0 Psi compression?! wtf

[Laine_16v]

Hi there,

just put my engine in some of you may have seen in my project thread. i took a perfect working 43k 172 cup engine, i drove the car i know the engine was good.

Took it out the car and did some "work" to it over the winter, it hasnt been started in a good 7-8 months. In that time i took the head apart completely bought new valves lapped them in and rebuilt it up.

When cranking it you can hear it "misses" on one of the cylinders so i compression checked it.

Cyls 1, 2 and 3 were all exactly the same 170psi.

However cylinder 4 was 0psi!, crankingi it with the tester in just made it sound like there was nothing in the spark plug hole...

Infuriated i ripped the engine apart, to reveal abssolutely nothing out of the ordinary, all bores and pistons looked perfect just as they did when i assembled the engine.

I put the cams in with the head off the engine and rotated them all valves open as they should.

I tested for leakage (allbeit with water and not diesel as i didnt have any), and there was not a smidgen of leakage past the valves.

Wat do?

 

[f0xy]

Did the headgasket look ok?

 

[Laine_16v]

headgasket was 100% intact and looks brand new still

 

[Laine_16v]

Should add 3 of the hydraulic lifters / lash adjusters were rock solid, 13 of them were squidgy. doubt that make and difference though

 

[ditz]

did you reset the lifters? could have been those holding the valves open on number 4...

done it a couple of times myself.. new valves and lapping will mean the valve stems are further up in to the head,,, lifters stay where they were so valves never shut

 

[Laine_16v]

Nope i bought the lifters 2nd hand as i misplaced my originals.

I literally dipped them in oil for 20 seconds and banged them in the head, are they all supposed to be springy? ill leave them all in a tub of diesel overnight this time i think, then compress them multiple times, should that do the trick?