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oil circulation

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Should there always be some oil allowed to seep into the sump whilst a dry sump lubricated motorcycle is not being used? I am concerned about getting enough oil to the valve mechanism above the engine when starting.  Was this the intension when designing the Norton Dominators ?

If a tap were to be fitted just below the oil reservoir tank feed to prevent oil flowing onto the pump on standing must I allow sufficient time after turning the tap on for enough oil to sink to the sump before kick starting?

 

 

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What you suggest wouldn't help valve gear much, because it's fed from the return.  And valve gear loads aren't as severe as cam lobe loads, where sliding contact takes place. For most of it's life, the ES2 didn't even have oil pumped upstairs. The later pressure feed to rockers was allegedly done to lesson the noise, not the wear.

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Start the engine, open the oil tank cap and put your finger over the hole where the oil is returning.

This forces all the returning oil upstairs.

30 to 45 seconds should do the trick.

job done. Repeat as necessary.

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When a Dominator engine ( & others) that has been running is stopped there is a considerable amount of oil caught inside it that then trickles back to the sump. This is part of the design so that, on the next re-start, oil is quickly available for the oil pump and some for splash lubrication of the camshaft lobes and followers.. The chief sources of the sump oil (up to 500ml) being the cylinder head, timing cover and crankshaft.  neil's 'finger' plugging suggestion is a good idea on any Dominator with low pressure rocker feed that is not run regularly.

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on about oil circulation, i hadnt got any on one side of the engine . i wonder if it had anything to do with what i found in the crank. see photo in attachment

 

barry

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Barry.......I bet those lumps did not do the engine balance much of a favour. These usually arrive thanks to using basic mineral engine oil.

At least there was enough room for the oil to still pass through.........unless you had previously done some chipping.

Attachments show a crankshaft from a Model 7 engine that I was recently asked to rebuild.  On the very early 1949/50 versions of these engines, the rocker spindles  often got so badly coked up that they would not pass through the spindle shoulder holes. Bracebridge had to change the design from a one piece combined spindle with brazed-on end plate to a separate spindle with two plates.

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on the wet sumping,... my es2 which i dont use much. i dont mind the wet sumping. i just kick it over now and then without starting it. just to over oil the parts. makes you wonder if the pumps were disigned to wet sump originally .

Hello , Philip....  i thought mine was bad but thats well blocked up. mine picked up on the shells and seized on the one side. it had loose sludge in it like a crispy burnt type over the oil hole area. also the shells turned in the rod.

 

 

Barry

 

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Since about the mid 60's (well into old age for the Dommie design) oils have normally contained dispersants to prevent small but mostly harmless soot particles from joining together to make up lumps that block things and cause more damage. I wonder if sludge traps from Commandos block as badly as Phil's example? Later machines should have been using better oils. Usually...

 


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