S400 low boost P24v puller

Checked compression and did a leakdown test on each cylinder. Checked it with the motor cold and hot.

Cold compression was 370psi on cylinder 1 and 6. 320psi on 2, 4, and 5, and 280psi on 3.
Checking it hot all the readings just went up about 10-15psi

Now when I did the leak down at 100psi cylinders 1 and 6 held 90psi.
But 2, 3, 4, and 5 only hold 45-55psi. There’s a pretty loud hiss coming out the exhaust. No hiss out the intake, no bubbles in the radiator, and nothing terrible coming out the crankcase breathers either. Cylinder 1 and 6 there was no hiss.

I searched a bit but didn’t find an exact spec for compression. I didn’t think that was too bad, the motor just not has 130k on it and it’s only been abused for about 2k miles.
Could it be exhaust valves not sealing contributing to my issue?

I still need to try another set of governor springs it it too
 
Scattered said:
Checked compression and did a leakdown test on each cylinder. Checked it with the motor cold and hot.



Cold compression was 370psi on cylinder 1 and 6. 320psi on 2, 4, and 5, and 280psi on 3.

Checking it hot all the readings just went up about 10-15psi



Now when I did the leak down at 100psi cylinders 1 and 6 held 90psi.

But 2, 3, 4, and 5 only hold 45-55psi. There’s a pretty loud hiss coming out the exhaust. No hiss out the intake, no bubbles in the radiator, and nothing terrible coming out the crankcase breathers either. Cylinder 1 and 6 there was no hiss.



I searched a bit but didn’t find an exact spec for compression. I didn’t think that was too bad, the motor just not has 130k on it and it’s only been abused for about 2k miles.

Could it be exhaust valves not sealing contributing to my issue?



I still need to try another set of governor springs it it too
Click to expand...
What for camshaft are you running?

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Forgive me for not reading through the whole thing, but has the head ever been off and checked? I was chasing my tail trying to figure out why my truck was down on power all last summer. Still ran ok but it wasn't how it should've been, boost was only down about 10psi from normal and had no leaks elsewhere. No matter what I did it wouldn't clean up and I had more than enough air. Compression test showed 1 & 6 about 50 psi higher than the others and they all had more leak down than I would've liked. Ended up pulling the head and found about a dozen cracked valve seats, new head and it was back to normal. Might be worth a check at this point.
 
zachu812 said:
Forgive me for not reading through the whole thing, but has the head ever been off and checked? I was chasing my tail trying to figure out why my truck was down on power all last summer. Still ran ok but it wasn't how it should've been, boost was only down about 10psi from normal and had no leaks elsewhere. No matter what I did it wouldn't clean up and I had more than enough air. Compression test showed 1 & 6 about 50 psi higher than the others and they all had more leak down than I would've liked. Ended up pulling the head and found about a dozen cracked valve seats, new head and it was back to normal. Might be worth a check at this point.
Click to expand...

Nope the head has never been off this engine since it was new. Sounds like your leak down results were the same as mine. Since there’s a pretty loud hiss coming out the exhaust I’m betting it does have bad valve seats. It’ll be coming off this winter for sure.
 
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