It does not bring me joy to be in this position, but my beloved 86' pickup has taken a turn for the worse. After the #3 cylinder not firing, and a compression test of 0, I am coming to the hypothesis of a burnt valve? Being that there was 0 pressure I feel like that rules out a busted piston ring. My question is what other steps should I go through to confirm that my thoughts are correct. If so I was planning on buying a new head from engnbldr with valves and all. Any opinions appreciated!

 

One of those things your not going to be 100% sure to you pull it apart .

Have you done a coolant system pressure test ??

I have seen Head gaskets fail not lose coolant but compression just bleeds off to the adjacent cylinder.

 

I had a trickle down test done, and i had a problem about a year ago with the coolant system overpressurizing after long drives and overflowing my reserve, this was after a compression test that showed #3 a little low, but a new radiator cap seemed to fix that problem. If i do the new head im going to replace every damn gasket i can get my hands on, and i assume with new head, valves, gaskets....that should fix whatever issues im having. Engnbldr is conveniently closed for the next week and a half so i guess ill just tear it apart anyways in the mean time. Fuun fun

 

get your parts from rockauto.com. engnbldr is good but way over priced. just buy the aisin stuff. will save you at least $300-400. and get you the same parts.

 

Something I take into consideration on a top end rebuild is just how many miles is on the motor. If less then 200k miles a top end usually will work. 300k miles I might consider the bottom end. Just wanted to throw that out there.

 

Hey just wanted to give a quick update. After taking the head off I found a chip out of the #3 valve as suspected. The cylinders and lower half all look to be in good shape, no glazing, and full o ring marks on the top stroke. Picked up a new top and + gaskets from engnbldr for under 400 bucks! thanks for the advice everyone, now for the re-build!