A 10in adjustable to crack them
30mm M8 allen to replace proper place will have them get home 6mm
Hey for your socket Set. Dont heat heads a light tap on the head of the bolt as you apply force sometimes shocks it in to movement

No offence to Ken but leave the bloody things on and put the cam shaft to TDC. I never remove the valve gear when fitting heads.

I think it's going to be a case of having to leave them on; I had a long chat with Sean on the subject, and I don't appear to have the necessary tools. I didn't expect the screws to be that tight. I'll see how I get on when the seals I've ordered arrive. I ordered a couple extra for when I knacker another one. Brimming with confidence, that's me. Not. Fingers and various other body parts crossed.

Viking,
that's probably OK for those of us who pull engines apart regularly and can put them back together with our eyes closed.
But, as you will know from repairing cylinder heads with crushed push rod tube ends, it's not easy to fit new pushrod tubes and ensure that they will stay in position.

Ditto for those 'pegs' on the bolts at the lower end of the rocker arms, not many owners have the correct tool for removing and refitting them.
Most incidents of broken rocker spindles can be attributed directly to those bolts working loose.

ken

I reckon that by the time I've finally got this engine back together and leak-free, I'll be up there with the best of you in the take-it-apart-and-put-it-back-together-with-eyes-closed stakes.

Or perhaps not.

Just to round this thread off, I took everyone's advice, except Ken's suggestion of removing the rockers (I couldn't get the screws undone), I used plenty of grease, did everything up finger tight including the manifold, before finally tightening everything, I annealed the (new) copper washers, shoogled the 'spectacles' around, did the banjos up to 8ft/lbs (anything less and I got a bit of oil seepage) and it's all back together and (touch wood) leak-free.

There's quite a lot of 2CV specific stuff to learn; I thought I was reasonably competent with engines until this somewhat humbling episode. Well, if there's a next time, hopefully I'll be better prepared than I was this time.

Thanks to Sean, Ken and Viking for your advice.

John,
don't forget to keep an eye on the torque of the exhaust manifold nuts, especially during the first 1,000 miles after reassembly.

The asbestos free gaskets available nowadays aren't as forgiving as the original items, so can be prone to early failure if the clamping force on them is allowed to relax.

ken

p.s. This might be of interest as regards running in...
http://www.citroentuning.de/doc/How_to_break_in.pdf

Thanks, Ken, I'll keep an eye on them. I've already had to tighten them up once.

That's clever alright, but what is the torque?! I can't find it in the manual.....

Eirikj,
Good point, as it's something which Haynes and others seem to have overlooked.

Fwiw, I've always used the same torque as for the cap nuts on the cylinder head studs, which is 20 to 23 N.m., so far without any hint of a problem.

Only time I did have a problem was when some bozo had used stainless steel Allen screws in this location and wound them up so tight that galling occurred.
Took a good bit of swinging on a breaker bar to free those off...

ken

p.s. Has the postman knocked once yet?