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68triton
68triton
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1952 Ariel Square 4 Oil Problem! Help!!
#812582 06/15/20 2:04 am
Joined: Jun 2020
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KevinP Offline OP
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Hi everyone. I have a 1952 Square 4 Mark I and not had it long. It's in pretty original condition but someone previously put a oil cooler on it. I have just started to start & run it to see what needs to be done and it has decided to dump a heap of oil on the ground. It has come from the breather on the oil tank. Am wondering if anyone has any ideas for me to start looking at to try and fix this oil problem.. Thanks.

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Re: 1952 Ariel Square 4 Oil Problem! Help!!
KevinP #812670 06/15/20 5:06 pm
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Just a thought, is it possible the sump was full of oil before you started it (drain down from the oil cooler ?). If you filled the oil tank before starting and there was oil in the sump it will overfill the tank.


Laurence Luce
Re: 1952 Ariel Square 4 Oil Problem! Help!!
KevinP #812677 06/15/20 6:14 pm
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kevinP you do know how notorious they are for needing the crankshaft sludge traps removing and cleaning out I hope . If it hasnt had them cleaned in a while you could have trouble . They are also quite bad at having low oil pressure when hot . The fix is to swap the oil pipe to the gauge with the one to the rockers , if it hasnt already been done ,so its the smaller one to the rockers , which still allows plenty of oil , and the larger to the gauge . mines a 51 with the oil gauge only set in the tank . [Linked Image from i.ibb.co]

Re: 1952 Ariel Square 4 Oil Problem! Help!!
KevinP #813042 06/18/20 2:46 pm
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The swapping of the oil pipe to the smaller one to the rockers is a bit of a contentious topic . Some say do it some say dont . I have an aftermarket oil pump on my 51 so have a lot of oil flow . If you have the older plunger type oil pump then maybe it isnt such a good idea . I am happy with the oil flow to my rockers/ camshaft with the rotary pump I have now fitted . and a lot happier with 40 lbs oil pressure when hot .

Re: 1952 Ariel Square 4 Oil Problem! Help!!
KevinP #813059 06/18/20 4:40 pm
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40 lbs oil pressure seems a bit much. Spec for an ohc Velocette is only 10 lbs. I have heard too much pressure can actually wash out plain big end bearings. Is there a way to adjust pressure on an Ariel Square Four? I have a '53 mk2 I have not yet run and was considering upgrading the oil pump.


Laurence Luce
Re: 1952 Ariel Square 4 Oil Problem! Help!!
KevinP #813074 06/18/20 7:38 pm
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pressure gauge goes up to 100 , which is where mine is on start up , goes down to 10 which is not where i want it so 40 is in the middle seems right to me . Velocettes are bearing big ends which are a lot less pressure than shell big end bearings too .

Last edited by ducati2242; 06/18/20 7:41 pm.
Re: 1952 Ariel Square 4 Oil Problem! Help!!
KevinP #813085 06/18/20 9:11 pm
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Triumph and BSA twins are happy with 40 - 50 psi on hot engine, Tridents even more so 40 psi in your case is probably right.
The question is how much revs this engine needs to keep 40 on a hot engine?

Re: 1952 Ariel Square 4 Oil Problem! Help!!
KevinP #813167 06/19/20 4:57 pm
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Good to know the reasonable range of oil pressure, thanks for that. Can't imagine AMC and Enfield twins with the puny little plunger pumps they used ever got even close to that. Maybe that is why Enfields had a reputation for breaking cranks despite the massive dimensions of their journals.


Laurence Luce
Re: 1952 Ariel Square 4 Oil Problem! Help!!
Adam M. #813254 06/20/20 7:55 am
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Originally Posted by Adam M.
Triumph and BSA twins are happy with 40 - 50 psi on hot engine, Tridents even more so 40 psi in your case is probably right.
The question is how much revs this engine needs to keep 40 on a hot engine?

Ticks over after a ride with 40 pressure . KevinP is asking the questions though I know mine is good .

Re: 1952 Ariel Square 4 Oil Problem! Help!!
KevinP #813319 06/20/20 10:08 pm
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Sorry for misunderstanding, he never wrote a second post?


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