V8 Porous Block fix?
Discussion
ZR1cliff said:
Why,how do they go pourous.
Think the liners leak between the liner and water jacket. Or rather the jacket leaks because it's thin and porous. Don't think there is a fix as such ,maybe try radweld but I doubt it will help.
Sure it's porous and not a head gasket?
Boosted
I don't think there is one, except replacement.
Also from casting voids, air bubbles in the casting.
Doesn't happen with injection molding, so not usually a problem with aluminium blocks and heads.
>> Edited by Trooper2 on Friday 9th September 18:15
ZR1cliff said:
Why,how do they go pourous.
Also from casting voids, air bubbles in the casting.
Doesn't happen with injection molding, so not usually a problem with aluminium blocks and heads.
>> Edited by Trooper2 on Friday 9th September 18:15
The Aluminium cracks near the top of the bore. It's a simple as that!
I did quite a lot of research and spoke to some of the Engineers on the Land-Rover team in the 90's.
About an inch below the surface of the block the aluminium surrounding the liner is at it's thinnest, cores always have a degree of float in the mould during casting and depending on how it sits we get varying thickness of wall. The issue is a classic engineering build up of tolerance, each dimension has an associated tolerance and depending where you datum points are for the machining, you can end up breaking through into the water jacket etc, nasty :-(
Anyway, the 3.5 had a smaller bore (3.5"
thus the build of tolerance on the wall thickness surrounding the liners didn't weaken the block, however when the bore was increased to 3.7" it became possible of the wall thickness to reach dangerously thin proportions! Thus the stress in the aluminium surrounding the iron liners became great enough to crack the wall and allow water to be pulled into the space between the liner and the block, and then up over the top of the liner and into the cylinder.
Hence the use of 'top hat' or flanged liners as these seat under the head gasket thus if the wall cracks behind the liner it doesn't matter as the back of the liner doesn't have a viable route into the cylinder!
Put some rad weld in it and see how you go, it's broken anyway.
Alastair
I did quite a lot of research and spoke to some of the Engineers on the Land-Rover team in the 90's.
About an inch below the surface of the block the aluminium surrounding the liner is at it's thinnest, cores always have a degree of float in the mould during casting and depending on how it sits we get varying thickness of wall. The issue is a classic engineering build up of tolerance, each dimension has an associated tolerance and depending where you datum points are for the machining, you can end up breaking through into the water jacket etc, nasty :-(
Anyway, the 3.5 had a smaller bore (3.5"
thus the build of tolerance on the wall thickness surrounding the liners didn't weaken the block, however when the bore was increased to 3.7" it became possible of the wall thickness to reach dangerously thin proportions! Thus the stress in the aluminium surrounding the iron liners became great enough to crack the wall and allow water to be pulled into the space between the liner and the block, and then up over the top of the liner and into the cylinder. Hence the use of 'top hat' or flanged liners as these seat under the head gasket thus if the wall cracks behind the liner it doesn't matter as the back of the liner doesn't have a viable route into the cylinder!
Put some rad weld in it and see how you go, it's broken anyway.
Alastair
Mine ( 3.9 V8 ) was using a lot of water so I thought I'd try a block sealer. I used this stuff :-
www.kalimex.co.uk/section.html?secpath=01.04.&pgid=17
Came highly recommended by a lot of people on the Land Rover forums. I must admit it seems to have worked, water useage is now nil. I had heard a few horror stories about how it could clog up the heater matrix so I bypassed this for a while until the K-seal had done it's stuff then connected it back up.
That was about 3000mls ago and it's still going strong.
Andy
www.kalimex.co.uk/section.html?secpath=01.04.&pgid=17
Came highly recommended by a lot of people on the Land Rover forums. I must admit it seems to have worked, water useage is now nil. I had heard a few horror stories about how it could clog up the heater matrix so I bypassed this for a while until the K-seal had done it's stuff then connected it back up.
That was about 3000mls ago and it's still going strong.
Andy
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