What are the right compression numbers???
 

I am buying a compression tester sometime this week to test the compression on my car before I put back together, does anyone what the compression tester should read if my motor is ok??? Or what it would read if my motor isn't ok??? Any help would be appreciated...

Are you going to buy a Rotary specific compression tester or an ordinary piston engine tester? The only way to get an accurate result would be using the first one, but if used properly even an ordinary tester can give you a pretty good reading(approximate). I know that the Mazda manual says that the compression should be at least 7bar(I think I forgot the units) which translates to approx. 105 psi.

I am going to buy a rotary specific one most probably, that is if I can find one..

I know they are availabe, I'll try to see if I can find one... I think the price is going to blow your mind though.........
The old style one's looked like kind of a primitive polygraph machine, the new ones are digital.

OUCH! You can be the first on your block to own your rotary digital compression tester for only $1,640.00 (plus shipping) from www.mazdatrix.com :doh:

:eek:


Thanks for finding that, at least I know I won't be getting a rotary one now.. I guess I'll stick with looking for a normal piston engine compression tester...

Yep, you can still get a pretty good baseline estimate with a "regular" compression tester. You'll need to get a Schraeder (sp?)valve to make it work right. I'll see if I can dig up how to do it - it's not really that hard. BTW, if you buy a compression tester get one with a stainless braided reinforced line. It will cost probably twice as much as an el cheapo but be much more accurate. When you do the reading this way you are watching the needle "bounce", and regular rubber (fiber) reinforced hoses are not that accurate. You'll also probably get a better quality guage as well. Stay tuned. (You are really smart getting a baseline reading on your new engine. It's probably one of the best ways to see what's going on now and in the future regarding wear)