[Mk2] [Turbo] Compression test oh dear

[kirkbona91]

Rev3 turbo

Did a compression test earlier from cold start and from the cambelt side i got 120 120 119 110. Now im no mechanic so i dont know if this is good or bad so im asking you guts for advice.
Only reason i did test was cars smoking when reved. I thought it was turbo changed that and still happening

[C35Rob]

assuming they're dry numbers, did you do a wet test too?

[Al-sw20]

They seem low because the engine is cold, they are reasonably even though.

Warm the car up and repeat.

[shinny]

120 120 119 110

Those figures, if taken on a warm engine, would be scary.

I normally get 175-180psi, dry. It's normally the difference that is is killer (max 14psi) but the minimum pressure according to the ST205 3s-gte is 128psi.

I never compression test a cold engine... cold numbers are irrelevant unless they're insanely all over the place or a cylinder reads zero. Warm the engine a bit and go again; it doesn't have to be properly hot, but it needs to have been run for at least a couple of minutes. Last year I did a check having barely warmed the engine and got a much wider spread than normal (12psi) while the check I did just a couple of days ago (I let the engine cool down for an hour after my commute home) only had 5psi spread.

[kirkbona91]

Right well i did it again this morning cold again but with the throttle open and each time the comp tester had oil on the end. I got for cambelt end
142 151 154 151.

[markstevieandmads]

Right well i did it again this morning cold again but with the throttle open and each time the comp tester had oil on the end. I got for cambelt end
142 151 154 151.

Numerous members have said to do a warm test so why are you still doing cold tests?
It's already been said that a cold engine test is useless.

[kirkbona91]

Right well i did it again this morning cold again but with the throttle open and each time the comp tester had oil on the end. I got for cambelt end
142 151 154 151.

Numerous members have said to do a warm test so why are you still doing cold tests?
It's already been said that a cold engine test is useless.

Maybe i never saw this until i last posted. So give me chance to do a warm test.

[kirkbona91]

Right guys iv done it warm like you said. Ran it for few mins then did test
For cambelt it went
154 160 162 161
Is this good ?

[jimGTS]

Nothing looks wrong with the numbers.

Though couldn't tell you why your getting oil on the tester.

You sure it's not just oil on the threads of the tester (from a worn cam cover gasket).

[kirkbona91]

There was oil on the plugs when i did the cold one this morning with throttle open but 5 mins ago when it was warm there was no oil

[markstevieandmads]

Leaking cam cover gasket

[kirkbona91]

Leaking cam cover gasket

Does this solve the smoking situation i have when i rev the car quite high?

[markstevieandmads]

Not necessarily but I would change the cam cover gasket anyway as its an easy job.

I'd also be taking the turbo hoses off and checking there for excessive oil in the pipework. While.it's off check the turbine in the turbo for movement. This will cause your smoking issue.

[kirkbona91]

I had a ct26 on which started smoking so thats what i thought it was so i replaced it with a ct20b. Smokes stil there and its darker. Not alot of oil in turbo lines either. Unless the smoke thats coming out now is from the old turbo and is just clearing?

[markstevieandmads]

I had a ct26 on which started smoking so thats what i thought it was so i replaced it with a ct20b. Smokes stil there and its darker. Not alot of oil in turbo lines either. Unless the smoke thats coming out now is from the old turbo and is just clearing?

very possible depending on when you changed the turbo.

[killerferret666]

What colour is the smoke?

[Al-sw20]

Those compression numbers are fine.

[shinny]

Right guys iv done it warm like you said. Ran it for few mins then did test
For cambelt it went
154 160 162 161
Is this good ?

Those numbers are well within spec

BTW, the cylinder at the cambelt end is referred to as cylinder one (and then two, three and four counting from there)