- Nov 20, 2004
brittwin said:"Wet sumping" means that the crankshaft's big-ends & flywheel whip up the oil in the crankcase, providing a rather "random" splash pattern and "oil foam". That kind of unwanted excess "lubrication" may (more or less reliably) help to initially lube the cams at start-up,
Doesn't that pretty much go against what you originally said?? *Immediate* cam lobe (over?)lubrication being beneficial as I see it.
brittwin said:but it's negative effects are far more signiificant. If most of the oil in the tank has drained into the sump, the oil pump's scavenging side can't pump sufficient quantities of the foamy oil back into the tank,
Well I'm not convinced the scavenge system isn't able to clear the sump of this alleged 'foamy oil'.
brittwin said:and it's pressure-feed side can't supply the engine's bearings & cylinder head appropriately - thus causing damages elsewhere.
I would never start up with an empty oil tank (and have said so in other posts).
brittwin said:The best way to avoid "dry cam" problems at start-up - particularly when starting the engine after some weeks in the garage - is to remove the rocker covers and to pour a tea-cup of oil into each one of the head openings.
And I'm sure many Commando owners do that.
brittwin said:That oil can be taken from the engine's sump if it is really "wet sumping". Doing that some hours before kicking her back into life will ensure that enough oil will will have found it's way down the pushrod tunnels to the cam followers and cam lobes at start-up. That's a method you can trust - "wet sumping" isn't.
I have previously suggested (in other posts) removing the majority of the oil from the tank with a suction gun and (keeping it in a container), as I consider it to be an easier method than removing it from the sump to return it to the tank.
The term *wet sumping* really refers to the scavenge system being unable to keep the sump clear of oil while the engine is running! Unfortunately it seems to mean something different these days (the result of oil draining to the sump).