Discussion
Johno said:
del 203 said:
No
This, but you may consider turning it over on the key with the king lead off to get the oil light out and then start up normally with the king lead back in place, a small safety net should you have forgotten to put the sump plug back in beore filling up 
well to a lessening effect anyway 
spend said:
The bearings don't rely on actual oil pressure to make them 'float', the eccentricity makes even the smooth surfaces act like a gyrator oil pump creating much higher pressures than you see at the oil pump on the bearing surface.
Main bearings don't "float" anyway, cranks do, don't you people know anything Ribol said:
spend said:
The bearings don't rely on actual oil pressure to make them 'float', the eccentricity makes even the smooth surfaces act like a gyrator oil pump creating much higher pressures than you see at the oil pump on the bearing surface.
Main bearings don't "float" anyway, cranks do, don't you people know anything spend said:
TBH, I think that is one of the urban myths spreading around out of control. The bearings don't rely on actual oil pressure to make them 'float', the eccentricity makes even the smooth surfaces act like a gyrator oil pump creating much higher pressures than you see at the oil pump on the bearing surface. Except for priming all the galleries of a freshly built or long standing stagnant engine I think cranking over is as likely to do as much harm as good?
As said, it's more to ensure yuo've not done anything stooopid on the way through than any real attempt to gain operating pressure.Like all the procedures for warming the engine up, nothing is as good as just driving it below certain revs until it's at operating temp. Simple often best.
Rather than urban myth, think cautious approach. A good example would be spanning on a Radical at Donington a few years ago when the owner had done an oil change, turn it on and fired it up for it to quickly dump a lot of oil into the undertray . . reason turned out to be a nipped gasket at the oil filter, turning it over on the starter would have shown it without spewing 3ltrs of oil all over the undertray and pit garage floor
As for more harm than good, it really takes very little to extinguish the OP light, if you're cranking away for an age then you have done something really wrong which may have been even worse had you started it.
Do I do this every time I do an oil change every 3k, er no
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