

The comment about rotaries not sealing well is garbage. The only time when these engines loose compression is if you don't change your oil as often as you should. Rotaries use an oil injection system to oil the rotors. When you have dirty oil, this is injected into the engine and the carbon builds up on the seals makeing you lose compression. The fix this. all you have to do is pour 2 ounces of ATF fluid into the carb or in the spark plug holes. Disconnect your ignition and turn the engine over a few times. Let your engine sit for AT LEAST 24 HOURS! Then remove your spark plugs and clean them, and start your motor up. Make sure you do this outside because there will be so much smoke coming out of the ehaust that your neighbors will think that mt saint helens just exploded! The smoke should go away in about 5 minutes. Drive your car and you will immediately find ALOT more power. The ATF treatment commonly gives the engine 20-50lbs more compression. It will feel like a new motor.

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miller · Post by **miller** » Tue Feb 18, 2003 7:23 pm

zenjoe
Would that cleaning technique be a bad idea for a turbocharged engine. It seems like all the carbon from the engine would ruin a turbine pretty easily. Whats your thoughts on that.

zenjoe · Post by **zenjoe** » Thu Feb 27, 2003 11:27 pm

It shouldn't damage the turbo in any way. The only thing that it will damage is a catylitic converter...if you have one.

for more detailed instructions on how to do this, go to http://www.mazspeed.com/atf.htm

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Jeff20B · Post by **Jeff20B** » Fri Feb 28, 2003 3:04 pm

Try MMO instead of ATF. It was meant to burn, unlike ATF. Also, change your spark plugs after ATF/MMOing you engine.

wdwflash · Post by **wdwflash** » Sat Mar 08, 2003 9:10 am

As I've posted before, I've got a VW based Kit car(Kelmark with a '74 pan), and have installed a '87 Turbocharge, fuel injected, intercooled, computer controled (Haltech E6K) rotary engine. It wasn't cheap to do, but in this 1800lb car its down right scary! Kennedy Engineered makes the adapters, flywheel, clutch, etc. and has done this a lot. They have some info on doing the rotary in a VW you can buy from their web site.
The engine leaks no oil what so ever and with the Haltech computer, I don't even lift the hood to tune the engine, just plug in a 486 computer(cheap), and type in how you want it to run.(this was after studying the manual and asking other owners on the RX7 web sites about everything!)
I really suggest 4-wheel disc brakes if you are going this route! Plus a beefed up trans and urethane bushings in the rear with coil over shocks help. I also went with a "prowlers" tube beef up kit for the trailing arms, bus CV joints and porsche 944 stub axles.

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Drakmare · Post by **Drakmare** » Mon Mar 10, 2003 1:22 pm

I have been hanging around some Rotary calssified forums, watching the engines that pop up for sale. I see alot of engines that need a rebuild. For instance I found one that has a failed O-ring. How hard would it be to fix this? and how expensive? Another I found has a "popped seal" Is this a difficult task to fix? I see many rotary's for sale anywhere from 19k miles to 180k miles. What is the expected lifespan of one of these engines? How many miles is just tooooo much?

Thanks,

-Drak

zenjoe · Post by **zenjoe** » Tue Mar 11, 2003 8:08 am

To replace ANY seal on a rotary required a complete rebuild. Nothing is sevicable unless you take the engine completely apart. I would stay away from rotaries over 80k miles. You just don't know what you are getting. If an engine has a bad oil seal, and low miles, you can pick it up. even though it would require you take the engine apart, an engine seal kit is $100 so thats not too bad. If you are looking at getting a rotary make sure that is has good even compression and that is doesn't smoke.

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Drakmare · Post by **Drakmare** » Tue Mar 11, 2003 9:48 am

These rotary engines cant be all that hard to rebuild right? I have rebuilt piston engines before, which was time consuming but not hard. Seeing as these have alot less moving parts it shouldnt take as long nor be any harder, correct?

-Drak

Jim Molloy · Post by **Jim Molloy** » Tue Mar 11, 2003 12:51 pm

To get an idea of what it takes to rebuild
a rotary engine ,go to a used book store.
Most likely there will be a Hayes or similar
repair manual for a RX-7.Buy it.

It won't matter what year as they all basically come apart the same.Maybe a few
more bells and whistles on the FI models

Worst case buy a new manual ,about $15. Consider it educational material.

I've seen some apart years ago ,but haven't
done a rotary overhaul myself.Some precision tools are needed like calipers and dial gauges.

To overhaul a VW engine yourself you would
still need most of the same tools.

Then maybe buy one of the $100 or less rotaries and tear it apart. See whats what,
maybe you'll be a new Rotary mechanic and
make millions of dollars off all of us perverts.

Thoughts are Things

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72 Super Beatle Convertible w/12A Rotary engine. 7000 RPM in third gear is 100MPH. YAHOO !!