Sq4 MkI - what now?!?

Singles, twins and fours.
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simon.holyfield
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Re: Sq4 MkI - what now?!?

Post by simon.holyfield »

Gui.dorey wrote: Thu Apr 21, 2022 6:42 pm
rschurr wrote: Thu Apr 21, 2022 3:38 pm As I understood, you installed a Morgo oil pump. A pressure relief valve is installed in this. So you don't need a pressure relief valve in the crankshaft. You can simply replace the end of the shaft with a short matching screw. This is how I did it.
Cheers Rudy
Are you sure? I don’t think the Morgo for the MkI has a relief valve. If I remember correctly that only comes in the version for the MkII.
Agreed. If my Mk1's Morgo has a pressure relief valve, it's news to me.
cheers

Simes

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Re: Sq4 MkI - what now?!?

Post by rschurr »

Gui, you are right, mine is a MK2 with a Mk1 Crank!
1923 James Model 12 500ccm v-twin -- 1960 Chevrolet Corvette C1
1926 Douglas EW 350ccm flat-twin -- 1967 Chevrolet Corvette C2
1936 Motosacoche 500ccm single --- 1979 Chevrolet Corvette C3
1948 BSA A7 500ccm parallel twin -- 1955 Ariel Square Four MKII :!:
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Re: Sq4 MkI - what now?!?

Post by allan.walker »

You most certainly do need a prv in the crankshaft when fitting a Morgo pump to a Mk1. The Mk2 has a prv on the body of the pump and 'blows off' into the timing cover.
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Re: Sq4 MkI - what now?!?

Post by keith wainwright »

Hi Gui so sad to hear about the sq 4, devastating. However some points to check on strip down the Mk11 Morgo has a built in prv. f using the front Mk1 crankshaft make sure you plug off the existing prv built into the front crankshaft. You will have to tap a thread into the shaft I use 5/16BSF and locktite a bolt into the end, cutting off flush with the end of the shaft. The same applies if using the original Mk11 pump. If using a Mk1 Morgo this pump has no built in prv. Neither has the original Mk1 pump. The prv is built into the end of the front crankshaft. Always fit new spring ball and split pin. Obtain one spare ball bearing to use to gently hammer the ball back into the shaft to reseat the valve in the end of the crankshaft. Best of luck on strip down hope the above helps. Keep us posted. So just to recap the Ariel's Mk1 and Mk1 Morgo have no built in prv. They use crankshaft prv . Ariel's Mk11 pump and Mk11 Morgo have built in prv's . Keith
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