Whats normal compression?
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Modular motor junkie
Joined: May 2009
Posts: 6,190
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From: Texas
Whats normal compression?
I tested my compression well doing a plug change and it was only 115-120 PSI.
What should it be on a normal, healty engine?
It seems to run great and I though it would be higher than that...
What should it be on a normal, healty engine?
It seems to run great and I though it would be higher than that...
Elder User
Joined: Apr 2010
Posts: 619
Likes: 6
From: Steeler Country
That is a low number but I dont know what the v-10 should be. It is listed as 9:1 in my 2003 owners manual. On Harley compression checks that would be anywhere from 170-180. The key is to disconnect the injector, ground the plug and open the throttle body plate completely. I dont know if it is the same on the trucks. Sorry to be of little help.
Did they all measure the same? That is the important part.
Did they all measure the same? That is the important part.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 423
From: Long Island USA
Bill, do you open the throttle plate while doing it, AND did you have all the other plugs out of the engine at the time?
Cam timing/duration has a lot to do with "static" compression, but you're right, I would have thought it would be higher than what you found.
Cam timing/duration has a lot to do with "static" compression, but you're right, I would have thought it would be higher than what you found.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 423
From: Long Island USA
But with it closed, as long as they all came out the same (or within 10% I think), that's PERFECT.
Sounds like you have a great long-life motor in there
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chamblizi
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Jul 26, 2012 06:02 PM
