Increasing oil flow to head

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Peter, if you read through this thread you see that if you do as you’re suggesting, you will A) fill the head with oil and then draw it down the guides and B) steal much needed oil pressure from the big ends.
I asked this question at the opening of this thread and my conclusion, after reading the feedback, was to leave well alone.
 
Allowing extra oil to the head just raises the oil temperature without doing any meaningful cooling to the head.
It would take more oil than is possible to put in or get back out with a Norton to change the head temperature very much.
 
RideItForever said:
I've got my '73 Commando/Combat head stripped and notice that rocker spindle oil way slots don't do align with oil feed hole from oil pump supply.
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"don't do align"

I assume you mean don't.

The spindle slots should line up with the feed drillings in the head.

If they aren't then the spindles are not aligned correctly.


Increasing oil flow to head


It's the rocker spindle feed holes that should not be aligned with the rocker arm drillings, so the spindle flats with the holes should always face outwards away from the head.

Edit: The tabs on the inner rocker plates should align with the slots and prevent the spindles from moving.
https://andover-norton.co.uk/en/shop-details/17154/r-spindle-locking-plate-d12-945-nmt2238-

However, even then, the drillings may not always line up exactly with the slots so need opening out.

https://www.accessnorton.com/NortonCommando/combat-rocker-shaft-oiling.17087/
 
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If its extra oil to the camshaft & followers that required, why hasn't someone drilled the front of the crankcase adjacent to the cam, run a feed pipe down from the rockers & concocted some sort of fitting/banjo bolt/ spray nozzle in to actually spray the lower valve train with lubricant??
 
olympus said:
If its extra oil to the camshaft & followers that required, why hasn't someone drilled the front of the crankcase adjacent to the cam, run a feed pipe down from the rockers & concocted some sort of fitting/banjo bolt/ spray nozzle in to actually spray the lower valve train with lubricant??
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That is basically what I do with my rifle drilled end fed cam.

And I have to keep a very small orifice in the line or I end up with too much oil in the cases and then the oil temperature skyrockets because the oil starts being whipped by the crank.

The orifice size is ~.007 inch.
 
olympus said:
If its extra oil to the camshaft & followers that required, why hasn't someone drilled the front of the crankcase adjacent to the cam, run a feed pipe down from the rockers & concocted some sort of fitting/banjo bolt/ spray nozzle in to actually spray the lower valve train with lubricant??
Click to expand...

Yes it has been done, way back in 1961 on the 500 Norton Domiracer that finished 3rd in the TT, only this bike had non standard valve adjustment.

There is another way, A third way????


https://www.nortonownersclub.org/support/technical-support-heavytwins/cylinder-head-oil-feed
 
Fast Eddie said:
No. The pump is more than capable of flowing more than the rockers allow to pass. It is the rocker shafts that are the bottleneck. A proper cooler (designed to flow) will not reduced flow to the head.
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Depends on which set up your Norton head has got, if it is an early Domi top end set up, your cylinder head is fed from the RETURN side of the oil pump,

Originally, low pressure oil was taken from the oil return at the point where it re-entered the oil tank, using a tee off a banjo. This was fed into the head via two drillings in the top of the cylinder head one left and one right. The rocker shafts were scrolled instead of plain, to encourage oil flow through each rocker. Although I heard some comments that the oil flow may be inadequate, I have never seen any evidence that a problem occurred,
but the later one, like the commando .............
 
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RideItForever said:
Just jumping in on a long running thread.
I've got my '73 Commando/Combat head stripped and notice that rocker spindle oil way slots don't do align with oil feed hole from oil pump supply.
As spindles are a tight interference press fit it looks as though there would be very little oil flow to rocker spindle>rocker rotating surface and ball end surface.
Have been told this is a Norton bodge up design to restrict excessive oil flow to the head and flooding due to higher perfoence oil pump.
Seems to me rotation of spindels to align with oil feed would improve lubrication for rockers etc and there is already a very resticted oil flow due to size of the hole in the banjo bolts.
Thoughts?

Peter
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Well Norton did this restriction because oil would flood the head. The right amount is the right amount .( a chef friend says this a lot) . Flooding the head on a Commando is not good because it simply cannot drain off quickly enough what with the small drain tunnels. The oil would build up levels and find the valves and guides to exit (and the proper route) , and that would mean SMOKING .
 
comnoz said:
That is basically what I do with my rifle drilled end fed cam.

