Quote:
Originally Posted by rheltzel
It pales by experience. If you know for a fact, based upon 63 years of building engines, that storage of a flathead Ford V8 crank in a horizontal position results in a bent shaft, I guess that ends the debate. Still, your certainty on the point does beg the issue of how long a Ford flathead V8 crank must lay in a horizontal position before it is ruined by gravity. Are we talking months, or years?
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I'm not saying the crank is ruined, I'm saying it will sag if not properly supported. When it is in the engine it is supported by the main bearings. Laying horizontal on the floor or bench it is supported on a couple of counterweights
When I first became aware of the problem it was a fresh ground cast iron 6 cyl crank. I installed it in the block and when I torqued it up it locked up. When I loosened the caps it turned but not freely I removed the maincaps and checked the runout with a dial indicator, It had about.005 . My first thought was the crank grinder had some how screwed up. I left it laying the block for a few days while working on another job. When I came back and tried it again it turned freely so I torqued it up and it still turned freely. This crank had laid on a steel workbench unsupported for probably 2 months since returning from the crank grinder. When it was installed in the block and properly supported for a few days the sag disappeared.
Just to clarify, Gravity will cause a crankshaft to sag, not bend. And the problem is worse on a cast iron crank than a steel crank. Also the problem is worse on a long crank than a short crank.
A Ford V8 crank stored horizontally and "properly supported" would not have a problem, If improperly supported could have a problem.
Most crank grinders store them vertical to prevent that problem. Bill