Oil valve solution to oil falling to crankcase

javifoto70

javifoto70

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Oct 20, 2022
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Hello,

As new on Norton I received some advice about Norton engines traditional problems from an experienced fellow and I would like you to tell me if is true and eventually how to solve it:
He told me every Norton engine tends to empty the oil tank when the bike is stored for sometime, it seems the oil falls into the crankcase and this can be a potential cause of troubles due to excess of oil pressure when starting the engine. Is it so?

I am restoring an MK3 and I would like to know if also my bike engine may suffer this problem. My friend installed a special valve that manually closes the oil hose going to the crankcase and also cuts ignition to avoid starting the engine without oil feed. It is this solution necessary and good?
 
Yes, they all wet sump to some degree.
The MK3 has a built in check valve to prevent this, but it only seems to slow the flow, not stop it.
You might get by just fine without the additional manual valve.
My MK3 takes about a month to wet sump. I can live with that.
As far as the manual valve with ignition cutout goes, those have caused many forum arguments, but so far, zero damaged engines.
Maybe try the bike without the added valve.
If you find the bike needs it, go for it.
Kingpin Components has a nice looking valve with cutout.

shop.kingpincomponents.co.uk

Oil Tap with Cutout Switch

A combined oil tap and switch which can be connected to bikes with magneto or coil ignition. This ensures that, if the oil tap is 'off', the switch will stop any sparks and the engine cannot be started until the oil is switched on.We are able to offer these taps in either 1/4BSP or 3/8BSP and...
shop.kingpincomponents.co.uk shop.kingpincomponents.co.uk

Glen
 
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The only real (very rare) problem wet sumping can cause is blowing out the crank main seal. You can avoid that problem by installing a 1-1/8" ID 3/32 wall viton oring between the primary sprocket and the main seal. Its a #122 oring and you can get them for cheap at suppliers like Mcmaster Carr. Wet sumping also makes it a little harder to kick over the motor but its not much of a problem on kirk start 750s or 850 Mk3s with electric start.

If your oil drains into the sump there will be plenty of lubrication for the crank and cam while the oil is pumping back into the oil tank.

By far the biggest problem with installing shutoff valves is from forgetting to turn them on and blowing up perfectly good motors. So be sure yours has an electric shut off if you go that way.
 
javifoto70 said:
He told me every Norton engine tends to empty the oil tank when the bike is stored for sometime, it seems the oil falls into the crankcase and this can be a potential cause of troubles due to excess of oil pressure when starting the engine. Is it so?
Click to expand...

Yes, that is basically correct but doesn't exactly result in an excess of "oil pressure" only that the excess oil in the crankcase can potentially blow out the primary seal, however, the Mk3 primary seal has a circlip that should prevent it.

javifoto70 said:
I am restoring an MK3 and I would like to know if also my bike engine may suffer this problem.
Click to expand...

Potentially, yes, however, the aforementioned Mk3 anti-drain valve in the timing cover can slow the rate of drainage but might not stop it completely because unless modified, oil can also leak between the feed and scavenge sides of the pump.

javifoto70 said:
My friend installed a special valve that manually closes the oil hose going to the crankcase and also cuts ignition to avoid starting the engine without oil feed. It is this solution necessary and good?
Click to expand...

Not exactly "necessary" if you ride often enough to prevent the majority of the oil from draining to the sump but a manual valve with an ignition cut-out is preferable to an automatic anti-drain valve (unless you were to fit an oil pressure gauge) in my opinion.
 
My MK3 crankcase seal failed due to a wet sump start.
The MK3 circlip did its job of holding the seal in place, however the neoprene lip on the seal popped outward and stayed that way, spewing engine oil into the primary.
It's a fair bit of work to change that seal, so I really try to avoid the wet sump startups.

Glen
 
When my MK2 primary seal blew, the flexible section was actually split and ripped away from the outer metal ring. This was likely an old if not original seal, embrittled by time and heat. But it was fractured when the bike had wet sumped significantly over two or three weeks sitting. First indication there was a problem, oil spewing all over rear wheel as primary began taking on too much oil from crankcase, splashing it out the primary case felt 'seal'. This could have ended very badly if I had not noticed the slippery rear tire in time.

I now run a manual shutoff valve with ignition circuit cut off switch. Something I cobbled together myself, cost less than $10. Works a treat.
 
Thank you everybody! Now I see my colleague was right and I will definitely buy and install an oil tap with cutout switch on my bike before the first kick over. I do not want to take any risk to damage the engine after the many months I will spend restoring the bike. And once the bike will be ready I will use it with pleasure but probably randomly because I own other bikes I also need to attend.
 
javifoto70 said:
He told me every Norton engine tends to empty the oil tank when the bike is stored for sometime, it seems the oil falls into the crankcase and this can be a potential cause of troubles due to excess of oil pressure when starting the engine. Is it so?

I am restoring an MK3 and I would like to know if also my bike engine may suffer this problem. My friend installed a special valve that manually closes the oil hose going to the crankcase and also cuts ignition to avoid starting the engine without oil feed. It is this solution necessary and good?
Click to expand...
Since it is a MKIII, in my opinion the cutoff would be "fixing" a "problem" that doesn't exist. While MKIII can wet sump, it can't blow out the main seal since it is held in place by a circlip. Kickstarting can be more difficult, but not much more if you have a reed valve breather. If you don't have one, installing one is a good idea as it lessens the chance of leaks and empties the crankcase quickly if wet sumped.

