E: Engine Vincent pilgrim pump in comparison

[Martyn Goodwin]

Tell the guy, it`s funny how some bikes managed to do hundreds of thousand miles with that useless pump, 750,000 in one case, and it still sported the original timing side main bearing.

Bannanaman told me of this mod years back. The oil pump itself relies on lubrication via an oilway in the timing case. On many motors this 'hole' is way too small. Open it up to at least 1/4" - the ONLY way oil can get to it is via splash. Take usual precautions regarding swarth.

 

[vibrac]

Ron Kemp added a alloy sheet gutter round his

 

[Little Honda]

Bannanaman told me of this mod years back. The oil pump itself relies on lubrication via an oilway in the timing case. On many motors this 'hole' is way too small. Open it up to at least 1/4" - the ONLY way oil can get to it is via splash. Take usual precautions regarding swarth.

View attachment 29232

if you open up the hole too much (thin oil), you shall produce bubbles in your return pipe, so weakaning
the valve mechanisme supply. So, think twice, before you start drilling.

 

[Peter Holmes]

Perhaps Phil Irving got the drilling diameter correct, I would assume he didn't just simply guess what it should be.

 

[ClassicBiker]

if you open up the hole too much (thin oil), you shall produce bubbles in your return pipe, so weakaning
the valve mechanisme supply. So, think twice, before you start drilling.

I don't see how. It is merely a dribble hole, it isn't under any pressure what so ever. It merely allows oil to splash on to the scroll and pinion of the oil pump. The oil being sent to the valve gear is impulse and not a constant pressure. This is evident when looking at the return in the tank, it spurts out intermittently rather than a steady stream as if constant pressure. Most dry sump systems are designed with the return from the sump having a volume greater than the feed side, that way oil does not collect in the sump. Any oil that splashes up there will drain back to the sump as it passes roller bearings either side of the scroll. I very much doubt a larger hole here will have a detrimental effect to the feed to the valve gear. I would caution about going too large as it is in the radius of the bearing housing area and very near the inner main bearing race.
Steven

 

[Little Honda]

Good reasoning, Classic Biker. The pulsing effect is normal for any two stage pump, as you say, that the return
volume has always to be larger than the supply volume. But these pulses come from the lowest point of the
crankcase, where a dry sump has to be maintained under any circumstance.
If you look at your splendid drawing above, you can see, that the feed hole has been designed in a stepped form, with reduced inlet bore to the larger collecting diameter. Widening the collecting cone would probably
easy feeding the pump, but widening the reduced diameter will possibly reduce the short moment of suction
by the piston of the pump which is needed to collect the oil around OP31- worm, which should be fed with
oil only, as on top of the reduced diameter should always be full oil coverage, so keeping up suction to the
collecting point in the crankcase and not adding air volume from a second point.
As this hole has been bored by a chosen drill during machining, I am convinced, that PEI put some thought
into it.
Somewhere in his books, he mentiones, that they used to have glass windows on the timing cover, to observe
the lubrication process on this side of the engine, when they eventually observed sparks with MKII cams at
the time.
If there is too much air in the return line, not only too much oil remains in the engine, so producing overheating, but also at some time an overflooding in the drysump, when the engine starts oiling
at a very sudden for seemingly no visible reason. Worn cams and spindles not only result from wrong
positioned feed holes in the spindles, but from some other reasons, too.
My starting question related to many complaints in MPH about the pilgrim pump, PEI was not
amused about, writing a comment in MPH or somewhere else - which I do not remember, as it is too long ago -
where he listed feed rates and pressure figures of other oil pumps in contemporian engines, showing
competetive figures for the chosen design. This pump is more than sufficient for both Vincent engines:
Twins and Singles. The oiltank is very effective as an oilcooler, visible during winter, when it is difficult
below zero degree figures, to achieve operating temperatures, asking for stuffing the airspace between oiltank and fueltank.
All said only for the original design. Irving Engines are a different matter.

 

[Marcus Bowden]

Yes a splendid drawing indeed and choice of colures, I use to love looking at ships drawings and various pipe systems all in different colures but todays presentations leave a lot to be desired with black lines with bunny hops when passing over another pipe.

 

[ClassicBiker]

Good reasoning, Classic Biker. The pulsing effect is normal for any two stage pump, as you say, that the return
volume has always to be larger than the supply volume. But these pulses come from the lowest point of the
crankcase, where a dry sump has to be maintained under any circumstance.
If you look at your splendid drawing above, you can see, that the feed hole has been designed in a stepped form, with reduced inlet bore to the larger collecting diameter. Widening the collecting cone would probably
easy feeding the pump, but widening the reduced diameter will possibly reduce the short moment of suction
by the piston of the pump which is needed to collect the oil around OP31- worm, which should be fed with
oil only, as on top of the reduced diameter should always be full oil coverage, so keeping up suction to the
collecting point in the crankcase and not adding air volume from a second point.
As this hole has been bored by a chosen drill during machining, I am convinced, that PEI put some thought
into it.
Somewhere in his books, he mentiones, that they used to have glass windows on the timing cover, to observe
the lubrication process on this side of the engine, when they eventually observed sparks with MKII cams at
the time.
If there is too much air in the return line, not only too much oil remains in the engine, so producing overheating, but also at some time an overflooding in the drysump, when the engine starts oiling
at a very sudden for seemingly no visible reason. Worn cams and spindles not only result from wrong
positioned feed holes in the spindles, but from some other reasons, too.
My starting question related to many complaints in MPH about the pilgrim pump, PEI was not
amused about, writing a comment in MPH or somewhere else - which I do not remember, as it is too long ago -
where he listed feed rates and pressure figures of other oil pumps in contemporian engines, showing
competetive figures for the chosen design. This pump is more than sufficient for both Vincent engines:
Twins and Singles. The oiltank is very effective as an oilcooler, visible during winter, when it is difficult
below zero degree figures, to achieve operating temperatures, asking for stuffing the airspace between oiltank and fueltank.
All said only for the original design. Irving Engines are a different matter.

I disagree with your assessment. It is not a feed hole for the pump. It is merely a hole that allows splash lubrication to access the worm. It does not feed oil to the return plunger. If it were the return pickup then the oil level in the crankcase would be over the main shafts, definitely a case of wet sumping. There are several threads here on the forum discussing modifying the lubrication system with a Honda pump. The modification is also outlined in the data bases https://www.vincentownersclub.co.uk/resources/a-new-oil-system-for-vincents.1708/. It is from these threads that I have taken the following images. Which show where the scavenge pump draws oil from to return it to the tank. In the data base and thread I took these images from, both take pains to explain that the modification draws oil from the same place as the standard pump, inside the crankcase not the timing chest. Again I re-iterate that hole plays no part in the oil scavenge. It does not feed the return plunger with oil. It merely allows splash lubrication of the worn gear.
I can not take credit for the illustration in my earlier post. That comes from www.thevincent.com .

 

[Simon Dinsdale]

Also the hole in question was only introduced in 1948 from engine number 375 onwards. Earlier engines had no hole at all and it was introduced to allow better lubrication of the oil pump worm to plunger area. As classicbiker explains it has nothing to do with the return pump operation and just directs oil running down the crankcase wall towards the worm on its way down to the sump.
I have just recently had to drill the hole in a 1947 engine whilst rebuilding it as advised in the Paul Richardson book.
Simon

 

[Vincent Brake]

Silly conversation here.