I had a compression test done on my 94 RX-7 and the results are 7.4 / 7.4 / 7.3 on the front rotor and 6.7 / 6.7 / 6.7 on the rear.



The 1994 Mazda Workshop Manual calls for a minimum of 7.0 (100 psi) and a maximum difference of 21 psi between the front and rear rotors.



What could I expect in terms of usability from this motor?



Thanks in advance,



Mario





more on the car

Are you having any problem starting or loosing power from your car? If you are not having any issues, I wouldn't worry about it.



Personally, I would do compression test done when I'm having issues with my car and after I eliminated other possibilities of engine problems.. I had a guy come up to me asking for compression test done (I have 2 Mazda testers (old and the digital). But I told him if he's not having any issues, he just wasting his money and time..



PHIL

yeah those numbers are ok.

No problems as of yet though I just purchased the car. The car starts fine (such a cool sound firing it up; I love it) and there is plenty of power. There is no visible smoke when the car starts though you can smell the burnt oil coming out the tailpipe. The previous owner looked after it well and it has a lengthy service history with the local Mazda dealer. The car does have 85,000 miles on it and and the only real work went into replacing some vacuum hoses and the AST (replaced with OEM). I know that I am going to have to put money into this car along the way; I just want to budget accordingly.



Thanks for your response

Did you get the compression test done by the mazda dealership?



glad you like the car. I love mine even though it gave me headaches in the past..



Also, the compression testers aren't the most accurate machines.. I know several people have had issues with their digital testers.. As long as you don't have problems with the car, i wouldn't worry about it.



Welcome to the world of rotary!

some indicate compression results will vary between a cold and warm motor ...

where cold yields slightly higher numbers..

I was told the opposite when I picked up my engine from them shop that built it. It showed mostly 8's but a few 7.8 and 8.1's. I just dyno tuned and he checked it at Front = 0.75k, 0.67k, 0.79k / Rear = 0.75k, 0.73k, 0.71k. So he didn't tune more then 13lbs even though I asked for 15lbs becuase he said the compression was too bad. It starts fine, sounds healthy with a spark plug out and only had problems starting when I had racing 10 plugs. He changed to 9's for the dyno run. My base dyno was 321whp@10lbs on a dynojet and today it was 259whp@13lbs on a mustang dyno. wtf? https://www.nopistons.com/forums/pub...IR#>/blink.gif