To the Engine forensic specialist of the Board
09-26-2007, 11:22 AM
#18
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If it was a blown head gasket with a seized exhaust vavle that overheated, steam could do that. Steam is wicked when compressed if not released in a given way.
09-26-2007, 01:08 PM
#20
Three Wheelin'
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improperly sized or installed guides. Looks things were really in a bind to cause a crack like that, it's too clean to be heat related unless it was hit with cold wwater while that hot. was there a piece of old gasket material or something in the dowel hole possibly that prevented the head from seating properly?
09-26-2007, 01:17 PM
#21
Burning Brakes
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If they stuck partly open and kept getting slapped shut by the pistons then I guess the belt would be pretty worked over but maybe not broken....
I am leaning towards the valve guides myself... but that crack... Unless the head or block needed seriouuuuuuuuuus shaving.... I couldn't hazard a guess....
Unless there was no coolant flow at some point and after super heating the head it got hit with coolant but I don't know... Just armchair QB at this point...
JC
I am leaning towards the valve guides myself... but that crack... Unless the head or block needed seriouuuuuuuuuus shaving.... I couldn't hazard a guess....
Unless there was no coolant flow at some point and after super heating the head it got hit with coolant but I don't know... Just armchair QB at this point...
JC
09-26-2007, 01:57 PM
#22
Three Wheelin'
If it ran for 15k miles, couldn't we assume the guides and valves were OK? I think the bent/seized valve is a result of the overheating. I do not think a seized valve would cause the engine to overheat that rapidly.
Here is my theory:
Head gasket fails
Steam generated in the water jacket of the head forces the front plug to pop out
Rapid coolant loss
Overheated valves seize
Overheated head cracks
George loses a big chunk out of his wallet
Maybe the plug came out and caused the whole catastrophe.
Here is my theory:
Head gasket fails
Steam generated in the water jacket of the head forces the front plug to pop out
Rapid coolant loss
Overheated valves seize
Overheated head cracks
George loses a big chunk out of his wallet
Maybe the plug came out and caused the whole catastrophe.
09-26-2007, 03:02 PM
#23
Drifting
If it ran for 15k miles, couldn't we assume the guides and valves were OK? I think the bent/seized valve is a result of the overheating. I do not think a seized valve would cause the engine to overheat that rapidly.
Here is my theory:
Head gasket fails
Steam generated in the water jacket of the head forces the front plug to pop out
Rapid coolant loss
Overheated valves seize
Overheated head cracks
George loses a big chunk out of his wallet
Maybe the plug came out and caused the whole catastrophe.
This was my guess also. I can't figure out why the head gasket failed though. I wasn't gettin on the car. I think I got a bad tank of gas on the freeway. I was sad, till I realized that a 3.0 would replace this motor. Lart got a good block out of this though. He better hone the cylinders prior to rebuilding.
George
Here is my theory:
Head gasket fails
Steam generated in the water jacket of the head forces the front plug to pop out
Rapid coolant loss
Overheated valves seize
Overheated head cracks
George loses a big chunk out of his wallet
Maybe the plug came out and caused the whole catastrophe.
This was my guess also. I can't figure out why the head gasket failed though. I wasn't gettin on the car. I think I got a bad tank of gas on the freeway. I was sad, till I realized that a 3.0 would replace this motor. Lart got a good block out of this though. He better hone the cylinders prior to rebuilding.
George
09-26-2007, 05:14 PM
#25
Nordschleife Master
Judging by the look of the fire ring one theory would be that that head saw head lift at multiple, repeated occations.
If so, it should have spitted out some coolant, but with the overflow hose in stock config that wouldn't be noticed while driving.
Head lift would probably raise the temp a lot in parts of the head that weren't designed for it.
Pressure in the coolant areas would pop the tank cap and possibly an old hose at best. But pressurized coolant popping the freeze plugs? Sounds unlikely..
If so, it should have spitted out some coolant, but with the overflow hose in stock config that wouldn't be noticed while driving.
Head lift would probably raise the temp a lot in parts of the head that weren't designed for it.
Pressure in the coolant areas would pop the tank cap and possibly an old hose at best. But pressurized coolant popping the freeze plugs? Sounds unlikely..
