How to test for seal chatter
 

How do you test if your apex seals are chattering at high rpm's. If one build a performance motor and threw in carbon apex's....how would you determine when they will start chattering?

It is the heavy steel seals that have the chatter problem, not the light carbon seals.

so carbon seals will not chatter? or they will not be a problem if they do?

The check for chatter is simple... you look at the rotor housings. Housings that have been chattered upon have lines running across them (edge to edge, not around the circumference). Mostly seen along the top of the housing, sometimes along the bottom, rarely if ever along the sides (at the pinches).

I have in my collection an engine that must have seen some VERY abusive use... either the chattering actually hammered the chrome out, or it flaked off some chrome deeply enough that the seals would catch and bounce off the surface and land hard... but there are whoop-de-dos in the housing, and the actual sheetmetal insert is worn down and polished.

I've also never seen chattermarks in a 2mm seal engine, although I'm sure it's *possible*... the 2mm seals seem to be much more housing-friendly.

This is iron seals only... have yet to play with the carbon-aluminum seals, but supposedly they are very, very housing friendly. Because of this, I *do* plan on playing with them, possibly using them exclusively for 3mm seal engines. (I don't "do" turbos)

Thanks, very helpful. If anybody has any expierence with carbon seals, please add in here..

I road race PP motors with carbon seals, and have not had chatter problems.

i had a set (somewhere theres pics) of some badly chattered s5 na housings. 210k miles on em though