Failed head repair

[Andir]

I've just finished a rebuild on my 6.2 / 6.5 mixed motor that started with a leak on cylinder 2. After a stripdown this was obviously a cracked head. I had the head repaired as per The Diesel Page method with the K-Liner. Now after putting it back together it still leaks in the same bore (heads back on the same way round).
Now I was thinking that as I span the engine on the starter a few times (+- 60 seconds) before fitting the radiator and filling with water could the commpession crush the K-Liner as the water is not present to absorb the shock and open the leak again? I must say that the K-Liner did look flimsy.
Cheers
Andir

[john8662]

Tell me a little more about the 6.2/6.5 engine, what's 6.2 and what's 6.5.

I'm guessing that the cracks that you found were the short cracks that appear between the valves, but none elsewhere?

Most of the cracks between the valves are surface in nature and usually don't leak, but that's where the K-line liners are for. They should be thin in nature, to maintain a flow of coolant through the passage.

Which cylinder is leaking, are you bleeding compression presure into the cooling system or are you getting coolant into the cylinder causing a hydrolock situation?

What clues were visually there to determine that the cracked head was the source of coolant into the cylinder?

J

[Andir]

John
It's hard to know exactly as there are very few of these motor here in South Africa to compare to but the pistons and crank were 6.5. the heads possibly 6.2 (there were 6.2 out of round head gaskets on it), 6.2 front cover and unknown DB2 pump. The rear seal was 1 peice if that helps define anything. The motor came in a Landrover I bought but I know the motor was brought used from the States by a cowboy mechanic who could have done anything to it before it found its way into this car.

The head crack was as you describe but extended through the valve seats and into the runners. It didn't show a leak when pressure tested but this was when it was cold. Prior to rebuilding the engine would hydrolock after it was parked and turned off but not always. If the water was cleared by turning it over to squeeze the water after it was cool then it would not hydrolock again.
Now the motor (which has not yet run) is leaking coolant and hydrolocking again.

Cylinder 2 is the leaking one and I am pressurising the cooling system but not too badly. (no combustion yet only starter motor)

The only clue was the crack and the assumption that the coolant was leaking through it. The head, piston crown and the top of the bore were badly pitted with rust so I think this has been leaking a while.

When it was rebuilt I put +20 pistons in so the block was bored and reveiled no sign of a crack in any bore (6 + 8 were lind to correct previous poor machine work) but I did not deck it so I don't know about that if it will indeed leak from there into a bore.