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Three questions: 1) cylinder head loosening sequence important? 2) B230 interference? 3) What causes a head-gasket to fail?
I bought an 88 244 (~ 175K miles) with "a blown head gasket" (per previous owner). It started with some difficulty; ran & drove somewhat; missed and smoked a lot.
I had planned to replace the motor with one of my several spares but pulled the head anyway for a look.
The head gasket and head-sealing area look burned between the middle cylinders. The oil is a light foamy brown - an oil-coolant colloid/ suspension.
Using a crude straightedge the head seems to be warped up in the middle ~ .020. Haynes spec calls for .010 max.
Q1: I wasn't thinking and loosened the head out of sequence. Might this have caused (or added to) the warping of the head? Haynes and Bentley both stress loosening in small bits in reverse order of the tightening sequence. Anyone have direct experience with this?
Q2: Haynes says not to turn the cam with the timing belt off as piston-valve contact might occur. I thought the B230 was a non-interference engine. If it was one, a timing-belt break would ruin the engine. Is the manual wrong?
My options are: a) pull a head from another motor and replace this head; or b) replace the motor itself (I have a good 86 already out of the car). I think I will do (b) because of concern about bearing damage when the engine was run with the oil-coolant mix. The mix feels oily but that's a poor test.
Q3: What causes a head-gasket to fail? PO said that that car was running fine and suddenly started to smoke.
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240s: 2 drivers and some parts cars
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