57 on singles , return pump check valve in timing cover.

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John Todd
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57 on singles , return pump check valve in timing cover.

Postby John Todd » Tue Jun 04, 2019 10:51 am

I believe from 1957 on the single had an additional check valve fitted in to the timing cover for the return line. This is fitted with a 7/32 ball and spring, does anybody know the size and depth of this hole required to fit this check valve thanks. Regards John.

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Keith.owen
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Re: 57 on singles , return pump check valve in timing cover.

Postby Keith.owen » Tue Jun 04, 2019 4:08 pm

There was a service note for this (attached).

I have carried out the mod on my 1950VH - it is simple to do but it involves removing the outer casting and using a pillar drill.

ariel oil pump non return mods.pdf
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BR,
Keith
Keith Owen
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1950 Rigid Ariel VH
1951 Rigid Ariel NH (under construction)
1973 Norton 850 Commando Interstate

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Re: 57 on singles , return pump check valve in timing cover.

Postby John Todd » Thu Jun 06, 2019 2:02 pm

Thanks for that Kieth , that will save me guessing. The cover I am altering is 1956 and I have redrilled it for a pump fed supply to the rockers and thought I might do the return mod as well. Regards John.

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Re: 57 on singles , return pump check valve in timing cover.

Postby Keith.owen » Thu Jun 06, 2019 4:01 pm

Hi John,
If you are in the mood for it, I think the cam oil level mod is also worth doing.

I have done it on my VH and coupled with the direct feed to the rockers, the cam gets a good oiling. I understand that it has long been considered a shortfall of the engine in that the cam and followers wear prematurely due to poor lubrication. David Anderson of the Australian section of the forum kindly sent me a write up of the mod.

Keith
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Re: 57 on singles , return pump check valve in timing cover.

Postby John Todd » Fri Jun 07, 2019 2:09 pm

Thanks for that Kieth , I have looked at that in the past and thought it would be difficult to seal that pipe at the cam cover end with any certainty as hot oil is very viscous. Also what about the leak path behind the half time pinion via the timing side main bearing is this not a problem , and are you happy with the mod.
I have never been a fan of feeding the rockers off the return , it seems to me a easy way to avoid over oiling of the guides but at the expense of a decent flow down the push rods and onto the cam if it can get past the followers anyway. I am looking at a metered flow off the return via a drilling in the cam chest near the breather and running a small bore pipe behind the inlet follower ( forked variety ) across to the top of the cam lobe where a drip feed would drop onto the cam. Yeh I know I should get out more. All good fun.
In all the years I have run Ariels both on the road and racing it has always been the return pump failing that tests your patience. In the end I carried 2 spare pumps , I was riding long distances , I even reco'd my pumps with hard chrome plungers the lot, still not 100% reliable. In the end I rigged up a visual indicator on the handle bars ( a gutted oil gauge) which told me that the return pump was working . This saved me running out of oil as I had a large bore breather which passed all the oil out of the motor without the usual tell tale of a slowing motor as it filled up. Sorry for being long winded. Regards John.

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Re: 57 on singles , return pump check valve in timing cover.

Postby nevhunter » Sat Jun 08, 2019 7:44 am

You need a friction modified "decent" oil as well as having oil there. Open valve gear engines have no oil coming down the tubes and on the OHV's the front tube has some of the hottest oil around when on an iron head motor. Plenty of Ariels and Rudges have metal flecks in the oil and cams that look decidedly "ordinary" particularly the exhaust one on the twin lobe set up.. I never run the heavy original VH valve springs. They just about push the rockerbox off the engine. Nev

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Re: 57 on singles , return pump check valve in timing cover.

Postby Keith.owen » Wed Jun 12, 2019 2:54 pm

Hi Nev,
What would you recommend for exhaust valve springs on an iron head VH?
Also, any thoughts about an iron head NH?

John,
I have had no problems resulting from the mod; well at least so far!

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1951 Rigid Ariel NH (under construction)
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Re: 57 on singles , return pump check valve in timing cover.

Postby nevhunter » Thu Jun 13, 2019 7:05 am

I just run the VG ones. There are people who supply tapered (conical ones) Franklin cams New Zealand. The iron 350 OHV doesn't seem to run particularly hot, but oil from the exhaust area valve is Bl***Y hot The push rod tube tells you so. Nev

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Re: 57 on singles , return pump check valve in timing cover.

Postby david.anderson » Thu Jun 13, 2019 11:18 am

John
The raised oil level in the timing chest was an Ariel factory modification. Yes there are clearly leak paths but the path alongside the timing side mainshaft is virtually at the raised level in any case. The ¼” copper pipe that is used in lifting the oil level fits into a ¼” hole. Th oil leak path past the pipe would not be fast enough effect the raised oil level while the engine was running.
In over 40 years of riding my VH I have experienced 2 return oil pump failures. On the first occasion a friend who was riding behind me advised me of the oil leak from the crankcase and 10 minutes roadside had the pump removed and fixed. On the second occasion I pumped all the oil out the crankcases and did not find out until arriving home. After that I fitted the extra ball and spring to the timing cover and have not had another failure.
Keith
The heavy VH springs become coil bound with the extra lift of the HS cams and the seat pressure is too high for use even with a standard cam (about 300lbs seat pressure0
The VG springs are inadequate if the bike is revved hard and will bounce. They only have about 80 lbs seat pressure. They weaken quickly and should be changed regularly if used. They are more than adequate on the NH with its smaller lighter valves.
To substitute springs otherwise means having custom top and bottom retainers made and I have tried LS1 V8 and ecotech V6 springs with some success. I have also been told that some are using BSA gold star valve springs and packing under the spring to achieve about 110lbs seat pressure.
David


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