Re: Analyze my compression test please...
[Re: T/A CARe]
#473562
09/20/09 05:37 PM
09/20/09 05:37 PM
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Joined: Mar 2005
Posts: 1,373 Rancho Cucamonga, CA
D_C
pro stock
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pro stock
Joined: Mar 2005
Posts: 1,373
Rancho Cucamonga, CA
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Usually, compression testers have a check-valve that doesn't allow pressure to leak back into the cylinders.
Does your tester not have a check-valve or did you remove it?
Also, even "good" cylinders leak down after a relatively short time.
That said, if the compression is Ok according to engine specifications and within around 10% cylinder-to-cylinder, highest to lowest, your rings "may" be Ok.
A test is squirting some oil in the cylinder and retesting to see if there is an appreciable rise in PSI.
The oil-burning "may" instead be as result of valve-seals, worn valve-guides, leaking intake-manifold gasket, etc
I had similar results on an engine I tested a couple months back. Though the engine had had a complete valve job with new seals around 8-months earlier, I replaced the valve-seals and that stopped the oil burning.
Another Moparts member recently had an intake manifold, leaking oil from the underside into the cylinders.
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Re: Analyze my compression test please...
[Re: T/A CARe]
#473563
09/21/09 09:47 AM
09/21/09 09:47 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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what motor did you do the test on? i got a 73 valiant all stock with a 318, 80,000 miles on it and did a comp. test in my auto tech class and i had an average of 145 psi.
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Re: Analyze my compression test please...
#473565
09/21/09 03:11 PM
09/21/09 03:11 PM
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Joined: Jan 2003
Posts: 5,394 Pikes Peak Country
TC@HP2
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master
Joined: Jan 2003
Posts: 5,394
Pikes Peak Country
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Quote:
what motor did you do the test on? i got a 73 valiant all stock with a 318, 80,000 miles on it and did a comp. test in my auto tech class and i had an average of 145 psi.
TA Care's altitude of 6000 ft puts a 120psi cranking pressure the equivilent of 150 psi at sea level, with certain engine assumptions, but, you get the jist of the difference.
The cylinders that had 130 and held pressure tells me there is a valve in the guage to hold pressure, otherwise all the cylinders would have quickly leaked down. So there may be some other issue.
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Re: Analyze my compression test please...
[Re: T/A CARe]
#473567
09/21/09 04:32 PM
09/21/09 04:32 PM
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Joined: Jan 2006
Posts: 8,162 USA
360view
Moparts resident spammer
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Moparts resident spammer
Joined: Jan 2006
Posts: 8,162
USA
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After checking the threaded connections on your gauge, you might consider doing a "Dynamic Compression Test" which has the potential to more accurately 'zero in' on what might be wrong: http://www.misterfixit.com/dyncompr.htm
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Re: Analyze my compression test please...
[Re: T/A CARe]
#473569
09/22/09 07:21 AM
09/22/09 07:21 AM
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Joined: Jan 2006
Posts: 8,162 USA
360view
Moparts resident spammer
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Moparts resident spammer
Joined: Jan 2006
Posts: 8,162
USA
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http://www.amazon.com/Milwaukee-2300-20-M-Spector-Digital-Inspection/dp/B001AOVBHGnotice how the price has come down on inspecting for the source of oil you would snake into the valve cover looking at intake valve stem seals that might have pop'ed up, and then snake into the combustion chambers looking upward at intake valves in both the closed and partially open positions by carefully turning the crankshaft ... but don't let the piston crush the camera !
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Re: Analyze my compression test please...
[Re: MoparforLife]
#473571
09/22/09 11:36 AM
09/22/09 11:36 AM
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Joined: Jan 2003
Posts: 1,046 Colorado Springs
T/A CARe
OP
super stock
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OP
super stock
Joined: Jan 2003
Posts: 1,046
Colorado Springs
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No smoke when I start it. I have noticed a little blue fog in the mirrow at high rpm shift points. And sorry, haven't had the chance to check the exhaust pipes for oil residue (yeah, I know it's easy, I just keep forgetting... that and bending over these days is asking a lot! ) I have an H pipe so won't be easy to tell which side might have a problem...
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Re: Analyze my compression test please...
[Re: T/A CARe]
#473572
09/22/09 11:47 AM
09/22/09 11:47 AM
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Joined: Feb 2003
Posts: 12,675 Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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If the plugs are oily, you know it's getting in the engine and burning it. If you decide to fix it, pull the intake and see if it's coming down the intake valves as it will be easilly visible. If the ports are all wet with oil and fuel, you will need to work on the tune after the work. If it smokes at rpms, it's ring seal.. Or more precisely oil control ring issues and it won't go away until you get deep into it. The compression figures are ok for your altitude but oil drops octane dramatically so you may have ping or detonation issues too.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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