Oil cooler

Thanks Ken ..... good info and easy to understand
Craig

Cooler or no cooler? Go for a hard ride and stick a meat thermometer in the oil tank. If you are still undecided at that point, seek out an petroleum engineer.

JimC said:

Go for a hard ride and stick a meat thermometer in the oil tank. If you are still undecided at that point, seek out an petroleum engineer.

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Now THAT is pragmatic. It really gets down to problem definition.

For those interested, do a search on optimum oil temperature and maybe even bound it to search pertaining to air cooled engine to see what you come up with. A rough summary is:

at or below 180 F - too cool.
180 F to 210-220 F - decent range and favor the higher end
220 F to 250 F - tolerable
250 F to 280 F - something is wrong and/or in need of an oil cooler.

The more time you spend at or below 180 F the more damage you do to the engine due to:

Running with moisture and oxides that form as a result of moisture
Not having low enough viscosity to report to critical areas.

To the best of my knowledge, Norton big twins were never sold with oil coolers and from my observations and temperature measurements on various Norton applications, the stock Nortons do not need them. There may be some extraordinary circumstances where an oil cooler may be desirable on a Commando as I mentioned in my previous post and Ken elaborates on a particular application with his race bikes. Even bumping compression up and/or tweaking the fuel/air ratio may push one into an area where an oil cooler would be desirable.

It would be interesting if LAB or anyone else can reference factory recommendations for oil temperature.

http://www.inoanorton.com/docs/OilTemp.pdf

I found the article above in regards to some testing done on multi grade oils used in the Commando. It refers to operating temperatures and breakdown in regards to a few different brands of oil. I'm no expert, but have always preferred straight weight oils in my motorcycles as well as a cooler. Years ago before you could buy an oil cooler, we would go to the local junk yard and get a Ford power steering pump cooler. They worked great for $5. I feel it depends on your riding conditions and habits, but if you don't have one, it sure won't be there when need one. I run coolers on my 74 850 Norton, 96 Harley 80". and 69 Triumph 650, no thermostat. If it is obviously a cool day, just put a cover on it. It's really not rocket science. Just warm your bike up as you usually do, and handle it accordingly. Your bike will love you. Yes, there are preferable operating temperatures, but being unknown, I'd rather run a little cooler than have thermal breakdown. Change your oil often, it's a lot cheaper than rebuilding your motor. All this being said, if you ride your bike for 25 miles at a clip on Sundays, do the recommended road speed, and only in 70*F weather on the open roads, you don't need an oil cooler. I ride hard, in all types of weather. Full throttle. Below is a link to some inexpensive power steering coolers which can be modified to accommodate the Norton, or you can spend a few bucks $80-$200 and get a Sifton/V Twin or JAGG vertical mount cooler which mounts to the down tubes. Both, as well as the power steering pump coolers should work with 3/8" hose, the vertical mount coolers should have the hardware to mount to a 1" down tube.

http://www.jegs.com/p/Derale/Derale-Pow ... 8/10002/-1

NORTSTER1974 said:

http://www.inoanorton.com/docs/OilTemp.pdf

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The author collected some interesting data but with a critical review, It really does not make a case with technical merit for an oil cooler.

An oil cooler with a thermostat is fairly benign. I ran an oil cooler on my 850 with a Drouin supercharger (w/o thermostat) back in the day because the instructions recommended it and I can concur that it was a smart choice. I have raced an ultra short stroke with and without an oil cooler and determined an oil cooler was not necessary. I campaigned (raced) two Commandos with out oil coolers (one is a Combat) For several seasons without a tear down and rebuild. The list goes on.

The key is to get the oil warmed up to an adequate temp as soon as practical. The adequate temperature range is known and quite broad. Excursions into to the very hot zone are typically far and few between unless your Norton is hauling an airstream camper uphill out of Death Valley in the summer time.

For those who are contemplating an oil cooler, Do the research on recommended oil temps and take some oil temp readings or just install a cooler with a thermostat.

