I am currently doing a rebuild and am considering 2mm ceramics.

I did a search and read all the old threads dealing with ceramic seals going back to 2001??

Anyways the confusing I have is the opinions that have changed.

I thought that the general consensus was that ceramics had:
1) low friction
2) lighter
3) better vacuum
4) easier on housing
5) slightly more resistant to dentonation.

however, I read an old post by Jimlab who stated that those are all myths and that the only real data is that they are low weight low friction but produce less vacuum and less horsepower than if you used stock seals...

Is this the general consensus? Anyone with current real world experiences or opinions?

I realize that there is a difference between 1 vs 2 piece. I was considering 2 piece ceramics...

(this is planned for a FD)

 

From what I've been told from Rob@Pineapple, the new ceramics do make more power. You might want to call him, and find out when the ceramic apex seal group buy is going to happen. I know Blake had talked about it. But they are suppose to be realy cheap compared to the normal price. CJ

 

from what I "Heard" only use ceramic seals on new housings. Or else your engine won't seal right.

 

Cheers,

I read that too on an old post, however if all of the parts are within "spec", shouldn't it seal correctly?

 

the cermaics are lighter so you will have to increase the spring force to get them to seal well at lower rpms

 

Rob talked me into getting the 1pc 3mm ceramics. Sealing properties are less desireable at lower rpms, but the overall toughness (resistance to pinging) is greater than the 2pc 2mm ceramics.

 

While they are lighter, much more wear resistance, and therefore easier on housings, they won't seal as well at low rpm without stiffer springs (as mentioned), and they are not proof against detonation.

Roger Mandeville killed two sets of 3mm ceramic seals tuning a Motec-controlled 13B-REW limited to 10 psi. It turned out that the harness for the Motec was bad, I was told, but the results were the same. A little detonation, and they'll go almost as easily as a stock set. According to the owner of the engine who was present for the dyno tuning, they held up for a couple more pings than normal and that was it. The engine in question eventually blew again after tuning, still limited to 10 psi.

Considering that most performance rotary engines will never see 100k+ miles, the wear properties of the ceramic seals are only a fringe benefit and no justification for the expense. It is said that if they do break, at least they won't damage the rotor or housing, or take out the turbine fins when they exit into the exhaust, but I've also heard that is not necessarily the case and may be another "hyped" benefit.

Bottom line, if you want to spend your money on them, be my guest. I've owned a set myself, heard other's experiences with them, and my opinion is that stock seals hold up just fine in a properly tuned rotary, even at very high (40+ psi) boost levels, and don't cost an arm and a leg. The only downside is that if they do break, you'll likely be replacing a housing and rotor, and the turbine wheel of the turbo they went through on the way out the back of the car. As far as I know, though, there's no guarantee you won't be doing the same with ceramic seals, and you paid a hell of a lot more for the privilege.

 

Jimlab's words X 2 !

 

arent the ceramics really for the endurance racers who need something to live longer at the 10,000rpms than carbon or steel?

mike