How long does it take to clear a wet sump
- Thread starter comnoz
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check me math.
start to bubbles = 170 sec or 2.83 min. Oil volume pumped ~ .9 quart, so 1500 rpm pumps almost 1/3 gt a min. Implies grossly 1.3 gal / min @ 6000 rpm or 78 gal an hour @ 6000. So with leaks and over estimates imples might be able to mostly fill a fish tank over 60 gallons a hour on turnpikes. Gallon oil wt. is about 7.7 lb so 6000 rpm for an hour should pump at least 500 lb of oil, which has a thermal capacity of ~.47 but/lb per degree F so this oil at say 175 degrees ( hour of 6000 rpm heating) circulates in ball park of 40,000 btu/hr .
75 gallon aquarium
40,000 BTU Forced Air Propane
start to bubbles = 170 sec or 2.83 min. Oil volume pumped ~ .9 quart, so 1500 rpm pumps almost 1/3 gt a min. Implies grossly 1.3 gal / min @ 6000 rpm or 78 gal an hour @ 6000. So with leaks and over estimates imples might be able to mostly fill a fish tank over 60 gallons a hour on turnpikes. Gallon oil wt. is about 7.7 lb so 6000 rpm for an hour should pump at least 500 lb of oil, which has a thermal capacity of ~.47 but/lb per degree F so this oil at say 175 degrees ( hour of 6000 rpm heating) circulates in ball park of 40,000 btu/hr .
75 gallon aquarium
40,000 BTU Forced Air Propane
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He did the math but I still don't know the answer. Or the question.
Don't forget that this is scavenge side calculations.
The pump can scavenge a lot more than it delivers...
Delivery is nothing like that figure, of course - it operates under a maintained pressure (hopefully),
and only bleed from the big ends and flow to the rocker gear makes up the delivered volume.
(+ possibly some flow from the prv, in some models).
The pump can scavenge a lot more than it delivers...
Delivery is nothing like that figure, of course - it operates under a maintained pressure (hopefully),
and only bleed from the big ends and flow to the rocker gear makes up the delivered volume.
(+ possibly some flow from the prv, in some models).
A
Anonymous
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Hi hobot.
From your calcs, at 78 gallons (assumed U.S.) per hour with oil tank capacity at 6 U.S. pints then the oil tank turns its contents 104 times per hour. Oil coolers and your oil-in-frame mod are looking good for increased capacity alone.
Ta.
Hi comnoz.
When modifying my Combat cases I thought about installing a tap valve where I tapped the old pickup but don't have a wet sump problem so didn't. If standard cases have the same front plug then this may be an improvement to investigate (rather than having to drop the sump plug out).
Ta.
From your calcs, at 78 gallons (assumed U.S.) per hour with oil tank capacity at 6 U.S. pints then the oil tank turns its contents 104 times per hour. Oil coolers and your oil-in-frame mod are looking good for increased capacity alone.
Ta.
Hi comnoz.
When modifying my Combat cases I thought about installing a tap valve where I tapped the old pickup but don't have a wet sump problem so didn't. If standard cases have the same front plug then this may be an improvement to investigate (rather than having to drop the sump plug out).
Ta.
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ugh thanx Needs and LAB for checking my double math failure going by sump side not supply side. I use 30 gal/hr 6000 rpm when thinking clearer to figure. I got back into Norton while Mr. Hudson was alive and was a mentor for a time. To me wet sump is a non issue as long as no leaks outside of crank cases and enough oil above pump to make pressure in a few seconds, just ride off at over 2000 rpm soon as I can. As wet sump only happens at home over some days (unless something popped loose on the road) might consider an air tap to pressurize oil back through breather-valves and some past pump gears till feeling good to go. Peel has air tank so might use as pre-oiler, The Slow turn over comnoz shows pushing oil out from pistons decent sounds good at first but would need to be repeated a handful of times to move much oil and each slow turn of cam on lifters rubs them raw more.
A
Anonymous
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Same sum. Different data from L.A.B.
At 31.2 U.S. gallons per hour with oil tank capacity at 6 U.S. pints then the oil tank still turns its contents 41.6 times per hour at 6000rpm.
This in a closed system with limited heat dissapation opportunity for the oil. Cooler and increased capacity still look good.
Ta.
At 31.2 U.S. gallons per hour with oil tank capacity at 6 U.S. pints then the oil tank still turns its contents 41.6 times per hour at 6000rpm.
This in a closed system with limited heat dissapation opportunity for the oil. Cooler and increased capacity still look good.
Ta.
Has anyone actually measured the oil flow to confirm that figure ?
Half a gal per minute seems a very large number for such a small pump ?
Even unrestricted (ie not maintaining pressure) it wouldn't do that volume ??
Thats pumping out (and back in) about the entire contents of the oil tank every 30 seconds.
I thought, from nowhere in particular that it was 12 or 14 gals per hour.
Wouldn't have time to pick up heat out of the engine.... ?
A Vincent, by comparison, is rated at 4 gals per hour (roller bearing motor, of course).
That was a lot for back then (1940s).
And a Honda 4 has a massively larger oil pump than a Commando, by comparison.
Wonder what its flow figures are claimed to be.
Its oil hoses are considerably larger diam, for starters.
Half a gal per minute seems a very large number for such a small pump ?
Even unrestricted (ie not maintaining pressure) it wouldn't do that volume ??
Thats pumping out (and back in) about the entire contents of the oil tank every 30 seconds.
I thought, from nowhere in particular that it was 12 or 14 gals per hour.
Wouldn't have time to pick up heat out of the engine.... ?
A Vincent, by comparison, is rated at 4 gals per hour (roller bearing motor, of course).
That was a lot for back then (1940s).
And a Honda 4 has a massively larger oil pump than a Commando, by comparison.
Wonder what its flow figures are claimed to be.
Its oil hoses are considerably larger diam, for starters.
My "works loaner" 650SS could drain a sunstantial percentage of the oil tank contents into the crankcase in about 30 minutes after shut-down (it did have 130,000 miles on it according to the odometer). As far as I remember, the tank filled back up again in about 2 minutes after I started it to go home or come to work. I would guess that in the time of a workday, all the oil had drained.
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A few years ago on 1st Trixie start up after another rebuild from something not my fault, I oiled crank till oil fell out the open sump plug and liberally oiled rockers, closed up and kicked off to wait over 30 sec to see foamy grey oil being returned to tank via pump and Combat breather. A couple years ago when carb boots let grit into Trixies rings for blowby smoke and leaks everywhere, after new rings she would start on wet sump and not smoke any till 15-20 sec later as oil pressure hit head and leaked past head gasket gaps then would clear up as heat seemed to expand to seal better, until I gave Combat much throttle or over 70 mph. Seems to me unless wet sumped and pre oiling head we have 15-30sec w/o much or any oil pressure on initial start up. Not a bad idea to leave crank near TDC to retain some oil in big ends to cover this interval of nil oil pressure.
So can seasoned reasoned experts fill me in - or correct my acquired habit of starting and reving straight over 2000 to clear sump and hopfuly surf on lingering oil film till pressure hits. ??
So can seasoned reasoned experts fill me in - or correct my acquired habit of starting and reving straight over 2000 to clear sump and hopfuly surf on lingering oil film till pressure hits. ??
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