R32 Gtst Compression Test

[Tofu]

Hey Guys,

Ive been looking at buying a 32 for the past nine months. One came to my attention and have been eagerly following it for the last week or so. He sent me across the compression/leakdown test and here are the results:

1-134psi/20%, 2-127psi/20%, 3-149psi/10%, 4-133psi/28%, 5-146psi/10%, 6-136psi/28% .

From what i have read the compression should be about the same across the board. What do these mean to you? Would like to know if it is screwie before i throw down the cash.

Cheers.

[carl h]

compression is piss poor, spec is 175psi.

there is alot of varience across the board there, engine might not be in good condition.

[Tofu]

Thats what I was assuming.

175 hey, thats not to shabby

[Tofu]

Could the test been done incorrect? Also how is the test done?

[PlasticStan]

Could the test been done incorrect? Also how is the test done?

<{POST_SNAPBACK}>

The test is done by connecting a pressure gauge to the spark plug hole on each cylinder. The engine is then turned over and the maximum pressure in each cylinder will be recorded on the gauge. The more wear in things like piston rings, valve stem oil seals, cylinder bore etc. the more air will leak from the cylinder giving a lower pressure in the cylinder.

It is possible to do the test wrong, you have to have the throttle fully open and the engine oil up to working temperature to get the best readings.

[blind_elk]

I think the leakdowns are pretty crappy as well. Anyone who can do a leakdown should know how to do a comp test, anyway.

[Beer Baron]

hey, at least the bloke was honest! lol

[Sydneykid]

Hey Guys,

Ive been looking at buying a 32 for the past nine months. One came to my attention and have been eagerly following it for the last week or so. He sent me across the compression/leakdown test and here are the results:

1-134psi/20%, 2-127psi/20%, 3-149psi/10%, 4-133psi/28%, 5-146psi/10%, 6-136psi/28% .

From what i have read the compression should be about the same across the board. What do these mean to you? Would like to know if it is screwie before i throw down the cash.

Cheers.

<{POST_SNAPBACK}>

Compression test are too easily affected by outside factors, so I rely on the leak down test results.

Leak down around 20% (or less ) is OK for 12+ year old car. The 28% on 2 cylinders is a bit more than I would be happy with.

cheers

[ToF]

compression is piss poor, spec is 175psi.

there is alot of varience across the board there, engine might not be in good condition.

<{POST_SNAPBACK}>

Actually according to the R32 manual, the RB20DET's factory value is 170psi and actual limit value is 128psi. The allowed variance between cylinders is 14.2psi....

I doubt anyone with a 15 year old engine is going to get 170psi.

[yogi000]

how do u exactly do a leak down test, always been curious about this.

[Tofu]

thanks guys....I think i will leave that test alone.

[limpus]

Remember to hold the throttle fully open before cranking the engine as stated in the factory manual....