Head gasket change - now no compression on 3 of 4 cylinders

I got round to changing the head gasket on an Astra over the weekend (C14NZ engine).

All seemed to go fine until the point of starting the engine which flatly refused to start.

On refitting the timing belt, I'd ensured that both the crank and camshaft were lined up with the TDC marks, and confirmed the camshaft by checking that the rotor arm was in the position to fire on cylinder 1.

However, cranking the engine resulted in just a smooth turn over - no "compression stutter". Continued cranking resulted in a slight stutter at which point I got the compression tester out. Cylinder 2 showed about 9 bar after 2-3 strokes. However, cylinders 1, 3 and

4 registered nothing.

I'm thinking that it's now officially dead, but what's bugging me is:

- What's happened to it - compression was fine before the gasket went

- Did I miss something (to do with the valves maybe?)

Cheers Paul

Reply to
Paul
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"> - What's happened to it - compression was fine before the gasket went

It's not dead! Vauxhall OHC engines are known for this! Keep winding it over and over. Might need a second battery! Sometimes the hydraulic tappets can take ages to pump out, and before then, they spin over like you have all for spark plugs out! I had one once, where I nearly done the starter motor in because it got so hot from spinning, so don't spin it continually for more than 30 seconds at a time. When it does burst into life, it might be just on one cylinder, and when it's able to run on it's own, it'll probably misfire for quite a while afterwards!

Good luck, let us know how you get on!

Matthew

Reply to
Matthew Long

Matthew Long ("Matthew Long" ) gurgled happily, sounding much like they were saying:

Blimey, I know the hydraulic tappets on the Saab took forever to pump up and quieten down after doing the HG. I'd idled it up to the fan kicking in, and they were still loud. It was only when I took it for a run that they shut up. I'd hate to have to do that on the starter motor...

Reply to
Adrian

assuming you have not done something very silly, then you may find that after leaving it for a while it will go. Sometimes the tappets expand while unloaded, they then take a while to recompress and in the meantime hold the valves open, hence no compression. I changed a Rover HG the other day, on starting it was three at first with blowing back in the inlet, after a few minutes of running on three the other one came in and the chuffing stopped, in that case I am certain that at least one valve was being held open.

Reply to
Mrcheerful

Good call!

I went out last night with the intention of using up the last of the battery before charging it overnight to continue cranking today, but it burst into life almost straight away. Went from no compression in 3 cylinders when i left it on Sunday suddenly to being fine last night.

It is still a bit rattley, so I'm charging the battery up anyway and will take it for a run tonight. However, it's parked on a steep hill and was able to do a hill start fine so can't be down on power too much.

Cheers! Paul

Reply to
Paul

frightening isn't it? you think you must have cocked up at first and start going over everything, been there done it etc.

Mrcheerful

Reply to
Mrcheerful

Sure is.

Not knowing what was wrong was bugging me more than the fact that the car seemed dead, when all seemed to have gone well while I was doing it. (That and a few hours down the drain!)

I'd kinda come to the conclusion it must be valve related, but couldn't work out why. I didn't realise it had hydraulic valves - Must admit I didn't really look at them too closely when I took it off.

All good experience....

Reply to
Paul

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