Wet sumping, oil not returning to tank...

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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rsimo
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Joined: Wed Aug 18, 2021 9:54 pm
Location: UK

Wet sumping, oil not returning to tank...

Post by rsimo »

Hi ,
Bit of a long read I know, but Any help greatly appreciated.
Picked up a 64 CSR14 as a project. Engine was running, but noisy. Once stripped, outboard mains bearing holder was butchered, ie bearing held in place by peaned over casing cap. So replaced L/H casing with an older one. Which meant having to make up a tube for breather stator, as there was no bolt hole in new casing.
Rebuilt engine, started up, within 5mins or so, it started blowing oil out of breather, (a lot),
So read somewhere that new stators are incompatible with old casings.
So found an old stator, with tube, rebuilt engine. Started up, same problem!! Runs fine for 5 mins or so, then oil tank empties into sump, and chucks oil out of breather.
Getting return from barrel, but nothing through filter tunnel return, even with filter out. Although it looks to be coming through the back end of filter tunnel.
I'm obviously getting something wrong, which I hope one of you kind folk will set me right on.
Getting fed up with stripping and rebuilding for no reward.
Any info as I said, would be greatly appreciated.
Cheers
Richard
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clanger9
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Location: Chester, UK

Re: Wet sumping, oil not returning to tank...

Post by clanger9 »

Tricky. A '64 CSR should have the "long" filter housing and high capacity oil pump. If the older LH casing is the shorter type, perhaps something doesn't line up in the oil return circuit?
1989 Moto Morini Dart 350
1993 Ducati 750SS
rsimo
Posts: 10
Joined: Wed Aug 18, 2021 9:54 pm
Location: UK

Re: Wet sumping, oil not returning to tank...

Post by rsimo »

Thanks for reply.
Having now read all the related threads I have come to the conclusion,that the 6.5" filter I have for the csr casing is not compatible with the scavenged drive side casing im using.
So I've ordered the shorter filter.
I also read that the csr pump is incompatible with older casings, is this true??
Because it also says the pump fits all!!
As my next step was to rebuild with matching set of older casings and lose the log book match.
As always, any help fully appreciated.
Thanks in advance
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clanger9
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Joined: Sat Jun 20, 2015 9:38 am
Location: Chester, UK

Re: Wet sumping, oil not returning to tank...

Post by clanger9 »

You mustn't fit a CSR pump to non-CSR casings. The longer stroke means it may jam. However, I don't think CSR pumps are available anywhere.
You can fit a standard oil pump to any casing.
1989 Moto Morini Dart 350
1993 Ducati 750SS
rsimo
Posts: 10
Joined: Wed Aug 18, 2021 9:54 pm
Location: UK

Re: Wet sumping, oil not returning to tank...

Post by rsimo »

Good to know,
Next question, how to tell difference?
As always, any and all help appreciated.
Thanks in advance.
rsimo
Posts: 10
Joined: Wed Aug 18, 2021 9:54 pm
Location: UK

Re: Wet sumping, oil not returning to tank...

Post by rsimo »

Post Thu Nov 12, 2020 6:05 pm
The standard pump has a stroke of 3.24mm.
The late CSR pump has a stroke of 4.48mm.
All other dimensions identical.
Just refound this, will measure the groove tomorrow.
rsimo
Posts: 10
Joined: Wed Aug 18, 2021 9:54 pm
Location: UK

Re: Wet sumping, oil not returning to tank...

Post by rsimo »

Also, tried the shorter filter in the l/h casing, thr front end with top hat covers return to oil tank.
The longer filter comes well past hole, so I assume the long filter is the correct one.
rsimo
Posts: 10
Joined: Wed Aug 18, 2021 9:54 pm
Location: UK

Re: Wet sumping, oil not returning to tank...

Post by rsimo »

Just an update.
After measuring, we found out we had the long travel pump, which has very little clearance on the rear plug cold. so concerned about the expansion, I filed 1.75mm off plug, which if I measured correctly should give me around 1.5mm clearance. 🤞🤞
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clanger9
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Re: Wet sumping, oil not returning to tank...

Post by clanger9 »

Perfect! If you have a usable CSR pump, the extra capacity is worth having.
Should be fine with that clearance on the end plug. 👍
1989 Moto Morini Dart 350
1993 Ducati 750SS
rsimo
Posts: 10
Joined: Wed Aug 18, 2021 9:54 pm
Location: UK

Re: Wet sumping, oil not returning to tank...

Post by rsimo »

Think I will be bench testing it first before refitting to the frame. Just to make sure oil is returning correctly.
Thanks for all the comments.
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