OK well my na s4 is running great so i figured i'd check my copression I got 115-115-115 , 115-115-115, tryed two compresion testers and couldn't belive it, has anyone ever heard of an stock 86 with 106000 mile having this good of compression? god i love buying cars from old people!

 

My '86 with ~124k pulled about 100 all the way around. If they were treated well its not all that uncommon, but yours do seem unusally high. How are you testing it?

 

testing in upper spark plug hole with throtle open, i think the numbers are right, my track time agrees with them ,

 

Was the CAS and EGI unpluged along with the engine being warm? these could all affect numbers.

 

explain how tge cas being plugged in would affect compression?

 

Isn't that so that the ECU doesn't mess with timming while your doing the test? I remember being told to disconnect it.

 

I got 110psi on my S5 with ~160k+

 

Well I suppose but if you remove the EGR fuse then it won't do anything when it comes to timming anyway! But if you want I suppose if you wanted to do it for extra protection you could! Wouldn't hurt anything!

 

i pulled fused to be sure that there was no fuel being injected i wouldn't want it to try to start while testing

 

I looked at the FAQ, but I could not find where it says how to test compresion with a standered tester. Should I take it to a dealer to get a better reading? What other major things should I test for?(like if seals are going bad or somthing)

 

rotaryresurrection.com and search the websight. it tells you how to get a compression test with normal compression checkers. those are damn good numbers. your engine is in superb condition.

 

Santiago- I think you're having a flashback from reading the Haynes or FSM- one of 'em tells you to disconnect the CAS plug instead of just pulling the proper fuses (either one will prevent ignition). I'd much rather pull the fuse than mess with the old, heat-hardened CAS plug/ wiring and breaking something...

 

just checking, but how'd you go about getting three compression numbers per rotor with a standard tester and still get numbers that high? doesn't add up.

 

go to rotary resurrection.

if you take the mazda compression checker for rotaries, you get three numbers. add them togeather and you get about the same as if you used a regular compressions checker. understand man?