Ok folks, a little more involved

[blacksnapon]

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.

 

[slmann]

I'm just guessing but I say tech A.

 

[O'Rattlecan]

valve leakage...

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

Ryan

 

[lenny1carl]

you show offs with more than 1 cam

 

[mrfixit]

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]

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.

 

[Brian_B]

Subscribing. These threads are interesting if nothing else.

 

[O'Rattlecan]

valve could be bent..?

Ryan

 

[Blue Goose]

Neither.........I'm looking down for the answer, but all I can see is my feet...

 

[Brian_B]

Neither.........I'm looking down for the answer, but all I can see is my feet...

Did you lose weight recently?

 

[Blue Goose]

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]

We've been training him....

 

[Brian_B]

Ryan was not here so I was filling in.

 

[Blue Goose]

It's showing in his posts....

 

[mrfixit]

Ryan's not here??? he guessed the bent valve....!

 

[Brian_B]

Ryan's not here??? he guessed the bent valve....!

Shhhhh! He was not supposed to notice that.

 

[O'Rattlecan]

just tell brad to turn his resolution up to 1600x1200, and you won't hear from him for a few days.

Ryan

 

[mrfixit]

It's OK: Remember GOOSERULE #37: ALWAYS own up to your abuser status. It keeps him from dozing off at the computer.

 

[blacksnapon]

It's OK: Remember GOOSERULE #37: ALWAYS own up to your abuser status. It keeps him from dozing off at the computer.

Ya mean he can count to 37?

 

[mrfixit]

Which HE? Oh, never mind... don't want to embarrass the both of them...