Engine oil cooler

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Agreed, Slick but I’d prefer to cool the head’s oil and the head. How about increasing drainage capacity at followers?

As I understand it the rocker spindles oil might be re-clocked to allow more flow, but that assumes that the oil pump can keep up, holding psi at the crank.

I don’t know enough about the internal architecture to picture how the lirocker box floor might need modification or how lifter area might be modified to allow more drainage
 
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xbacksideslider said:
Agreed, Slick but I’d prefer to cool the head’s oil and the head. How about increasing drainage capacity at followers?

As I understand it the rocker spindles oil might be re-clocked to allow more flow, but that assumes that the oil pump can keep up, holding psi at the crank.

I don’t know enough about the internal architecture to picture how the lirocker box floor might need modification or how lifter area might be modified to allow more drainage
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Increasing drainage at followers will not likely change any flow dynamics at the floor of the rocker box where the thin film of oil is in contact with the hot surface off the head.

I do not know if oil pump can keep up, but increasing flow to rocker box can be simple as drilling a small hole into the side of the rocker box and feeding this orifice with a "tee" off the rocker supply line.

Re: rocker box floor modifications. Someone who is obsessed about this issue would have to study a bare head to work out a plan of attack.

Is oil degradation at head really a problem? Consider these factors:

1) oil smokes at 250 +/- deg. F. The smoke is degradated oil.
2) oil flashes (spontaneously bursts into flame) at 450 +/- deg. F if oxygen is present.
3) the floor of the rocker box temp is estimated to be as high as 450 F.
4) oil does not likely reach 450 F .... if it did, we would have fire if we ran our engines for any length of time with a rocker cover removed.
5) oil may reach smoke temperature, but with rocker box covers in place, the vapors in the sump and by extension, the rocker boxes, are blow by gasses and are not likely to have much free oxygen, particularly if a one way breather is in use.

Now ....., if oil reaches 250 F, but no oxygen is present, will it smoke? Will it degrade? I do not know, but these are questions worth investigating before one is obsessed with solving a problem that may not exist.

A thermocouple probe inserted in the oil drainage path of an exhaust rocker box would answer the question of oil temperature. Good quality hand held VOMs have temp. function if one is fortunate to have one, or is willing to shell out $150 for one to find out.

Perhaps there is a chemist or lubrication engineer out there who can answer the questions I posed above more definitively than me.

Slick
 
How about this for an ‘outside the box’ oil cooler location...

Engine oil cooler
 
My bike came with nice vents cut into leading edge of oil tank side covers front and rear .... wonder if it was meant as an oil cooling aid , looks similar to some older Ducati’s I’ve seen over the years , must admit I like the look , and curious if any benefit ....
 
Craig said:
My bike came with nice vents cut into leading edge of oil tank side covers front and rear .... wonder if it was meant as an oil cooling aid , looks similar to some older Ducati’s I’ve seen over the years , must admit I like the look , and curious if any benefit ....
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In my old workshop manual it has a last chapter section for high proformance moderfcationns it tell you to cut slots in the side of your side covers front and back of the side cover so cool air can flow over the oil tank to help reduce heat, but they also recomend using a oil cooler up front as well, this section in my book helped me to build my engine for my hot 850 Featherbed way back in 1980.

Ashley
 
I only got the pic off t’internet, I’ve never seen the bike.

Yeah, the cooler looks to be in an odd position for sure. But as John Britten showed, air flow THROUGH the bike can be extremely useful. I don’t know what’s in front of this cooler, if it’s blocked, I can’t see it doing much, if not, it might just work like a Britten !
 
I fitted a Hyde 'bottle brush' oil cooler 20-odd years ago because, when I'd occasionally ride my Commando to work and back for a change from the train, when I got home and checked the oil level a wisp of smoke would curl out of the tank. That never happened after fitting the cooler, bottle-brush style or not. It fits between the front down tubes, in front of the engine. Actually I ordered a cooler and thermostat per their listing, but was told that the thermostat was discontinued. When the weather's cold I wrap aluminium foil around the cooler, it helps. I'd still rather have a thermostat, though.
 
Here is what I have found trying to use oil to help Norton head temps.
I have gone as far as installing large supply and scavenge pumps in the magneto position in an attempt to reduce engine and cylinder temps.

The stock Norton pump does not have anywhere near enough volume to appreciably affect the cylinder head temp.
Suzuki attempted engine cooling with oil in their early GSXRs. Their pumps supplied >20X the volume of the Norton pump and they used oil jets in the head. They had a large radiator for the oil. The results were poor and overheating was a common problem around the racetracks.

When I used a large pump and jets to supply large enough amounts of oil to help the head and barrel cooling on a Norton I ended up with too much oil in the crankcase to be able to scavenge it. The design and volume of the crankcase is such that even with scrapers on the crank the extra oil would be caught up in the windage of the crankshaft and then I could not get it back out of the crankcase without dropping the rpms down to around idle for a period.
Running the engine even for a short period with oil caught up and being whipped by the crankshaft resulted in the oil being overheated and burned.
Even a 10 X 12 X 2 inch radiator mounted in place of the front number plate could not control the oil temps.
I eventually gave up on this idea.

The best I have done is to cool the oil supply to the head which resulted in a small drop in head temp.
If you increase the oil flow through the head you will end up with very high oil temps.

