Fluids

74 MKII Commando


I know...I know....this has probably been a hotly discussed topic ever since the beginning of the forum.

I searched previous threads, the best I know how.....it gets very high tech and beyond my needs for more power, racing etc.

I have my original charts in the original owners manual, but this is 38 years later, and options sure have changed.

For an average rider doing average riding, in average Canadian conditions (yawner eh!) I was just wondering if Mobil fully synthetic 20-50 is OK to use for engine?

I know it's all about personal preference, but I just want to know if this alright to do. I didn't do a rebuild on the egine, just took it all apart to check it all out.

Thanks for your thoughts

OH, NO, an oil thread. You should be good with any oil you prefer. Some is better than none. Some seem to prefer the high zinc, and the Valvoline VR-1 (not synthetic), comes in 20W50 and also straight SAE50 and has the high zinc, I use the SAE50 but am thinking about going to the 20W50. Of course since it's racing oil, it's not for street use. YMMV.

Dave
69S

Tnx Dog T. and I guess high zinc might be a good thing so why not do it!

Chester ,you are a Canuck like moi ,so good luck trying to get the Valvoline VR1. I plan to drive to the National and pick it up on the way back and huge amounts of discount booze for my own lubrication and leave the taxman behind in Canada. I've used Mobil 1 Synthetic and found it leaks out of gaskets/seals quicker. But once I fitted the Mikes XS reed valve most leakages vanished. It's all good. Try to find some V. in Toronto. I have money. Whew.

Yeah, I put some synthetic on an old compressor motor and it leaks it out like a sieve. Personally, I'd stay away from the syn with the antique bikes unless you are really wanting to use it. I'm sure it's good, but you better have a really tight engine and good breather. If you need the Valvoline VR1 and can't get it, I'd be glad to send it, it just may be a bit pricy with the shipping, it's rather expensive, even just to buy, as I remember it's maybe around $6 a quart. The local auto store in my neck of the woods has it. CAN may have regs that don't allow it, don't know. I change it maybe a couple times a year, and that's not expensive at maybe $12 a change. Peace of mind.

Dave
69S

Thanks Dog T , will pick some up Vermont Stateside , Zinc is a badass metal like horrid - lead in fuels, here in Canada ,we legislate everything to death ,but I agree with it in the long run. My understanding is that Zinc will render your catalytic converter useless. My Beemer has a catalytic converter !

I think that's why they call it 'racing oil'. You don't want to use it in a modern car with catalytic converter. Yeah, get it in VT, but don't tell the TSA what you have, much less the CAN guys, they wouldn't know anyhow. I guess we have to live with this issue now.

Dave
69S

I like the VR-1 50w for the ZDDP content in my 850.
I run VR-1 30w in my stroker VW engines.
Both are flat tappet engines.

I had a cam wear issue with a Web camshaft I was running in my Combat. I called Web and spoke to the owner. She asked what oil I'd been using. When I told her Mobil 1 she got very agitated. While she was a proponent of synthetics, she had nothing good to say about Mobil 1. BTW, she did replace my five year old cam for $100.

The other thing I would say about oil and Nortons, they benefit greatly from the addition of an oil cooler. The oil that passes through the rocker boxes in the head takes a real beating from heat. IIRC, some who have done testing reported temps in the 450º F range. Those kind of temperatures render any oil less effective if not cooled quickly. According to an engineer I spoke to at Spectro Oils, the oil temperature in the tank should not be higher than 220º F. He thought a 180º-200º temp in the tank would be ideal. He also warned about too cool temperature, as well. Need to boil off moisture. Hence, the need for a thermostat.

An oil pressure gauge and a meat thermometer in the oil tank will tell you a lot about what's happening to the oil in your Norton.

Oil in my tank after a 50 mile run is 195° F. No cooler.

Dave
69S

There is some good reading in the tech section here:

http://www.zddplus.com/

I particularly enjoyed the section on pre-WWII engines.

Oil in my tank after a 50 mile run is 195° F. No cooler.

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That's great.

My observations have been that oil temperatures in the tank vary widely, dependent upon ambient air temperatures and speed at which you are running. On a hot 90º+ day running at freeway, 75+ mph, speed for 60 miles pushed the temperature way over 220º F on the meat thermometer I was using. Other times with an air temperature of 60º or so, running in town, the oil temperature never got above 165º F. I wouldn't take the meat thermometer temps as a true measurement, but I would definitely say the oil temperatures vary greatly. All said and done, I feel that the oil cooler is well worth it.

