Oil Feed Pipe Filter

Information relating to the Matchless G9 or AJS Model 20 500cc twin
stuart132
Posts: 58
Joined: Fri Nov 28, 2014 11:02 am
Location: Australia

Oil Feed Pipe Filter

Post by stuart132 »

Can anyone give me the benifit of there experience when fitting the oil filter, part # 015198? in the oil tank feed pipe
First of all I should mention the engine is a 1956 model, the bike is a 1954. The oiling parts of the engine are 1956 (ie. no oil relief valve in timing side crankcase) Is there a difference in the oil tank on 1954 and 1956 bikes

After the engine rebuild I removed and cleaned the oil tank and noticed that there was no oil filter fitted (P/No 015198) I ordered one from the spares department and when arrived, noticed that the 'flange' hole at the bottom of the filter was 1/4" (6mm), the inside diameter of the oil tank feed pipe is 3/8" (10mm). My concern is, with the filter fitted the diameter of the feed pipe is reduced to 1/4" could this cause oil starvation ?
I am using Penrite 'running in oil' as the engine has only covered 150 miles without the above filter fitted. Is the following normal:- when I start the engine after standing overnight the oil return pipe does not return any oil for 3 to 5 seconds and then returns oil in a steady stream then settles down to 'spurts' on tick over? If this is correct should there be any difference with the filter installed?

Fitting the Filter:- I take it that the filter fits inside the oil tank with the flange sitting on the end of the external oil tank pipe, what stops the filter from dropping down inside the 'rubber' oil pipe?
Any comments on the above two points would be appreciated.
I have attached a photo of the end of the filter flange and the oil pipe showing the the reduction in the diameter
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Mick D
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Location: Aberdeenshire

Re: Oil Feed Pipe Filter

Post by Mick D »

Hi

As I understand the system you are correct in inserting the oil strainer into the oil tank. The flexible hose delivery pipe should prevent the strainer dropping down, (the flange should be an interference fit in the pipe).
I don't have a photo, but from memory my strainer was the same as yours.

Regards Mick
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REW
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Re: Oil Feed Pipe Filter

Post by REW »

On my '53 M20 the filter is held "up" the inside of the oil tank spigot by the end of the copper oil feed pipe that abuts against it - the rubber pipe merely holds one against the other.

I too was concerned at the internal diameter of the filter flange but have been assured that the internal diameter is more than enough for the oil feed - look at the two holes in the banjo bolts.

That said I had already drilled the flange out before I was reassured but I took great care to avoid swarf dropping inside the filter. I won't bother next time.
Ron

1951 Matchless G3L thumping round the Durham Dales.
stuart132
Posts: 58
Joined: Fri Nov 28, 2014 11:02 am
Location: Australia

Re: Oil Feed Pipe Filter

Post by stuart132 »

Thanks Ron & Mick, you have put to rest my concerns with the reduced hole in the filter flange.

With regard to my question about the delay and 'amount of oil from the return pipe when starting the engine after standing overnight' could you please check if this is the same on your bikes. Reason for asking is that the previous owner had had oiling problems due to incorrect parts being fitted. I have since fitted the correct parts so just want to check that I haven't missed anything.

Stuart
Mick D
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Location: Aberdeenshire

Re: Oil Feed Pipe Filter

Post by Mick D »

Hi

A 3 - 5 second wait before seeing the oil return is fine, once any accumulated oil is pumped from the sump the flow will become sporadic so I'd have no concerns at what you are seeing.

Unless I've got things wrong, the oil in your system is filtered on it's return to the tank by the felt filter. Part number 015198 is a strainer intended to stop large particles entering the engine, (either introduced through the filler neck or if the return filter goes into bypass and something happens within the engine). The gauze on the strainer will not have any noticeable effect on oil flow.

Regards Mick
stuart132
Posts: 58
Joined: Fri Nov 28, 2014 11:02 am
Location: Australia

Re: Oil Feed Pipe Filter

Post by stuart132 »

Thanks for the information Mick, yes thats right, the oil on return is filtered through a (spring loaded from the top), felt filter.

Stuart.
stuart132
Posts: 58
Joined: Fri Nov 28, 2014 11:02 am
Location: Australia

Re: Oil Feed Pipe Filter

Post by stuart132 »

Hi everyone, any comments or suggestions on the following would be appreciated.

O.K. I fitted the filter and secured it in place. Filled the oil tank and started the engine, as per normal after a second or two I had a good stream of oil from the return pipe and it then slowed down to a trickle (and I mean a very slight 'start stop' dribble out of the pipe) It seemed that once the excess oil from the sump had been returned, the oil supply was insufficient to allow a reasonable amount of oil to be returned.

I then removed the hose from the oil tank feed to check the amount of oil flow, the stream of oil was less than two mm in diameter. I then removed the filter and had a good stream from the oil feed pipe (about 10 mm in diameter.) I might add that the oil tank has been cleaned and the filter is new.

I am at a loss as to what the cause would be, I have left the filter out at this time as I do not want to run the risk of oil starvation to the engine.

I must add, I am unsure how the engine oiling system works with reference to the amount of oil one should see from the return pipe after the initial stream has stopped?
QUESTION, Does the oil feed pump rely on the amount of oil supplied from the tank or is there a constant reservoir of oil that is being pumped round and lubricating the engine and so the supply feed is just topping this up any excess will then be returned back to the tank via the Return pump?
Mick D
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Location: Aberdeenshire

Re: Oil Feed Pipe Filter

Post by Mick D »

Hi

The oil pump will 'suck' oil from the tank via the feed line, by all means try running without the strainer and observe the oil flow back to the tank but I don't think you'll see any noticeable difference.

The oil to lubricate the engine is supplied by the pressure pump, it circulates the engine via oil ways and the external pipe to the rockers, once it's done it's job it drains under gravity to the sump where it is collected by the return pump and fed back to the tank - there is no internal reservoir. The return side of the pump has a greater pumping capacity than the pressure side and hence the system operates on a 'dry' sump principle.

Are you sure the pressure side of the pump is correctly assembled after the re-build? It sounds like the return side is working correctly but the pressure side is not pumping much oil around the engine. Another possibility is a blockage in the internal oil ways.

Regards Mick
stuart132
Posts: 58
Joined: Fri Nov 28, 2014 11:02 am
Location: Australia

Re: Oil Feed Pipe Filter

Post by stuart132 »

Hi Mick,

I have done as you suggested, removed the strainer, which I have now left out, after the initial spurt from the return pipe, the oil flow settles down to a sporadic flow. The quantity is far more than with the strainer fitted.

I was not aware that the 'Feed' pump had two functions, one to suck the oil from the supply tank and the other to pump the oil to lubricate the engine. If this is the case, the cause could be an inefficient 'Feed' pump. Would checking the oil pressure with a gauge, as per the manual, confirm the pump condition? or is there another way? I have noted when checking the tappet clearances there was a smear of oil on all the parts as well as a smear on the inside of the tappet covers so I know oil is reaching this area.

Thank's Mick, any suggestions are welcome.
Mick D
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Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: Oil Feed Pipe Filter

Post by Mick D »

Hi Stuart

I'm surprised that removing the strainer had that effect, but it's another step forward.

The oil pumps on your bike are gear types and by their nature will suck oil in and blow it out so the feed pump should suck the oil it needs through the strainer. If the strainer being in the system is affecting the output of the pump then I'd suspect the pump was drawing in air from somewhere and cavitating. I'd check that the paper gasket, (23), is not damaged or missing and is correctly fitted, also that the screws, (14), are not loose.
oil pumps.png
Regards Mick
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