Fuel Filters

[Diesel Dave]

Poor old Sluggy's been a bit sluggish of late, now I know that's his name and nature but even so.....

He even started 'missfiring' on occasion and I've never had that before.

With images of replacement injectors and pumps costing quite a few quid in my head time for spot of cheap investgation.

Definately felt like fuel starvation and I could see air bubbles surging in the clear see through fuel pipe.

First check - fuel flow from the tank - seems ok on main and reserve but I did the usual cheat of attaching a piece of spare pipe to the tap and blowing back into the tank - clears the crap from the filter screen inside the tank.

Next in line was the aftermarket inline filter and it was my intention to clear out the trapped air inside, so disconnect bottom pipe and turn on tap - nowt; nada, nothing at all exited from the bottom - Ah Ha!

Now casting my mind back to when this was fitted; I can't even remember properly but it was al least 40,000 miles ago. That's just 220 gallons or a tad over 1000 litres - ooops. seems a lot of crap does get past the tank filter and magnetic trap.

As the casing was opaque it's not possible to see inside so I cut it open to have a look see:



Just goes to show - don't forget those fuel filters! The replacement is see through si it shouldn't happen again.

I've been out for a test ride - quite a bit more power so it must have been sucking hard to get fuel through, I shall need to reset my max fuel delivery now.

Happy Bunny though

[andrewaust]

Yuk, that looks like crude on the paper . Must remember to check my filter for flow come to think of it.

Our one lung slugs need every drop of fuel they can get .

Id guess those running WVO would need to keep a firmer eye on there filters.



A

[Nanko]

That looks like biofilm contamination read: http://www.diesel-fuels.com/ for more info

[Diesel Dave]

I've had fuel contamination before in the old fuel tank.

It would make up a brown sludge that clogged the screening gauze that sticks up inside the tank from the tap.

A petrol or white spirt slosh in the tank seems to kill it.

It's always a bit dodgy to have a reserve that is never used as this is where any water and solids tend to accumulate.

I do use a water trap but have never suffered from any problems in this area - there's a little magnet inside it too to attract all the rust particles and this works well.

It goes without saying that I'll be sticking to the clear casing type filters from now on!

[arnaud]

I use the 2 euro fuel filters from any moped store, the same i use for other motorbikes, and change them once a year..
Checking the petcock for flow and cleaning it when nessesary is also a part of annual maintenance

[Crazymanneil]

Check out the filter for a diesel smart car. Its a pretty chunky looking thing that should last a while and its nice cos its inline too. Takes 8mm pipes. I think I paid like £6 for one a while ago. They have an aluminium case as they are designed to be fed by a lift pump at a couple of bar, but seem to flow easily enough at least when new. (the idea with the newer filters is the small ones can last longer because they are fed at pressure)

One thing confuses me about it though is that there is no water drain off screw or anything like that on it? Is this not necessary anymore (common rail engine) or does it just store any water up and you bin the whole filter water and all?

Neil

[jeremy]

From my experience, the new water-separating canister-type filter elements soak up the water and stop-up completely when they can absorb no more.

I agree the picture seems to indicate the sludge resulting from bacterial infestation, a subject I became very familiar with last year after feeding my ford diesel truck some contaminated biodiesel. The bugs live in the layer between fuel and water in your tank, getting oxygen from the water and feeding off the fuel as well as dispersing their spores throughout the fuel. They break down the fuel oil into its constituent parts (the varnishy, tarry sludge + solvents) and create acids while they're at it (think: yogurt) which all wreak absolute havoc on delicate ferrous machinery as I discovered. It's ironic that as we attempt to consume ecologically-more-sensitive fuels like bio and vege, we must consider adding highly toxic bacteriocides such as "Biobor" to survive them.

[smokyjoe]

In reading this ancient thread I thought about a problem I had with my old Chevy Diesel pickup truck. It had pretty long rubber fuel lines and I used an aftermarket Racor water seperator with a small filter. Once I started using a fuel additive to prevent winter waxing, my filter would clog quite rapidly. I found that it was black rubber gunk from the hoses (which were new) being dissolved by the additive. I switched lines for some that had a liner and the problem disappeared. This has been a problem for a local university that has switched to Biodiesel also.

