Oil pumps and wet sumping

What I do is machine the body to take 2 X rings, one on each shaft. This removes the leak from the feedside to the return side via the shafts inside the pump. Once it gets to the return side is has an easy route to the sump. I couple this with a machined timing side cover to include a non return ball, similar to the MK3 cover but with a ball not a plunger and block off a gallery in the crankcase to revert to the pre-Commando state again as MK3.

This package is a copy of the AMR of Tucson mods, I use X rings not the O rings they use in the pump for extra sealing surfaces. 

http://www.amr-tucson.com/nortech.html

It helps to have a Vertical milling machine to do the machining.

The typical reconditioning only address 1 of the 4 leak paths. It is WAY over rated.

The scavenge can only wet sump the hose and oil filter volume of oil. It does however pass oil through the shaft from the feed side.

The AMR(JH) mod does address the second of four failure modes which I have addressed several times previously.

Pump with X rings in place

https://i.postimg.cc/TYRz5vVV/X-ring-to-pump.jpg

A few years ago I met a chap who had machined a recess in the back of the drive shaft end plate. This being just large enough to hold a thin O' ring. I wasn't too sure that this was the best solution to his wet-sumping problems as it reduced the shaft bearing surface area and also the position of the seal would stop the shaft from receiving any lubrication from the inside of the pump.

On many Commando oil pumps the face machining is extremely poor and must be one of Dave's four sources of leaks.There is no way this kind of finnish is going keep in hot oil. Example in attached photo.

hello Now we have had all these topics before  and their  is lots of infortion on the site  to cover all this you only have  fill in the bar with your question  and answer will be there from the Techinacl team  yours anna j

Yes, the INOA timing cover mod reads like mine but does not mention the blocking of the crankcase galley that feeds the excess oil coming from the OPRV back to the feed side of the pump and the reopening of the timing cover OPRV to sump route for an alternative route for this oil. Bit in italics may be wrong way round

The seal can go on the feed or return side just as long as its only one side and not both, doing both will reduce the running surface for the shaft in the body too much.

I will post the seal dimensions tomorrow sometime.

Or the more fun route to cure wet sumping, just ride. But the figures from the survey says many don't ride much. 

The X ring is size 012 in buna shore 70, you need an 1/2" end mill. The X ring is 0.070" cross section, its compressed by both the shaft and OD of the slot so the extra 0.020" depth of the slot, to give a total of 0.090", takes the side expansion of the X ring.

I worked in machine shops for 50 years, never heard of an x-ring. Why not flat the faces of the pump on a surface plate with fine wet and dry glued on it? I have a couple of pumps, so will use your information to look at a better solution. I thought the covers were supposed to be half a thou wider than the gears, so not leaking. My N15cs never wet sumped, when new. Thinking, you must be using a double lip seal in the back of the gear recess?

Paul's point about x-rings...it's easy to find suppliers of o-ring kits, metric and imperial, but x-ring kits seem to be unavailable (or they were last time I looked).

X rings are harder to find because using X in the search term finds X section and so you get all the O rings. But they are out there and if you use Quad seals as the search term instead then you home in more.

Last lot I got from here

https://maydayseals.co.uk/35-quad-rings-

X ring chains are available and are thinner than the same sized chain in O ring form.

As X rings are designed to fit the same sized O ring groove they work well as direct alternatives, as on the Gearbox outer cover hole for the kickstart shaft on a Commando.