rotermotor

87 rx7 with 200k on it

just got it as a gift so..... i checked the compression today and it bumped even 3 times on both housings 60 psi, 95 over all. Is it time for a new motor? I see ppl saying that it has to be over 85, is that the bumps or over all?


thanks

misterstyx69

iTrader: (142)

tell "us" how you are performing this Compression test.

LoLsmileyFC

iTrader: (37)

hmm not bad for a motor with 200k.

i say 95 psi is average for a motor with 130-150k well atleast the owns that ive owned.

rotermotor

i used the top plugs with the motor hot. the 60 psi was with the valve out. 95psi was with it in.jumped to 60psi even each time the motor was cranked.

rxtasy3

iTrader: (2)

removing the schrader valve when using a piston engine compression tester is how it's done. it's the only way to get a true reading for each rotor face. 60psi is too low. it MIGHT start cold but hot starts will be impossible.

RotaryRocket88

iTrader: (7)

"Total compression" is a meaningless number. You really just need to remove the schraeder valve, and watch the pulses. Spec is > 85 psi, but ideally you want to at least be in the 90s.

This is the best compression test writeup I've found. I think I put it in the FAQ too.
http://www.banzai-racing.com/compression_test.htm

lever2000

So what do you do if you have bad compression in a rotary?

LoLsmileyFC

iTrader: (37)

wait for it to blow then rebuild