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RustyPile · 05-13-2023, 08:34 PM

If adding oil to a cylinder with low compression, raises the compression, that's a sure sign of worn or dry rings..If the compression doesn't go higher, you probably have burned or rusty valves and or valve seats.. Did you add oil to #8 ??? If so, what happened there??? Have you bore scoped the cylinders?? Doing so will reveal wear progression and perhaps the accumulation of rust on the walls.

You have two routes here.. Finish the install, get the engine running, and drive the truck a few hundred miles and hope the condition gets better... Or, turn the engine over to a reputable rebuilder..

[EDIT] The compression tolerance between cylinders is 20%.. That does not mean +/- 20%, it means 20% between the highest and lowest..

05-13-2023, 08:34 PM	#2
RustyPile Registered User Join Date: Dec 2017 Location: Elkhart, Texas Posts: 1,541	Re: Low compression on 5.3 swap If adding oil to a cylinder with low compression, raises the compression, that's a sure sign of worn or dry rings..If the compression doesn't go higher, you probably have burned or rusty valves and or valve seats.. Did you add oil to #8 ??? If so, what happened there??? Have you bore scoped the cylinders?? Doing so will reveal wear progression and perhaps the accumulation of rust on the walls. You have two routes here.. Finish the install, get the engine running, and drive the truck a few hundred miles and hope the condition gets better... Or, turn the engine over to a reputable rebuilder.. [EDIT] The compression tolerance between cylinders is 20%.. That does not mean +/- 20%, it means 20% between the highest and lowest..