MkIII Commando Timing Cover Installation

I've got the timing cover off of my MkIII Commando to try to sort out the "wet-sumping" problem, in which all of the oil in the tank ends up in the sump in about 10 days.

Between the new-for-1975 "anti drainback valve" that Norton installed but doesn't appear to be there on this particular bike, and sorting the oil pump, I should be able to get fixed ...

Question is, does the timing cover need the paper gasket for "spacing" it out from the engine case when I reinstall it? Since I discovered Loctite 515/518, I only use paper or fiber gaskets when they are dimensionally required; in all other applications, I use the anaerobic Loctite gasket-maker for flange and cover-type joints and have NO leaks anywhere I use it, including BSA cylinder base gaskets. (I still use copper head gaskets and copper drain seals, there's no substitute for them).

Thanks for any info and experience.

Lannis

Lannis said:

I've got the timing cover off of my MkIII Commando to try to sort out the "wet-sumping" problem, in which all of the oil in the tank ends up in the sump in about 10 days.

Between the new-for-1975 "anti drainback valve" that Norton installed but doesn't appear to be there on this particular bike, and sorting the oil pump, I should be able to get fixed ...

Question is, does the timing cover need the paper gasket for "spacing" it out from the engine case when I reinstall it? Since I discovered Loctite 515/518, I only use paper or fiber gaskets when they are dimensionally required; in all other applications, I use the anaerobic Loctite gasket-maker for flange and cover-type joints and have NO leaks anywhere I use it, including BSA cylinder base gaskets. (I still use copper head gaskets and copper drain seals, there's no substitute for them).

Thanks for any info and experience.

Lannis

Click to expand...

Yes, you need the paper gasket both for the intermediate gear end play and the proper amount of squish on the conical seal. Jim

Lannis said:

Between the new-for-1975 "anti drainback valve" that Norton installed but doesn't appear to be there on this particular bike

Click to expand...

Presumably, all it needs is a new plunger (06-6199) and spring (06-6198) to replace what's been lost/removed (or, less likely, never fitted).

L.A.B. said:

Lannis said:

Between the new-for-1975 "anti drainback valve" that Norton installed but doesn't appear to be there on this particular bike

Click to expand...

Presumably, all it needs is a new plunger (06-6199) and spring (06-6198) to replace what's been lost/removed (or, less likely, never fitted).

Click to expand...

...which may slow it down substantially, some, or not much... :mrgreen:

L.A.B. said:

Lannis said:

Between the new-for-1975 "anti drainback valve" that Norton installed but doesn't appear to be there on this particular bike

Click to expand...

Presumably, all it needs is a new plunger (06-6199) and spring (06-6198) to replace what's been lost/removed (or, less likely, never fitted).

Click to expand...

If your engine has the MK3 timing cover fitted without the oil plunger you will loose a substantial amount of oil pressure as then the oil has a bypass through the orifice in the back of the plunger cavity :!:

You need the MK111 T.C. fibre gasket. The full gasket set comes with a new plunger and spring ,at least mine did last rebuild. Have heard of some MK111,s that did not have the passage for it bored at all what with factory labour issues and prolonged strike so can you photo this area ?

There can be a little burr where the plunger goes in and out. Mine tended to drag just a bit. With the spring not being very strong, the plunger needs to move smoothly.
Although the MKIII cover does help in this regard, it is not perfect. The timing chain inspection port is quite nice though.
Also, you may already know this, but the MKIII cover calls for a MKIII conical seal washer for the pump along with the pump insert that hold the seal.

All -

Thanks much for all the advice, it all seems to be right on target.

I'm going to send the oil pump and cover (don't REALLY need to send the cover but the Flat Rate postage is the same) to AMR (Tucson) today.

They're going to replace the missing plunger with a ball, replace the spring, replace the seals and gaskets (conical seal, shaft seals, and provide a TC gasket) and do their patented handworking of the oil pump.

As L.A.B. says, it may just "slow the oil down" a bit on its way to the sump, but surely having SOMETHING there rather than just a blank space will be better than nothing - and if I can get an improvement on the 10-day-draindown that I've got now, I'll count it as a gain.

I also got talked into a Pazon ignition for the bike - I was having the "won't go back to idle" problem and was considering new heavy-duty AAU springs, but then bill50cal reminded me that "This fiddling with the mechanical AAU is never going to end" and so I called Frank at Clubman Racing and discussed the pros and cons of Boyer, Pazon, Tri-Spark, and Wassell, and after we talked he suggested the Pazon even though cost was no object (well, the range is only $119 for the Wassell to $259 for the TriSpark so it wasn't a big deal).

So what with new longer-and-heavier Hagon shocks to improve cornering clearance with a load on, new Ferodo pads, a new ignition and new anti-drain valve, that should be IT for now and I'm going to be riding it quite a bit this year .....

Lannis

Lannis said:

I'm going to send the oil pump and cover (don't REALLY need to send the cover but the Flat Rate postage is the same) to AMR (Tucson) today.

They're going to replace the missing plunger with a ball, replace the spring, replace the seals and gaskets (conical seal, shaft seals, and provide a TC gasket) and do their patented handworking of the oil pump.

Click to expand...

Well, if they do all that lot, then I think you should see a significant reduction in the rate of drainage.

L.A.B. said:

Lannis said:

I'm going to send the oil pump and cover (don't REALLY need to send the cover but the Flat Rate postage is the same) to AMR (Tucson) today.

They're going to replace the missing plunger with a ball, replace the spring, replace the seals and gaskets (conical seal, shaft seals, and provide a TC gasket) and do their patented handworking of the oil pump.

Click to expand...

Well, if they do all that lot, then I think you should see a significant reduction in the rate of drainage.

Click to expand...

That's all I'm really after. None of these old bikes is going to be perfect; some design issues, you can't do much about.

My A10 BSA takes about 4 weeks to get all the oil into the sump. And if you forget, and start it up with all that oil in there, it will puke 70% of it out of the breather onto the floor in a few seconds! Nothing to do about that except a new oil pump, probably .....

Lannis