Oil pump
- Thread starter clevtrev
- Start date
The original I took out of OPC 194 did at about 200k then fitted a double start in 1970 and renewed it again in 1990 after 100+k then that was replaced in 2010 at another 109k miles all very knife edged and elongated at the run out end where teeth have been milled (scavenge end), double starts wear out twice as quick, but then I do like plenty of lubrication, life is no good with out it. I still have all the old scrap, I'll photo and send if you want Trevor good examples.
Happy Christmas to one and all,
with heaps of banana's & cream.
Happy Christmas to one and all,
with heaps of banana's & cream.
Hi Trev all the ones i have removed looked like this one tooth nearly worn away. i have seen another from a Comet which been raced where that paticular tooth had an arc in it where metal had orn away and it then stopped rotating, Ken
Some people fit a twin start worm to a standard plunger without realising that if the pitch on the worm is coarser then the teeth on the plunger have to be angled to match. Do you all know that the pump housing is angled to the axis of the main bearings to take account of this with the standard set up? If you do not know this then now is a good time to think about it and to learn a bit of simple engineering. I have also seen teeth in the plunger cut with too large a diameter cutter so that the lead out at the end of the cut is too shallow and causes binding and premature wear of both the plunger and the worm. Sorry if this sounds bossy, it is not meant to.
The pump axis is at 2 Degrees from the horizontal.this leads to assemblers trying to screw in the hexagon plug square on to the bore. I have seen several stripped threads due to this , and in the worst possible case where the housing splits, usually in a Comet where the wall thickness is small. A repair is to mill off the split threaded area and weld on a collar and retap the thread. Why was it designed like this ?
I read that the 2 degree offset is an engineer's trick used by Phil Irving that makes the gear cutting geometry much simpler. I know that about a decade ago a number of pumps were cut without the offset and it caused all sorts of problems.
Looking forward to the answer of the odd wear pattern!
David
I understood that as its a reciprocating pump and at portions of the rotation the oil is constrained and then unconstrained there is a varying load on the drive and since it cannot by its design have a 'hunting tooth' wear will build up in one place in the rotational cycle - Perhaps someone can tell us at what speed relative to the main-shaft it rotates at with double and single worms?
from my racing experience I have never seen any great point in a two start worm lubrication has never been a problem so far but then (regular readers will know whats coming
) I use 'R'
from my racing experience I have never seen any great point in a two start worm lubrication has never been a problem so far but then (regular readers will know whats coming
) I use 'R'
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