Head Gasket ??

[dynoman]

While I was chasing down a exhaust leak I decided to do a compression check . All cylinders were 170 to 173 psi except I believe they are #4 & #6 (pass side middle & rear) which were 150 psi (middle) and 120-125 psi (rear). I checked them 3 times , am I right. If so can you change just one side ??? If I pull both heads should I have them O-ringed ?? What gaskets is everyone using ? Thanks Sam

 

[Just a Six??]

Was the engine warm & throttle blade wide open when testing?
Why do you think its a head gasket?
Also a leak down test should be done before you tear apart anything.

 

[dynoman]

Car was cold cause it has been apart for a week waiting for header gaskets & getting header welded. Would it matter if the throttle wasn't open cause the middle & back cylinders on pass side were the only ones lower the rest were all identical. I had a bad FP gauge that was reading 9 psi low and the FP was adjusted to that. I was getting backfiring and knock retard on scanmaster before getting the FP straightened out. After adjusting FP the car ran great with no knock but when I drove near a gaurd rail I could hear what I thought was an exhaust leak . Pulled the car in the garage and listened , it was coming from the pass side. I pulled the crossover , downpipe & header . Header gasket looked bad (passenger side rear), and had a crack in the collector near the turbo flange. I did a compression check just to be sure and that was my results.

 

[dynoman]

Does anyone else have any opinion ? I really want to get it back on the road before summer ends . Thanks Sam

 

[mike lee]

Head gaskets

DO A CYLINDER LEAKAGE TEST YOU MIGHT HAVE BURNED VALVE OR SEAT OR POSSIBLE PISTON ISSUE

 

[pajo]

?

You are doing something wrong since your compression is high on some cylinders ...My two cents said it should be in the neighbourhood of 140-145 psi on all cylinders.Throtle blade open and all spark plugs out and if I am wrong somebody will chime in ..?>:biggrin: good luck with whatever the outcome is ..

 

[dynoman]

The compression check was pretty straight forward . All plugs out, throttle open, & 6 compression cycles per cylinder . I could watch the gauge on each cylinder during pump up and all got to their final reading by the 5th cycle , the 6th didn't go higher (did it 3 times). I guess other than a misadjusted valve I'm going to be pulling the head anyways, correct ?