Fitting an oil filter

[Greybeard]

Hello chaps,
This is almost certainly a stupid question:
Please would you explain to me why an external oil filter must be inserted in the pump return pipe. It would be simpler to fit it in the feed pipe;  no need to worry about the rocker pipe assembly.

Neil Ives UK

[muskrat]

G'day Neil. If it's in the feed side it will hinder flow, must get oil in as easy as possible. I plumb mine in before the rocker "T".
Cheers

[A10rocket]

Hi Neil,
if you fit the filter in the return , it cuts the sludge and any debris going into the oil tank.
If you keep the oil tank clean, you'll always have clean oil to the engine plus as Muskrat says
you don't want to hinder flow to the pump.
 
 Cheers, Ken.

[bonny]

On most triumph twins it is possible to take the flow of oil after it has left the pressure side of the oil pump but before it has entered the crankshaft and pass it through a filter. There is a hose carrying the oil that comes out of the rear of the timing cover to the oil filter and then another hose back from the filter into the front of the timing cover. This way it is always clean filtered oil that enters the crankshaft. kirby Rowbotham does the conversion but it is relatively easy to do yourself. I am not as well up on bsa engines , is it possible to do the same ? it would greatly increase the life of the timing side bush. 

[Brian]

Personally I dont think that is a very good way of fitting a filter.

The oil becomes "dirty" while in the engine, minute particles of metals from the bores, bearings etc and combustion contamination so it makes sense to me to filter the oil as soon as possible after it becomes "dirty".

By filtering the oil as it exits the engine you are sending filtered oil back to the tank so no or extremely reduced sediment (as Ken points out) in the oil tank and filtered oil is being delivered to the pump to start the cycle all over again.

By fitting the filter between the pump and engine you have "dirty" or unfiltered oil going through the whole system including the oil pump.

An added advantage with the BSA having the filter in the return line is you are sending filtered oil to the rocker gear.

[bonny]

Quite possibly brian. It was just another idea i was throwing out there. After all the bush is the critical component on these twins, that and the big ends getting clean oil would be far more of a worry to me than the rocker gear. Any oil filter is a good idea of course as it gives extra capacity and acts a cooler of sorts i suppose. 

[The pirate]

If you change the oil at the correct interval with good quality oil, then you should have no problems. If you fit an oil filter and a magnetic sump plug these are just further insurance to stop wear or 'bits' going round the engine. A good number of our bikes would suffer more wear from never getting red hot and being run that way. I am sure short cold runs and start ups do far more damage to the oil and the engine wear than not having an oil filter.

[muskrat]

 Too true TP, over half of all engine wear (and oil degradation to a degree) occurs at cold start up. Oil is the life blood of your motor.
 I rarely start a bike up if I can't run it for at least 15 minutes.
Cheers

[Greybeard]

I bought a Norton 850 oil filter head and filter from Ebay intending to fit it in the toolbox of my plunger frame GF as others have done. However, the assembly was too wide to fit in the toolbox so I have mounted the filter on the rear mudguard behind the gearbox using nylock nuts.
Both parts are dull black so fairly inconspicious.
When mounted the filter head union stubs point towards the chain.
I've used Goodyear 8mm (5/16") ID reinforced rubber pipe to do the plumbing.
The oil feed pipe from oil tank to pump union pipes is as original.
The return from the pump is carried over the top of the gearbox, down between the vertical frame tube and the gearbox  then gently curves around to meet the filter inlet stub.
The filter outlet pipe is routed tightly underneath the gearbox and then up behind the pump union assembly so it appears adjacent to the original metal pipes. It lines up nicely with the rocker feed banjo and oil tank connector.
Finished off with proper hose clamps it looks neat and not too obtrusive.

[Rocket Racer]

I've seen a number of engines that run the filter after the oil pump on the feed side, but typically the oil pump is considered a disposable item to be replaced at each rebuild. A (BMC) mini oil pump is an example, quite inexpensive. Unfortunately not the case for an A10 where SRM pumps are definitely not a throw away item.

The big issue with an A10 is that it isnt easy to plumb in a filter after the pump although I have seen it done where the Dynamo/generator is not fitted. In practice a return line fitting is much more practical as long as the oil tank is cleaned first. At least then the oil pump get clean oil.
I run mine on the return side for ease of access and minimal modification effort as most of us do.

[Worty]

Bit late on this topic I know, but thought I'd throw something in here.  My '61 Flash was built at a time when oil wasn't as good and there were no paper oil filters (which we all know).  I also reckon owners weren't as conscientious as we're being now and left the oil changes for much longer than they should - but the beasts did keep going.  So, the bikes are now rarer and not two-a-penny as they were.  For me, I change my 20/50 every 1200 miles and/or annually (would like to get more mileage in but not always possible!!).  I have a magnetic sump plug that catches a small clump of iron filings.  For extra cleanliness, I use a large medical syringe with tube attached to extract the contents of the bottom of the oil tank (the bit that doesn't get drained off),  then use a magnet and clean rag to get rid of the minute amounts of slightly gritty residue at the bottom.  For me, this should be enough rather than faffing around with extra filters.  I also agree with muskrat in not starting the bike unless it's going to get a good run! 
Couple of questions though.  #1 Has anyone come up with a paper filter element or set up that fits on/around/replaces the existing 'tea strainer' arrangement and, #2 Would a magnetised version of the 'tea strainer' provide extra protection like the sump plug does (although this would be much harder to clean).  Perhaps for the latter a magnetised 'tea strainer' covered with filter paper in cartridge form.....??  Any thoughts....?

[bsa-bill]

For me, I change my 20/50 every 1200

most 20/50 are detergent oils (unless you found one that states it isn't), as such a detergent oil is designed to carry dirt (sludge ) around the engine until it gets filtered out through a filter, I use 20/50 and a filter but only after the engine had had a full strip down and the sludge trap thoroughly cleaned, a detergent oil could well be capable of lifting grunge out of the sludge trap and circulating it round the engine if used without a filter

a magnetised version of the 'tea strainer'

Would have the metal sludge sitting on the top of the strainer and impede oil flow through it, best to have it collect on the magnetised plug below the strainer as you have

[Triton Thrasher]

Having cleaned sludge traps out with drills and screwdrivers, I'd say it would take a bloody good detergent to "lift grunge" out of it.

A filter in the scavenge line is easy to fit and appears to have no bad effects at all.

A filter in the gravity feed from tank to engine is not safe.

A filter between the oil pump and the pressure relief valve involves work and it surrounds the timing cover with fragile plumbing full of the engine's entire supply of hot, high pressure oil.

[Tomcat]

If you fit an oil filter in the return line there is another advantage.
Drain engine oil from tank, refill tank with new oil. Remove oil filter and start engine, the dirty oil in the sump and lines will be pumped out the return line till fresh oil comes through. Stop engine and fit new oil filter. 

[Worty]

I do admit fitting a simple in-line filter on the return makes sense - any advice other than what's already been posted?

Cheers