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2 start oil pumps

Puddle jumper

Well Known and Active Forum Website User
Non-VOC Member
Hi guys,
What are the views on 2 start oil pumps or changing the oil pump for a gear type pump,
Also, what about fitting valve oil seals?
Cheers Paul
 

bmetcalf

Well Known and Active Forum Website User
VOC Member
Gear pumps for post war Vins are very rare, except for an auxiliary Honda pump those wonderful Froggies came up with.
 

John Appleton

Well Known and Active Forum Website User
VOC Member
Hi guys,
What are the views on 2 start oil pumps

If the standard oil pump was known to have shortcomings then I would be the first to change it . However, they dont have, so stay as standard and enjoy the ride. Valve stem oil seals are a different matter altogether. Fit them and slash oil consumption, eliminate one cause of oil smoke, improve idling by reducing air ingress at inlet valve stem, improve plug life and cold starting and again, enjoy the ride.
John
 

Len Matthews

Well Known and Active Forum Website User
VOC Member
Two start Oil Pumps came about when the Factory was developing the Picador engine. That had to run flat out continuously, something a bike rarely does. For all practical purposes the standard pump is perfectly adequate. One useful idea some riders have adopted is to fit a filter in the return line to the tank, bearing in mind that what the scavange side of the pump picks up from the bottom of the crankcase may be full of you-know-what. A magnetic drain plug is a must. Installing a gear pump would be a major engineering task although I think it has been done. Beneficial or not? Comments please.
 
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Tnecniv Edipar

Well Known and Active Forum Website User
VOC Member
I'm not so sure about the oil pump. One of the reasons modern engines are so durable is the high rate of oil flow generated by efficient gear or lobe type pumps. I've always been curious why PCV went for the ancient type of pump he did. As far as I can determine it could be a weakness of the Vincent , they seem to have issues with cam wear , valve train wear and the oil takes an age to heat up which shows that circulation is slow. Correct me if I'm wrong though , those with more experience may be able to prove my view to be incorrect ?
 

bmetcalf

Well Known and Active Forum Website User
VOC Member
The roller main and rod bearings only need a small quantity of oil and would actually fail if given oil at the pressure and flow a modern high performance engine delivers. I assume that PEI put some good thinking into the plunger pump that was selected, since the pre-war bikes had a gear pump and they didn't stay with it.
 

Tnecniv Edipar

Well Known and Active Forum Website User
VOC Member
I know that roller bearings use less pressure, but it's flow I'm talking about. The bevel cam drive Ducati's have a roller bearing big end and ball bearing crank , but they use a high flow gear pump , pressure is less than 15 psi.
 

clevtrev

Well Known and Active Forum Website User
VOC Member
Two start Oil Pumps came about when the Factory was developing the Picador engine. That had to run flat out continuously, something a bike rarely does. For all practical purposes the standard pump is perfectly adequate. One useful idea some riders have adopted is to fit a filter in the return line to the tank, bearing in mind that what the scavange side of the pump picks up from the bottom of the crankcase may be full of you-know-what. A magnetic drain plug is a must. Installing a gear pump would be a major engineering task although I think it has been done. Beneficial or not? Comments please.
Not quite right Len. The Picador ran a two start worm wheel on a single start pump.
 

Puddle jumper

Well Known and Active Forum Website User
Non-VOC Member
Hi Guys

How about this for an idea, fit a 2 start pump, valve stem oil seals and feed the rockers from the main side of the pump, not on the return side, giving better flow to the cams which need all the oil they can get, via the rockers, push rods ect. Then fit an oil filter to the return side before the oil reaches the tank.
Feeding the rockers from the pressure side of the pump is Steve Hamel's idea, not mine, sounds good to me,
What are your thoughts guys.

Cheers Paul
 
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