Making a better felt filter for the oil tank

Helpful information and requests for assitance and advice
Member
User avatar
Posts: 9895
Joined: Mon Jan 01, 1990 12:00 am
Location: ESSEX UK

Re: Making a better felt filter for the oil tank

Postby Rob Harknett » Tue Feb 05, 2019 1:27 am

I am sure felt seals & filters were once made of pure Lambs wool. Good enough to start an industrial revolution, man made fibres cannot equal it. We are now eating it instead. It was recently reported, tins of imported Tuna fish contained no Tuna, when a tin was opened, put in a sieve, after running it in water for a short time, all that remained were wool fibres.

Member
User avatar
Posts: 1368
Joined: Thu Jul 10, 2003 12:00 am
Location: HAMPSHIRE UK

Re: Making a better felt filter for the oil tank

Postby Duncan » Tue Feb 05, 2019 5:37 pm

Would that be dolphin friendly wool Rob?

Member
User avatar
Posts: 1095
Joined: Wed Oct 12, 2005 9:45 pm
Location: CO DURHAM UK

Re: Making a better felt filter for the oil tank

Postby REW » Tue Feb 05, 2019 8:33 pm

Time has flown and, erm, no, I haven't managed to create a new filter similar in quality to the old. But:

I do now have an original filter (thanks Roy) that has been washing itself in white spirits for a year. The felt is as thick as the new felt I bought - felt invoice in the photo in my earlier post. And yes it is 100% pure tuna wool, ah no, sheep wool Rob. The metal frame is much thicker wire than the modern type too.

Now, the original problem is that the new filter I bought was too short and it flopped sideways in the filter tunnel, blocked the outlet and oil failed to return to the tank, filling the sump (Model 20) instead. I stopped just in time to avoid the engine running without oil and eventually this filter project was born.

The temporary (if not permanent now) solution? A couple of chunky, close fitting "O" rings placed over the protruding nipple at the base of the filter tunnel before the filter is then placed on the remaining exposed nipple (ooer). This means the top of the filter is now trapped in the lower neck of the filter tunnel as it would be if it were a bit taller and cannot flop sideways. What's more, the filter base is jammed onto the "O" rings, seals better and prevents the rings getting free.

Was it worth it? Doubt it because the felt is just as thin. I will try to make a new felt filter eventually but the biggest problem of all turns out to be cutting the felt so the ends curl around the neck of the wire former neatly and in a way that can be stitched, without getting too thick to fit in the tunnel.

What a faff. But then, it has been snowing and I really can't go out to play bikes at the mo.
Ron

1951 Matchless G3L, thumping round the Durham Dales

Member
User avatar
Posts: 202
Joined: Tue Nov 29, 2005 8:51 pm
Location: Herts UK

Re: Making a better felt filter for the oil tank

Postby Group Leader » Tue Feb 05, 2019 8:59 pm

Thanks Ron,

I take it your original looks like mine, with the really heavy duty mesh?

I took the precaution of measuring my filter up and doing a sketch of it. I've done some hunting around and it seems easy enough to get the correct size mesh so I might have a go at fabricating a new frame up. A slight quaundry though; the mesh looks a bit like stainless to me although the seam appears to be soft soldered. If I recall, stainless doesn't solder so perhaps it's just plain steel and is still very shiny because its been imersed in oil for 66 years?

Should you ever dismember your filter with the intention of re-felting it I would be most obliged if you could take a couple of photographs of it in all its nakedness and then post them on here. It feels like there are some sort of end rings on the ends of the mesh (which would be logical) but of course you can't actually see them because they are covered by the felt!

With regard to the felt; I wondered if the method of construction was to stitch it up to form the over-long tube, then feed it through the mesh with the surplus overhang each end, with the tube ends carefully turned back over the mesh. I'd start folding back on the side with the seam then press down on the seam with my thumb to provide some strain relief for the stiching as you coax the rest of it back over. It looks like the doubled back ends are then stitched all the way round to keep the lot in place.

Does that sound sensible do you reckon?

I must buy some mesh and some felt ....

Alan
Last edited by Group Leader on Tue Feb 05, 2019 11:24 pm, edited 1 time in total.
1953 AJS 16MS, 1939 BSA 250 and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:

Member
User avatar
Posts: 9895
Joined: Mon Jan 01, 1990 12:00 am
Location: ESSEX UK

Re: Making a better felt filter for the oil tank

Postby Rob Harknett » Tue Feb 05, 2019 9:57 pm

We used to use thick Lambs wool felt on our belt sanding pads back in the 60's. In the wood working trade. It was very compressed and hard about 10 m.m. thick. Lasted for ages. As years went by, we noticed how the felt quality supplied deteriorated. It became less compressed, crumbled in bits. Useless as it left sanding marks. Getting supplies of the good stuff became as hard as finding Gold. I guess the same applies now, felt may be the same thickness, but compressed c so hard.

