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Location:
Sunshine Coast
Registered:
January 2005
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compression test question,,........
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Sun, 29 May 2005 06:31
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Hi everyone, does anyone know much about dry compression testing? what is good? The nice fellow that i have bought my 1jz off has done a dry test on my motor for me and i have no idea what is good. i have heard that 'scores' of 170 is good in a wet test. what about the dry compression test method? this is what i have been told:-
Just done a dry compression test on the engine mate
Results are
1/ 150
2/150
3/150
4/145
5/150
6/150
any help wpould be greatly appreciated. cheers Matt
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Location:
Sydney
Registered:
February 2003
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Re: compression test question,,........
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Sun, 29 May 2005 07:16
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that is a fair result.
i wouldnt worry so much about lower results, just large differences between cylinders.
a wet compression test will help to eliminate ring leaks so you can pinpoint it as a valve problem. unless the results are bad i wouldnt worry about a wet test.
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Location:
Parra
Registered:
January 2005
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Re: compression test question,,........
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Sun, 29 May 2005 07:30
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hey im getting my 4AGE compression tested next weekend ., i dunno wet or dry 
but what should it be like if everythings fine???
thanks
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Location:
Brisbane
Registered:
February 2003
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Re: compression test question,,........
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Sun, 29 May 2005 08:27
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you should always test dry AND then wet - not just one.
so you can make a more educated guess about ring and valve condition.
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I supported Toymods
Location:
Perth, Western Australia
Registered:
December 2002
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Re: compression test question,,........
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Sun, 29 May 2005 17:23
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| OUTRUN wrote on Sun, 29 May 2005 15:30 |
hey im getting my 4AGE compression tested next weekend ., i dunno wet or dry
but what should it be like if everythings fine???
thanks
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I've had bigport, small port and silvertops hit 200psi on dry cold compression tests - good luck!
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I Supported Toymods
Location:
Nthn Beaches, Sydney
Registered:
October 2004
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Re: compression test question,,........
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Fri, 03 June 2005 02:16
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Hey Clint (or anybody else?!), what's a dry comp test? Vs wet?
I've done a comp test, just pulled the plugs out just after driving it (it was up to temp) and tested, so this would be a wet right? How do i test dry?
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Location:
Sydney
Registered:
January 2003
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Re: compression test question,,........
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Fri, 03 June 2005 06:52
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a wet test is when you squirt a little bit of oil down the bores then test the compression..
if the wet test has considerably higher pressure than the dry test it usually indicates that the rings are on the way out...
a wet test will always be a bit higher though.
from memory, 170-180psi on a 4ag is good.. but i'm not 100% sure,
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Location:
Parra
Registered:
January 2005
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Location:
Adelaide
Registered:
September 2003
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Re: compression test question,,........
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Sun, 05 June 2005 01:19
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OUTRUN
did you then retest each cylinder with a squirt of oil down each to compare the results????
i don't know if 210 would be considered too high, i think the more important thing is that they were all around the same mark of 210 and one cylinder didn't vary significantly from the others.
if i can find my instructions on compression tests, i have a vague recollection of high readings could have something to do with carbon build up in the cylinders, but then i could be talking out my bottom, if someone could confirm that would be great cos i can't find the instructions at all.
then if it was carbon build up there were a few things you could do to fix it, including different heat range plugs or something you could put into the cylinders to clean them out (after running for a little while but it creates LOTS of smoke).
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Location:
Wollongong
Registered:
May 2002
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Re: compression test question,,........
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Sun, 05 June 2005 02:13
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You have to remember that testing a 4AG will give you much higher numbers than a 1J. Compression on a 1J is 8.5:1, where a 4AG is probably around the 10:1 mark. As mentioned above, its more important to get consistent numbers across all cylinders than to reach an specific number.
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Location:
Parra
Registered:
January 2005
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Re: compression test question,,........
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Sun, 05 June 2005 09:03
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no , no oil
i read in one of those books you buy from auto shops , like NOVA / COROLLA 89 - weneva,, and it said if its high it could be what you said or worn piston rings.
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Location:
Adelaide
Registered:
September 2003
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Re: compression test question,,........
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Sun, 05 June 2005 14:09
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worn piston rings i would think give a low reading as there would be leaking in the cylinders.
that would be so when dry compression testing.
with a bit of oil in the cylinders, it would seal the piston ring and then give a high value, then you could lead towards a piston ring issue.
but your values are high (and consistent) just as they are when dry, so i would fathom at a guess that there wouldn't be much wrong at all with your 210 readings, but if you are worried it is high try a method for cleaning out the carbon and then see how you go again.
personally i wouldn't bother though.
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Location:
Parra
Registered:
January 2005
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Re: compression test question,,........
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Sun, 05 June 2005 15:06
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ok thanks mate , dont think ill bother , the car runs fine but it seemed to be burning oil thats why the test waz done , maybe just need to fill up more oil , lol....extreemely minor oil leak so that cant be the problem.
and the oil pressure gauge in the dash , what is that really? the "pressure " of the oil huh??
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Location:
Sydney
Registered:
April 2004
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Re: compression test question,,........
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Sun, 05 June 2005 15:15
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| Quote: |
and the oil pressure gauge in the dash , what is that really? the "pressure " of the oil huh??
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yes.
oil pressure
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