Sump, 'Correct' Volume of Oil

Tonight, to avoid Strictly Come Dancing, (US: Dancing with Stars, I think?), I finally got round to removing my 'automatic' shut-off or anti sumping ball valve in the oil feed line. I have the Feked manual valve, with ignition cut out arrangement, ready to install. But, I would prefer to avoid it if I can. So, tonight I simply installed a straight through oil feed pipe. Now, I am planning to monitor the amount of oil I find in my sump over the next few days, to decide whether I need the Feked manual valve. Hence this question: How much oil should I expect to find in the sump of a 1975 Mk3 if it is not wet sumping?

I guess they nearly all wet sump to some degree, so to qualify the question, does anyone know what is the 'usual' amount of oil I would expect to find in my sump IF I didn't have a wet sumping problem worth correcting, after about a week from its previous run?

Before removing the auto ball valve, I fully emptied the sump, via the sump drain hole and measured. It was a fraction under 400ml. I didn't remove the screen filter in the sump. I haven't run the engine. I put the plug back in and will check if there's a build up of oil overnight, if it looks like just a dribble, then I'll take it for a ride and then see if I can keep off the bike for a week, then measure what comes out of the sump. So, some measure of what I should expect to be in there, would be really helpful.

Thanks.

Shouldn't be to much oil there be a little so 400mls should be right or a little less.

What comes first, the chicken or the egg? Is there such a thing as a "standard" or usual amount of oil to wet sump,
and over what period or time? ok, 2 variables. Answer: Every bike is different. Want to find out? drain the sump
and wait a measured amount of time. Then drain the sump again. That is the answer. Then, either ride more often,
or install that nifty Feked manual valve with the ignition interlink. Or don't. Maybe do both and stop worrying.

At some point where you know you will be out of town or otherwise engaged for 2+ days remove the sump plug when you get back to the mothership. what comes out is operational, shouldn't be much more than 30 cc or an ounce; good idea to let the oil drain into a graduated cylinder, a pyrex measuring cup will be sufficient; I'd note the date and time you start this trial.

Check when you get back or become disengaged. Subtract the operational oil quantity from the volume collected extend the trial if you can or start trial 2 some other day. Obviously ambient temp will affect the apparent oil viscosity, but you will get the data you are looking for.

Best.

Just ride the bike and don't let it sit to long, mine never wet sumped in most of it life as it was a everyday rider since new but these days its semi retired and now if I let it sit for 4 months I just drain the sump before taking it out for a run I can see right into my oil tank and know where the level should be and if its down I drain the sump so easy and the good thing if it does sit for a while the wet sump keeps the cam lubed, if the oil tank is down I normally drain the sump the night before a ride so far in 46 years of ownership I have only drain the sump 4 times from wet sumping.
Some Norton's WS quicker than others and every bike will be different so just look for the signs before any ride, but after any ride there should be very little oil in the sump if things are working right.

Ashley

When I purchased my 850 in '06, the oil tank would drain down to the delivery pipe in 8-10 days. I then resurfaced the oil pump as per the Norton service manual. It now takes 4-5 weeks for that to happen.

My original 1971 Commando never wetsumped!

Of course, at that time I had never heard of wet-sumping and it wouldn't have occurred to me to look for such a thing. I just checked the oil when re-fueling and added oil if necessary.

I know I’m covering old ground here, but…

A Comnoz sump breather helps to evacuate oil from the cases, back to the tank, very quickly. It also ensures little or know pressure, which is normally the issue because when a sump full of oil is compressed by the descending pistons, the pressure often has nowhere to go except making its way out by pushing the primary drive side oil seal out.

For me, the ‘rule of thumb‘ with a Comnoz breather fitted is really simply. If when I look in the tank I either cannot see the gauze filter, or if it’s only just visible, then I start the bike and don’t worry about it at all. I know that in a few second the excess sump oil will be returned to the tank, and I’ve never had any issue with the oil seal or anything else. If the oil is lower than that, then I’ll drain the sump (which lets be honest, takes no time at all), I do this mainly through fear of the oil being low enough to possibly cause cavitation.

Eddie,

Thanks. At this stage, I'm just trying to guage whether mine is normal, or more prone to sumping. The HNW breather valve I recently put on, has grown on me. Bike runs quieter, smoother and the head seems to be oil tight. So, prefer not to mess with that!

I'll just be watchful, now I've removed the ball valve and manage it.

Thanks for the replies.

I use a valve in my oil line which I close immediately after a ride.

With that installed, I expect to see an egg cup (about 40ml) of oil subsequently drain down into the crankcase after shutdown.

If I ever see more, then I know I am either over oiling the top end, or there is a blockage in the little drain hole at the right side rear of the cylinder head (I found a lump of red silicon goo in there once, courtesy of a previous owner)

1/4 cup

VERY GENERALLY SPEAKING...

So the debate will now centre around 'cup' sizes? (No sexist comments, please )

Mart UK said:

Eddie,

Thanks. At this stage, I'm just trying to guage whether mine is normal, or more prone to sumping. The HNW breather valve I recently put on, has grown on me. Bike runs quieter, smoother and the head seems to be oil tight. So, prefer not to mess with that!

I'll just be watchful, now I've removed the ball valve and manage it.

Thanks for the replies.

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The HNW breathers work well, no question. They just don’t help with sump emptying.

EstuaryBoy said:

So the debate will now centre around 'cup' sizes? (No sexist comments, please )

Click to expand...

I believe the service manual specifies a "teacup" of oil, which Google says is 6 fl. oz.

When I change my oil, I always pull the sump plug (small in my case - Combat). I typically get about 200 ml of oil out of it - I have never measured it. I pull the plug more to see what is stuck to the magnet.

I have a AWS valve fitted, so this is the oil that is not picked up by scavenging.

Just leave the drain plug out for awhile and watch the steady drip, drip, drip.
Or drip ....................... drip if you are lucky!

Glen

maylar said:

I believe the service manual specifies a "teacup" of oil, which Google says is 6 fl. oz.

Click to expand...

That's an a-cup @EstuaryBoy

worntorn said:

Just leave the drain plug out for awhile and watch the steady drip, drip, drip.
Or drip ....................... drip if you are lucky!

Glen

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Did just that, so far 40ml since 8pm last night and I'd have thought some of that must be further drain down from the case walls. Looking promising!

Mart UK said:

Did just that, so far 40ml since 8pm last night and I'd have thought some of that must be further drain down from the case walls. Looking promising!

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You have got oil in the tank, right ?

grandpaul said:

1/4 cup

VERY GENERALLY SPEAKING...

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I opened the drain plug about 3 hrs after a ride and collected over twice that volume (c.15fl.oz, 400ml). How 'generally'?

Fast Eddie said:

You have got oil in the tank, right ?

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Ha ha. Yes, I put what drained out back into the tank and it's now on the full mark, but I haven't run it since. I expect it to drop to about half way between the marks, once it's run for a few minutes, which is where it was last run. Cap is on the tank.