E: Engine Oil Viscosity

stu spalding

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I heard of the Harley objection about 30 years ago, whether it was fact or myth, I've no idea, but at the time it made sense, bearing (sorry) in mind that a roller is always skidding to a minute degree anyway. Cheers, Stu.
 

clevtrev

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Harley recommends their own brand of synthetic oil for trans and motor. I have heard of roller bearings "skidding" but never found a definitive technical article. Is it a synthetic myth?
All you need to do is think a little. AS the bearing rotates the rolloes touch on different places on the pin and the eye, so no way can they possibly rotate as one might expect. They are jumping from one point to another so hence the skidding. It`s all about geometry, rotation and force.
 

stu spalding

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All you need to do is think a little. AS the bearing rotates the rolloes touch on different places on the pin and the eye, so no way can they possibly rotate as one might expect. They are jumping from one point to another so hence the skidding. It`s all about geometry, rotation and force.
The circumference of 1" pin is 0.785". The circumference of a 1.5" bore is 1.767". Any 1/4" rollers in there have to skid sometime. Cheers, Stu.
 

clevtrev

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VOC Member
All you need to do is think a little. AS the bearing rotates the rolloes touch on different places on the pin and the eye, so no way can they possibly rotate as one might expect. They are jumping from one point to another so hence the skidding. It`s all about geometry, rotation and force.
Sorry about the typo`s
If you want proof of what happens, find someone who has really worn a big end down, you will find square rollers.
 

Martyn Goodwin

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Sorry about the typo`s
If you want proof of what happens, find someone who has really worn a big end down, you will find square rollers.
I had a set of square rollers! In my case the pin itself had not been hardened 'correctly' and the rollers wore a trench in it. Then with the extra room the pins were quickly hammered into a square profile - all happened within 100 miles of first start up after the 'new' non-hardened big end was fitted.
 

chankly bore

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Non-VOC Member
Hi All, I'm getting my first Vincent next week:) but now wondering what oil should I use. As my knowledge of oil only runs to virgin or sunflower.....
Never run-in a sunflower; as to the other, my favourite American mechanic e.e.cummings wrote a beautiful poem starting "she being Brand-new; and you know consequently a little stiff". Recommended reading.
 

Black Flash

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VOC Member
I have been reading all oil information I could get hold of and from what I learned the zddp content is the thing to look out for when it comes to wear protection.
I have phoned up a few companies like Liqui moly in Germany, multi lub, Fuchs oil etc all the readily available brands here in Germany as they rarely state the zddp content of their oils on their websites. Highest zddp was 1200 ppm on a Miller pistoneeze oil, the best [cheapest] of Liqui moly oil had 800 all the rest was about 600 to safe the life of the catalytic converters.

Now in the old days up to 1400 were more or less the norm. So I bought zddp additive to add with every oil change. It is quite cheap especially in the states and gives me a peace of mind.

As for oil thickness. I had an old Suzuki 4x4 which used a lot of oil. So I topped it up with what I had.
When I had used up all the straight 40 I still had. I thought it was time for a complete oil change. When replaced with the proper 15W40 I was gobsmacked about the cranking speed of the starter and the idle of the engine even at moderate temperatures.
That change made a huge difference and totally unexpected the car also used a little less petrol as well. Obviously as I only used it for short trips only.
Bernie
 
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