aben8057

So i decided to tackle replacing the head gasket on my 951. I sent out the head to have it resurfaced for the job.

Long story short is that everything is back together but my compression is 60 on all 4 cylinders. The car starts up and there no oil/coolant mixture.

Any idea's?

Grandpa#3

Have you done a leak down test yet? Depends how many miles were on the head, but did you have the valve guides replaced and the valves ground when they lapped the head?

Cheers,
Larry

aben8057

Hello Larry,

The machine shop did a valve job with new guides. I also added oil to the cylinder heads and the number increased to 65-70 across the board. This was done with the engine warm and TB open. Leak down test is next but i find it very unusual that the numbers are even on all 4 cylinders.

MAGK944

I once put my plugs in by hand using a socket and extension and forgot to torque them down fully. Car started fine. Thought power was down until I had an ah-ha moment a few days later.

car_slave

Valve timing?

aben8057

I was thinking the same thing..could be off a tooth or two have such an affect?

dontnow

Is it low on power? How many miles on rings? It should run quite crapy on only 60 psi, can you try with another tester if the engine runs ok?

JohnKoaWood

Double check the cam timing, but this in unlikely..

MORE likely is the valve job done by the shop..

I had a well respected shop have to repeat the valve and seat grind on a head they rebuilt... a "defect" was found durring re-assembly of the head when the shop applied a vacuum to the port to verify valve sealing.... 2 of them leaked... seats and valves were re-ground and all was good once completed the second time!

Leakdown test will tell you WHERE a leak is... if the valves are leaking, I would have a talk with the shop that did the head work!

aben8057

In first gear it is low on power where i have to get the RPM's up in order to roll. I have tried 2 testers with both having the same outcome. My initial thought was the Autozone renter tool was damaged but which I then borrowed my friends with the same results.

Mrmerlin

you should check the timing first.
if the cylinders are all even then that means the valves in all of the cylinders are doing the same sealing job.
it would be unlikely that all of the piston rings are damaged

could you have installed one of the timing gears backwards? thus timing is off a few teeth

Tedro951

+1 on cam timing. Only takes a flashlight and a few minutes.

aben8057

UPDATE: Thanx for the replies and yes my timing was slightly off hence the even compression across all 4 cylinders.

car_slave

Good to hear. What kind of numbers are you getting now?

dontnow

Congrats on it being a reasonably easy fix.