Keep in mind that the Original Poster on this thread is from Norway.

Thought I'd provide some, albeit limited, empirical data to the discussion regarding oil temperature.

The machine: 1974 Norton 850

The test: 100 mile run (30 to 70 mph)

Weather: 70F

Oil tank temperature: 170F

Oil used: Redline 20/50 Synthetic

I have done this test twice now, same mileage, same weather, same results.

pierodn said:

Please,
could you explain the oil line to mount an oil cooler, with or without oil filter.
Thank you.
Piero

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Ircken tells how to route lines for maximum heat removal:

" Running the oil lines below the engine helped keep the system reasonably simple. The flow was from return port on the engine, to the cooler, to the filter, and back to the tank."

This route delivers hottest oil to cooler, and provides maximum temperature difference between ambient air and the oil, resulting in maximum heat transfer.

Slick

The real issue though is whether an oil cooler is needed. I'd say in most situations that an oil cooler is not required on a Norton.

cNwRestomod said:

The real issue though is whether an oil cooler is needed. I'd say in most situations that an oil cooler is not required on a Norton.

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The original post was answered by Ircken, I gave the technical reason why. This thread has morphed into a discussion of whether an oil cooler is needed. My thoughts ....

1) The stock Norton engine does not need an oil cooler. I rode across the desert, leaving Needles CA with the temperature at 114 F (45 C). The Atlas took it, I couldn't. I had to seek shade and wait for sundown.

2) Back in the good old days, when fuel was 100% gas, and oils were usually single grade, it made sense to cool it a bit, especially in hot climates. With alcohol absorbing water, and multi-viscosity oils with additives, an oil temp near 200F is optimal. Thus if one runs a cooler, a thermostat would be recommended.

3) A modified Norton engine, or one used to race, can benefit from a cooler. I have made some calculations. Depending on the area of the cooler, a 20 to 30 degree F temperature drop can be obtained, and the oil will dump about 5 1/2% to 8 % of the heat to satisfy the engines cooling needs. As stated in 1), the stock Norton is not running so close to seize-up that 8% more cooling is essential, but race engines may be pushing it.

4) All Nortons have an oil cooler. Oil is cooled in the oil filter (if one is fitted), and then it resides in the oil tank for about 2 minutes before it is recycled to the engine. Steel oil tanks have a large surface area and will lose a lot of heat to the air in two minutes. The Norton oil pump has a capacity of about one liter per minute at 3000 rpm, the oil tank about 2 liters, do the math.

Slick

Also worth mentioning is the heat loss through the aluminum crankcase and timing chest that is hanging out in the breeze.

The real issue though is whether an oil cooler is needed. I'd say in most situations that an oil cooler is not required on a Norton.

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I don't know about racing

but I do personally believe that an oil cooler on a Commando is not only not necessary but may even be harmful(without a thermostat) in not allowing the oil to get hot enough to burn off condensation on shorter rides

unnecessary - I have twice loaded up my Commandos and taken off on month long trips across the United States without bothering to hook up an oil cooler

day after day after day....75mph on US Interstates in mid summer with temps in the 90s and averaging 400 miles a day, around 4000 miles each trip, no overheating, no issues of any kind, period

from my own experiences, adding an oil cooler is totally unnecessary, just another source of potential leaks, and a solution to a problem that largely does not exist

My 1973 850 came with an oil cooler on it that the previous owner had installed. My friend is an expert on nortons and he has ridden the same commando on the road every year since 74. He looked at the oil cooler and asked " did the previous owner live in Arizona?"

I ride mostly in Michigan so it was promptly removed. I do prefer the look of the bike without it. I am interested to try the food thermometer in the oil tank after riding to know what my temperatures are like. Thanks for the idea

Trialbyfire said:

My 1973 850 came with an oil cooler on it that the previous owner had installed. My friend is an expert on nortons and he has ridden the same commando on the road every year since 74. He looked at the oil cooler and asked " did the previous owner live in Arizona?"

