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Increasing oil flow to head

Discussion in 'Norton Commando Motorcycles (Classic)' started by Fast Eddie, Dec 21, 2018.

  1. ludwig

    ludwig

    Joined:
    Aug 30, 2006
    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 ?
     
  2. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    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?
     
    xbacksideslider likes this.
  3. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    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?
     
  4. xbacksideslider

    xbacksideslider VIP MEMBER

    Joined:
    Aug 19, 2010
    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
     
  5. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    Perhaps that was it? Maybe he will chime in and let us know
     
  6. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008
    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.
     
  7. NKN

    NKN

    Joined:
    Mar 28, 2016
    If one hole is good, could two be better? Without weakening too much this part of the head?

    [​IMG]

    Where ever you put it. Not to mention saving weight :)

    [​IMG]
     
  8. cash

    cash

    Joined:
    Nov 10, 2006
    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
     
    xbacksideslider likes this.
  9. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008
    That goes along with the results I have seen from installing the oil coolers in the overhead line on my bike.
     
    xbacksideslider and cash like this.
  10. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    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!
     
  11. Onder

    Onder

    Joined:
    May 11, 2010
    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.
     
  12. oldmikew

    oldmikew

    Joined:
    Jul 25, 2015
    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
     
  13. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    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.
     
    xbacksideslider likes this.
  14. oldmikew

    oldmikew

    Joined:
    Jul 25, 2015
    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...
     
  15. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    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!
     
    xbacksideslider likes this.
  16. Onder

    Onder

    Joined:
    May 11, 2010
    Be so good as to post a few pictures of your oil cooler effort please.
     
  17. marinatlas

    marinatlas

    Joined:
    Nov 4, 2007
    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).........!!!
     
  18. oldmikew

    oldmikew

    Joined:
    Jul 25, 2015
    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
     
    Nater_Potater likes this.
  19. Onder

    Onder

    Joined:
    May 11, 2010
    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.
     
  20. RideItForever

    RideItForever

    Joined:
    Jan 29, 2018
    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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