Alpine Sandy's HEAD OFF - see pictures: cyl. 3+4!

[el-saturn]

fot those lovely, most honourable gentlemen who have already helped: the gasket at the left bottom of the gasket / at cylinder 4 or 1500hrs there's a crack and only in that area the gasket doesnt stick to the block and it seems like thats where it leaks!? - there's also done of the composite material which may have been flushed awy? the head shows nothing in particular - the engine ran fine, no overheating etc... and always loads of oil pressue sandy ----- and lots of good news: everything turns nicely and hoping it's just this gasket

[el-saturn]

.....just hoping a gasket guru will comment my LEAK problem/gasket cheer Io sandy

[rgh0]

it looks like the gasket failed due to internal pressure and possibly insufficient clamping force. When you hydrolocked the cylinder when cranking that may have been the cause of the failure and crack you can see. The rear of the head looks strange, has it been epoxy filled to bring up the surface in that area? The fire ring and gasket does not appear to have been seating correctly in this area and letting the water leak into the cylinder. There appears to be plenty of metal on the cylinder head so i would skim it to ensure a flat metal surface
cheers
Rohan

[rgh0]

I would also use a larger bore gasket a 84mm gasket on a 83.5 mm bore is getting to close, find a 85 mm gasket. You can see on your No3 cylinder where the gasket fire ring is overlapping the bore next to No 4 cylinder and well clear of the bore on the other side. Small errors in bolt hole location or gasket fire ring location mean that this movement can occur and your need at least 1 mm larger gasket that cylinder bore.

cheers
Rohan

[74Twincam]

Looks like progress on the diagnosis- for what it's worth, (probably already well known) but I also use two alignment studs when installing the head and gasket. I made mine from two 6-inch long shoulder bolts, and cut the hexagonal heads off of each, then ground the burrs smooth. Then I screw them into two of the head bolt locations and only tighten by hand. They provide a nice guide to align the head gasket and keep it in position when placing the head. Once the head's on, I unscrew them and replace with the head bolts for those two positions, if that all makes sense.

Out of curiosity, what IS the weird discoloration on the head at #4? Is this epoxy as Rohan guessed, or staining?

[el-saturn]

thats some CREAM(emulsion) which i didnt clean off; epoxy wouldnt "last" very long. as 1/4 of the gasket didnt stick anymore, is that how cylinder 3 sucked water from those waterpassages. 3+4 were full of water. i think i used a dropped / or brocken ajusa - didnt use my glasses sandy .....................and: THIS IS THE FAILURE and not the waterpump!?!?

[el-saturn]

thats some CREAM(emulsion) which i didnt clean off; epoxy wouldnt "last" very long. as 1/4 of the gasket didnt stick anymore, is that how cylinder 3 sucked water from those waterpassages. 3+4 were full of water. i think i used a dropped / or brocken ajusa - didnt use my glasses sandy .....................and: THIS IS THE FAILURE and not the waterpump!?!?
those triangular water channels/holes evidently "supplied" the water to both cylinders, right???? sj