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Compression test ( block only )

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Old May 2, 2013 | 09:39 PM
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Default Compression test ( block only )

Just wondering if there's anyway of testing compression on the block only. Engine was fire damaged and stood outside for some time. Water was in the oil upon engine strip.
Is there anyway of testing it as I'd rather not split it
Thanks
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Old May 2, 2013 | 09:51 PM
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If there was water in the oil and it's been sat for a while it's gonna need a refresh anyway IMO.! No better time to do it if it's out of the car already.
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Old May 2, 2013 | 09:53 PM
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When you say "block only" i assume you mean the long engine ie heads attacked to the block? The way to do it would be a leak down test. this is where you set eack cylinder in turn to TDC with intake an exhaust valves closed. The test equipment them fills that cylinder with a measured amount of air and measures how much leak out. This gives a fair indication of the engine condition. You can also listen where the escaping air is coming out. If it comes out the exhaust manifold it leaking exhaust valves, intake manifold is intake valves , crank case breather is piston rings or bore.
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Old May 2, 2013 | 10:15 PM
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Cheers for the help. No the heads are off its literally sat with with pistons in with the sump off. Next stage is to split it in half and rebuild it properly. Didnt really want to have to go down this route as im unsure how much this would cost. any advice would help. Thanks
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Old May 2, 2013 | 10:30 PM
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Originally Posted by dtmautotuning
Cheers for the help. No the heads are off its literally sat with with pistons in with the sump off. Next stage is to split it in half and rebuild it properly. Didnt really want to have to go down this route as im unsure how much this would cost. any advice would help. Thanks
Then there is no point in a "compression" test as there is nothing to compress !
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Old May 2, 2013 | 10:53 PM
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Originally Posted by chopperman
Then there is no point in a "compression" test as there is nothing to compress !
Looks like the pistons will have to come out. Our worry is that the rings may have rusted. It's an 05 sti bottom end that was cheap, and we were hoping to use this to fix a v4 with a damaged bottom end. Without it costing a fortune.
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Old May 3, 2013 | 12:17 AM
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Like has been said and you already know. Break that engine right apart and check the crank is ok too. Rebuild properly and do it once. The 05 sti block is a good starting point. Are the cylinder walls corroded at all?
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Old May 4, 2013 | 04:21 AM
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Originally Posted by chopperman
When you say "block only" i assume you mean the long engine ie heads attacked to the block? The way to do it would be a leak down test. this is where you set eack cylinder in turn to TDC with intake an exhaust valves closed. The test equipment them fills that cylinder with a measured amount of air and measures how much leak out. This gives a fair indication of the engine condition. You can also listen where the escaping air is coming out. If it comes out the exhaust manifold it leaking exhaust valves, intake manifold is intake valves , crank case breather is piston rings or bore.

Last edited by SLAB; May 4, 2013 at 04:32 AM.
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