Increasing oil flow to head

ludwig · Dec 21, 2018

Fast Eddie said:
Ludwig.. what’s that other extra hole on the inlet side of your head?

Of no importance . probably weight saving ..?

Another cooling trick is using a narrower head gasket ( on an 850 ) , or have done that allready as well ?

Fast Eddie · Dec 21, 2018

I’ve been using a standard AN composite gasket on the 850.

On the 920 I have to use a copper gasket, which I assume is better for head cooling as it allows greater heat transfer to the alloy barrel?

baz · Dec 21, 2018

Didn't comoz post on here once about fitting a separate oil pump to the head and pumping oil through?
Or did I imagine this?

xbacksideslider · Dec 21, 2018

baz said:
Didn't comoz post on here once about fitting a separate oil pump to the head and pumping oil through?
Or did I imagine this?

Don’t know about a pump but he did discuss two oil coolers each mounted in each side of fairing and offering significant exchange area with both feeding the rocker spindles

baz · Dec 21, 2018

Perhaps that was it? Maybe he will chime in and let us know

comnoz · Dec 21, 2018

Tried that a couple different ways.

It just makes the oil hotter and leaves less oil for the rod bearings. If their was any change in the head temp -it was minimal.

Plus the main oil supply for the cam is from the oil leaving the sides of the rod big ends -not the overheated oil return from the head.

NKN · Dec 21, 2018

Fast Eddie said:
Ludwig,

I’ve already added the “Ludwig hole”. Likewise, I’ve not measured it’s impact, but the logic is sound IMHO.

If one hole is good, could two be better? Without weakening too much this part of the head?

Where ever you put it. Not to mention saving weight

cash · Dec 21, 2018

I drilled ludwig's hole in the head years ago as it does appear to be a logical idea and has to be beneficial, though I never took any differential temperature readings.

There has been a lot of good info on the forum on worryingly high oil temperatures around the exhaust valves. With this in mind I had a pitbike alloy oil cooler kicking about and modified it to withstand the high cold start oil pressure. Fitted it in the rocker feed about 2 years ago and with my very crude temperature instruments used before and after shows it to reduce the heat around the exhaust tappet chamber wall by some 5 or more deg C. Temperature of the oil in the tank appears much the same. At the same time the motor oil consumption has reduced from 800 mpp to hardly moved in 980 miles. I've just changed to fully synthetic.

So far so good.

Dave

comnoz · Dec 21, 2018

cash said:
I drilled ludwig's hole in the head years ago as it does appear to be a logical idea and has to be beneficial, though I never took any differential temperature readings.

There has been a lot of good info on the forum on worryingly high oil temperatures around the exhaust valves. With this in mind I had a pitbike alloy oil cooler kicking about and modified it to withstand the high cold start oil pressure. Fitted it in the rocker feed about 2 years ago and with my very crude temperature instruments used before and after shows it to reduce the heat around the exhaust tappet chamber wall by some 5 or more deg C. Temperature of the oil in the tank appears much the same. At the same time the motor oil consumption has reduced from 800 mpp to hardly moved in 980 miles. I've just changed to fully synthetic.

So far so good.

Dave

That goes along with the results I have seen from installing the oil coolers in the overhead line on my bike.

Fast Eddie · Dec 21, 2018

Righto chaps and chapesses, that settles the matter for me at least.

I’ll leave the oil supply untampered with in terms of flow and will try to pull my finger out and get the cooler plumbed in to the rocker line as I’ve been pondering for some time now!

