75 on rear 80 on front after 2k on my rebuild
11-14-03, 05:15 PM
#1
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75 on rear 80 on front after 2k on my rebuild
sweet guys my rebuild techniques are a piece of ****. after 2000 miles and over 5 thousand worth on stuff. i got the shittiest compression numbers EVER! on a rebuild. IM so very happy is great to knwo you waste dmad money because i thought i was able to rebuild an engine. the mechanic said it might have to do with the porting job being abit to big but i doubt thats the cause. The car runs fine it semms to have good hard pulls in all gear and is smooth as hell on idle and warm up. i guess i will never redline it 
.
mY OIL PRESSURE IS FINE, and i have no leaks. man this really sux oh well...
.mY OIL PRESSURE IS FINE, and i have no leaks. man this really sux oh well...
THE CAR RUNS PIMP!
11-14-03, 05:32 PM
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well like i said it was done by two different mechanics the first compression check was done right after teh rebuild... ( the guy didnt know im using premix, the entire OMP is gone an dteh lines off is completly blocked off) and eh read 75 75 teh second guy used a mazda rotary compression.. and he read 80 front 75 rear. im thinking he fogot that sinc ei run premix their is no il on the rotors... what do you think icemark>? thanx fo rteh help by the way. i kept up with a vr6 all the way to 60 mph we were shifting under 4k but still i dont think my rotors should have that low of a compression
11-14-03, 05:36 PM
#5
Former Moderator. RIP Icemark.
After 2K miles I wouldn't think that it should be so low, that is why I was wondering if they did the check holding the throttle all the way down (as you are supposed to on a Rotary).
11-14-03, 05:44 PM
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yeah im not sure i dont wanna sound like i know more than him i mean he has liek 5 rotaries and all his sons oen one ive seen them he has pictures of him racing a 12a first gen... i dont know the car semms to pull hard all the time im gonna get it dynoed after 2000 more miles... and see whats goign on you think tahst a good idea?
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11-14-03, 06:31 PM
#9
What R U thinking self?
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A rebuild yourself is less than $1200 .. I know I did it myself. It does not sound like it is "going to ****" ....... he has higher numbers the second time then the first .. and It will prolly still improve from there. He said "i dont know the car semms to pull hard all the time" ... All I am saying is THAT is the part that counts, don't sweat the numbers... that could be anything. If you had not had a compression check would you be happy? If so ... then it's fine, don't sweat it.
-Robert
-Robert
11-14-03, 07:55 PM
#10
I just did my own rebuild also. It's my 2nd rebuild and the first (different motor) was a failure but a HUGE learning experience.
I noticed you said you have larger then stock size ports...?
How much larger are they...?
I know my ports are quite larger then stock and I also have ALOT of time and $$$$$ invested into this rebuild.
So my question would be... Wouldn't porting effect your compression readings..?????
I noticed you said you have larger then stock size ports...?
How much larger are they...?
I know my ports are quite larger then stock and I also have ALOT of time and $$$$$ invested into this rebuild.
So my question would be... Wouldn't porting effect your compression readings..?????
11-14-03, 09:45 PM
#11
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I think ports that close later cause the compression to go down very slightly when doing the standard compression test. Something having to do with there being less starting volume in the combustion chamber right when the ports close comprared to stock short duration ports.
To the original poster: Did the rebuild have used housings and what kind of apex seals did you install?
To the original poster: Did the rebuild have used housings and what kind of apex seals did you install?
11-14-03, 10:15 PM
#12
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yes it had used housings but they were in really good condition an di used 3 piece apex seals. could it have naything to do with the premix?
11-14-03, 11:20 PM
#13
Banned. I got OWNED!!!
Dude, IT HAS NOTHING TO DO WITH THE PREMIX!!!
IF your housings were exceptionally shitty, the engine won't ever built too much compression, but I would think it would be much more than 80 psi. Im thinking the tester probably didnt put the throttle open when he ran the test.
BTW, you dont need to pay some one for this. Go to autozone, buy a $24.99 compression tester and use it yourself. Remove BOTH lower plugs, test the front rotor by cranking with the EGI fuse remove and gaspedal on the floor for 10 seconds, take your reading, then repeat for rear.
The engine in my convertible, with about 1400 miles and a MASSIVE early-opan/late-close streetport and a bit of abuse before breakin was even close to being over, reads 115psi front and rear and is still climbing. Very good housings were used, although not new. Even with shitty housings, you usually see 95psi after 2500 miles.
Bottom line, I dont think you did anything wrong. Most of the compression numbers a motor puts out are either in the test procedure, or the wear of rotorhousings/apex seals. Its obvious your seals arent worn, so you dont have much to worry about. Hell, even if your compression never goes any higher, the thing is almost guaranteed to run well for several years, because the new seals aren't just gonna up and break, unless you do something dumb. Compression numbers arent everything...be glad you have some as opposed to none, like some folks on here...
IF your housings were exceptionally shitty, the engine won't ever built too much compression, but I would think it would be much more than 80 psi. Im thinking the tester probably didnt put the throttle open when he ran the test.
BTW, you dont need to pay some one for this. Go to autozone, buy a $24.99 compression tester and use it yourself. Remove BOTH lower plugs, test the front rotor by cranking with the EGI fuse remove and gaspedal on the floor for 10 seconds, take your reading, then repeat for rear.
The engine in my convertible, with about 1400 miles and a MASSIVE early-opan/late-close streetport and a bit of abuse before breakin was even close to being over, reads 115psi front and rear and is still climbing. Very good housings were used, although not new. Even with shitty housings, you usually see 95psi after 2500 miles.
Bottom line, I dont think you did anything wrong. Most of the compression numbers a motor puts out are either in the test procedure, or the wear of rotorhousings/apex seals. Its obvious your seals arent worn, so you dont have much to worry about. Hell, even if your compression never goes any higher, the thing is almost guaranteed to run well for several years, because the new seals aren't just gonna up and break, unless you do something dumb. Compression numbers arent everything...be glad you have some as opposed to none, like some folks on here...
11-15-03, 11:50 AM
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those numbers should be alright. The motor isnt even really broken in yet. The numbers are near passing if not passing so i wouldnt worry about it. If you used housings that were used before then these numbers could be alright until they wear down to fit your apex/side seals better. Are you loosing any oil? Are you loosing any coolant? Does it smoke, how much, have you done a power balence? Those are the things i would worry about more than your numbers be a little low, just remember the motor is still pretty new.
11-15-03, 01:09 PM
#20
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NOTHING no leaks whatsoever , no smoke, it takes only tiny bit of oil. evrythign seems fien except for the freaking idiot light telling me my ebrake is on 24/7 ghey.. i even tried the cold coldering thingy and it still doesnt work plus my clock reads 1:00 o clock all the time, when i opened it up it had a burnt mark on the rigth side of it so mayeb it just blew up.
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