Fluid Dynamics

That is a great story to hear for those of us with the RA two-spring seals installed.



Thanks for sharing.

BDC

There's been alot of buzz about these seals on the forums but no real data to date

until now. I just recently tore down an engine that we were building for a race-type of auto application using these 2mm 2-piece seals as a test after about 4,500 miles of use (almost all street-driven and highway).



I cleaned up the apex seals and measured two of them. I measured 0.309" and 0.310" in heighth respectively and widths of 1.93mm. I'm not sure what their stock heighth is, but if these are manufactured to stock specs then that's only 0.005" to 0.006" of wear! An equivalent seal, a 3mm 2-piece (presumably stock but unsure) design with twice the miles shows 0.293 and 0.295" of total heighth, a full 0.015" shorter!



So far, I give them a huge thumbs up. They're hard as rocks but not too hard for the rotor housing apparently. I noticed that, upon disassembly, the steel lining of the rotor housing was nearly mirror finish on both of them. I'm not sure if these seals have anything to do with that but I find it odd because these housings are not new.



The only potential long-term issue that I might see happening (thanks for mentioning this, Mike!) is accelerated wear of the "pressure" side of the rotor's apex seal groove -> the part of the groove that the apex seal is constantly pushes up against. I regret that I didn't measure the apex seals when they were new and I also didn't measure the both rotors' apex seal grooves before or after so I have no numbers for you guys here. I apologize for this.



I'm looking forward to using these seals more most definitely.



B

scathcart

Are you measuring height at the center? I'll measure a set I have.



I didn't get pictures this weekend, but I plan on it this week, around thurs evening.

BDC

I measure at the edges of the inner (short) apex seal springs.



B