I dunno why I'm even posting this. I guess it cuz im bored. I pulled the motor out of the crate I shipped it on, had it on the crane. I hooked up a spare tranny bellhousing, with a starter. I built this motor a couple of years ago in Japan. I streetported it also. I never compression tested it, I guess cuz I was afraid that itg was low, although it idled perfectly and pulled hard. Heres my results aft about 6 months without being started. I poured some oil in the exhaust ports and let her rip...this is pretty ghetto, until I get my shop set up..anyway, heres the pics...

 

heres another...

 

heres the front rotor compression numbers....speed was a bit slow at 218 rpm

 

and the rear compression results....not bad, eh?

 

wow congrats!

 

thanks kouki

 

whats the conversion into psi on those mazda testers?

 

kg/cm^2 x 14.223 = psi

9.3 kg/cm^2 = 132psi
9.8 kg/cm^2 = 139psi

and those numbers are soo inaccurate because he added oil to the chambers. the oil sealed up all the possible compression leaks that would have normally existed.

granted, i would have added some sort of lubricant as well. be kinda dumb to crank a motor that has been sitting for such a long time without lubing the housings. just not a convenient time to do a compression check. also, motor is supposed to be warm and at WOT.

i'm not flaming you or anything, just giving my imput....

 

uh....um...hmm...let me think a minute....ok, 9.5 bar is 137.7 psi

so, going by that calculation, my compression is as follows in PSI for all you non metric users

front 134.8, 134.8 , 133.4 (psi)
rear 142.1, 143.5, 140.6 (psi)

 

fstrnyou,

I know the motor is supposed to be warmed up, and all that. But I added oil just as you said, just to have lube. I didnt want to be cranking a motor that has been out of a car for 6 months. Also, as metal heats up, shouldnt the numbers be better, not worse? I dunno. I just wanted to see what i would get. Also, there were no manifolds installed, so, theoretically, it was at WOT...im not trying to flame you, im just trying to clear things up. im not trying to say this is my compression in normal use. this is what my compression looks like after not running for 8 months and a capful of oil into each chamber, and cranking slow...

 

yeah, no problems at all, and besides, i'm not the one to talk about compression numbers. i just tested mine the other day and i'm only getting 85psi in the rear rotar and 65psi in the front. needless to say, i'm not driving it anymore until i rebuild it.