1996 ka-t in 91 coupe compression

[djrpm]

i have a 1991 coupe with a 1996 ka-t swap.the car is smoking pretty bad but not all the time.i checked the compression and it was 126 127 126 126sounds low but pretty even across.what are some of the things i can do to fix this problem.i hate smelling like burnt oil all day..................................please help,thanks,jason

[Rucca]

Do a compression test, then squirt oil in the cylinders and redo the compression test. About a tablespoon of oil or two should be sufficient. If the numbers increase significantly it means your rings aren't properly seating which would be my guess. If the numbers stay the same then the problem is either in the head (like headgasket, crack in the head, or valve seating problem) or a crack somewhere in the block...

There is nothing you can do (short of an actual repair) to fix this.

[480sx]

You need to rebuild your engine. Those compression numbers are horrible. Theres nothing that you can do besides rebuilding the motor that will do a damn thing to stop its smoking.

[remotecow]

you need to rebuild your engine bro...

[djrpm]

ok i guess ill start next week. i need some cash for this...

[r3v_v3ng3]

how did you do your compression test? was the throttle all the way open and the engine was warm?

just asking cause if you didn't do the ones stated above it may lower your reading, and your reading seems to be consistent. it could be something else easier like a blown seals on the turbo

[ken240sx]

sounds like you're in need of some new rings...was the engine built to begin with or stock?

[djrpm]

when i did the test the throttle was not all the way open. didnt know it needed to be. it went from 135 all the way across to 185 all the way across when i added a little oil to each one. now its jerking every once in a while. not all the time. it did it like 3 times yesterday. like its stalling. i guess i just need to take it all apart and send it to an engine builder. thats what i get for buying a modded car from a kid...the motor has stock internals.

[ken240sx]

ehh, when I did my compression test I forgot to do full throttle and it showed low 160's...when I did full throttle it only brought it up to the 170 range +- 2....didn't use any oil either....engine all stock.

[r3v_v3ng3]

when i did the test the throttle was not all the way open. didnt know it needed to be. it went from 135 all the way across to 185 all the way across when i added a little oil to each one. now its jerking every once in a while. not all the time. it did it like 3 times yesterday. like its stalling. i guess i just need to take it all apart and send it to an engine builder. thats what i get for buying a modded car from a kid...the motor has stock internals.

so when you added the oil you still test the way you did in the first one right? not the throttle fully open but open.

[djrpm]

no, when i first tested it was 135 on all 4...then i added oil and it was 185 on all 4... both of the times i just used the starter no throttle.. didnt know i was supposed to use throttle...

so im going to try again today.. i need to add no oil, press down to full throttle, and turn key 6 to 8 turnovers...right?

[djrpm]

what does the throttle open have to do with anything????? ive done compression test on multiple vehicles before and never used the throttle. thats why im asking.....

[ken240sx]

You want to be able to get as much air in the cylinders as possible to get the best results.I think it may also help narrow out if your valves are leaking. If you have a closed throttle, you're butterfly is closed, which means if there was compression leaking out of your valves it might not be noticeable other than a slower build-up of pressure during the test. If your throttle is open and your valves are leaking, it's easier for air to get out and you'll notice it if it doesn't have much compression. That one's just a hypothesis tho, so don't take my word for it.

[480sx]

Regardless of if he had his throttle plate open or not, at this point its obvious his rings are shot. The throttle plate being close will O/C lower his compression reading slightly, however it really doesnt mater much because it was a constant factor in his test.

Initial test, bad compression

Added oil, great compression

This gives you enough information to diagnose exactly what his issue is.

OP - Your only supposed to crank your car for two seconds when doing the test.
Modified by 480sx at 6:24 PM 4/25/2008