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99 Volvo 3l, Bad compression, leak down tests shows valve blow-by, pictures inside


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northernterritory
New User

Oct 8, 2017, 9:45 PM

Post #1 of 3 (334 views)
99 Volvo 3l, Bad compression, leak down tests shows valve blow-by, pictures inside Sign In

I know this isn't a boat forum, but an engine is an engine. Any advice for me?

My manifold had a crack in it causing water intrusion. The first compression test shows erroneous results; some cylinders with no compression. The second compression tests showed cylinder one 80/90, cylinder two 140/150, cylinder three 95/100, and cylinder four 90/159. That’s dry/wet numbers. I went ahead and did a leak down test. All cylinders had significant air blow-by past the valves. There was so much valve blow-by on cylinder four, I don’t see how it created so much compression wet.

I removed the head. I have attached pictures. Piston three looks like, to me, to have detonation signs. Would you look at the pictures please and give me an assessment? What should be my next move? Note, that the whiteness on the other pistons is from the flash.






















Tom Greenleaf
Ultimate Carjunky / Moderator
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Oct 8, 2017, 10:45 PM

Post #2 of 3 (321 views)
Re: 99 Volvo 3l, Bad compression, leak down tests shows valve blow-by, pictures inside Sign In

Quite familiar with marine issues. Hard to pick up raw water and last can about say heat has been an issue and gasket shows indication of one cylinder effecting another.
Longer lasting if FWC engine and manifolds but still blows raw water out exhaust which get's clogged such that no water out, no new cool water in or too common the raw water impeller was run dry - a whole minute too long can wreck one - even less if fully dry. Intake must be kept clear at a screen of whatever dirt, grass like growth or barnacles. IMO one pic show pitting in a cylinder wall to me.


Clairvoyance: This is fresh water raw water not salt and water invaded the combustion chambers of some worse than others can't take that for very long or you would get this. Most would declare that don't both and get a new block and redo head(s) sent out.
IDK - you may find the block isn't Volvo at all but they used one by another mostly GM stuck with marine as Ford, Chrysler seemed to quit bothering?


T



Discretesignals
Ultimate Carjunky / Moderator
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Oct 9, 2017, 10:06 AM

Post #3 of 3 (284 views)
Re: 99 Volvo 3l, Bad compression, leak down tests shows valve blow-by, pictures inside Sign In

Send the head out to a machine shop and have it checked for cracks and worn out valves.

Check to make sure that the rods are not bent. Make sure all pistons come up to deck.

What did the spark plug look like on the cylinder you suspect detonation?

When it is all back together check to see how the cylinder is doing by reading the plugs.





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