Astra cambelt kaput!!

Yes pin only goes in at one point so at least I can't mess that up! I managed to get the remaining non broken rockers out using a bar to press the valve spring - at tdc I pressed the middle cylinder valves then turned the crank half a turn to press the outer valves. I tried to slide out the camshaft but could only get the end to clear No 8 valve. But looking on the net this tool seems to be what I need without removing the cam;

I imagine I will need to have the camshaft in its correct position relative to the pistons with the new belt in place before fitting the rockers as I will need to turn the engine a bit to clear the lobes and fit the rockers?

last time I messed about with not taking a head off one of those, I hired a set from a tool hire place, it did all the valves at once so you could put the cam back in.

The way to reassemble is to turn the crank BACK a quarter of a turn from TDC, this will move all the pistons to the centre of their travel, meaning that you can put the cam in at any position then rotate it to the right position without worrying about valves touching, then turn the crank slowly forward till it is back at tdc, then put the pin back in. Then put the belt on and check the exact timing.

Mrcheerful

Well I got the new rockers in today but it doesn't look promising!! I used the tool to press the valves and fit the rockers but noticed number 2 valve was not closing when the clamp was released. If I give the valve spring a helping prod with a screwdriver it then snaps shut. Looks like that valve may be bent as when I compress the spring, I then push in the ends of the valves to make room for the rocker shims - all the other valves were easy to push but No.2 was very hard and needed a tap with the hammer. When the valve is closed if I rotate the cam around it'll open the valve but remains open and doesn't spring back.

I take it the next step is off with its head!

Absolutely. Take a very close look at the head before spending any money on it. These heads frequently crack between the valves. When the valves hit they sometimes crack the guides too, so they must be changed and the valves seats re-cut.

Good luck is all that can be said.

Finally got the head off today, not had chance to have a good look at it yet (ran out of light) but I'll probably see if the local breakers have one in and stick that on. Head came off pretty easy with the gasket intact and I've cleaned the block & pistons but I notice that No.4 piston has an imprint of the valve scored into the piston which isn't on any of the other pistons. Just wondering if this would cause any problems?

Dents in the piston crown are quite common and will make no difference unless really serious when the piston cracks!. Look very carefully at a head from a scrappie, especially between the valves which is where they tend to crack

Local breakers only had the Isuzu lumps in so I got a valve compressor and decided to overhall this one. 1 valve was definitly bent and took a bit of force to come out and two others were slightly bent as they didn't slide out of the guides cleanly. After cleaning the head I noticed what looks like a small hairline crack between the narrowest part that seperates the 2 valves (7&8) for No.4 pot.. It doesn't look deep (like a surface scratch) and just noticable when I run my finger nail over it. Do you think I can get away with this or not worth the risk?

If it is a crack then the heads scrap

Get it pressure tested. Your local FER shop should be able to do it for under £20

Yup it's scrap. My mechanic friend had a look and says it's not worth the risk as it'll only get worse. He rang a couple of his mates but sodding typical they had the same head sitting around for ages and recently scrapped them!

I've managed to get hold of another head. Between the valves appear ok, just a light mark between number 4 valves but doesn't spread across. There is however light cracks around the injector ports. The crack around number 2 was sitting slightly proud of the head so I used a dremel grinder to remove the excess and it know feels flat. Do you think this will be worth taking a risk, i took a pic below.

Doesn't look bad to me, but I'd still get it pressure tested & seats recut before fitting it.

Yeah will do that, this is one job I don't wish to do again for a very looooong time!

then don't leave the cam belt change for so long in future.

As sods law goes I was thinking about having the belt changed a few days before it went! Had the van given me and only use it as a spare knock-a-bout around town running on veg oil. On the plus side I've gained much more understanding & knowledge about the workings of an engine and now feel confident of doing future cambelt changes myself so what it's cost in parts to put right I'll more than recoup on garage labour costs by doing future belts myself.

Ok I'm slowly getting the beast together but am a bit confused about the pump timing. The crank locks into position via the pin in the flywheel housing but I notice that for every full 360 degree turn of the crank the diesel pump moves 180, so when aligning the pump mark it could either be spot on or 180 degree out. Is there any way to determine the pumps correct position?

It worked. It both wound it in and it took up the slack.

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Were you there? No. So keep your WRONG opinions to yourself.

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So you're still a knuckle dragging mechanic then? At least I had the sense to see it for what it was - the typical refuge of the school remedial classes.

Most mechanics then and now are people who were incapable of passing O levels. Thanks to the fact I passed my 11+, I got a nice raft of O levels so was able to get out of spannering when I finally recognised it for what it was - the best that 11 plus failures could hope for.