I have an 87 n/a with a 1200 mile old s5 engine. Checked compression because the car sounded a little uneven on starting. I came up with 100 an all sides except one, where I am getting 110. This can't be good, but how bad is it? The car runs great. I used a fairly large street port on used(barely) housings, Balanced/lightened eccentric shaft and rotors, S5 maniflods and fuel system, Atkins 2 piece apex, new apex/side springs, used but straight side seals, solid corner seals. The engine went together fine, with exception of one apex seal spring that was bent during install, and replaced with a new Mazda unit. It is my understanding that an apex problem would cause 2 chambers to be high/low, not one, so this should be a side-seal problem, right?? Other then the car sounding a little uneven when I start it, there are no driveability problems. Just wondering if I should worry about this!

Thanks!

 

I don't think that would be the cause of your idle problems. Possibly a vaccum leak or running real rich at idle.

 

The car actually idles quite nicely.. I'm just talking about turning the motor with the starter. You should get a nice.. how should I put this.. poof.. poof.. poof.. etc, that is very even. I get a poof... poof.. pooooof.. and it seems like this one compression pulse and the chamber I have with higher compression are caused by the same thing. Just wondering if this is bad or not for a 1200 mile motor.

 

If those numbers are accurate, you shouldn't be concerned.

 

good deal.. just wanted to be sure before it goes up to redline