OP: Oil Pump Quill

timetraveller

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A lot of the quills I have taken out show signs of more wear on one side than the other suggesting lack of perfect concentricity between the main shaft hole and the hole in the timing cover. However, that does not seem to cause big end failure. What does cause that on every original design Vincent or Alpha big end I have worked on it the annular groove at the timing end of the crank pin. Dirt in the oil centrifuges out of the oil and fills up this groove until such time as the oil cannot flow into the big end and it fails. It is possible that the combination of modern oils and paper filters might have solved this problem but I am not sure.
 

Bill Thomas

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There is always a bit of rubbing Bruce, So hard to say how much is too much ?.
Like I said if it feels OK to ride, I would leave be ?.
 

Peter Holmes

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When we all use to swear by Filtrate graphited oil, I think I purchased my last can from Ron Kemp, but with the benefit of hindsight, I think it was said that the graphite could centrifuge out of oil anywhere where that the oil flow was also spun, and once it had built up sufficiently it could cause blockages. Never did with my bike though. One only has to see the oil filtration system on a Honda CB72/CB77 to see what a centrifuge can achieve, zero filters of any kind, just a round canister that spins very fast as the oil passes through it, it is incredible what it removes from the circulating oil.
 

Bill Thomas

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My first reaction is that the Flywheels have shifted. Soon the mains will walk, then you'll hear the sound change.
Morning, I would be interested in your thoughts about Twin main bearings,
What do you think about lipped mains, Is it too much of a Bodge ?,
Knowing the weakness of the cases,
I do not like the idea of a plate and small screws,
We did a Comet some time ago for a friend, And somebody ground a huge pair of flats in the outer !,
We had a hell of a job getting it out !.
Cheers Bill.
 

timetraveller

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Bill, you probably already know that the original drive side inner main bearing was thinned down for Vincents. If the spacer between the inner and outer drive side mains in thinned down at its outer edge a full width inner bearing can be fitted. This gives more area to stop the bearng walking inwards. Additionally, if the work is done carefully, there should be no problems with putting either flat strip or large headed screws in to prevent the bearings moving.
 

Bill Thomas

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Yes Norman, I know of this, Funny I bought some lipped bearings for my next job,
Whatever that will be ?,
And also a thinned alloy Spacer !!,
So that won't work :) ,
I helped Big Bill Telfer with Lipped bearings, On His Twin,
Just wondered what Dan thought of it .
Cheers Bill.
 

oexing

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Nothing exotic about lipped roller bearings, I did just that with metric types in the HRD. A plain outer race is pure silliness and we all know what that does ! The problem in the times of Vincent production was possibly the non-availability of lipped outer races in imperial sizes ?? Lipped outer roller races are standard in many engines and I like them a lot for ease of assembly , no string magic around rollers with the original setup for slipping the lot into non-chamfered outers.
As the crank is pretty wide I control lateral position between lipped roller bearings on the drive side, with a real seal in between bearings. The outmost bearing has a plain inner race and the lip is either an extra part from FAG for roller bearings or you do a special with extra wide faces for all the ESA spring side load to spread on more area to prevent fast wear on the inner race as is seen on standard sets.
The timing side got lipped roller bearings as well, only the smaller outer bearing is slipped onto the shaft from outside. Assembly is a bit more interesting as I got all rollers in outer races so you have to slip the oil pump scroll onto the shaft while putting the timing side crank case onto the rest. The scroll is bigger diameter than the i.d. with rollers in outer race, that is why. The scroll has to be dropped into that space before you drop in the big main bearing. Anyway, no walking plain outer races with all typical consequences .

Vic
P1070540.JPG



P1070547.JPG



Timing side pump scroll between bearings:
P1070655.JPG
 

Bill Thomas

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Funny , I have just bought a pair of Comet Cases,
And one of the inner Main Bearings is very hard to slip out !,
God knows what he's done ?,
Also the big end is as tight as anything ?, Almost no side play, ie not free !,
But the alignment is very good !,
It's like one man did one job and another did the other part ?.
Lots of strange things have been done to the cases, But I think I can get them to work.
It will be interesting to get it all stripped out , But I am just polishing and making
them look better for now and saving up for a BIG Piston and Liner.

I have a barrel Hole in the cases of 100mm !, Looks like the liner will be 96mm at it's widest,
Which will leave a space of 4 mm/ 2mm = 80 thou" each side !!, I know I will have to block off
the cylinder feed, Any body think that is NOT good ?,
I mean the "D"s have a 5 thou gap around the lower liner, ie not touching,
So I thought it might be OK ?.
Cheers Bill.
 
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