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Wet Sumping Poll
- Thread starter Jerry Doe
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One thing I have always wondered: If the oil tank is empty and all the oil is in the crankcase, where does the oil pump get the oil from to build up pressure to feed the head and the big ends and wherever else oil is required (obviously until the oil pump has pumped sufficient oil back into the tank.)
robs ss
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The oil pump has two sides to it.
The smaller volume (thinner) one takes oil from the tank and feeds the engine (crank, big-ends etc)
The larger volume (thicker) one is dedicated to returning oil to the tank (and feeding the rockers on some Nortons).
So.. the second one will have a good head of oil when wet-sumping has occurred. Will sure take some good kicking to return all that oil to the tank though!
click
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That's what electric starts are for
I had the Norton 850 (880) MK3 out today. It had been lying up for about 6 weeks. Oil was below the gauze filter in the oil tank.
I was going to drain the sump but being lazy & impatient I hit the kill switch & used the ES. It took two two blasts of about 30secs to get enough oil to cover the gauze filter.
I have Jim C's crankcase breather which replaces the large oil strainer on the underside of the engine. Between this & the normal oil return it gets the oil out of the crankcase very quickly
I started my MK3 with a full sump a few years ago and it promptly blew the crankcase oil seal. I don't have one of Jim's reed valves, that might have prevented this.
Over the years I have started various dry sump bikes that have been sitting and have full or half full sumps. They all smoke like crazy until things are normalized.
I feel that any cam benefit from sloshing in oil is more than negated by all of the coke that is deposited on head and valves by the oil burnoff, so I try to avoid that fullish sump startup these days. They either get started more frequently, get drained or wear a valve with interlock.
Am I the only one with bikes that smoke a couple of packs when started with too much oil in the sump?
If you ride a bike infrequently and it goes thru that smoke up every time, it won't be long before the top end is a mess.
It will still run but not that well. Valve seats get crudded up, compression loss increases, combustion chambers get a nice thick layer of black which is unhealthy.
Rather like a smoker's lungs!
Glen
Over the years I have started various dry sump bikes that have been sitting and have full or half full sumps. They all smoke like crazy until things are normalized.
I feel that any cam benefit from sloshing in oil is more than negated by all of the coke that is deposited on head and valves by the oil burnoff, so I try to avoid that fullish sump startup these days. They either get started more frequently, get drained or wear a valve with interlock.
Am I the only one with bikes that smoke a couple of packs when started with too much oil in the sump?
If you ride a bike infrequently and it goes thru that smoke up every time, it won't be long before the top end is a mess.
It will still run but not that well. Valve seats get crudded up, compression loss increases, combustion chambers get a nice thick layer of black which is unhealthy.
Rather like a smoker's lungs!
Glen
Last edited:
jimbo
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I am just guessing but with an cold engine and the oil burn at about 30secs, I do not think there will be much carbon build up.
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