Oil return

[G Dicko]

Hi
I'm a new member to this club and I'm a born again biker. In December I purchased a stunning 1950 AJS model 18 and a very nice Matchless G3 Mercury. Regarding the oil returning from the engine. The matchless floods back at quite a good rate through the two hole's at the top of the pipe. The pipe in the oil tank on the AJS is a much smaller diameter and the flow is a trickle in comparison and occasionally momentarily stops and just drips. Is this right or should it flow like the Matchless ?
Do I need to take the engine out for a complete strip down to recon the pump ?
Any advice would be very much appreciated.
Cheers
Glen

[dave16mct]

Is your Matchless Mercury a late model with Norton oilpump? 1964 on? That would give a very good return whereas your model 18 has the sort of return normally found on earlier singles with the plunger pump.
Dave.

[ISITME_LAPSED]

The oil return rate on my '57 18 is much as you describe also.

[G Dicko]

Is your Matchless Mercury a late model with Norton oilpump? 1964 on? That would give a very good return whereas your model 18 has the sort of return normally found on earlier singles with the plunger pump.
Dave.

Not sure if its a Norton pump, its a 1962 bike and the engine is a 350 short stroke if that helps. I have a club certificate to show its the original engine. it has the little plates with 4 screws each end of the plunger. it really pours oil back in the tank compared to the AJS.

[G Dicko]

The oil return rate on my '57 18 is much as you describe also.

That's re,assuring, thanks.
I was thinking this morning that it could be that the bulk on the oil is going to the rockers. it could be that someone has not set the flow screw properly and i'm just not giving it time for the oil to sink to the sump, because on start up it flows good for a minute then almost stops. I know that's the only flow that can be regulated and it should be a 6th of a turn from closed. I'm going to check it tonight.

thanks for both replies chaps.

cheers
Glen

[Greybeard]

The return flow will become less a minute or two after start up, Glen, and will probably become intermitent with the odd bubble. Its because the return pump is bigger than the feed side to stop the sump filling up. On start up its clearing the oil thats drained down into the sump. All totally normal

Steve

[SPRIDDLER]

I was thinking this morning that it could be that the bulk on the oil is going to the rockers. it could be that someone has not set the flow screw properly

That metering screw with locknut is the feed to the inlet valve only and should be as you rightly say, about 1/6th turn open. The rocker system as a whole is fed by the external pipe from the front of the pump to the top of the rocker box which has non-adjustable metering inserts.

Your description of the return flow is (and as Greybeard mentioned) the same as with my '54 G3 at tickover/slow revs; initially a steady but gentle flow until the drained-down oil has been cleared from the crankcase then spurts and bubbles.

[G Dicko]

Thanks for all the replies. You've really put my mind at rest. I just couldn't bear the thought that I could seize the engine on such a great bike. Roll on summer so I can get out on it 😊.
Stay safe.
Glen

[Taid]

I was lucky with mine .. some PO had changed the feed and return round .. luckily the level of the oil in the tank was very high so there was a feed ..