Temperature of the Oil in the tank?

john robert bould said:

I agree with your point...now i realize your aplication.....A race bike constant 6000 rpm [nealy] and 60-120 wind ,plus a bigger alloy tank?
Compared to a sadate road bike...with a hidden steel tank..
I still stand by my statement..a Road use Steel oil tank will remove little heat.... I didnt say NONE.
One member stated Commando's are AIR cooled ...Not OIL cooled

Do we agree that race bikes are a differant beast? Placing a high speed fan [100mph wind] draft in front of a oil tank will considerbly reduce the tank surface temp..
Totally agree. Cover it up and have little wind......?

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I do see your perspective and there's not much oil tank room (volume) in a stock bike to increase volume enough to matter without creating another problem. We certainly carry a larger volume tank on the race bikes but surprisingly do not carry that much more oil than that specified for stock engines (at least I do not for starters). As mentioned earlier, I bump it up a bit if I see the need; it's almost automatic now for me.

I agree that the bit about oil cooled engine is a bit off track from some sad, poor miss guided soul. Yes oil removes component specific heat and yes we sometimes need to cool oil more before it returns to the motor but only to assure that it will not go up in smoke doing what it needs to do, which is lubricate.

From a surface area standpoint I will make a SWAG that the aluminum engine cases have on the order of twice the surface area of a standard steel oil tank. Steel has roughly 1/4 the thermal conductivity of aluminum. So at first glance one would think the aluminum cases have it over the steel tank but thermal conductivity of a material used is dependent on the thickness of the product so now I will make another SWAG that the engine cases are on the order of 10 times thicker than the steel on the oil tank; not good for engine case cooling. On the other hand, the oil in the crankcase is likely hotter than the oil in the tank and the greater delta Temperature also drives heat transfer, this is certainly a plus for the aluminum crankcase out in the breeze versus the oil tank stuffed under the seat. Yet, on the other hand, another factor in the thermal conductivity dimension is Time. So for all things held equal, and by example, if one doubles oil quantity in the system then one doubles the time oil spends in the oil tank cooling.

So I understand your perspective and why one would say who knows for sure.

I know the effects on the race bikes. I will make the hypothesis for a standard Commando which is: that for a given set of environmental and engine conditions, reducing the quantity of oil available for circulation in the engine will increase the overall oil temperature in the tank." This can also be easily tested and I venture to say one will see the similar results. And in fact I recall doing just that when I ran a Commando racer with a steel tank but it has been too many years I don't recall whether I did many measurements.

I recall Dunstall or some other "tuning for speed" publication recommended venting or louvering the side cover over the oil tank to facilitate cooling.

I would say our opinions differ on how much oil heat is lost from the steel tank versus the rest of the system. What I am seeing is the factor of time where increasing the time an oil has to cool off (more volume in the system) will be somewhat directly proportional to how much heat is lost.

Nice to chat about these things, stay lucky and keep the shiney side up

Gosh this is more rerfreshing than bickering on oil types.

Ok Here's a tid bit to apply directly on weather the oil is heating the cases more than the cases are heating the oil > when JIm Comstock made a lower drain hole in the TS case for his breather, it lowered the oil level which significantly lowered temps in TS case, ie: the oil was heating the cases, so the cases were definitely cooling the oil.

Majority of references state by far the oil heat is from the shearing action of being pumped into tight spaces under pressure to be sheared and chewed on then spit out, trading its heat carried away for the heat of metal friction that would otherwise develop and stay put. Going by info collected here so far, apparently our oil only gets combustion heated in the portion flowing though the exhaust rockers. That is only like 1/6 of total pump output at a time gets degradingly hot. There is a time element as well as temp factor on how bad this is to the oil, very hot a short time may not degrade as much as if all the oil was not quite as hot but all the time.

As to the thickness differences of steel tank vs Al cases and the temps involved, its about a wash because once each is heat soaked through then its back to pure surface area ridding the most heat. If thick enough to act as insulator to outside then its thick enough to be its own massive heat sink, never getting hot enough to conduct very fast to outside, same as say a 5 gallon oil tank might never get hot enough to cook off moisture or activate its additives. In long enough steady state of course even massive heat sinks get above ambient to rid heat produced inside.

In data logged Peel I'll diddle oil thickness while watching pressure and temps. I have a sense she'll like thinner 40 grade best, for a little more heat absorbing by thinner fluid and a little less friction pumping and circulating inside stuff.
Shrapnel's dragged me into his camp > not to use 30's weight in our clunkers.

