In-Line Oil Filter

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Whiskey98
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Joined: Wed Oct 26, 2022 1:56 pm
Location: West Yorkshire UK

In-Line Oil Filter

Post by Whiskey98 »

Hi everyone,

I'm still working on my 1959 G12 and it's my intention to fit an in line oil filter to the return oil line. I appreciate many people go down the route of no in line filter and simply change the oil more regularly but I just want to give my engine the best chance possible after all the work I'll have put into it! There are of course those ones you see with a screw on style filter but I have been told those filters are for a snowmobile engine (= poor availability in the UK) and these have a non-return valve which is great for a supply line but unnecessary for a return line filter plus the pressure to overcome the non-return spring will add unnecessary strain to the return pump.

I visited Thunder Engineering a few months ago to pick up a set of their conrods for my G12 engine and we got talking about other stuff, he mentioned he started making return line oil filters that uses a modern motorcycle shot glass sized cartridge style filter fitted into a machined aluminium body. They looked very smart and would be ideal although he made them to fit pre-unit triumphs, not very useful for a G12!

Has anyone fitted anything similar to their heavyweights? Whether it was a bought product or something you made yourself and where did you mount it on your bike?

Many thanks
Peter
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Les Howard
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Joined: Sat Jan 07, 2012 9:57 am
Location: Somerset UK

Re: In-Line Oil Filter

Post by Les Howard »

Why bother. Your engine already has an oil filter built in and is in the correct position, that is: in the FEED to the big ends (via the centre-main bearings)...Most after market filters clean the oil on the way back to the tank, which is better than not having a filter but not quite as good as cleaning the oil directly before it goes into the plain bearings which require meticulously clean oil to last. It is, however, on the small size but simply change the felt often as you like but the intervals being based on what state the old one is in when you change it. This will save wasting time and money. You might add a small samarium cobalt ring magnet to inside the filter to further improve ferrous particle pick-up...Another tip is to change the oil regularly at say half or a third the normal interval but drain the old oil into a clean 4-6 pint plastic milk jug. Leave this standing in a cool place with the cap on. Over several weeks the microscopic sludge and dirt will fall to the bottom and the oil will become very clean again and you will be able to use it by decanting it off to leave the crud at the bottom of the jug (easily seen) and do a swap with the oil you drain out and do the same for that. The TOTAL usage time of any one batch of the oil should be roughly the same as you would do a normal oil change to discard it but I reckon you will get more miles out of each change this way ;)
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Expat
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Location: Tennessee, USA

Re: In-Line Oil Filter

Post by Expat »

Hi Peter,
7CA12FE9-4346-42AC-A317-C3AD497A203B.jpeg
If this has worked, here's mine on the G3.

Hope this helps

Steve
Keep shiny side up.

These are my principles, if you don’t like them, I have others. (Groucho Marx)
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Expat
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Posts: 1033
Joined: Thu Nov 12, 2015 2:22 pm
Location: Tennessee, USA

Re: In-Line Oil Filter

Post by Expat »

This may be a better way to view it.


download/file.php?id=5657
Keep shiny side up.

These are my principles, if you don’t like them, I have others. (Groucho Marx)
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Les Howard
Posts: 1017
Joined: Sat Jan 07, 2012 9:57 am
Location: Somerset UK

Re: In-Line Oil Filter

Post by Les Howard »

Not really needed on singles with roller bearings, the hard steel easily resists wear from carbon and softer metals, even hard metals. Plain bearings are completely different as regards requiring microscopically clean oil...Even so. Norton twin engines without any real filter (the tank has a simple straining gauze) seem to last for at least 50,000 miles with recommended oil changes, big end wise, use plain bearings. ;)
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