Yeah, I don't go out in the heat. Most of my riding is done below 80F and very little interstate riding. I measured the oil temp in my tank with my Fluke 189. I'm pretty sure it's accurate. I should measure the head temp sometime. I measured the surface of my wood stove with it last winter and it was well over 500F.

Dave
69S

Sadly I am not being successful in copying text from the documents mentioned above. The free Adobe Reader has its limits.

But the article on how hot is very interesting, but the conclusion is based on the oxidation of the oil after a test period. This is only part of the problem. If you go to this article:

http://www.zddplus.com/TechBrief14%20-% ... ngines.pdf

and read the section under the heading "Path of force..." on page six, pay particular attention to the second to the last paragraph on that page where it talks about cams and non-roller lifters in classic engines. Read it...there is some really good stuff in there.

Basically you need to find oil with a rating of SF through SH (or equivalent levels of zinc) or add ZDDP to a modern oil.

Russ

Dave,

The Fluke is probably a wee bit more accurate than my made in China meat thermometer.

When I was checking oil temperatures for a few weeks, I got to thinking of all the top end and camshaft issues I've had with air cooled British bikes over the years. I figured most of these could be chalked up to poor lubrication. It was then I contacted Spectro Oils who confirmed my suspicions about poor lubrication in my Norton. The engineer I spoke to, at length, was familiar with older British bikes and highly recommended an oil cooler. When I considered the fact that most modern air cooled bikes run oil coolers, I hung one on my Combat.

BTW, is that a Combat you tested? A higher compression engine is going to develop more heat than a lower compression engine of the same version.

Do you just put the thermometer in the oil tank ?

Thanks much for the offer to send the V Dog T.
I end up in Grand Forks and Fargo a fair amount and do some shopping for...well...the other fluids as well.
Anyway I'm guessing somebody should have some down there.

Do you just put the thermometer in the oil tank ?

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That's what I did. Bought a rubber bottle stopper to fit the oil tank fill opening, drilled a hole in it and inserted the meat thermometer. Harley-Davidson sell something similar, although, I don't know the size of their oil tank fill opening.

FWIW, temps below 176 degrees F inhibit the ability of zinc additives to protect your cam and followers. So for a guy like me who lives in a cool climate, I would benefit more from a heater in the oil tank than an oil cooler.

Of interest:

Castrol Edge Sport 25W-50 has an API SG rating and has Zinc content of 0.116% maximum and Phosphorous content of 0.106% maximum. Attached is the media release for the Castrol Edge Sport 25W-50 and below is some information as discussed with one of our customers regarding ZDDP content of engine oils.

"Further to our discussion regarding flat tappet cam wear and ZDDP, we contacted one of our technical guys in Australia and he explained to us that the Castrol Edge 25W-50 went through some rigorous cam wear tests, done by a guy who specializes in modifying cams etc, he tested over 30 to 40 different oils and the Edge 25W50 was one of the best oils in cam wear protection performance.

He also discussed the use of diesel engine oils, which has more ZDDP, in this particular application and he pointed out that although some diesel engine oils do have more ZDDP they also have a lot more detergents, which compete for the surface area as well. Tests were also done with a diesel engine oils which had high Phosphorous and these oils had worse cam wear results than oils with lower Phosphorous.

As discussed with Neil the most important factor when running in engines is that the oil must not be cold, the oil needs to be about 80 degrees Celsius or above to get the zinc anti wear additive activated, at low temperature the zinc anti-wear additives are not fully activated and this causes the cam to have metal to metal contact resulting in wear on the cam. Also, running the engine at low idle also causes extreme wear to the camshaft, the engine should run at around 2000rpm and the oil needs to get to around 80 degrees Celsius. Engines should also not run too high initially this will add increased load on the cam which would result in wear .On assembly of the cam you could also apply a light film of moly grease (SBX 2) to the cam lobes so on the first few revolutions of the cam it has lubrication on the surface. The first 10-15 min is the most critical, so you would need to run the engine at fast idle between 2000-2500 rpm and the oil temperature needs to get to at least 80 degrees Celsius."

There is no doubt that oil temperatures can be too cool. Of course, you have to consider that the temperature of the oil in the tank is not indicative of the oil temperature throughout the engine. I do think a thermostat is necessary if you use an oil cooler. My suspicion would be that the oil temperature on the cam lobes is sufficient to activate the zinc during normal running, even when tank temperature is below 176º F. No doubt, at start-up, the oil temperatures are way too cool. I suspect that's the reason for the recommendation of not dropping below 2,500 rpm during a new camshaft break-in. That new cam would probably benefit greatly from preheated oil for the initial start-up.