Member
User avatar
Posts: 1095
Joined: Wed Oct 12, 2005 9:45 pm
Location: CO DURHAM UK

Re: Making a better felt filter for the oil tank

Postby REW » Tue Feb 05, 2019 11:17 pm

I will take a few photos Alan to show some of the progress I did make. I have not yet taken the original filter to pieces so can't tell if there is a soldered ring on the ends. However I had worked out that the cut wire mesh on the pattern parts just poke into the felt and cannot come close to sealing things (though the aforementioned "O" rings help). I did therefore solder some rings of copper wire to the pattern mesh. The thick felt needs a flare in its construction so the folded over ends don't rip apart - this is proving trickier than expected.

More fun tomorrow.
Ron

1951 Matchless G3L, thumping round the Durham Dales

Member
Posts: 113
Joined: Tue Mar 29, 2016 6:19 pm
Location: CALVADOS FRANCE

Re: Making a better felt filter for the oil tank

Postby Dave T » Wed Feb 06, 2019 8:43 am

In the past I too had a long felt want, but that would be for a different forum!
My previous 1954 G80 had indeed a long felt filter. Having built the bike up from large pieces I never knew if I had an original filter but the new one I bought did seem a bit flimsy and was at best an approximate fit.
Moving on to the present and my "new" 1959 G80: TA DA! NO FELT FILTER! Just the gauze one in the oil pipe.
So the ten thousand dollar question is, "what happened in those intervening years?" Were the engines so different? Had oil techno-lurgy made huge advances? Who knows?
So, if a felt filter is no longer needed why not just leave the oil tank filter compartment empty, screw on the cover and forget it? Is this a viable plan?
Dave.

Member
Online
User avatar
Posts: 3476
Joined: Mon Jan 01, 1990 12:00 am
Location: LONDON UK

Re: Making a better felt filter for the oil tank

Postby clive » Wed Feb 06, 2019 8:51 am

Some years back I had a pattern filter on a single which I think had too deep a turn back on the felt. This then blocked the outlet tube from the filter housing and consequently also made the pressure relief device on the top of the filter useless. Started the engine and blipped the throttle and the rubber join on return blew off the pipe. Messy. I should take care to eat all the tuna before you use the lambs wool Ron.
clive
if it ain't broke don't fix

Member
User avatar
Posts: 2492
Joined: Mon Jan 01, 1990 12:00 am
Location: HAMPSHIRE UK

Re: Making a better felt filter for the oil tank

Postby ajscomboman » Wed Feb 06, 2019 11:06 am

By 56 the filter had gone on the comp models and I have to admit I don't even have the gauze one in the pipe on the CS's. The bikes oil get's changed every 1000 miles more or less so it's not worth having them in there.

Member
User avatar
Posts: 1095
Joined: Wed Oct 12, 2005 9:45 pm
Location: CO DURHAM UK

Re: Making a better felt filter for the oil tank

Postby REW » Wed Feb 06, 2019 11:56 am

clive wrote:Some years back I had a pattern filter on a single which I think had too deep a turn back on the felt. This then blocked the outlet tube from the filter housing and consequently also made the pressure relief device on the top of the filter useless. Started the engine and blipped the throttle and the rubber join on return blew off the pipe. Messy. I should take care to eat all the tuna before you use the lambs wool Ron.


Yep Clive, I had the same issue years ago on my G3. Makes a mess. I have eaten tastier tuna too.

As for the need for a filter, well no, probably no need at all given the regular oil changes most of us carry out. However, it should be possible to get the filter working effectively so for those of us with an OCD streak it keeps us occupied. I must say though, I did find a garden pea sized piece of silicon sealant in the filter of my M20, so it did achieve some level of filtration. I know not whether there are other pieces of silicon around but I have done 1000 miles since without a repeat, so, fingers crossed.

Below is the filter frame modified with a soldered on end ring. Awaiting felt application...
You do not have the required permissions to view the files attached to this post.
Ron

1951 Matchless G3L, thumping round the Durham Dales

PreviousNext

Return to Help

Who is online

Users browsing this forum: No registered users and 10 guests