ET: Engine (Twin) Engine Oil

[Monkeypants]

Oils with very high amounts of zzdp additive ( zinc) did not produce good results in the scar testing.
Jim Comstock was forewarned about that by a Petroleum Engineer whom he interrogated.
Several Norton owners were using a very expensive Redline product that boasted 2200 ppm zzdp, almost twice as much as VR1. The Redline went to smoke very easily.
VR1 was far from the best oil tested, but it did do quite well and it doesn't cost a lot. That tends to encourage one to change the oil fairly often, always a good thing.
If I was located in the UK I might use Castrol Classic XL 20/50. It also tested very well and is reasonable in price.

I recall that the worst oil tested was AeroShell, a special blend for flat tappet small aircraft engines, Cessnas and the like.
It went to smoke as soon as pressure was added to the arm. That means it offered virtually no protection to engine internals. Bad enough for an old motorcycle engine, but what a scary thought for an aircraft engine. When I read on small aircraft forums, many are experiencing premature cam failure and worse. I wonder if the specialty oil is the problem.



Glen

 

[fogrider]

One of the factors that made me favour a 10/40 was the Amal 170 jet on the way to the cams and followers.
The quill has plenty of holes in it to bias oil to the crank bearings. But if you imagine a funnel, full of cold heavy oil, slowly bleeding down into a bowl via that tiny jet.............? Which , of course , relates to the 15 mile warm up to thin the oil a bit. It just strikes me that the slightly thinner 10/40 has the advantage of somewhat quicker circulation.
It's an opinion , I'll be paying for the damage if it does'nt pay off !

 

[Tnecniv Edipar]

Vincent engines don't get the oil upto operating temp very quickly, especially in moderate climates, and the oil tends to run relatively cool, like it's doubtful you would see much more than 80-90 deg c, even in a warm climate. So, a multigrade is advisable, so that cold start circulation is achieved as soon as possible, as most engine wear occurs at cold start. Also, as oil change intervals are quite frequent, synthetics aren't any advantage, especially considering the low specific output and low revving Vincent engine. I've had very good experience with Penrite and Motul. My choice would be Motul 3000 4T, 20w50, high spec mineral oil at API SL, much better than the so called classic oils which tend to be API SG, which is an 80's rating, and at a good price.

 

[Monkeypants]

Motul had two oils in the " oils that might cause damage in a Norton Commando" category.
Penrite had 1.

Motul 300v 20W60 Le Mans synthetic was tested and did poorly. The second Motul in that category was a break in oil.

Penrite conventional 20/50 also performed poorly.

Motul 3000 4 t 20/50 wasn't tested, it could be excellent.

Glen

 

[fogrider]

I remeber an article about oil in one of the main-stream motorbike adds, sometime in the 90's. After all the technical stuff, the journalist asked the oil expert how to be sure he was buying the best oil. The answer was -
"The one with the advert that impresses you the most"

 

[vibrac]

I know for years I have been accused of being biased on Castrol R
now I really am....

Castrol Classic Oils | Sponsorship

www.classicoils.co.uk

 

[Tnecniv Edipar]

Motul 300V synthetic Lemans is an automotive oil, as in cars, so maybe not well suited to the Norton.
The 3000 4T is a motorcycle specific oil. My Velo likes it as does my Ducati 750 S bevel twin.

 

[chasbmw]

I will be using the Motul 3000 in my Bevel Ducati

 

[Tnecniv Edipar]

Being pragmatic about this, I suppose we have to remember the Tony Rose test, during which he was using Filtrate with colloidal graphite, if memory serves. Not knocking Filtrate products from that time but they would have been utter cr4p compared to modern lubricants but that Vincent survived with minimal wear, so I suppose any modern, motorcycle specific oil of the appropriate viscosity would be totally ok.

 

[Monkeypants]

The older oils had fairly high zinc content which worked well to protect the cams and followers. In the 1990s, zinc was found to destroy an expensive new component, the catalytic converter. Oil companies slowly reduced the zinc levels to find a level that let the catalytic converters live but still offered enough protection for ohc motors. Flat tappet engines weren't part of that plan and they suffered. I don't believe that all modern oils are good enough for these old engines.

Glen