5.7 with low compression on 1 cylinder

[bill_k]

1996 5.7 LX all cylinders are at or around 160-165 except for one of them is at 135-140. I had a tech look in the cylinder with a scope and he said there was some scoring on the walls and looks like it had overheated at one time he stopped there and didn't perform any other tests.. my question is - the motor seems to run fine except the RPMS run about 400 lower then the other motor at WOT, he is saying the motor needs to be replaced. should I check anything else or just take his word for it and replace the motor.

 

[bertg]

Bill
For my money you are bordering on the industry standard of 15% difference between readings. I'd let it go, keep monitoring and enjoy the ride.
Bert

 

[guyjg]

I 2nd Bert's advice. Mechanic must need the work.

 

[chiefalen]

maybe it's a valve ?

maybe the gauge is wrong ?

Maybe the mechanic is starving.

Switch the wire on the tachs run the boat.

But whatever you do, DON'T USE THAT MECHANIC ANYMORE, AND DON'T CHANGE THE MOTOR.