So after all the work trying to help cooling with extra oil I found it was a waste of time.

Now I am in favor of supplying just enough oil to the head for lubrication.

With reasonable rocker arm to spindle clearance enough oil can be supplied through a very small orifice.

I do not use a restrictor in the overhead line on my streetbike [although I suspect it would help with oil life].
Cooling the oil with a cooler in the overhead line does reduce the amount of oil supplied to the head due to viscosity. I have found this is an advantage.

I did end up using a .010" jet in the overhead line on my racebike. That supplied all the oil needed and helped keep oil temps under control. I also did some work in the exhaust spring seat area to help get the oil to drain better.
 
About time Jim!

Seriously, thanks for sharing your insights. It sounds like the Norton head is ‘happy’ enough running at a temperature above what ‘seems’ ideal. Your tests with increasing oil flow seemed to show that rather than extra oil cooling the head... the head overheated the oil.

Certainly not what I’d have expected. But I’m glad you tried it and shared it!

I’ll leave my oil flow well alone. But I will endeavour to fit the cooler into the rocker feed as I’ve been planning for a while now. I already moved the coil out of the way to make room for the cooler. Just gotta finalise a bracket design for it etc. I think the 920 motor is just the motivation I need to get this done!

Jim, what are your thoughts on double feed versus single feed for the rockers (with modified spindles)? I like the idea of a single feed as I’m a simplicity fetishist, however the oil has a longer path to travel with only one feed, getting heated along the way. Is this an issue, or am I over thinking things again ??
 
Fast Eddie said:
About time Jim!

Seriously, thanks for sharing your insights. It sounds like the Norton head is ‘happy’ enough running at a temperature above what ‘seems’ ideal. Your tests with increasing oil flow seemed to show that rather than extra oil cooling the head... the head overheated the oil.

Certainly not what I’d have expected. But I’m glad you tried it and shared it!

I’ll leave my oil flow well alone. But I will endeavour to fit the cooler into the rocker feed as I’ve been planning for a while now. I already moved the coil out of the way to make room for the cooler. Just gotta finalise a bracket design for it etc. I think the 920 motor is just the motivation I need to get this done!

Jim, what are your thoughts on double feed versus single feed for the rockers (with modified spindles)? I like the idea of a single feed as I’m a simplicity fetishist, however the oil has a longer path to travel with only one feed, getting heated along the way. Is this an issue, or am I over thinking things again ??
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I have drilled the intake spindles on every Norton I have owned and eliminated the external crossover.
Then I use the extra hole in the head for an oil pressure gauge.
 
So after all the work trying to help cooling with extra oil I found it was a waste of time.
--------------------------------

I have not experimented with cooling. I did ride my 72 Combat 5500 miles to the west coast of the United States back in 1973.
Across the plains at 75mph with temps constantly around 90 all day long, across Death Valley at night temps at 100.
No engine problems whatsoever. Being 21 years old I was too young and dumb and no one told me I should worry about my oil temp.
 
comnoz said:
I have drilled the intake spindles on every Norton I have owned and eliminated the external crossover.
Then I use the extra hole in the head for an oil pressure gauge.
Click to expand...

Good enough for me Jim! Thanks again.
 
comnoz said:
I have drilled the intake spindles on every Norton I have owned and eliminated the external crossover.
Then I use the extra hole in the head for an oil pressure gauge.
Click to expand...

also works on pre commando top feed?
 
I’ve owned an oil cooled GSXR 1100 since ‘86 and that idea - oil/air cooling- was eclipsed by water cooling simply because of water’s far superior ability to exchange heat. That design - air/oil cooling - was a last gasp effort to avoid the weight and complexity of water/oil cooling.

The next gen “water” cooled engines made more power by cooling their heads better - with water and oil.

My water cooled 2008 Honda CBR, for instance, does use substantial internal oil cooling - under piston jets and under valve cover oil flows to help control detonation. It’s oil is then cooled by way of a water cooled heat exchanger that dumps the oil’s heat into the bike’s huge radiator
 
Hummm...
It might not be the place for the following solution in our highly competitive world, where adding this and that looks to be the rule, but... would lowering compression be a good way for lowering oil temp? :D:D:D


mdt-son said:
Another idea of mine is to create an artificial aluminum oil pan / oil cooler designed as a heat sink and a flat plate welded together after creating a suitably large cavity inside. Fittings would be screwed or welded to the flat plate.
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I tried this once on another motorbike air cooled 1000cc engine:

Engine oil cooler


Adding more than 52% of the stock oil capacity, temperature lowered from 140° to 130° celsius only. IMHO not worth it. Like it was mounted on an off road bike, I finally took it off because of the loss of ground clearance.
 
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Yes it would.

As would sleeving it down to 500cc :D

And fitting a rev limiter capped at 2,000rpm :D:D

But seriously, yes you’re correct. As has already been discussed, a standard tune Commando ridden modestly, in all but hot climates, probably has little to no bennefit in fitting a cooler.

The further one goes from that, the more a cooler appeals.

My motor is gonna be 920cc with over 10:1 CR and is gonna spend a lot of time in the higher rev ranges. It’s asking a lot of a head originally designed for a 500 low CR ride to work bike !
 
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