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Ok folks, a little more involved

blacksnapon

blacksnapon

Moderator
Staff member
9,461
301
waynesville,mo.
A double overhead cam vehicle, with a v8 is showing low compression on one bank of cylinders. Vehicle has no outward signs of trouble (leaks, misfires, overheating, etc.) Technician a says that one timing chain is off one tooth. Technician b says there is a vacuum leak on the intake manifold on that side. Who is right? Tech. a--Tech. b-- both--neither.
 
O'Rattlecan

O'Rattlecan

Redneck Prognosticator
26,687
797
Belton, MO
valve leakage...

Although I should be guessing timing chains on one cam, otherwise you wouldn't have mentioned the DOHC setup.

Ryan
 
lenny1carl

lenny1carl

7,086
459
upst ny
you show offs with more than 1 cam
 
mrfixit

mrfixit

Chief Chaotic Engineer
8,334
171
Malfunction Junction, Fidelity MO -or- Mound City,
Neither. One tooth isn't enough to cause all cylinders to read low, as it isn't opening the exhaust valve just yet as it has crested the power stroke. especially on a v8. couldn't be the intake, as that has no bearing on the compression. could be warped head, bad bearings/wrist pins/rings/valves, but not the intake unless the intake ports were severely restricted. Being as it is the whole bank, I'm going with warped head as my initial look-see.
 
6L PWR

6L PWR

Kansas Chapter member
7,961
255
Osage Beach, MO
I'll go with neither also. Vacuum leak? That shouldn't cause low compression. Maybe the chain off by one tooth, but I don't think so.
 
Blue Goose

Blue Goose

16,116
781
Fenton, Missouri
You dawg!!!! You were the last one I was expecting an answer like that from...I was expecting something like that from the usual list of suspects and now I have to add you to that list...
 
mrfixit

mrfixit

Chief Chaotic Engineer
8,334
171
Malfunction Junction, Fidelity MO -or- Mound City,
Ryan's not here??? he guessed the bent valve....!
 
mrfixit

mrfixit

Chief Chaotic Engineer
8,334
171
Malfunction Junction, Fidelity MO -or- Mound City,
It's OK: Remember GOOSERULE #37: ALWAYS own up to your abuser status. It keeps him from dozing off at the computer.
 
mrfixit

mrfixit

Chief Chaotic Engineer
8,334
171
Malfunction Junction, Fidelity MO -or- Mound City,
Which HE? Oh, never mind... don't want to embarrass the both of them...
 
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