Oil Cooler

Well, Since the cooler is on there, I will leave it there. But I will find some sort of thermostat or by-pass valve to install soon.

Thank you all for your comments, it was most informative.

How many Nortons have clapped out valve guides with less than 20,000 miles? Not to mention flat cam lobes, low compression from piston ring/ cylinder wear. I figure the Norton does not have the advantage of today's superior metallurgy and today's machining, so it can use the help from an oil cooler.

Study of oil and Norton Twins gives following data points to consider wisdom of oil cooler unless in unusual extremes of very dry air riding up hill with the wind behind. You can not over heat a Cdo sitting still and idling unless you insulate it from all air and convection. Heat only goes up to matter with increased mixture burning

OIl cools about 6% of engine hetat, most of that is flash heated over 300'F in the thin spaces it passes, if its thin enough to get in and out in time to matter. Oil cooler will not effect this flash heating at all. You can not expect cold oil to make measurable difference in engine temperature and even engines designed for oil cooling fell out of favor as rather ineffective. Cooler worth while if oil is getting into 3-400' F range in the tank.

Thin oil carries off heat better than thicker oil.

ZZDP only forms protective layer called nano pads, when oil temps get to boiling range and wears off from engine parts cool below that. If you don't get oil near boiling temperatures you might as well not bother about ZZDP.

ZDDP is a surface modifier that alters bearing and journal surface characteristics to prevent metal-to-metal contact. Under conditions of increased
heat and pressure, the ZDDP molecule quickly plates over the contact surface with an extremely thin glass-like film and provides a sacrificial coating. As soon as the engine conditions get back to normal, the film dissipates back into the oil solution. This action prevents the lifter and cam from making contact and greatly reduces the tendency of parts to scuff and gall under heavy-loaded boundary lubrication situations.

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ZZDP works best in the 1000-1300 ppm concentrate, more is not better.

ZDDP is most effective if the concentration is between 0.18 % and 0.2 % by weight. Tests have shown that concentrations above this amount, up to as much as several percent have no effect except to prolong additive life.

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Any moonshiner knows it take essentially boiling temps to cook out moisture in one's life time.

Until it is mixed with motor oil, ZDDPlus™ has a tendency to absorb moisture, not unlike brake fluid. Absorption of water will degrade its performance; however, the ZDDP can be restored by slowly heating to a temperature slightly above 100C.

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So if oil temperature don't get close to boiling temps then moisture remains to form corrosive acids and the ZZDP protection is prevented. ZZDP mainly protects on cold starts and when engine and oil gets really hot for the Norton crowd.

I may be mis-led on my understanding so please set me straighter on it if ya can.

300 to 400 in your tank and your motors toast, Maybe some should read this: http://www.reiffpreheat.com/Article-Visser3.htm
:wink:

Hobot states that thin oil carries away heat better than thick oil.
He may be right from his reading research, I don't know.
But, why then shouldn't we all have say a straight 30 weight in motor if it carries heat away better than 50 weight?
Why would Norton then not recommend a thinner oil?

Those living in very dry climates do not see any or very very little water or condensation in their oil.
There is nothing to "burn off" and so no need to get the oil real hot.
If one lives in such a climate and has say a maximum sunday one way ride of no more than 30 miles, the oil does
not very hot. In such a situation based up the comments, there would no legitimate need for an oil cooler, correct?

"You can not over heat a Cdo sitting still and idling unless you insulate it from all air and convection. Heat only goes up to matter with increased mixture burning"

I'm calling bullshit on that one, Hobot. I burnt up a Commando head riding in a Christmas parade in Brevard County, Florida. This was a head with less than 10,000 miles on it. The many prolonged stops got my bike so hot it quite running. After cooling it restarted and I rode it directly home. When I pulled the head, metal had transferred from the seats to the valve faces. Guides were shot as well. Compression was below 100 psi in both cylinders. Needless to say, I don't ride in anymore f'in parades anymore with my Norton. I have a water cooled BMW for that kind of nonsense.

1up3down said:

Hobot states that thin oil carries away heat better than thick oil.
He may be right from his reading research, I don't know.
But, why then shouldn't we all have say a straight 30 weight in motor if it carries heat away better than 50 weight?
Why would Norton then not recommend a thinner oil?

Those living in very dry climates do not see any or very very little water or condensation in their oil.
There is nothing to "burn off" and so no need to get the oil real hot.
If one lives in such a climate and has say a maximum sunday one way ride of no more than 30 miles, the oil does
not very hot. In such a situation based up the comments, there would no legitimate need for an oil cooler, correct?

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Because the factory specced the oil based on the native climate. Ask Frank how much time he spent testing the bike outside the UK. :mrgreen:

ONLY reason not to use straight weight oil is people are usually too un-attentive to put in the proper grade for the temperature of the season and then mainly its just to pick it thin enough to start and flow right away. New Multi grades are a good thing as can flow ok cold or hot over wider temp variation.

i spoke with a thermal heat exchanger engineer about oil grade and heat absorbing and transfer capacity to verify thinner oil like water works better than thicker oil. Oil grade in our engines needs to be thick enough for the engine heat not to thin it so much it can not develop-maintain the hydrodynamic oil wedge parts surface on.

