chrispayze

Well, the head is off! All done without too much of an issue, so thanks for all the advice.

The only minor problem I found was that, after a week exposed to the cold air, the cams had a tiny bit of surface rust on them from condensed water. My new dremel and a polishing attachment soon cleaned them up though. They'll be kept in the warm house until refitting.

The pistons have a decent amount of carbon build up. Is it worth cleaning this off, or could it be more trouble than it's worth, having loose bits of carbon around the pistons/cylinders?

surfer_crx

This is a can of worms.

I always try to clean them the main reason being if I am rebuilding an engine the chances are I have performance in mind, carbon build up in the combustion chambers is a catalyst for detonation especially with forced induction and nitrous where the ability to tolerate detonation is significantly reduced.

Vacuum cleaner with some 8mm(ish) fuel hose taped on to the nozzle and suck it as you scrape, always makes sure the piston is at the top of the cylinder and do one at a time, that way if any debris goes between the piston and cylinder wall you can move the piston down and it should expose the debris and allow for removal.

chrispayze

I'm supercharging this summer, so it probably is worth doing for me then. I've seen some comedy forum posts saying to leave it be because 'it increases compression'! But the detonation point is a good one.

I've also seen some advice to plug the piston/cylinder gap with grease to catch any stray carbon, which can then be mopped up after lowering the piston. Seems reasonable.

What do you usually use to scrape it with? Presumably hard plastic to prevent damage?

chrispayze

It currently looks like this...

[attachment=71798::]

fluffyninja

Just seen this after a busy xmas/new year.
Can you post a pic of the gasket damage? I'm interested to see the damage from a chain replacement.
I know a significant cause of leaking can be poor cleanliness during build rebuild and the head block chain cover joint has high thermal loading meaning stress as the three parts move relative to one another. This exagerates the problem

Ultra_Nexus

Bores looks great!

I'd have left the cams alone and wouldn't advise dremelling them. Bit of petrol and a rag would remove everything.

As for carbon build up, your engine looks in very good condition and requires nothing doing on the bottom end side of things!

chrispayze

The damage was that the front portion of the gasket (the bit that covers the top edge of the chain case) had been broken off and the gap filled with sealant. So not surprising that it leaked after a while!

It was done by a guy at my trusted garage, who no longer works there... The garage owner has been pretty decent about it. To be fair, 2.5 years on, he could have washed his hands of it and gone with the "anything could have happened since then" stance. But he hasn't, and I've had some recompense.

chrispayze

Thanks Ron, there's certainly no scoring on the bores, all looks lovely,which is nice to see. :-)

The dremelling was less severe than it sounds. A few of the marks wouldn't just wipe off. But I was very gentle, using a polishing/buffing pads and not even the original grinding marks have been affected, so it certainly hasn't affected the surface of the cams.

Ultra_Nexus

Yes yes, I know the ones! Sorry, I thought you'd used a wire brush because I didn't read your post properly!

Yeah, buffing wheel is fine It'd all have gone within about 3 seconds of starting your car anyway

chrispayze

Eek! No way I'd have gone in that heavily! I probably would have gone on startup, but I didn't want it to start pitting, so thought I'd get rid asap, treat with a little rust cure and oil it up to keep moisture from getting at it. It won't be starting for a month, by the time I've finished putting it back together.