Darn it

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
Allen_F
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Re: Darn it

Post by Allen_F »

Wet sumping with the engine running would be tricky.
Hope all your troubles solve themselves because you are unlikely to
Allen_F
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Re: Darn it

Post by Allen_F »

a gift for you.
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REW
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Re: Darn it

Post by REW »

Allen_F wrote:oil pump animation.
That is nice! I haven't tried to visualise the single pump in operation before and this certainly does it.

Re the OP's question and oil not returning properly to the tank - I have suffered this (single and twin) when the felt tank filter has become displaced and blocked the outlet from the filter housing to the tank proper. I take it this doesn't apply here?
Ron

1951 Matchless G3L thumping round the Durham Dales.
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clive
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Re: Darn it

Post by clive »

good point Ron. There were some filters around the jumbles a while back that had too full a turn over at the top which then blocked the outlet hole from the housing to the tank proper. In my case the engine did not wet sump instead the return pipe blew off the bottom of the oil tank. Bit messy.
clive
if it ain't broke don't fix
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Harry44
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Re: Darn it

Post by Harry44 »

Allen_F wrote:Wet sumping with the engine running would be tricky.
Hope all your troubles solve themselves because you are unlikely to

That sounds like a challenge, and it is accepted. :D
si is does non opportunus vos postulo a maior pango
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Pharisee
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Re: Darn it

Post by Pharisee »

Allen_F wrote:Re :- wet sumping :- apparently if you leave the piston at tdc on compression stroke this does not happen.
I think you'll find that that's a bit of an "urban myth".

For any given engine at TDC on compression, the oil pump could stop at any one of four possible points (90° apart) in its cycle due to the fact that it takes 8 revolutions (4 working cycles) of the crankshaft to move the oil pump through 1 working cycle.

When the oil pump was assembled to the engine, the piston could be meshed with the crankshaft in any one of 16 positions as there are 16 teeth on the pump piston, so theoretically, with the engine at TDC on the compression stroke, the oil pump could be in any one of four positions out of a possible 64 positions.

John
I'm from the Fens.... Gimme six.
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dave16mct
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Re: Darn it

Post by dave16mct »

It's worth doing anyway. It closes the valves, relaxes the valve springs and often is in the right place to stop some wet sumping. I also do it with the twins. :D
Dave.
Andy51
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Re: Darn it

Post by Andy51 »

In Tech Tips there is a proposed solution (Tech Tips, 'Wet slumping, the definitive solution') that enables you to position the engine at tech with the pump plunger in the right position. I tried this and, while the theory is sound, the practicality of feeling a plunger while turning the engine with the kickstart was less than ideal, so I removed the modified end plate and resorted to draining the sump after a long lay-up. Cheers, Andy
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Harry44
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Re: Darn it

Post by Harry44 »

Well the colon hydrotherapy worked. :rofl: A sneaky bit of debris had got itself sucked into the scavenge pump. Removing the end plate and reverse flushing the pump back into the crankcase with the drain plug removed did the trick.

Thanks for the helpful advice :D

Cheers Harry
si is does non opportunus vos postulo a maior pango
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Harry44
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Re: Darn it

Post by Harry44 »

Allen_F wrote: Fri Jun 05, 2020 9:39 am Wet sumping with the engine running would be tricky.
Hope all your troubles solve themselves because you are unlikely to
Well a year after I fixed the wet sumping its running beautifully.
When first rebuilt the engine was very tight, hard to start and wasn't happy to tick over (idle) smoothly.
Now with a few thousand miles on the clock those issues have gone away.

I'm pleased with myself.

Cheers Harry
si is does non opportunus vos postulo a maior pango
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