Engine oil vs oil tank oil?

Cmmoz made a comment in crankshaft porn post that when he looked in tank of well run engine he guessimates there's quart of oil working-flowing inside engine while running down the hi way. I can see and have had this happen on a Combat held in upper power band a while but when I check oil I ether look right after shut down or run it a couple min to check. If not i've seen an extra qt or two flow out of tank vent to puddle at feet and tires. So unless full wet sumped how much oil gets divided between oil tank and engine?

It'll be the internal capacity of the crankshaft assembly plus the amount sprayed onto the inner surfaces. The pump return gears have a greater capacity than the feed gears so the sump should contain virtually no oil. Can't see why it would amount to two pints.

To look in the oil tank while running down the highway usually requires removal of the seat and/or oil filler cap. How is this best achieved?

Good question Si !!

There will be oil in crank, pump also rocker feed pipe an rocker spindles etc. Then the oil in the drains inside engine through head barrels an over tappets etc. as well as that sprayed over inside of head an cases.
When engine stops an so pump stops this oil will drain down and collect in Sump oil in timing case will seep thru main bearing also in time. There is a lot of space in timing case that will fill with oil also oil in filter an return lines will seep back till the level of arch in return lines over gearbox.
When I put 5 pints in oil tank of my fully drained engine with new pipes an filter it dropped by pint or more once all these spaces where fill as engine ran.
So it doesn't sound to far off the mark to me as we here in England don't talk of quarts an have different number of pints in a gallon I might be wrong. But as long as the return keeps up with the supply an level inside motor is ok then why worry ?

toppy said:

as we here in England don't talk of quarts an have different number of pints in a gallon I might be wrong

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Same number of pints to the gallon = eight. Just different size pints (and gallons).

1 Imp gal. = 1.2005 US gal.

1.0 US quart is just a little less than a litre (946cc).

Sounds about right then. When I took motor out of frame after 30 years stood there was at least that much inside it

toppy said:

Sounds about right then. When I took motor out of frame after 30 years stood there was at least that much inside it

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You'd have to make an allowance for wet sumping though. Draining the sump immediately after a run I'd expect no more than 0.5 pint.

That's not much oil but makes sense.

Not sure where comoz made the statement of about a quart inside engine while runing but I can not see how in non-Combats. a Few table spoons puddle in head and similar in sump and teaspoon in mist suspended and ~1/3 cup trapped in cam case and left in hoses. We see the oil pump keeping ahead of input by returning half oil and half air spittle like into oil tank. Implies more like 1/2 pint left outside the tank on the fly. At 60-70 should move whole oil volume per min or so. Its not academic to Peel as her OIF knocks off about a quart capacity worth of thermal heat sink mass I hope the frame tubes will be enough to cool before entering engine again.

If you use Goodridge type braided oil pipes they will transfer heat out of oil better than rubber. It may not make great deal of difference but every little helps as they say but it would be better to have proper oil cooler in system or even heat sink type braided fins on oil carrying tubes. If its to far down the line for such things then research into a suitable oil to operate at higher temperatures my be your only option

Oil cooler factor ? If concerned. Never had an overheat as per stock. Mobil 1.

I'll just have to see what temps Peel get various things and fluids to, to decide to add extra cooler. Mere past Peel could get the older good'r quality Mobil One to almost 200' F in lower tank while burning fuel furiously to stay ahead of higher hp bikes for 30-45 min long flings. Was pleased to see it drop to 165' F in 3 min at mild 90 mph return home light fuel burn with just tank radiation. Oil can't really cool whole engine just the friction tight places and maybe valve springs a bit, so best to get it in and out soon as can or tends to cook in head.

Though you may have less oil in total if you are using frame tubes as the oil tank then you should have far great surface area of cooling of both in oil touching tube sides an air passing around outside than the standard oil tank. You will even conduct heat through frame tubes to other parts of frame that have no oil in them like steering head rear loop ISO plates an so on. So you may be ok but as you say you will have to see what happens when its all up an running.

An oil cooler will pull a lot of heat off an engine. I have one on my Atlas....never did a temperature comparison, but I could not keep my hand on the oil tank before the oil cooler, now I can.

I put the cooler on after installing 10.5 / 1 comp pistons ( back in the 60's when fuel was cheap, 100 octane, and pure fossil fuel hydrocarbon) and was concerned the high CR might lead to overheating, especially in the Texas summer heat. I have not had a problem since.

In liew of an oil cooler, try to duct air over the frame tubes...if your main reservoir is the big center tube, try to get airflow in there twixt the tank and tube. Finning the sump will help, but this is not an easy thing to accomplish. Most bang ( or delta T) for the buck is an oil cooler.

Slick

Actually unless on some record attempt I suspect I'll have to insulate the spine to get oil temp up to cook off moisture, but Peel has another feature to mostly take care of that w/o hi oil temp. I tempted to try thermal change paint which usually goes clear some what under 100'F to expose base color and motto's. Also debating to sand blast all raw or just light sand the remaining powder coat to paint over. Peel gets a handful of thermometers and would not be hard to plumb in extra cooler for some special intervals of extra fuel burn. As much as I like to hear how much oil cooler helps cool oil in hot rod C'do, look up Harley oil cooled heads to make you cock you head like hound dog me on what that actually means to engine/head temps.

Any counter points-corrections to my guesstimates of trapped oil volumes while running being about half a pint.