Can anyone tell me what to look for when apex seals go bad? I don't have much experience with rotaries and wanted to make sure that I spotted a problem early on.

Also, has anyone tried the trans fluid on the rotors trick to try and prolong the life of the seals? Does it work or snake oil?

 

Easiest thing is to take the plugs out. There should be 3 even pffts, if one sounds a little funky (or if there aren't 3) you've got a problem. It should be reall obvious if you've got a blown seal, the car should run like complete **** (or not at all). If you do have one bad, don't run the engine just for grins, a steel seal can ruin your housing like it was it's mission in life.

 

When mine went there was a faint POP then the car had NO power at all. almost didn't make home which was only 2 miles and over 3 over passes. Like the man said it runs like ****. I have talked to several builders since it happened and they all said the same thing. Seal goes the housing is gone. rips up realy bad.

 

No ****. Good one Chris.

 

If you rebuild, carbon's all the way. They may not last as long, they may not seal as well, and they may cost more, but godamned if the housing is okay when one of them shatters, breaks, or goes bad. Hell, my newly blown motor still has good seals, it just doesn't have any bearings! (yes, I did blow my motor... for the third time).

Oh, and on your first rebuild, unless you have somebody who's an expert looking over your shoulder, expect to blow it up eventually.

Clutch in when you spin, too, these engines apparently don't like to be in a forward gear when you fly off the track at ~100mph backwards....

 

So, when they fail, they fail catastrophically, not in some progressive way?

Anyway to prolong their life while they are still decent?

 

Usually, yeah. The steelies can also bow, turning compression to 0 and making you run around like a headless chicken. (ask me how I know ).

Why don't you tell us why you think you have an apex seal going bad. You can also lose a side seal, corner seal, etc., which will make things interesting for yourself.

 

I actually don't think I have one going bad. I just wanted to know what to look for.

I do have a spare car that put out a bunch of white smoke that went away after about 3 minutes. But that motor hadn't been started in over 6 weeks. Other than that, it was fine.

 

Best way to tell state of seals, short of tearing the engine apart, is to get a proper compression test.

 

Yup. And if you're still in doubt you can pull off the exhaust manifold and then look into the exhaust ports with a flash light. Now have someone slowly turn the engine over by grabbing the front pulley and rotating it (Do not crank it over with the key) until one of the apex seals come into view. Use a flat screwdriver to push inward on the seal. Repeat for all six apex seals (3 per rotor). They should float freely under pressure from the springs that are under them. If one or more of them don't they're likely plugged with carbon. This not only causes poor compression but also can damage the rotor housing and eventually the seal will get tossed, ruining the rotor and housing on the way out the exhaust port.

If there are carbon-plugged seals you "may" be able to free them without engine disassembly via an ATF treatment.

Another thing that will cause the apexes to vacate the premises is an oil metering pump that quits. If those clear nylon lines leading from the OMP to the carb (or rotor housings, depending on 12A or 13B) are clear rather than golden brown it means they're empty. Pre-mix 2-cycle oil in the fuel at fill-ups until the problem is fixed.

 

What's an ATF treatment and how is it done?

 

Pour ATF down the carb and turn the engine over to let the ATF soak into the rotors and moving parts. Some of the chicken littles here will go apeshit when they read this and tell you you'll blow up your motor, but that's just another way to pick out the idiots on the forum. MMO "might" be better, but it's not as plentiful in my shop... they're "basically" the same thing, the chemical makeups are different, ATF has paraffin and some other strange stuff in it, but all of my motors have had ATF in them at some point or another, and very few of them are blown.

The ATF/MMO treatments will unstick a rotor if one of yours has seized, or if one of your seals have seized. You'll see lots of smoke come out the tailpipe with this method, but it's a good trick to have up your sleeve if you do a lot of work on rotaries.

 

When I blew a seal in my 1st street ported engine it went all at once & was obvious by the sudden shutter, loss in power then bucking & side rocking when I slowed down. The Mazda dealership was a few blocks away so I pulled in & my mechanic who built the engine came out & said,” Lets go to a 13B next.” I shut her down & she didn’t start again until the new ported 13B was onboard.
My mechanic recomends the ATF only if you are going to let the car sit for a while or have already let it sit for months.
Otherwise, make sure your oil metering pump is working well & never run lean.

 

Hi so I just bought a 2004 Mazda rx8 and it runs and drives fine until it warms up and I have to feather the throttle so it doesn't die. If it does die after it is warm I can't get it to start up again until it cools down. So my question is what is my problem? I have had people tell me apex seals but I wouldn't have compression for it to even run so please help everyone.

 

This can be a sign of low compression. Try doing a compression test.

 

I'm no expert, not nearly as knowledgable as some of the guys on here for sure.
However comma,
My sister owns a 2005 RX8 and had a similar issue. Only, it could heat up and idled just fine. Only problem was that trying to put any power down would cause the engine to stutter. Turned out to be a spark plug/spark plug wire.
I won't guarantee this is your issue, but for sure take a look and see if it could be a potential cause!