Onder · Dec 21, 2018

Royal Enfield Interceptor has a very small amount of oil going up to the heads and those heads already run hot. Very little as the flow only
happens when the OPRV blows off which isnt very often once the engine warms. This is in the interest of keeping the OP on the crank which
the bogus oil pump struggles with. The Norton pump is light years better as is the head design.
I think it is a hopeless task to try to flood the head to cool it.

oldmikew · Dec 23, 2018

Perhaps I am missing something here ,but if an oil cooler is plumbed into the head rocker feed then there will be less flow... a wedge of cooler oil will present a restriction to the hotter oil between the oilcooler and the pump

Fast Eddie · Dec 23, 2018

oldmikew said:
Perhaps I am missing something here ,but if an oil cooler is plumbed into the head rocker feed then there will be less flow... a wedge of cooler oil will present a restriction to the hotter oil between the oilcooler and the pump

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.

oldmikew · Dec 23, 2018

Yes it is the shafts that are the main bottle neck . But though it is an incremental detail -cold oil pumps less well. It is worth checking that the tangs on the shaft inner plates are not causing an obstruction-only one is need per shaft to stop rotation.. Interesting idea to rotate the exhaust rocker shaft.. Suspect it will rob the inlet side but if like me you have cast iron inlet guides and bronze exhaust it will not matter...

Fast Eddie · Dec 23, 2018

Mike, consensus on this seems to be that rotating the rockers will starve the bottom end. Rotating just the exhaust might do the same, or as you point out, at least starve the inlets.
My mind, at least, is made up to leave them be!

Onder · Dec 23, 2018

Be so good as to post a few pictures of your oil cooler effort please.

marinatlas · Dec 23, 2018

oldmikew said:
Yes it is the shafts that are the main bottle neck . But though it is an incremental detail -cold oil pumps less well. It is worth checking that the tangs on the shaft inner plates are not causing an obstruction-only one is need per shaft to stop rotation.. Interesting idea to rotate the exhaust rocker shaft.. Suspect it will rob the inlet side but if like me you have cast iron inlet guides and bronze exhaust it will not matter...

I had noticed recently when rebuilding some heads , that I have two different kind of shafts and some have an "enlarged " tang slot just on one side , thus not to restrict the oil flow , never seen before (or notice).........!!!

oldmikew · Dec 23, 2018

Onder said:
Be so good as to post a few pictures of your oil cooler effort please.

Nothing special about mine... its off a CBR 600 and is mounted high up on the frame rails. The coils are elsewhere. The layout is arranged so that the inlet to the cooler is higher than the sump return to the tank.. It means the whole thing can be switched in and out of circuit by one tap. It will cool a tank full of oil in about 10 or 15 motorway miles - that is from bulk temp of around 90-100C to 30C . Normally i run at about 70 bulk in tank temp.
Even without a fairing when newish it would run upto 100c after a short period of 70-90 mph cruising. the villein of the piece was the fastback glassfibre tank. it is very restrictive of air flow.. Now without a fairing but with an alloy tank it is not necessary to use it. With the Avon fairing its use was a no brainer. I did not like crossing london after a fast run with no oil pressure at traffic lights.
I am frankly amazed that Norton did not fit a cooler as standard for export models

Onder · Dec 23, 2018

Remember that Triumph (and BSA) did fit a radiator to the triples from the start. Also note that apparently only the outer inch or so on each
side did much cooling due to the masking of the unit by the front end. When they raced the bikes at Daytona they had a slot in the fairing to
feed cool air. So just where you put the cooler matters and Id like to see pix of the installation.

RideItForever · Jan 9, 2019

Fast Eddie said:
Following on from an earlier thread, I’ve been looking at the head and rockers again.

As we know, rotating the rocker spindles 180 degrees so the flats line up with the oil feed is all that’s needed to increase flow to the point whereby the inlet guides will be submerged and oil consumption increased.

But... what about the exhaust side? Surely, any excess oil there is just gonna exit down the pushrod tunnels and aid cam / follower lubrication?

Is this right?

If so, it would seem a good way of flushing more cooling oil over the hottest part of the head AND splashing more of it down to the cam.

Another question this would raise is; would there be any negative effect on oil pressure or flow to the bottom end?

As I run Carrillo rods, I already run without the oil holes in the con rods, which should, in theory at least, aid oil pressure.

Thoughts please gents: is rotating the exhaust rocker spindles in order to increase oil flow over the exhaust side of the head a good idea or not??

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

Increasing oil flow to head

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