Forum

[marsie]

In my view, Problems associated with the bushed big end bearing are not just removed by fitting larger oil pumps, but are caused by contamination of the oil. Of course when upgrading the engine,higher oil flow cannot be a bad idea.
Enfields themselves recognised the superiority of the plain bearing over a roller type for this application and it has given excellent service in parts of the World where high air temperatures are the norm.
Providing the bearing is run with clean oil at constant pressure it will last almost indefiniteley.
Unfortunately, short jouneys in a cool climate quickly produce emulsified oil and water collecting in the oil compartment. Drain the Engine and first comes out clear water. Not so good for any parts of the engine, let alone the big end.
There is little to be done to cure this,( a project for our Host perhaps )apart from short intervals between oil changes.

[ChrisD]

Hi gents, I too have just fitted the high cap pumps. I followed the route of double gasket and lighter springs but even so, after I had lapped them in to what looked smooth, I still couldn't turn the worm by thumb pressure, as Another Allan said. I believed that was because they weren't properly lapped, so I took them apart, cut discs to fit of 200 then 400 grit paper and stuck them on with spray on glue on both sides alternately for both pumps. Then I lapped them properly and finished with Solvol as discussed abovge. After that I could turn with thumb pressure and have now, after ~500km, removed the extra gasket and can now turn the worm OK with thumb pressure.
ChrisD.

[Chris]

A question about the feed pump having to create a "vacuum". The tank oil level is higher than the pump, so I don't believe that once the flow is established, that a vacuum is required, or that it goes dry when left standing. To prime a feed pump after an oil change you can pump oil down the hole in the feed plug screw hole.

[John J]

Just another thought;- One of the springs turns against the rotation ,and under friction this probobly gets slightly wound -up against this friction,causing an oscilLutory loading on the worm drive. A left and right spring winding would help this.

[Les H]

Hi Chris. I know my first reply is a long way back, and you might have forgotten all the tedious details but for the record I said "The FRONT SCAVENGE pump has to create a vacuum to lift the oil to the pump"...I made mention that the FEED pump is under a head of oil so does not require priming....I did not say the feed pump needed to create a vacuum...have another read of it or just that bit again if you have the time...ATB...Les

[trevorch]

I presume for "vacuum", we should understand "Suction", but not -1 bar.
Cheers

[Les H]

G'Morning Trevor. Your absolutely right. Suction is the correct word. I've used the word vacuum several times incorrectly, and more often made countless spelling mistakes too. It would be nice to be able to edit after posting, but I know all one has to do is to check the message more thoroughly before sending. I have to say I do but my brain reads it as I want it to read and completely overides what my eyes are seeing, a sort of word blindness. It's only after a time lapse has occured that I can see all the mistakes and then I just have to cringe. Nice to know you are still around Trevor. Wishing you well...Les

[John J]

Hi, Vacuum(though not a perfect one) is the correct term. The "suction" is due to an outside fluid, at a higher pressure, filling the "vacuum" ie low pressure. Suction does not provide an inward force, this comes from the external pressure.

[trevorch]

Hi Les H,
Being retired has some advantages - time at last to read on this site and sometimes to add a minor contribution. must have learnt something from 4 years with an iron barrel. My new EFI is a bunch of mysteries, eventually, will have to buy the factory workshop manual. Having the right side cover off at my dealers to change the from sprocket at least let me see something new, like the oil pump is driven by a nylon type gear meshed with the valve gears. Cheers Trevor, still in Ch.

[Dennis C]

Hi JohnJ. Just for fun, copied from a dictionary, Noun:
A space entirely devoid of matter. Now is it suction? or is it vacuum?, I feel that it is probably suction as it is never "devoid of matter" the meaning of the term vacuum has been distorted over the years by "vacuum cleaner" makers, perhaps Electrolux where the ones who got it right way back it time with their TV advert which stated that, "nothing sucks like Electrolux" which did nothing to improve sales in America.