G3 oil feed to cylinder jets.

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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sno335
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G3 oil feed to cylinder jets.

Post by sno335 »

Hi,I'm rebuilding a '54 G3 bottom end and I was attempting to check all the oilways before assembly.I tried to poke a probe down the oil hole on top of the timing side case which feeds the oil jets in the barrel.It feels solid.Is there a non return valve or ball bearing or is it a blockage??
SPRIDDLER
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Re: G3 oil feed to cylinder jets.

Post by SPRIDDLER »

Yes, there's spring and a ball. You can remove them by screwing in a 3BA screw and levering it all out.
On later models it was discontinued/blocked off.
I blocked off mine on my '54 G3LS and no probs in 25k miles with the original cylinder with oil holes. I also used the base gasket without the cutaway for the oil hole.

Have a look at the illustration and text on page 10 ref blocking it off in this article
http://archives.jampot.dk/technnical/Sp ... hanics.pdf
Oil block cylinder.JPG
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sno335
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Re: G3 oil feed to cylinder jets.

Post by sno335 »

Thanks that's great.I'll block it off, the more oil to the bush the better.I tried to download the manual but my printer went haywire.
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Duncan
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Re: G3 oil feed to cylinder jets.

Post by Duncan »

Hi Neville, I need to fit a later barrel to a 1952 18S how did you block off your cylinder wall oil feed? Did you use a 3BA grub screw or similar or some other method??
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Re: G3 oil feed to cylinder jets.

Post by SPRIDDLER »

Duncan wrote: Mon Jul 04, 2022 10:07 pm Hi Neville, I need to fit a later barrel to a 1952 18S how did you block off your cylinder wall oil feed? Did you use a 3BA grub screw or similar or some other method??
Yes Duncan, a grub screw - 3BA screw with the head cut off and a bit of a screwdriver slot hacksawed in the top. I Wellsealed it in place rather than using Loctite thread locker in case I would need to remove it. It was a while ago but I think I left the bush, spring and ball in place since if removed I'd be certain to have mislaid them if needed in future. There's no great oil pressure in the feed so I imagine that just a base gasket without the cutaway might be sufficient as it's pinched hard 'twixt cylinder and c/case but it's simple enough to fit a belt 'n braces grub screw.
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Duncan
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Re: G3 oil feed to cylinder jets.

Post by Duncan »

Thanks for that Neville , now its time to rummage through all those little jars of screws that I just knew would come in handy one day.
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