A few years ago I had become concerned about the temperature in the tank on my Commando. I contacted Spectro Oils and had a lengthy conversation with a petro-chemical engineer from Spectro about oil temperatures. What is all gets down to, according to the engineer, is oil has a temperature operating range. Not too low, nor too high. Its been years and I kept no records, but I believe I was measuring temperatures somewhere in the 230º-240ºF range in the tank after high speed freeway runs. I live about 50 miles from Daytona Speedway on Interstate 95 and I usually put the whip to the old gal on the way to the races. The Spectro engineer was concerned temperatures above 230ºF was marginally too high. We discussed oil coolers. He cautioned about using a cooler without a thermostat. Based on his information I installed a Lockhart cooler with a Lockhart remote thermostat. I reduced the the high temperature by about 20°F.

Like has been said here before, oil temperatures reach a much higher temperature in places other than the oil tank. I'm not a petroleum expert, but I think the concern about lubricating oils is the flashpoint. As I understand it, once the flashpoint is reached the lubricating quality is severely diminished. I guess this is where synthetics are superior to dino oils, as synthetics have a higher flashpoint. As has been stated by others, there are ways to keep oil temperature down: larger oil reservoir, cooling the tank, etc. I guess it all gets down to practicality. For me the most practical solution was an oil cooler with a thermostat.

hobot said:

As to the thickness differences of steel tank vs Al cases and the temps involved, its about a wash because once each is heat soaked through then its back to pure surface area ridding the most heat.

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Wrong......................again.

Thickness is a significant factor. Do some reading on thermal conductivity.

Thanks for a frosty day wake up with heated attitude Johnny Shredder. I ain't disagreeing that heat will flow faster through thinner material be it a heat conductor or a heat insulator. I've made fires in thin containers that became essentially transparent so could see each lick of flame against the wall brighten and dim as it leaped and retracted in real time nil delay. In the thickness we are dealing with in our cycles though its about a wash that mainly depends on the surface area exposed to the heat and cooling differences. Best would be lots of thin surface area though there is still something to be said for just plain ole massive heat sink to stablize temps and even out hot spots. I'm in your camp a thin oil tank in the wind is a good heat idea but then so is a thicker wall tank with even more surface area like Peel's OIF. Here's article on heat flows that covers this nicely.

http://203.158.253.140/media/e-Book/Eng ... 3_ch03.pdf

john robert bould said:

Nice to chat about these things, stay lucky and keep the shiney side up

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I like to think it is more than luck: keeps me thinking I am in control and I will be safe. :lol:

I thought for a bit that this thread was going nowhere, but now I realize it has helped me come to the conclusion that I should put a blanket around my oil tank.

Thanks!

Russ

I asked what I thought was a simple, basic question and it started ALL OF THIS!
I have learned better than to ask questions anymore!!

Vince

Unclviny said:

I asked what I thought was a simple, basic question and it started ALL OF THIS!
I have learned better than to ask questions anymore!!

Vince

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Yes, but at least you got answers to your question, along with all the rest. Hey, it's not a perfect world.

Ken

Unclviny said:

I asked what I thought was a simple, basic question and it started ALL OF THIS!
I have learned better than to ask questions anymore!!

Vince

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Some of the best threads here have come from just such a humble beginning. I don't know if this thread will qualify, but I really have decided to put a blanket around my oil tank after thinking about some of the posts here. There is a lot of worry in general about hot oil but I bet I am not the only guy who rides in cool temperatures. I really think my bike will benefit from warmer oil. I am already designing a neoprene sleeve that can be put over the oil tank and easily removed should I get lucky enough to ride in warmer temps. A digital thermometer will become a standard part of my kit, right along with my tire gauge.

Russ

Viny.....keep im commin!...these debates keep the old grey matter in tune.

john robert bould said:

Viny.....keep im commin!...these debates keep the old grey matter in tune.

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+1 That's the outlook!:

This custom-Commando has made me do "mental gymnastics" many, many times.
I had to redesign the electrical system around the horn (it draws 5.5 Amps!) and figure out how to wire in the LED's and the non-standard switchboxes but with help http://www.arman-publishing.com/bcat.htm (the second book on the page) I am sure that I've got it.
Adapting Boat parts, Car parts, stuff from the Model-shop and non-Commando stuff has been fun and interesting.