I'm as tempted as anyone one to run oil cooler on stock Combat in summer but especially so on developing big blown Peel. Yet I've about run Peel out of oil d/t filter loosening to make rear squirrel-y as I tested leaned traction before actually hitting serious tight spots, pulled over to see oil line on hwy and oil way down low in tank. I'd say more than half lost so maybe a qt left. Used road trash to screw filter on and then rode back watching oil temp at bottom of tank to see it stayed exactly same as when full of oil at 55-60 mph, 125'F. hm good but hm just how much heat was oil really pulling from engine and what would I gain by a cooler if oil was not entering engine as hot as we like our showers in low 140's F zone.

There sure ain't nearly enough head oil flow to matter a Whitworth there, I've seen it spray out inlet and out lets and its too meager amounts to significantly cool head. Yet there is ~3 gal/hr oil through head @ 6000. I'll bet a couple 100 watt light bulbs might get 3 gal too hot to touch in an hour.
I did some napkin calculations IIRC stock Cdo can burn like 60,000 btu an hour.

Main reason there were oil cooled engines was because water cooled froze.
I've read up to 60% of air cooled fin engines is via oil like aircraft. Maybe with special oil passages but I don't feel our cdo tanks are shedding 45,000 btu an hour.

I fear too cold of oil than too hot is all.

Hobot, personally I can't think of anything worse for a air cooled engine than to sit idling getting hot with no air movement.

Yet you maintain the opposite, that no harm is done.

Please provide link, your credible source for your contention.

Also, now that you will have your Commando running again, will you be running a thinner oil than recommended
because this thermal person told you that thinner removes heat in a Commando oil better than the specified grade?

Thanks in advance

If I were to take a guess, what you aren't taking into account is oil composition technology and metallurgy. In the 50s and 60s in order to get the kind of performance from the oil to protect the metal of the day the factory decided on the 50 wt.

Nowadays with much better metals, engines run much higher tolerances, which in turn require thinner oil to get between the parts. And you need a better oil to put up with the stress, which are available.

So in sense Hobot is correct, but he forgets one factor: We are dealing with old motors, using old metal and old tolerances.

Which is why I used 50 wt old. :mrgreen:

I am the link 1up. Ms Peel had dual CHT, daul EGT and oil temp 1" off tank bottom. I parked her idling out side my clinic window mid July high noon on cement full heated pad, next to wall so I could peer out and watch the meters while idling 1000 rpm in direct sun light about dead still air to see highest head temp 250' F, highest EGT 950'F, highest oil temp 100' F. After over half an hr stable and cool I got on her and careful oh so careful eased off the pad to road and gave least amount of throttle to roll and saw all temps begin to rise. Coolest Ms Peel ever got was sitting still at real road use idle. Later I flipped the two dual scale gauges under the bars for sleeker view from side but still fine view of their faces, same with mirrors.

hobot said:

I am the link 1up. Ms Peel had dual CHT, daul EGT and oil temp 1" off tank bottom. I parked her idling out side my clinic window mid July high noon on cement full heated pad, next to wall so I could peer out and watch the meters while idling 1000 rpm in direct sun light about dead still air to see highest head temp 250' F, highest EGT 950'F, highest oil temp 100' F. After over half an hr stable and cool I got on her and careful oh so careful eased off the pad to road and gave least amount of throttle to roll and saw all temps begin to rise. Coolest Ms Peel ever got was sitting still at real road use idle. Later I flipped the two dual scale gauges under the bars for sleeker view from side but still fine view of their faces, same with mirrors.

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What was ambient temperature and relative humidity? Best guess if you don't know.

What I have seen agrees with Hobot's findings.

Different story if the engine is freshly rebuilt, they will get too hot in a few minutes.

No there is definitely not enough oil circulation in the right places in a Commando engine to do any real cooling. The only place the oil is exposed to real heat is in the head and it moves slowly and sets there long enough to get too hot and oxidize but the quantity is so low it does not raise the overall oil temp very much nor does it remove much heat from the head. Jim

Ok Hobot, again you know more than "conventional wisdom"

Because you think it, then it must be true. And seemingly the more controversial and more challenged by virtually everyone else on this forum, you are your own "credible link" for your expert source.

Just like you state that a single Mikuni will develop more horsepower than a twin carb set up

Just like you state now that no harm can come to an air cooled Commando motor under prolonged idling when there is no moving air flow.

Just like you state now that a thinner weight than recommended engine oil is better for our Commandos.

You are indeed your own best source.

I reported what I experienced and measured on past Ms Peel and referenced reasons for not jumping on oil cooler wagon, if ya don't believe me then fine. I await your better reports on testing back to back various mods and oil levels and temps please.

Same standard 750 head: with dual Amals and race needles got CHT 375, EGT 1300, oil temp 180 and speedo 125, Miki carb gave CHT 425, EDT 1375, oil 195 and speedo 135+. Miki could supply more to burn, dang it as I don't like their looks.

