18-04-2019, 07:32 AM
An engine on loan has come to grief.
The rear stud holding the block to the crankcase has snapped, along with the three on the oil filler side of the engine.
The tappet side and front studs are intact, though some of the nuts were loose.
I cannot find anything amiss in the crankcase - no little end bolt floating around, for example.
The nuts were checked (not by me) not long ago.
This is the first engine I put together with a silicon block to case gasket.
Why would this happen - at the very least I would expect trouble to come first from the tappet side.
I tend to under tighten, rather than over tighten, and the other person used the traditional small spanner approach.
The only thing I can suggest is that the studs were over tightened earlier in the engine's life - I doubt if I replaced them during a hurried build up.
But why not the tappet side snapping first?
Any ideas?
Simon
The rear stud holding the block to the crankcase has snapped, along with the three on the oil filler side of the engine.
The tappet side and front studs are intact, though some of the nuts were loose.
I cannot find anything amiss in the crankcase - no little end bolt floating around, for example.
The nuts were checked (not by me) not long ago.
This is the first engine I put together with a silicon block to case gasket.
Why would this happen - at the very least I would expect trouble to come first from the tappet side.
I tend to under tighten, rather than over tighten, and the other person used the traditional small spanner approach.
The only thing I can suggest is that the studs were over tightened earlier in the engine's life - I doubt if I replaced them during a hurried build up.
But why not the tappet side snapping first?
Any ideas?
Simon