And I have to keep a very small orifice in the line or I end up with too much oil in the cases and then the oil temperature skyrockets because the oil starts being whipped by the crank.

The orifice size is ~.007 inch.
Click to expand...

new folks luuv those details!
 
Same issue discussed at length on NOC site and....
"15k miles ago I rebuilt my 850 Mk3 Commando and discovered this same oil feed alignment issue. On Les Emery's advice I opened up the oilway in the head to give a clear feed to the rocker spindle by careful work with rat tail files and a Dremel. The bike has now done many high speed and low speed miles and I have never seen any evidence of oil swamping the head. "
 
The NOC thread is about getting the right amount of oil, the spindles are still pointed outwards to restrict flow, the problem was a further restriction upstream.
 
It wouldn't look good but some simple duct work to direct more air across the head should help.
 
seattle##gs said:
It wouldn't look good but some simple duct work to direct more air across the head should help.
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I have to agree with this, PW did that on his wheelbarrow Arter Matchless, but I don’t often see it used by anybody else.


If you really want to improve the oil flow, why not get a thin grinding wheel, dress a U profile and holding the shafts in your hand carefully grind slightly deeper in the helix oil groves. But a warning. Metal once removed cannot be put back!
 
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In response to the thread on the virtues of fitting an oil cooler.
https://www.accessnorton.com/NortonCommando/oil-cooler-thermostat-bedtime-reading.26956/

It seems Jim's observation in this thread's #26 isn't backed by an experiment. Conducting an experiment under controlled conditions require extended runs on a dynamometer. Adding an oil cooler to the rocker feed line apparently lowers the exhaust tappet chamber by "some 5 or more deg C" as reported in #28 of same page, also seconded by Jim in entry #29. The heat load isn't stated though.

Increasing the oil flow to the head (along with an oil cooler) will certainly lower the temperature even further. If the tappet chamber temperature is reduced by say 15 degrees for a standard motor @ specific maximum heat load, this means there is a margin for increasing the heat flux on a high-performance engine thereby maintaining thermal efficiency, or maintain thermal efficiency of a standard motor in hot climates generating the equal heat load. I believe this is exactly what the race department of N-V descided upon in 1973/74 when they fitted a much larger oil pump.

The advantage of increased top end oil flow and heat dissipation in a standard motor is debatable. It depends on how and where it is run. Motors subjected to light duty in modest ambient conditions will probably benefit from lower thermal expansion of the top end at the expense of increased expansion at the lower end, less likelihood of oil leaks, and increased life of wear components due to lower oil degradation rate, as well as improved thermal efficiency when maximum power is called off. Thus, I can't support Jim's conclusion on increased oil flow , "without doing any meaningful cooling to the head". If the estimated gains are met (yet to be verified), I think the added cooling is very meaningful.

Of course, the limiting factor is the standard oil pump, as noted by Jim in #42 of this thread. Increasing top end oil supply requires a balanced high pressure / low volume and low pressure / high volume oil pump. I guess this is what the race department of N-V did for the 1974 season. See image below.

Increasing oil flow to head

Photo taken from Albert van der Heijden' site.

-Knut
 
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olympus said:
If its extra oil to the camshaft & followers that required, why hasn't someone drilled the front of the crankcase adjacent to the cam, run a feed pipe down from the rockers & concocted some sort of fitting/banjo bolt/ spray nozzle in to actually spray the lower valve train with lubricant??
Click to expand...

Were there only a trough of oil for the cam lobes to dip into!
 
Anyway to dissipate heat of the Commando engine is a good thing, however it’s done. My experience has been with a Lockhart cooler w/thermostat. It kept temperature of oil in the tank below ~200 degrees F. Without the cooler, oil temp in the tank would rise to ~ 220 degrees F after a hard run. According to an engineer from Spectro Oils 200F in the tank was too high.

What was the original Norton twin engine putting out? 20 hp? Later derivations more than doubled the horsepower. Horsepower is a function of heat.

Interesting read: https://www.enginebuildermag.com/20...-heat-keeping-cool-heat-handling-accessories/
 
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