Busted Valve, Help Needed!

[adam 32]

after rebuilding and replacing the turbo a valve has let go on the 'test run'

this was only at 10psi and under 5500rpm so not heavy conditions. at first it was a misfire so i changed coil packs, spark plugs and ignitor amps. nothing. ran a compression test, and it came up with 0 compression in cylinder 4. so it something to do with the valves

i pulled the rocker covers off and rotated the cams and all 4 lifters work fine so its not the valve springs. all looks fine from the top of the engine. so it must be a bent valve or something from the bottom...

can anyone give me any advice with regard to pulling the head off to check from the bottom if a valve is stuffed. how much for a workshop to do this kind of job or any help is greatly appreciated. my budget is already stretched from the turbo job so i have little cash to play with

thanks in advance for any help anyone has it is much appreciated

[blind_elk]

I think its a good days work (for one person) to remove the head. (it took me 2 easy days when I blew a head gasket)

I'm dubious on the bent valve theory - wouldn't you see the lifter stay down if the valve underneath it was bent and not coming all the way back into the seat?

Sounds more like the valve head has broken off, but I'm only guessing here. Can you stick one of those magnetic probes down the spark plug hole and see if you can pick anything up?

If there's no compression, its almost certain you're going to have to lift the head to see what went wrong.

[adam 32]

well i was also thinking if it is a bent valve then youd hear it... theres no noise at all, apart from the engine running on 5cylinders it sounds fine...

possibly the seal has gone, either way somthing is letting the air through cos im getting absolutely zero compression