Hitchcocks Forum

Iron barrel oil pumps old one stripped gear on spindle but after cleaning everything brand new one wont work can only turn less than quarter of a turn tried other used spindles spare timing cover same swapped between mr H hi cap brass pumps and original steel ones different end caps double gaskets. Spindle turns ok with no pumps, anyone had problems with odd size drive pins on spindle but cant see drive pins catching on cover plates. HELP.

Fit one pump, either one, and see if it and the shaft will rotate? Remove that pump, and then fit the other...


A simple process of elimination to establish the cause.


You have renewed the worm-nut? Did you work out what was the cause of the worm stripping? Hi-Cap pumps are the second leading cause of the Worm stripping...

You have to relieve part of the pump housing by filing as arrowed in the photo the pointed part fouls on the larger piston of the scavenge pump. Assemble then turn by hand and you will see how it fouls and how much to remove.
Steve

You only need to remove the alloy under the contact area of the shaft itself, not all the way out across to the cover plate face.

Taken from the technical notes, left hand side...

Hi all looks like we found the problem, 2 of the spindles we have had a very slight bend in the pump spindle hard to pick up but my son spotted it just enough to jam slightly, suppose someone making these parts does one chucks it in a box and repeat repeat until hes done his 300 dont take much, onr with head barrel and clutch fingers crossed. Thanks for all the help and advice. Old chinese proverb many hands make enfield work.

Having experienced this problem with Hi Cap pumps I would also suggest you make sure that you have the light gauge springs that fit under the end caps as these are the only form of pressure release the Indian motors have and also ensure you are using a 20/50 oil rather than a straight 50 as I was. My feeling is now that unless I have a roller big end I wouldn't bother with the bigger pumps as the pump drive is the weakest link in the chain after than and its failure is potentially catastrophic. A roller big end would allow the oil to escape and provide the extra cooling that I was looking for but the white metal bush only allows so much oil through.

'Oil pressure' and the floating bush is something that only happens when the oil is cold. And then it is mostly due to higher viscosity and little to do you the bush. The 'Open Sided' floating bush with two surfaces and four edges for the oil to move past pretty much precludes oil pressure in the way such as is manifested with a radius ground 'conventional' plain bearing big end...


The oil pump disc-spring only regulates pump BACK pressure on the inward stroke of the plunger, there is no Oil Pressure Relief on the outward stroke on ALL Indian made Bullets from 1972 to 2002. The crankshaft timing side OPR was deleted due to too many floating bush failures, (Of which the factory seemed to have forgotten about?) and with its reintroduction saw a rapid rise in premature floating bush failures...


The potential 'problem' of excessive oil pressure with Hi Cap oil pumps is NOT on the feed side, but on the return, and mainly with Wet Sumped motors.


If you plan on running Hi Cap oil in ANY MOTOR!!! Floating bush or roller big-end, seriously consider fitting the OPR for the rocker oil return line...