I could rooster on THE Gravel easier with dual Amals than Miki carb but Miki carb pulled harder longer. Ignorant me thinks it may be d/t the 34 mm throat flowing more than a 32 mm at hi rpm and bit better velocity of the 32 mm on lower rpm. The split manifold sure didn't seem to hinder the single much as that is claimed a down side. Now Daul Amals feeding a single manifold might reverse my results.
At first I was pleased by dual Amals better response but had me fooled until I hit pavement.

swooshdave said:

If I were to take a guess, what you aren't taking into account is oil composition technology and metallurgy. In the 50s and 60s in order to get the kind of performance from the oil to protect the metal of the day the factory decided on the 50 wt.

Nowadays with much better metals, engines run much higher tolerances, which in turn require thinner oil to get between the parts. And you need a better oil to put up with the stress, which are available.

So in sense Hobot is correct, but he forgets one factor: We are dealing with old motors, using old metal and old tolerances.

Which is why I used 50 wt old. :mrgreen:

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The reason straight weight oils were recommended was because multi-weight oil would break down in an air cooled motor. The reason they would break down was they used VI improver or "spin additive" to make the base stock into a multigrade oil. It was this additive that would break down causing the oil to fail. Oil is no longer refined using the old process [mud pack] and no longer use VI improver so multigrade breakdown is no longer a concern except with low quality base stock oils. Many of the heavy duty oils refined today using the hydrocracking method use no additives at all to pass as a multigrade. Jim

What was ambient temperature and relative humidity? Best guess if you don't know.

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Swooh I know because I was testing for this. The idle test and top speed runs to heat were July in low 101-103's F and 55% humidity, miserable to ride as air heated me not cooled me off. My jacket with zip vents opened provided shade and some relief when inflated but not much. I stopped worrying about Peel over heating but had to stop now and then or faint. We are approaching those melting conditions and pissed me off that Trixie is so delayed as its not any fun to ride and get that hot so more riding life missed. Only good thing is the mostly naked gals on the big cruisers turning a nice inflamed
red. Also only time I can stand to get in our big spring feed creek.

1up3down said:

Ok Hobot, again you know more than "conventional wisdom"

Because you think it, then it must be true. And seemingly the more controversial and more challenged by virtually everyone else on this forum, you are your own "credible link" for your expert source.

Just like you state that a single Mikuni will develop more horsepower than a twin carb set up

Just like you state now that no harm can come to an air cooled Commando motor under prolonged idling when there is no moving air flow.

Just like you state now that a thinner weight than recommended engine oil is better for our Commandos.

You are indeed your own best source.

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Not really sure where this is going. Dunno that I agree that I agree with Hobot 100% of the time, but he certainly comes up with wisdom/good advice a goodly proportion of the time. We really don't need to attack one another, do we?

Not completely in my camp yet huh, well keep ya boots on and helmet handy.
Everyone knows idle is the worse state for an engine short of initial start up. Only thing I tested and report here under this subject is it sure ain't heat damage at idle nor anything a cooler can help with, its blow by gases and low oil pressure and slow surface translation speeds w/o oil wedge surfing that should be going through your mind sitting in traffic jam, not the heat waves and oil vapors. Heck if ya tried to cook a meal on idling Cdo it'd be a health hazard not a roast on the roll. Ugh its also too cool oil exposed to the most moisture from combustion blow condition the engine will see. Outside humidity is not a factor.

Oil temp near bottom changes with throttle with ~30 sec delay. It took scary transmission bush consuming WOT HI rpm with squids that had just sneered at my old rig before they took off to teach me to stay in my quaint obsolete world hehehe, poor dangerous corner cripples didn't know how to react soon after : )
But once we split I turned home and held mild 80-90 cruise, oil temp went from 195 to 165 in 3 min. Oh yeah the scary part wasn't out running new 600's on scrubbed fat tires, no sir, it was flying into blinds in sharps and over crests in loo loo land Ozarks. 120 I'd commute on back then gave 175 in oil tank.

CHT changes within a few seconds or so and EGT only lags throttle within a second by needle gauge.

Only got so much surface area in fins so only extra cooling can be gotten by more air flow faster or making it denser and linger longer by ducting &/or spraying a coolant on the fins. Piston crown hot spots can be tamed by oil jet, if about double the pump capacity sprayed at it. As mentioned by Jim S. alcohol or water ingested helps even more.

If you look up what engine industry considers hot oil that needs cooling we talking about upper 300 to 450' F not merely boiling 212'F zone worried about.

So oil additive chemistry needs 200+ heat to work, also to rid moisture during a ride as formed, there just ain't enough oil flow nor surface exposure to be an effective all over coolant and where it does get to over heat range ain't a dang thing we can do about it but change the oil often enough.

Here's some fascinating reading on similar heat energy issues as ours.

http://www.supercoolprops.com/articles/gwhite.php

Getting back to the thermostat issue...... what would be the optimum operating temperature for the engine oil? I am assuming by the responses that somewhere in the 180 to 195 mark should provide a nice stable temp that will burn off contaminants while allowing ZDDP additives to do their job properly, partiicularly in the head.

Opinions Please?