OP: Oil Pump A nice Ulimate Engine

[Vincent Brake]

Roller bearing cranks do not need lots of oil, especially too much pressure. But the cams and followers do........The stock feed system to supply these is hopeless. A better set up would be to direct flowing oil at each cam lobe and follower. I even thought about making some kind of trough or bath under each cam so that it consonantly rotates in a bath of oil, just like how modern OHC engines have their cams in the head that run a a bath of oil. You look at these modern engines with high mileage on them and the cams look like brand new. The cams and followers on a Vincent are way too small and this does not help. The other trick is to make up some "squirter nozzels" that direct an oil jet directly at the cam/follower like how the Horner's did to their Goodwood bike. The other trick they did was to run a vacuum pump on the engine to eliminate any breather issues that also plague these engines, that is one part of their bike that no one notices.

I have heard that Triumph did that also at some point, but the airflow arround the cams cleared out the oilbath.....

 

[greg brillus]

I didn't know Triumph's were that fast ..................

 

[vibrac]

Yes the oil bath empties as soon as the revs build I seem to remember someone trying this on a Vincent and quoting this in an MPH.
I believe one of our number is trying a plain big end project at the moment with additional oil pumps

 

[greg brillus]

Just as a point of interest, when I spoke to Ken Horner about the nozzles he installed between the pushrod tubes to supply oil to the cams/followers, he said that they did it from the oil return line rather than from the oil pressure side. It is hard to say, but I would have thought the pressure side more logical and also a quicker supply verses the scavenge side of the system. I think the position and the direction of these oil jets is very important as to whether it actually works well or not.

 

[greg brillus]

Getting back to the "Oil bath theory" remember that generally it is at cold start up that cam and follower wear would be at it's worst. I think we pretty much all agree that a lot of lubrication for the cams/followers on these engines come from the return oil down the pushrod tubes. So when you start the engine, it is generally a few seconds before any oil is seen going back to the oil tank, and this time is critical to highly loaded parts like the valve train. I think this is where an oil bath would be of benefit, when we talk about racing it is unrealistic to expect an engine to survive the same as we would on a road going machine. I don't believe it takes radical changes to improve the oiling system in a Vincent engine, but the cams and followers need all the help they can get.

 

[vibrac]

That is interesting Greg you are right. At the start that's when lubrication is needed, but do you think that after the engine stops there is enough 'drip' around to refill the baths?

 

[Vincent Brake]

yep always filling in oil through the valve adjusting caps is a bit cumbersome... allthough i do do it after a mounths lay up, as well as the cranck, i take it from the sump

 

[ernie]

If you have a wet sump you could use the scavenge side as the main feed.

 

[Marcus Bowden]

Forget about oil baths, more hassel than it's worth, just try fitting it, the cam must be in position, so to bolt it to the c/case wall under the cam the cam wheels must be drilled to get the screwdriver in to fix !
Pressurize the cam /cylinder rail.
When I start up there is two bar (30 p.s.i.) {no p.s.i. gauges on my ship} after twenty mile it's a steady one bar. All from a Honda pump. If it fails the jet holder that limits oil to cam is fitted with a 4 mm ball bearing that acts as a non return valve, failure of Honda pump, pressure (small if at all) from underneath opens valve to supply oil to cams.
My MK II cams have done nearly 300 k miles and had measurable wear after the first 100k then 1990 Herve' Hamon fitted the Honda p/p and negligible wear since.

View attachment 17395 View attachment 17395
THE CAM SPINDLES HERE AN OLD ONE A DAMAGED ONE ONE PREPARED FOR FITTING AND A NEW ONE. SOME SUPPLIERS DO NOT DRILL FOR EXHAUST CAM LUBRICATION. FIT EXTRA BUSHES SO OIL IS SQUIRTING FROM EXHAUST LOBE HOLE.
NOTE NOT ALL CAMS ARE DRILLED ON THE LEADING FACE,AND CAM FOLLOWERS TO BE WITH OUT HOLE IN FOLLOWER FACE AS IT WILL WEAR A NIPPLE ON TO P OF LOBE,

 

[stu spalding]

If you have a wet sump you could use the scavenge side as the main feed.

And use the gearbox as the oil tank as, I believe, Clem Johnson did on "Barn Job". Cheers, Stu.