Rotary Car Club - View Single Post - what aftermarket apex seal would you choose?

PSI · 06-19-2013, 05:28 AM

I finally pulled down an engine running RA seals that had done some hard work. It was the temporary engine from our own car that was built with fairly average used parts (but new apex seals/springs). It must have done at least 50 passes down the 1/4mile (9.1 on pump petrol best E.T with this engine) plus 100 or more dyno pulls, some dirt drags and burnouts, and a bunch of street driving. I know it suffered some decent detonation too.

The apex seals themselves looked good and were all dead straight with fairly minimal wear. A couple were a little shorter on one end than the other, probably because the spring would would have been closer to the shallow end.

The housings themselves looked good considering the basic semi-synthetic 2 stroke we were running (and not enough of it). They have scratches as you would expect, but they are not as bad as I thought they would be and would sand out easily.

If we were running the polyol ester 2 stroke oil we run now, and at the amount we run now, then I'm sure the housings would look even better. All in all I'm happy with the RA's and see no reason to change at this point.

We run them in our current engine which makes 740rwhp on 93 pump with WI and the compression never seems to change. Even with this engine we've had some decent detonation getting to this point but somehow the seals take it in their stride. For whatever reason they don't break and don't bend. The current engine has done a season of low 9's and high 8's plus street driving, and it seems fine so we'll run it again next season without pulling it down. Hopefully we can crack the 800hp mark on pump petrol, but I'm not holding my breath.

06-19-2013, 05:28 AM	#25
PSI The Newbie Join Date: Feb 2012 Posts: 18 Rep Power: 0	I finally pulled down an engine running RA seals that had done some hard work. It was the temporary engine from our own car that was built with fairly average used parts (but new apex seals/springs). It must have done at least 50 passes down the 1/4mile (9.1 on pump petrol best E.T with this engine) plus 100 or more dyno pulls, some dirt drags and burnouts, and a bunch of street driving. I know it suffered some decent detonation too. The apex seals themselves looked good and were all dead straight with fairly minimal wear. A couple were a little shorter on one end than the other, probably because the spring would would have been closer to the shallow end. The housings themselves looked good considering the basic semi-synthetic 2 stroke we were running (and not enough of it). They have scratches as you would expect, but they are not as bad as I thought they would be and would sand out easily. If we were running the polyol ester 2 stroke oil we run now, and at the amount we run now, then I'm sure the housings would look even better. All in all I'm happy with the RA's and see no reason to change at this point. We run them in our current engine which makes 740rwhp on 93 pump with WI and the compression never seems to change. Even with this engine we've had some decent detonation getting to this point but somehow the seals take it in their stride. For whatever reason they don't break and don't bend. The current engine has done a season of low 9's and high 8's plus street driving, and it seems fine so we'll run it again next season without pulling it down. Hopefully we can crack the 800hp mark on pump petrol, but I'm not holding my breath.