AJS & Matchless Owners Club

I'm planning to modify a set of 1963 cases to install an external cartridge filter into the pressure side of the oil pump (along the lines of the articles in the Technical section).
I have seen several kits to plumb a filter into the return side, and my question is are these suitable for plumbing into the feed side or will I need a setup specifically for a feed side fitment?
If yes, does anyone know of a suitable supplier of a sucha kit?

Just thinking of the different pressures to be catered for....

Cheers,
Ray.

Why the feed side?? There must had been good reason why all bikes I know of had a filter to clean oil on the return from the engine, into the oil tank.
I would had thought a filter in the feed line would restrict flow, also gradually reduce the oil flow even more, as it got clogged up.

I assume you are fitting a supplementary filter because you want better filtering.
If the filter is in the feed much of the bits and sludge in the contaminated oil leaving th'engine will settle in the oil tank first. Surely, it's better to trap it after it has become contaminated and before it enters the system?
If you feel that the original AMC filter arrangement will trap that stuff why fit another filter?

rayswadling wrote:I'm planning to modify a set of 1963 cases to install an external cartridge filter into the pressure side of the oil pump (along the lines of the articles in the Technical section).
I have seen several kits to plumb a filter into the return side, and my question is are these suitable for plumbing into the feed side or will I need a setup specifically for a feed side fitment?
If yes, does anyone know of a suitable supplier of a sucha kit?

Just thinking of the different pressures to be catered for....

Cheers,
Ray.

Many of us have mounted the filter in the return line just because we are chicken .
If the filter clog up the only thing that can happen is that the crank case will be full of oil.
Regards Ib

I guess there are several reasons...
I'm not averse to using modern or just later technology to make improvements - in my opinion obviously - to these machines.
I'm one of the original purchasers of the new twin cranks, I have fitted Carillo rods to my current engine and a BSA/Triumph 8" TLS brake to gain a bit there.

In the standard engine, AMC fitted a filter (mesh or felt) in the feed side of the oil system after the pump. The wire strainer at the tank prevents large bits getting through to the pump.
So all I am actually doing is the same as AMC, but with filter technology not available in the 1960s. All my more modern bikes and cars also have the cartridge filters after the pump.

With a cartridge filter I can also use modern oils with the detergents to help prevent the buildup of residue in the engine...
There are documented cases of the felt filter collapsing and blocking the oil supply anyway so I haven't increased that risk any as far as I can see. Regular filter changes should eliminate that anyway...

The final bit of the jigsaw that made me decide to go this route is I have access to the engineering skills necessary to make the conversion.

I agree that the easiest route is a return side filter, but that is mainly because little modification is needed. I believe that a feed side filter is the better technical solution though.

Kirby Rowbotham actually provide a service to modify the timing cover of Triumph twins to tap into the feed side of the oil system for just this reason...to insert a modern cartridge filter between the pump and the rest of the engine.

Hi Ray, I have just read a comment by Steve Campbell from Thunder Engineering, where he claims a twin engine with steel conrods (e.g., Carillo rods) will run harsher than an engine with alloy rods. I find it hard to believe from a solid mechanics point of view; maybe vibration caused by pressure pulses during combustion is at play .... Did you notice an altered engine response after fitting Carillo rods? I'd be very interested hearing about your experience (and others who have fitted steel rods).

Greetings and best wishes for Xmas

Knut Sonsteby

A PO of my bike fitted a cartridge filter on the return side, but it sat next to the carb and looked horrible (in my opinion). I re-plumbed it to sit hidden under the seat, where it works fine and everything looks standard.

A mate's Model 20 has a cartridge filter fitted to the end of the crankcase filter housing, so on the feed side. The cartridge/holder joint is fine, but the holder/crankcase joint is a pain to seal properly.

Malc

Surely fitting an external filter is restricting the flow of oil? you're creating a bottle neck where the oil goes in and out of the filter housing, giving the oil pump extra work to do which it was never designed for.
These engines were not designed for modern oils anyway.

Must admit to being bemused by the fashion for fitting oil filters on old bikes. It does seem like a solution looking for a problem. Mine have all managed the last 60 to 90 years without one so Im pretty confident that given the lower mileages they now do along with the mollycoddling they get when it comes to maintenance that they'll see me and at least one more generation out

Steve

Greybeard wrote:Must admit to being bemused by the fashion for fitting oil filters on old bikes. It does seem like a solution looking for a problem. Mine have all managed the last 60 to 90 years without one so Im pretty confident that given the lower mileages they now do along with the mollycoddling they get when it comes to maintenance that they'll see me and at least one more generation out

Steve

Hear! Hear!