specRX7_22

whats a typical compression reading for a 12a? i recently did a compression test and the results were consistant with each rotor (which leads me to belive that the apex seals are OK). the front rotor read something like 6.4, 6.3, 6.4 and the rear rotor read something like 7.1, 7.2, 7.3. if an apex seal is blown, one the the 3 readings for one rotor would be less, right? are these normal readings? thanks in advance.

specRX7_22

now i read someone else saying that normal compression is around 2.... i thought that a brand new engine should read about 8 at each chamber (or whatever you want to call it).... im confused here... am i right or wrong?

Mazderati

iTrader: (3)

I would be interested in knowing a good reading in the form of PSI also.

If a rotary has a dead apex seal, you will lose compression on two sides of the rotor, not just one. This is due to the fact that one apex seal, seals two sides of a rotor.

Kyle

RotorMotorDriver

iTrader: (1)

Check out this...I posted it a while ago, but they are the "official" Mazda compression numbers...Do with them what you want...

https://www.rx7club.com/forum/showth...2A+compression

~T.J.

zyounker

A good reading is considered ~80-125psi..


But i have seen good engines with as low as 60-70 Psi..


The more important thing is that there is not much difference between the #s...


Also make sure you test it correctly.. which means remove the valve and do it with the accellerator at WOT. and of course pull the fuel fuse..


-Zach