Off With Its Head!

I've been posting a lot of tripe on the HRG Faecebook page about my Bedford CF cylinder head woes. The latest was that I'd replaced the cylinder head with one from another 2.3 CF and now it boils within 7 miles. Having checked everything, flushed the system and checked everything again, I had to take the head back off. First thing I noticed was that the little bypass hose between the water pump and this little water manifold bolted to the front of the block was definitely on its last legs.

It was looking a bit plump before the multiple boiling episodes, but now it was looking like a pot-bellied dick. Anyway, it came off along with the water pump which, naturally, was fine. I was hoping that would be the nice, easy explanation. No such luck. With the head on the bench I gave it a damn good coat of looking-at but failed to see any problems.

It all looked pretty good. There was a lot of sludge that had accumulated in the water galleries despite repeated flushing, but not enough to actually stop the water circulation. I checked the intake manifold side against the old original head.

The original is on top; the replacement below (with the blue gasket-goo all over it).As you can see, the water jacket hole on the left-hand end is a lot bigger on the original, and there are a few slight machining differences, but not enough to cause any major issues, surely? I was starting to get really pissed off with the whole show. Then I had a shufti at the gasket itself, the brand-new, very expensive Payen head gasket that had covered about 25 miles.

Well bugger me with a gypsy's stick, there's a dink in it. A little groove going from No3 piston straight into the water jacket. If anything, this photo makes it look worse than it is, but it could certainly account for pressurising the cooling system, couldn't it? But here's the issue: I'm damn sure the damage wasn't there when I fitted the gasket, but did I do the damage while FITTING the head or while REMOVING it again afterwards?! Because the engine is half under the bonnet and half in the cab, plus it's canted over at 45 degrees, there's no easy way of dropping the head onto the block, especially not for a slack-sided glass-back like me. I could well have done this while fitting the head to the block, or equally easily while taking it off again.
I think what I'll end up doing is putting an exhaust valve from the head I've just removed into the original head, grinding half a mil off the tops of the valve stems and putting it all back together. It does mean I've got to shell out for another gasket set, though, damn it.
To top it all off, I thought I'd better flush the remaining sludge out of the water galleries in the block. I also thought it would be a fine idea to wait until it was almost dark to do this. Poke hose pipe in one gallery, watch rusty sludge and bum-gravy pour from another. Poke hose into another gallery, watch same crap pour from another. Poke hose into another water gallery ... and, nothing. Ah! Could this be the cause of the overheating?

No, it couldn't, you great bell-end, because you've just put the hose down one of the oil drain-backs and filled your sump with tap water. Better add another gallon of 20W50 bogwash to the bill, too...

Eugene