Oil Pressure Gauge or light?

Information relating to the Matchless G9 or AJS Model 20 500cc twin
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Re: Oil Pressure Gauge or light?

Postby sunnybob » Tue Jan 23, 2018 9:47 pm

Hi Jean,
I already sent him an email but I had no answer. Maybe it went lost...so I just sent another. I would love a pressure gauge, but if there is not enough pressure for a 5psi switch how can the gauge work?
A bientôt.
Roberto

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Re: Oil Pressure Gauge or light?

Postby JEAN-NOEL » Wed Jan 24, 2018 8:18 am

Hello Roberto,
the pressure gauge will not be fitted in the oïl return line, but on the filter tunnel cap. I think you haven't a discharge valve on your 1958 G20 (you can verify easily : this valve is inside the timing chest , just Under the dynamo. You can also see it after removing the oïl filter.) If it is not fitted, the pressure gauge range must be until 350 Psi ! When the engine is hot, at idle oïl pressure is about @ 25 psi. But you can fit an electrical sensor, wich has no broblèm in case of over pressure, instead of a mechanical gauge. The gauge must be an electrical one, for exemple a Smith for old Mini. Hope this could help you.

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Re: Oil Pressure Gauge or light?

Postby JEAN-NOEL » Wed Jan 24, 2018 8:32 am

You can see a pressure gauge in operation, following this link :

AJS 650 1965 restored first run part 3 + YouTube

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Re: Oil Pressure Gauge or light?

Postby sunnybob » Wed Jan 24, 2018 9:43 am

JEAN-NOEL wrote:Hello Roberto,
the pressure gauge will not be fitted in the oïl return line, but on the filter tunnel cap. I think you haven't a discharge valve on your 1958 G20 (you can verify easily : this valve is inside the timing chest , just Under the dynamo. You can also see it after removing the oïl filter.) If it is not fitted, the pressure gauge range must be until 350 Psi ! When the engine is hot, at idle oïl pressure is about @ 25 psi. But you can fit an electrical sensor, wich has no broblèm in case of over pressure, instead of a mechanical gauge. The gauge must be an electrical one, for exemple a Smith for old Mini. Hope this could help you.


Hi Jean, in order to fit a pressure gauge or switch on the filter tunnel cap should I machine it myself or there are any caps already ready on sale? Merci. A bientôt.
Roberto

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Re: Oil Pressure Gauge or light?

Postby JEAN-NOEL » Wed Jan 24, 2018 10:12 am

Hi,
Yes I have machined my filter cap : only a drill and a tap...
But I think you can order a new cap from the club with a plug to fit a union. It was the old model of the early 50th. Obviously you must ask the club, or AMC spares to be sure it is suitable for you filter type. See "WORKSHOP INSTRUCTIONS MANUAL 57-64, page 14 : checking oïl pressure. Page 21, fig 7, you can see the discharge valve.

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Re: Oil Pressure Gauge or light?

Postby sunnybob » Wed Jan 24, 2018 4:02 pm

Hi Jean, maybe I am wrong but my 1958 model 20 filter cap should be like this in picture
Image

if I machine it to fit a sensor or switch I don't think it will work till the filter is clean.. I mean.. I don't think to have pressure on cap because there is the valve.



Image

To use the 016179 cap I should forget to have the relief valve... Am I correct?
Last edited by sunnybob on Wed Jan 24, 2018 5:58 pm, edited 1 time in total.

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Re: Oil Pressure Gauge or light?

Postby JEAN-NOEL » Wed Jan 24, 2018 5:57 pm

Hi,
the part number required is 016179, available in limited stock from AMOC Parts Service. It is exactly the same as yours, except the plug to fit a gauge. The valve is only a non return valve, to avoid oïl in the camshafts area to go down in the sump, it opens when the engine is running. Look at the methode to check oïl pressure in your Owner's manual...or in the workshop manual. No problem !

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Re: Oil Pressure Gauge or light?

Postby sunnybob » Wed Jan 24, 2018 5:59 pm

Ok but To use the 016179 cap should I forget to have the relief valve... Am I correct?

What I mean there is a safe valve in case of clogged filter now. If I put a sensor or switch on type 016179 I will lost this security device?

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Re: Oil Pressure Gauge or light?

Postby JEAN-NOEL » Wed Jan 24, 2018 6:06 pm

No, the non return valve is the same, and you can dismantle the spring and the ball to clean them undoing the plug !

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Re: Oil Pressure Gauge or light?

Postby sunnybob » Wed Jan 24, 2018 6:09 pm

JEAN-NOEL wrote:No, the non return valve is the same, and you can dismantle the spring and the ball to clean them undoing the plug !


Jean thank you very much, I apologize if I'm a little bit off :oops:

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