At this point I am knee-deep in studying coatings, I need to "dechrome" and refinish the handlebars (the last Chrome-bit on the bike!) and at this point they are probably going to be Parkerised.

Vince

Until I got used to Nortons real normals while montioring I too thought they got too hot to quickly too. Some do some don't but how do ya know w/o a thermometer unless seeing milk shake in tank or smoke outside. If your insulation sleeve works very well it may have to stand boiling temps so hope it don't melt onto the tank. I've two reports now of rod bolt failure both showing about half the diameter darkened by corrosion following the granular crystal interfaces till popped then took out the other bolt that showed bright new fracture face all the way across. This was an oxidative failure not a tensile strength failure or faulty manufacture. Of course old rods and re-used bolts are risky business even with dry new oil, but in back of mind I wonder if moisture pushed over the threshold as my bolt sat up a couple years exposed inside shed before re-use with new nuts. Here's a blip on too cold of oil running besides just harder to start and get oil to parts inside.

http://www.eng-tips.com/viewthread.cfm?qid=177525
A co-incidental cause is that if the oil is real cold, the engine internals are also cold and clearances might be so far out from suitable running clearances that damage results, eg, piston to bore is to big and the pistons slap hard enough at WOT high rpm that they crack the skirt off behind the oil ring grove.

That's why most recommendations today are to start driving slowly as soon as the engine is started. Warming the engine for several minutes wastes gas, can dilute the oil and pits a warmed engine against still cold and stiff parts.


http://www.jalopyjournal.com/forum/arch ... 23677.html
There is actually more friction in a motor that is 20 degrees too cool,
than one which is 20 degrees too hot.
The oil needs to get above 210F as soon as possible,a 190 thermostat should do the trick.

well known saying " the more you find out, the less you know" and boy doe's this forum re-inforce that :!: :lol: After joining this excellent forum ,i can now confess to knowing "Bugger all" about Norton Commando's. Each post leaves many questions, and there i thought Nortons "where just" a simply twin cylinder motorbike....
Lets hope Stephen Hawkins doe'snt join,we would well and truely be STUFFED!...His post" Commando sub-atomic construction,and evolution". Now where's my Haynes Manual.

Naw Hawkins would be bored to tears on our oil temps but would perk up on what is revealed in quantum indeterminacy of hydrogen and ionic bonding plus Van derWalls force resonance of tire rubber hysteria and its interface with surfaces that has direct application to the mystery of land and under sea slides that run out way way further than current science can account for friction wise, once a fine enough device in the form of an isolastic Commando that don't mimic too flexy clunkers or too rigid diving boards is experienced. So what should we seek as the mean average of oil in tank temps that's not 20' F too cold nor 20' F too hot?

Yeah, I'd say "just right" is about right. FWIW...the neoprene jacket may be a bit of a problem regarding continuous temp rating, but I figure it will be the easiest to use to discover whether it makes any difference at all. I suppose I could dig out some of my exhaust wrap and turn the tank into a mummy. It is about 33 degrees here right now. I need a little more melting before I hit the road to test it out.

Russ

Russ I'm very interested in your feedback on tank insulation experiment and oil tank mayonnaise. In you Arctic condition the wet suit material is safe as Neoprene melts at 250 degrees. This will give us a sense of how much the oil tank is worth in cooling oil. The tank shape matters too as oil stored further from walls, thick or thin can't dump their heat till stirred a while. There is more air flow between cover side of tank that battery side so might have to remove cover and see what might stuff behind it and sitll close up. Cold crank cases definitely help cooling oilanyway and yours definitely in cold breezes. I don't guess a case diaper appeals to try? No one will believe you it ain't d/t leaving dropping where ever stopped.

Hot oil and you may still get Mayonnaise in the filler neck and cap of the oil tank.

Two separate things here.

One is maintaining a suitable oil temperature in cold weather riding. This is a simple test that can be conducted and checked with a thermometer. The other is avoiding or eliminating Mayonnaise (water/oil emulsion) from forming. With the later I suppose insulating the top of the tank and filler neck would help prevent it from forming. You could have plenty hot oil but the venting/return oil to the tank will more than likely form the white goo if the filler neck is sufficiently cold.

I recall getting the white goo forming when I road the 850 Commando in the Northeast US in the cold weather.