I ride mostly in Michigan so it was promptly removed. I do prefer the look of the bike without it. I am interested to try the food thermometer in the oil tank after riding to know what my temperatures are like. Thanks for the idea

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The oil temperature in my Commando was just fine, or so I thought, until I measured it. After monitoring oil temps, I installed a cooler and thermostat.

For those of you who steadfastly claim there is no need for an oil cooler on a Commando, I ask: Do you think there is any connection between things like abnormally high piston ring/cylinder wear, abnormally high valve guide wear and high oil temperatures?

[quote="lcrken"
This is the Lockhart cooler in the final form of the bike, when it was in AMA Pro-Twins configuration. Running the oil lines below the engine helped keep the system reasonably simple. The flow was from return port on the engine, to the cooler, to the filter, and back to the tank.

Ken[/quote]

running the lines underneath cleans things up immensely, what modification did you make to the oil inlet/outlet bracket to do the 180 deg discharge ?

As a Norton Commando owner since 1971, I can guarantee that unless you live in the Sahara desert (maybe even then), an oil cooler is an unnecessary complication. It won't hurt except for the additional potential sources of leaks, but it won't help. I installed one on my 1971 Commando, Chevy Corvair oil coolers were available from Chevy dealers back then and fit nicely across the down tubes, and it did not make any difference in terms on engine longevity compared to later Nortons that I owned, including my current 1975 MK 3.

yes, I remember Peter Williams fitted a Corvair oil cooler to his 1973 Isle of Man record breaking Commando victory winner, averaging over 105mph for the entire race

IIRC, aftermarket oil coolers used to come with an inline thermostat that would only open when the oil got to a certain temperature and would thusly hold the oil at that temperature minimum to prevent over-cooling. The oil (and the engine, for that matter) needs a certain amount of heat to flow properly (and to run efficiently), so running a direct-line, always-on oil cooler may not be the best thing for the machine.

montelatici said:

As a Norton Commando owner since 1971, I can guarantee that unless you live in the Sahara desert (maybe even then), an oil cooler is an unnecessary complication. It won't hurt except for the additional potential sources of leaks, but it won't help. I installed one on my 1971 Commando, Chevy Corvair oil coolers were available from Chevy dealers back then and fit nicely across the down tubes, and it did not make any difference in terms on engine longevity compared to later Nortons that I owned, including my current 1975 MK 3.

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I'd be interested upon what you base your statement that a Commando has no need of an oil cooler. Did you actually do any oil temp measuring? Before and after cooler installation?

Hi JimC,

As you may have noted, I posted some data a few posts ago on this site (170F) and that tells me that an oil cooler isn't necessary. I'd add that some of the best in the biz (cNw, NYC Norton, etc.) also do not offer nor do they install oil coolers on their bikes so I would say that they are not warranted. If they were, Matt Ranbow and others would be installing them and you can be assured that's a safe bet as Matt stands behind his rebuilds. I can't imagine that he be anything other than confident without an oil cooler as opposed to sending out a freshly built machine knowing that it won't last long because it has no oil cooler. That said, I intend to monitor the oil tank temperature over the summer months when temps. reach into the 80's and I'll post more data at that time.

Cheers, Bryan

I don't know that the increase of oil temp is linear to and directly related to the increase in ambient temperatures, but I'll guaran damn tee you running at sustained high speeds in +80º F will get the oil temp over what is recommended by a Spectro petroleum engineer. I base that on personal experience. If you have an oil pressure gauge you will also notice a drastic drop off of oil pressure at idle after a sustained high speed run in high ambient temps. From 10 psi to 0-2 psi.

For years, Nortons ran without an oil filter. Now hardly anyone will run a Norton without one. The fact that some Norton builders choose not to install an oil cooler doesn't mean it would not be beneficial to have one.