There are two main types. The Colorado Norton Works version screws to the rear of the drive side crankcase near the bottom - machining is required ( https://coloradonortonworks.net/cnw-machining-services ). The JS Motorsports ( https://jsmotorsport.com/product/sump-reed-valve-breather/ ) and NYC Norton ( https://nycnorton.com/product/reed-valve-breather-kit/ )versions replace the big sump drain/filter.
 
I have been pumping the oil out of the tank, when I park the bike (semi long term) using a cheap Harbor Freight hand pump. No more wet sumping. Problem solved.
 
So easy to check the oil level in the oil tank if no oil then undo the drain plug to drain the oil out of the crank case and put back in the oil tank, so simple, or install a reed valve that returns the oil back to the oil tank quickly don't put a valve on the oil line, the best fix is to ride the bike regularly and if you do let the bike sit for a while then having oil in the crank keeps everything nice a lubed

So many carry on and make a big thing about wet sumping, my 850 only wet sumps if I let it sit for a few months, but if I did that I just drain the oil out while checking everything else before a ride, takes 5 minutes out of your life draining the sump, no big deal really, if I ran my breather back to the oil tank I would put one of Jim's reed valve the pumps the oil back into the tank on first start up, but I thing you are trying to fix a problem your Norton might not suffer to me putting a shut off valve is not a fix for a problem, if I am going to let my Norton sit I rather have oil in the crank case if it sits for sometime.



This is my opinion and better to be safe, if the bike sits for sometime it's best practice to go over the bike before any ride and draining the oil while checking chain etc before a ride.




Ashley
 
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

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This makes it easy to empty the sumped oil out. Just undo the small bolt at the bottom, no wear on the engine case thread. I use this on my 850 Mk3 if I've not ridden it for more than a couple of weeks (rare, but happens). I usually get 0.4L to 0.7L, I think it sumps at about 0.15L a week. 8,000 miles since rebuild.
 
828c.c. Mk111 late production build and never a concern with wet sumping. End of winter start up .
Pull both plugs , reinsert into both H.T. leads and ground them out on the head fins using 2 plastic holder clamps . Fuel off .
Pull in the clutch , hit the starter button and hear her spin for say 30 seconds . ( observing the sparks is optional ) . You don't want any starter motor heat or battery heat developing , but simply put the plugs back in and hit the magic button again with the fuel choked , tickled or primed up , your choice . Get off the richness A.S.A.P. Good to go for the season . Enjoy .
 
marshg246 said:
Since it is a MKIII, in my opinion the cutoff would be "fixing" a "problem" that doesn't exist. While MKIII can wet sump, it can't blow out the main seal since it is held in place by a circlip. Kickstarting can be more difficult, but not much more if you have a reed valve breather. If you don't have one, installing one is a good idea as it lessens the chance of leaks and empties the crankcase quickly if wet sumped.

There are two main types. The Colorado Norton Works version screws to the rear of the drive side crankcase near the bottom - machining is required ( https://coloradonortonworks.net/cnw-machining-services ). The JS Motorsports ( https://jsmotorsport.com/product/sump-reed-valve-breather/ ) and NYC Norton ( https://nycnorton.com/product/reed-valve-breather-kit/ )versions replace the big sump drain/filter.
Click to expand...
When the MK3 seal blows it just pops the neoprene lip out.
An inny becomes an outy.

Glen
 
worntorn said:
When the MK3 seal blows it just pops the neoprene lip out.
An inny becomes an outy.

Glen
Click to expand...
I learned long ago to not say things are impossible, but that's improbable IMHO. The gap between the metal portion of the seal and the crank is tiny (just removed and inspected one today). The lip of the seal is much thicker than that gap. Then, if you have a reed valve breather, there is almost no pressure in the crankcase which makes it even more improbable. I suppose an all-rubber seal could do as you say, but if using one, there's no point in the circlip.
 
That's how my metal/rubber MK3 seal blew.
I've only had the one let go but I assume that if I ever repeat the conditions the result will be the same.
The hydraulic pressure when started with a full sump is great enough to push the earlier seals right out, so Norton added the circlip.
That's a lot of pressure!

I do not have a Comnoz reed breather fitted. They seem to be a very good item.


Glen
 
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worntorn said:
That's how my metal/rubber MK3 seal blew.
I've only had the one let go but I assume that if I ever repeat the conditions the result will be the same.
The hydraulic pressure when started with a full sump is great enough to push the earlier seals right out, so Norton added the circlip.
That's a lot of pressure!

I do not have a Comnoz reed breather fitted. They seem to be a very good item.


Glen
Click to expand...
Any breather works just fine , better than no breather in line valve for sure . I used a Cdn. Tire Moto Mite valve at $3 Cdn. for years . Best $3 ever spent on my Norty . Then blew the bank-wad and bought a Mike's XS 650 valve to put it in the same place , before entering the oil tank . $ 26 I think .
So many problems cured instantly . What's an oil leak ?
 
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