But this produced distinctly black gunk, not dark brown.

What I am using on everything I have diesel in now is the older VW spin-on fuel filter/water seperators. The bracket can be had at the wreckers pretty cheaply ($10 to $15) and the filters are only about $5 US if you shop around and buy in small quantity. The filter bracket has banjo fittings for hose or plastic tubing, and the body can be easily re-threaded for standard hose barbs. One of these should last forever on a diesel bike!

[Crazymanneil]

Interesting post smokeyjoe.

I put biodiesel through an Audi 80 one time and it found a leak where a metal hose was clamped in a rubber mount. The pipe had corroded long before, but the bio disolved the rubber that was making the seal. I fixed this issue only for the car to die completely. I think what happened was that the bio dissolved the seals in the fuel filter and then sent all the crud through to the injection pump. That engine had a lot of other issues (head gasket failure for one) so I replaced the entire engine and drove it for another couple of years before it was sold.

Bio eats the rubber but also cleans very well (might get some for cleaning my engine before putting it back together!). So in an older car it flushes the crud out of the tank thats buiilt up over the years and into the filter which then blocks. Seems to take a couple of filters before its ok again.

I know the spin on filter head you mean. I use one for an SVO conversion and they are pretty handy in that you can swap fittings round to suit your pipework.

Anyone any good brand reccomendations for fuel filters? I use Delphi ones which seem ok with high temp veg oil although I have heard that Caterpillar ones are meant to be excellent (although a bit big for a bike?)

Neil

[taildraggin]

Neil:

I found a little Kubota diesel filter on US ebay for $12. It includes an ON/OFF valve (no res):

[Crazymanneil]

Looks interesting. Does it separate water do you know? And what size is that bad boy?

[taildraggin]

It is not that large - good for my little Yanmar - it's quite compact and mounts easily (hole is for mounting bolt), but you will need larger for your Smart engine. I'd troll ebay for larger - saw some filters there for 36 and 45 hp kubota filters.

I believe that you just unscrew the plastic bowl to dump water.

[Darren]

Commonrail engines (like the smart) require better filtration than older mechanical injection engines.

Id only use a filter designed for a common rail engine.

My guess, from your description, is that the smallest you would find will be the smart filters.

You could of course use another filter prior to the Smart one.

There are filter canisters available to fit the VW/Bosch type spin on filters (mentioned above) that give the right level of filtration for a common rail engine.

I've set up a webshop selling a selection of filters etc. Like to think reasonable pricing.
b-e-t.org.uk[/u]

[Diesel Dave]

I've had a look through the various specs for fuel filtration, the best info seems to be available for marine use.

Their common method is to use 2 stage filtration the first at 10 micron and the second at 2 micron.

Petrol fuel filters and those clear plastic inline types seem to be 10 micron.

Perhaps I need to rethink my fuel filtration setup

[Darren]

That sounds a bit like overkill to me Dave. For non-marine stuff only commonrail engines would have such fine filtration. Thats because they use very finely machined parts and bigger particles could quickly cause enough damage to make a significant difference to the fluid flow characteristics. Its very high pressure and ware can seriously degrade injection.

Most non commonrail engines have filters in the 5 - 10 micron range. Measurement is not standardised so comparing ratings doesn't mean much. Most vehicle / stationary engine filters dont specify this performance - only place I've really seen it is with marine engine filters.

People tend to be much fussier with filtration on boats because you've got lots of water about, fuel can be of variable quality and you really dont want to break down in the middle of an ocean.

I've got an interesting booklet called "fuel conditioning guide" I got from Delphi - rang up and requested some catalogues for their filtration gear and they sent me this too.

I've covered the the main points made in the book at -
http://trueasset.org.uk/index.php?page= ... tem-design

I think that some kind of sedimenter and then a diesel vehicle / stationary engine fuel filter is plenty adequate for a bike. Sedementer being optional but recommended if your tank is a filthy as mine If you remember I got one of the glass/plastic ones you have fitted to sluggy.

Unfortunately vehicle filters are a bit to big to fit easily onto most bikes.

I recently sold my car so my 350HatzEnfield is now my main transport.... Enjoying it but slightly worried about the gradually falling temperature