Sq4 MKI - Oil return problems w/ Morgo pump

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Paul_Linden
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Re: Sq4 MKI - Oil return problems w/ Morgo pump

Postby Paul_Linden » Tue Jun 15, 2021 7:28 pm

Here are the two gaskets. The lower one is from a square four, 1937-51. The circular hole at 4 o’clock is for the oil pressure valve. The upper one is from square fours marks 1 and 2, 1951-58.
Mark 1 square fours have the oil pressure release at the right hand end of the front crankshaft. Morgo pumps for Mark 1s do not have a pressure release valve in them.
Mark 2 square fours have the oil pressure release in the oil pump. Morgo pumps for mark 2s have a pressure release valve in them.
40DE7E92-0DCF-49CB-8DB5-D2C4A2139D52.jpeg

3FDFCCC6-6039-40BE-93F3-9A7D8C2776C6.jpeg
Square 4 mk1, Square 4 mk2, Ariel Colt, Matchless G12, BSA C12.

klaus gerhard
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Re: Sq4 MKI - Oil return problems w/ Morgo pump

Postby klaus gerhard » Tue Jun 15, 2021 8:02 pm

Gui,
I can send you a Mk1 plunger pump to try. Send me a pm with your address and I am more than happy to help.

Regards Klaus

allan.walker
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Re: Sq4 MKI - Oil return problems w/ Morgo pump

Postby allan.walker » Tue Jun 15, 2021 8:14 pm

Thanks again Paul.
That's clarified the gasket situation.
I've removed the front crankshaft cap on the timing side crankcase to put a socket on it to check for movement in the coupling gears, but I saw no evidence of a pressure release valve. There's just a large nut with a washer behind it. Is the prv behind there?

Gui.dorey
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Re: Sq4 MKI - Oil return problems w/ Morgo pump

Postby Gui.dorey » Tue Jun 15, 2021 8:45 pm

Allan,
see the picture. That small nut in the middle of the crankshaft nut is the valve housing. In there is a ball, spring and they are held by a cotter pin.
Attachments
InkedIMG_1164_LI.jpg
1951 Ariel Square Four MKI
1954 Ariel NH Red Hunter
1929 BSA Sloper
1946 BSA B31 (project)
1954 BSA C11G
1960 Harley Sportster XLH
1951 Harley WL 45

Gui.dorey
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Re: Sq4 MKI - Oil return problems w/ Morgo pump

Postby Gui.dorey » Tue Jun 15, 2021 8:55 pm

klaus gerhard wrote:Gui,
I can send you a Mk1 plunger pump to try. Send me a pm with your address and I am more than happy to help.

Regards Klaus


Many thanks for the offer Klaus. That's very kind and I'll keep it in mind. Let's wait to see what Morgo says, and anyway I have to wait for the parts I need for the top end and get that done. At the moment I could only try it staticly, which wouldn't bring us any further. Once the engine is running again and I still haven't solved the problem with the Morgo, I'll give you a ring.
1951 Ariel Square Four MKI
1954 Ariel NH Red Hunter
1929 BSA Sloper
1946 BSA B31 (project)
1954 BSA C11G
1960 Harley Sportster XLH
1951 Harley WL 45

allan.walker
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Re: Sq4 MKI - Oil return problems w/ Morgo pump

Postby allan.walker » Wed Jun 16, 2021 10:18 am

Thanks for the picture, Gui.
To avoid cluttering your thread any further, I have started a new one.
viewtopic.php?f=4&t=11810

Allan.

Gui.dorey
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Re: Sq4 MKI - Oil return problems w/ Morgo pump

Postby Gui.dorey » Sun Jun 27, 2021 9:07 am

My pump is now on its way to Morgo for inspection and repairs. I’m curious to see what they find.

Anyway, here is Morgo’s comments about my problem.

“The rotary pumps are designed to release a little oil when running to lubricate the drive cross however not at the level you have describe below “

Cheers
Gui
1951 Ariel Square Four MKI
1954 Ariel NH Red Hunter
1929 BSA Sloper
1946 BSA B31 (project)
1954 BSA C11G
1960 Harley Sportster XLH
1951 Harley WL 45


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