Quote:
Originally Posted by Arsonism
They didn't have a machine there to grind down that crank though. He just informed me that it was warped when he pulled it out after the second incident.
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So the engine is already taken apart for the second time? (so after your 9 mile disaster on the highway?)
It's very difficult to see what happened without seeing the block and the parts obviously.
For all I know the new block you got from bmw has a fault.
What does the shop themselves think?
Especially about the loss of coolant.
I can imagine that they also arent happy with the situation.
About the warped crank, I dont know if you can measure that reliably with just a bearing cap off.
I'd imagine that you ideally want to have it lying in the block (so block upside down) on the bearings without the lower bearing caps on. and then use a micrometer to do a rotational measure of all the bearing faces.
I mean, if the crank is in the blok tightened down, tension of the other bearings can warp it. In that case: do you have a warped crank or a warped block. You'd never know imho.
Normally you check such things with a concentricity tester. I have one with rotating centers but much smaller (too small for a crankshaft), and that looks something like this (I use it for specific aircraft parts professionally):
But here the problem is that the I6 crank is very long and can maybe hang under it's own weight. And not being symetrical in design, it can hang more or less as the rotation goes.
So I dont know if it's so easy to measure if a crankshaft is warped.
I also don't know if you grind or polish such long camshafts one should use extra support. I dont know the preciese word in english, I think it's called a 'steady rest'. (a dutch machinist would call it a 'bril' but that probably means nothing to you)