what is good compression on a FB? we are going to buy an 85 gsl but we want to do a compression check before we bring it home. Thanks, Chris

 

To do a proper compression test you need rotary compression testing equipment, not just Joe Garage's universal kit. You may have known that already, in which case ignore this...

 

You can't do a regular compression test on rotary engines. You need the proper machine to do it.

 

You can get a decent test from a normal compression tester.. Just pull out the one way valve..


And you should see from ~75-120Psi on each rotor.. But more importantly, you should see 3 almost equal bounces and it should be close on both rotors..


-Zach

 

Could you not turn it over by hand and get peak readings on the gauge?

 

Oh, and make sure you pull the fues for the fuel, and hold the throttle at WOT when cranking to test..


-Zach

 

thanks zyounker

 

well did you buy the car or what?

 

it took her too long to get back to us, so we are going to look at it tomorrow, things never go as plained when ever I buy a car

 

I got that atkins rotary rebuild video and they demonstrate some compression tests. They used one of those universal adapters and gave a tolerance range. I forget what it was, tho. I've heard the compression testers that Mazda uses are very thorough and REAL high end expensive type stuff. Maybe she'd let you drive it to a dealership if you dont want to mess with a universal.
What you may also want to do is a coolant system compression test. I'd rent/borrow one of the testers tho, as they are a bit on the expensive side.

 

not a bad idea, but it my be too late to try and soruce one of those, unless, autozone has one in there loan a tool service....