It's been a blast and a worthwhile effort to replace gaskets, fit a new pcv breather and an anti-sump valve. The light rain of oil coming from this '71 Norton has decreased to an errant drop now and again. (Still trying to find that...) When I go to sleep at night, I rest well knowing my oil tank will be full in the morning. =)
With the addition of the anti-sump and an aftermarket exrernal oil filter, I do however notice a decrease in oil circulation. I'm guessing that's OK (figuring any oil circulation is a good sign) but I'm curious to know what you all think..... Hopefully I can get the video to post...
Thoughts?? I'm figuring the filter and valve and added hose is decreasing that flow some, but it doesn't look entirely troublesome.
Thanks!
--Alec
how to measure?
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Did you service the oil pump…
Did you service the oil pump (closed the clearances up in the pump) at the same time?
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Remember that...
the Norton pump is positive displacement, so extra resistance in the delivery side lines, filter or whatever have no effect on the flow rate.
If there is a extra restriction in the suction side, the pump may be trying to pull more in than the system allows, so in an extreme case, a vacuum could be created. (There is only 1 bar/atmosphere available to push the oil into the pump, but many bar available to push it out).
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It also takes a little while…
It also takes a little while to partially fill the timing cover and the filter. The oil in the timing cover then needs to get past the timing side oil seal and / or though the crankcase holes allowing the oil to drain to the crankcase sump from where it will drawn back into the return side of the pump.
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Thanks Team that helps. No…
Thanks Team that helps. No service to anything oil pump related in my gasket redo, just a wipe out of the inside of the timing case and chaincase, cleaning off the old gasket goop, sealing the magneto hose and the left case vent and then installing the JS Motorsport breather in place if the sump plug. Will definitely let it run longer next time and see if it picks up.
Anyone have handy a video of their oil return I could use for reference? Again here's the one I recorded:
https://photos.app.goo.gl/JqV2uQFE9QrCyQr3A
Does it look slow to you? More sputtery than usual? I'll try again tomorrow after letting it idle a bit longer. And Richard, I didn't know the bit about the displacement, so maybe it truly isn't primed yet....
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The oil should return with a…
The oil should return with a steady flow when the engine is first started, then start to "sputter" after a minute or so as the crankcase is cleared of oil.
John
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JS Motorsport Breather
Alec, just a thought.
The JS breather as it's fitted to the bottom of the crankcases will/can act as a return pump and perhaps is out performing the gear pump. Is this why the return oil has such short regular pulses? Is there nothing much coming from the JS breather valve other than air venting into to the oil tank?
It probably doesn't matter as all the sump oil will be returned, other than some of the oil will not be filtered.
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If I have interfered in any…
If I have interfered in any way with the supply-side of the lubrication system I always check the feed by slackening the rocker feed banjo bolts on the cylinder head and turning the engine until it is clear that oil is reaching that point.
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That makes sense....
@John Doig that makes sense. Prior to now the engine reliably wet sumped so what I used to see was a steady stream. New anti sump valve sorted that, so now I naturally see less oil (and sputtering is a good description).
And thslanks Julian that's a cool tip I haven't yet tried....
Cheers!
--Alec
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The 'anti sump' valve you…
The 'anti sump' valve you have fitted, does it have an ignition cutout incorporated within it?
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With an oil filter, it can…
With an oil filter, it can take a worryingly long time for oil return to appear at the tank. If you don't mind the mess, you could remove the return pipe from the engine and kick it over. It should come out of the engine a long time before it has filled up the oil filter. The Twins (with shell bearings) are much more sensitive to short period oil shortage than the SIngles (with ball bearing big ends).
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obviuosly , can only gauge by watching return to tank. So need to wait long enough , could be several minutes , before full return flow has stabilised.