OP: Oil Pump Oil Pump

[davidd]

Maughan's normally pride themselves on close tolerances, is there any reason why a 2 x Start oil pump would be more susceptible to passing oil into the sump than a single start pump.

It may be that they have given up on owners who jam the sleeve into the case, which closes the sleeve down on the pump worm. Constant complaining about problems caused by poor installation of the oil pump probably resulted in the larger clearance. It is a guess, but that is what seems logical.

David

 

[greg brillus]

I had a bike with a new set of cases, it would empty the oil tank into the engine within a couple of days...........Stripped the bike down to the bare crank........destroyed the pump sleeve getting it out.......the pump bore was about 2 thou undersize. The builders of the bike had hammered the sleeve in with the cases very hot, then you guessed it.......the plunger was too tight a fit, so they linished the pressure end of the plunger down, and reamed out the scavenge part of the pump sleeve bore to make it fit.........be nice to tell you lot in the Uk who built the bike, but that might upset some on the forum.

 

[stu spalding]

I had a bike with a new set of cases, it would empty the oil tank into the engine within a couple of days...........Stripped the bike down to the bare crank........destroyed the pump sleeve getting it out.......the pump bore was about 2 thou undersize. The builders of the bike had hammered the sleeve in with the cases very hot, then you guessed it.......the plunger was too tight a fit, so they linished the pressure end of the plunger down, and reamed out the scavenge part of the pump sleeve bore to make it fit.........be nice to tell you lot in the Uk who built the bike, but that might upset some on the forum.

Hell no, Greg. I've had all manner of garbage from so called experts over the the years but I'm just muggins down at shadetree engineering and I'm hardly qualified to criticise "experts". It needs someone of standing in the Vincent world to have a go and, just maybe, some good might come of it. As I see it P.C.V. was more interested in making a quality product than making money whereas today it's more about profit. I realise that, compared with some marques, we're very well off for spares and workmanship, but it could be a whole lot better. Whinge over. Cheers, Stu

 

[vibrac]

Yes fitting an oil pump sleeve is a bummer of a job funny thing is I did it on the racing Comet when I was young and brash and its still ok I must admit nowadays I would think hard and long before doing it.
Sometimes experience makes you overthink things

 

[greg brillus]

A new one inch parallel reamer is the best........one pass up the bore to remove any burrs and the pump sleeves push in easy as. As to my above post lets just say the bloke responsible has a last name beginning in "M" and ending in "Y"........ I can't say if he actually did the work himself, perhaps his 12 year old apprentice did.

 

[Bill Thomas]

I think Knowledge is King, I now have an 1" reamer, Wish I had had it years ago.

 

[greg brillus]

In fact my machinist ordered that 1" reamer back when I did that job, since then I've used it many times. Best thing ever and makes changing an oil pump far less stressful........As one of the issues is aligning the sleeve with the peg hole as the sleeve gets close to fully home, you can quite easily rotate it to do so. One trap to be extra careful of is if the large inner timing side roller race is in place. I had one where the reamer clipped the edge of the hard race and lightly damaged some of the cutting edges of the reamer blades (flutes whatever you call them) so be careful of that one. I think changing an oil pump is probably one of the hardest and risky jobs to do on these engines, and careful preparation is an absolute must. I always start an engine assembly by installing the small timing side outer bearing ring first, then the pump sleeve, and then the remaining bearings and the spindles last. The wife doesn't even ask what all the noises coming from the kitchen are anymore....................... .................

 

[Bill Thomas]

There is also a very thin bit of casing near there, I get rid of unless it's sound,
Also make sure the plunger spins free, There are some bad OP36 screws around,
Too long or too fat and you have trouble !.
I prefer doing Pumps to that Twin front cam follower spindle,
On my L/ning when I bought it as Scrap, There was very little left, Bob Dunn had to do a bit of MAGIC in there.

 

[stu spalding]

Something that Billy Purnell spotted was the hole for peg screw OP36 not being dead right causing the sleeve to bind on the plunger. Cheers. Stu.

 

[bmetcalf]

There is also a very thin bit of casing near there, I get rid of unless it's sound,

I forget why I pulled the sleeve out, since I put it back in, other than to thoroughly clean the cases, but I found that a knife edge of the case had bent down in the bore. I was able to scrape it back and get the sleeve in nicely. That is probably the same spot you are talking about.