leakdown and compression test results... pretty good?
#1
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does anyone know if these numbers are good for leakdown test
cylinder 1= 10%
2= 9%
3= 10%
4= 8%
compression across all 4 cylinders was between 120-115
are these good numbers. the motor is running very well
thanks
cylinder 1= 10%
2= 9%
3= 10%
4= 8%
compression across all 4 cylinders was between 120-115
are these good numbers. the motor is running very well
thanks
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are you serious? how bad are the numbers? the car still puts out over 285hp and pulls very hard. how could those be bad numbers? at what point is it time for a rebuild?
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Thank you MAS. i was about to have a heart attack. My car only has 84,000 miles on it and blows away everything i've ever raced including several corvettes and several other porsches including my bosses 1999 carrera. does that sound to you like a motor that is just about dead? i sure hope the numbers are just wrong... you said any shop you could it.. i'll take care of that monday. thanks again
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The 170-175 that MAS quoted is from a motor with higher compression, a turbo will not create this much pressure. I'm far from being an expert, but I've always heard that leakdown up to 10% or so is OK. I've also heard that 140-150 is "normal" for a turbo, as AKA951 said, but I don't know what is considered "bad".
As long as it's running "very well", there may be no need to do anything yet (unless you have a bunch of cash to get rid of), also keep in mind it may just be the head as opposed to the whole engine.
As long as it's running "very well", there may be no need to do anything yet (unless you have a bunch of cash to get rid of), also keep in mind it may just be the head as opposed to the whole engine.
#11
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I think anything over 125 (and very close between cylinders) is good for a mileaged 951.
That is entirely my opinion, however.
Make sure the vehicle is at operating temp, and perform the leakdown with ALL the plugs removed and WOT.
Anyone agree/disagree with this procedure?
That is entirely my opinion, however.
Make sure the vehicle is at operating temp, and perform the leakdown with ALL the plugs removed and WOT.
Anyone agree/disagree with this procedure?
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I did the leakdown test myself. Before I bought the car I had a knowledgeable shop do a PPI. They told me it was 125 all across (this was after head replacement) and said that was good. I imagine it might depend on how many times they let it crank over for the compression test. In the factory manual it lists something like 150 as the optimum spec.
I suppose that with all the plumbing installed you would get significantly different numbers than with just the long block. When doing a compression test, you could try opening the throttle body and maybe even disconnecting the boot to the throttle body so that the air isn't going through the stalled turbo.
Maybe someone else who actually knows could comment on this.
I suppose that with all the plumbing installed you would get significantly different numbers than with just the long block. When doing a compression test, you could try opening the throttle body and maybe even disconnecting the boot to the throttle body so that the air isn't going through the stalled turbo.
Maybe someone else who actually knows could comment on this.
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Originally posted by keith:
<STRONG>Make sure the vehicle is at operating temp, and perform the leakdown with ALL the plugs removed and WOT.
Anyone agree/disagree with this procedure?</STRONG>
<STRONG>Make sure the vehicle is at operating temp, and perform the leakdown with ALL the plugs removed and WOT.
Anyone agree/disagree with this procedure?</STRONG>
After reading over your post, it looks like you may have meant compression rather than leakdown. If that's the case, ignore what I said.
#14
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Optimium compression numbers = compression ratio (8.0 for a 951) multiplied by 18-19.
8.0 x 18/19 = between 144 and 152.
I just did a test on the 951 motor I am about to drop yesterday...100, 100, 100 & 80...eeek...I even did it wet (with oil) which caused the numbers to rise idicating a ring problem...
8.0 x 18/19 = between 144 and 152.
I just did a test on the 951 motor I am about to drop yesterday...100, 100, 100 & 80...eeek...I even did it wet (with oil) which caused the numbers to rise idicating a ring problem...
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