Wet sumping while running

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Re: Wet sumping while running

Postby Stan Palmer » Wed Dec 11, 2019 8:44 pm

There’s a message from Don Madden describing cleaning out the intersecting drilling’s. I didn’t fully understand it, I guess you need the crankcase in hand, but it certainly sounded like the problem you have. He fished out bits of gaskets and various goo.
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Re: Wet sumping while running

Postby Dixter » Thu Dec 12, 2019 5:15 am

Yes and yes. You must remove the pump spindle. If one were to run a metal rod, like the aircraft length twist drill, I’d mentioned earlier, up the scavenge gallery, and remove the upper slotted screw in the image you attached, you can touch the tip of the twist drill with a piece of wire thru the now open port.

Obviously when I mention a twist drill, it is NOT powered by a drill motor, only light finger pressure. The advantage of a twist drill is to rotate the drill and catch any loose scarf in the twists.

Ciao, DC
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Re: Wet sumping while running

Postby cfaber » Thu Dec 12, 2019 6:06 am

Dixter wrote:Yes and yes. You must remove the pump spindle. If one were to run a metal rod, like the aircraft length twist drill, I’d mentioned earlier, up the scavenge gallery, and remove the upper slotted screw in the image you attached, you can touch the tip of the twist drill with a piece of wire thru the now open port.

Obviously when I mention a twist drill, it is NOT powered by a drill motor, only light finger pressure. The advantage of a twist drill is to rotate the drill and catch any loose scarf in the twists.

Ciao, DC


So you're not recommending I put the twist drill on my impact drill and go to town? :mrgreen:

Yeah, I've got it all apart now, and plan to measure everything and probe the drilling in the next day or so. I grabbed some pictures and some initial measurements with my cheapy chinese special micrometer and will be posting them here shortly.
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Re: Wet sumping while running

Postby cfaber » Thu Dec 12, 2019 3:52 pm

cfaber wrote:Does this drilling intersect the drilling for the sump?
Image

And if it does, do you need to pull the pump to access it fully or can I check that it's clear with the pump in place?


To answer my own question, yes the pump needs to be pulled, unless you're crazy lucky and the pump is perfectly positioned with the notch right inline with the drilling.

Also, it's the bottom of the two screws which allows you to access the scavenge drilling which appears to be at the top of the bore.
Last edited by cfaber on Fri Dec 13, 2019 3:16 am, edited 1 time in total.
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Re: Wet sumping while running

Postby cfaber » Fri Dec 13, 2019 3:14 am

Today I grabbed a 12" 3/16" bit and ran it all the way up the drilling to discover..... Nothing at all. I think stuck the air gun up the drilling hole and to my surprise, a nice steady stream of air coming out of the port in the pump. I did get a telescopic gauge from my buddy (until my set arrives) however it was the wrong size, so I'll check the bore tomorrow. That said while I was digging through the parts that came with the motor I found another oil plug, this one had an aluminum washer a was shorter, same thread, however it had a metric head (so maybe a replacement?) In any event if the bore sizing checks out then I'm thinking that maybe the other oil plug was just a bit too long and it wasn't bottoming out but it was reducing the clearance around the scavenge hole just enough.

So tomorrow I'll head back over to my buddies shop, swap out the telescopic gauge, return his 3/16" drill and try again. if it checks out I'll reassemble and test the theory
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Re: Wet sumping while running

Postby cfaber » Fri Dec 13, 2019 5:58 pm

The bore diameter is 0.715"
Scavenge side of the shuttle is 0.714"
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Re: Wet sumping while running

Postby Dixter » Sat Dec 14, 2019 5:14 am

Colin, did you compare the measurements you took to the Army Inspection Standards I sent you?

The values you posted do not add up.

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Re: Wet sumping while running

Postby Mick D » Sat Dec 14, 2019 7:25 am

Hi

Wasn't there a photo or two showing the plunger and other components dis-assembled posted earlier?

I was going to comment that the pin was quite depressed in it's screwed housing - is it stuck and if not is the spring installed.

Of course I may have been imagining things again.

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Re: Wet sumping while running

Postby clive » Sat Dec 14, 2019 3:25 pm

Mick D wrote:Hi

Wasn't there a photo or two showing the plunger and other components dis-assembled posted earlier?

I was going to comment that the pin was quite depressed in it's screwed housing - is it stuck and if not is the spring installed.

Of course I may have been imagining things again.

Regards Mick


I think your imagination is running wild Mick there is a photo of the pump but nothing disassembled in this thread. The pin housing you refer to though in the picture on this thread does not look original. I wonder if the internal dimensions are too long. Or if the pump pin matches the dimension of the groove in the pump. Not sure what spring you are referring to as possibly missing.
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Re: Wet sumping while running

Postby Mick D » Sat Dec 14, 2019 3:32 pm

Or did the edit 13,12,19 remove them? ;)

My bad - no spring under the pin - :oops: :oops:

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