Unleaded Fuel filter on a Zil131

[onewatt]

Hi,
Has anyone fitted replacement fuel filters suitable for petrol?
Fitted a pair of Delphi housings with 296 filters but the paint is affected and to be fare, there specified for diesel.
It’s possible it needs to be sealed unit, but just wanted others thoughts.
ATB
Chris

[MrRussian]

Providing you clean the filter by the tank and change the stone filter by the carburettor. Fitting additional filters is just OTT if fitted incorrectly will cause more problems than they will solve. On the original filter by the tank you cam simply drain the crap, by simply undoing the bottom screw. Or you can remove the filter and clean the inside rings. On a replaceable filter you have to carry a spare, and you don't often know what is going on inside. Also, diesel filters tend to be very fine and fitting these can upset the sequencing of fuel cleaning. With filtering fuel, you firstly need a course filter to remove the boulders/clay/sand. OK, maybe not all this. But, course filter is there for the large crap and water. Then you need fine filter. Just fitting a fine filter will give you problems.

My additional advice is to inspect the fuel tanks.

Petrol has a short shelf life of around a year. With a safety LED torch, look Inside the tank. It should be nice and clean. The problem is many of these Zils have been sat for years. Old fuel evaporates and sulfurizes to a hard gum. The mistake people make is simple ignoring this, and filling the tank with fresh fuel. What happens is the fresh fuel will start to break up this residue into very fine particles. These particles will pass through the tank filter, but will get caught by the brown stone filter by the carb.

These stone filters will gradually block up and start to restrict fuel. You will notice this when you least need it, like on a hill. It gives the same prognosis as a failing fuel pump. Remove the awkward base securing nut filter, and remove the brown cup. Inside, you will see the stone filter. Pull it off and have a close look. It should be evenly coloured light brown. If you see a difference in the brown, with darker areas. You need to change it. Another way to check is to suck through it. There should be no resistance.

Do all this, and your Zil will go on for years...

[coldwarjohn]

Where abouts can you buy these filters ?

[onewatt]

Appreciate that, but I don't have the original filter. When I bought my zil the filter had been removed and a straight inline fitted. I'll see if I can source an original filter. Thanks for the advice.
ATB

[Abrs]

Just get your self a CAV type twin head filter housing, these usually come with a glass bottomed sediment trap one one side and a fine filter on the other, they were originally fitted to the likes of the MF tractors, diggers etc, & virtually anything else from the 70's or 80's with a Perkins diesel engine. I've been using one for years on the Zil with no trouble, and the glass bit is really useful to let you the filter probably wants changing! They take the Coopers AZF015, CAV 296, Crosland 522, etc etc filter elements which are the cheapest of any of the more decent type filter housings.

[onewatt]

Hi,
Thanks for info.
That’s what I fitted but didn’t realise the paint on the filter would be stripped by the petrol and block the filter. I’ve also found the seals on the filters don’t like petrol (or at least the additives.
I’ve found some filters unpainted where it’s in contact with petrol and now just need to find seals that will work, most likely viton I recon.
ATB
Chris

[Abrs]

CAV housings are a type of cast aluminium, there shouldn't be any paint on them anywhere. As for the filters they aren't painted on the inside they're electro plated for the very reason you mentioned, not to mention it also makes them rust resistant. The additive you are thinking of is ethanol, it's found in both petrol and diesel fuel these days and causes no end of issues with older vehicles.

Not had any issue with the rubber rings so far, maybe try another brand of filter. I use Coopers myself as they cost us about £1.25ea in bulk, so far so good.