adding an inline filter for biodiesel (MK 1 diesel)

[iain]

Hi, I want to ask a couple of questions of the experienced biodiesel users here.

I'm going to fit an inline filter before the main fuel filter to deal with any crap coming out of the tank. I plan to just replace the piece of hose coming from the metal pipe (coming from the tank) that goes to the main filter for now.

Will I have to prime the fuel system in some way after replacing this and adding a filter? I know this is probably a dumb question but I'm new to this - any advice welcome!

Cheers, Iain.

oh, it's a 79 golf gld

[brackie]

G'day, Iain.

Efficient filtration is essential when running on biodiesel. It's not so much about what the fuel is made of but what it cleans from your existing fuel system. Biodiesel will scour any dirt or corrosion from your tank, fuel lines and any rubberware that is perished. This can end up in the injection pump and will cause no end of damage. Also, it inevitably will contain some water, so the filter that you fit should include a water dropper as it will remove not only water but any big lumps of debris. I would advise that you fit a generic fuel filter housing (off a tractor or stationary diesel engine) that uses cheap elements. The ones that I use are only ~$4.50 each and you can afford to chuck them away regularly (and you will!)

If you intend to make your own biodiesel then do your research and make it properly. Poorly made biodiesel has the potential to kill your fuel injection system.

If you diecide to go ahead with it, yes you will need to bleed the system so fit a filter housing with a priming pump. The type used on Peugeot 505 diesels is ideal.

Lastly, I don't run on biodiesel. I have run my cars and tractors on 100% virgin canola using a two-tank system, however now that the price of canola rivals that of dinodiesel I've given up on it. I would never use WVO.

Hi, I want to ask a couple of questions of the experienced biodiesel users here.

I'm going to fit an inline filter before the main fuel filter to deal with any crap coming out of the tank. I plan to just replace the piece of hose coming from the metal pipe (coming from the tank) that goes to the main filter for now.

Will I have to prime the fuel system in some way after replacing this and adding a filter? I know this is probably a dumb question but I'm new to this - any advice welcome!

Cheers, Iain.

oh, it's a 79 golf gld

[iain]

Hi Brackie,
Cheers for the reply.

I have more questions:
I noticed in my poking around in the engine bay today that the filter in the golf has some kind of water releasing device at the bottom of the filter - is this not sufficient?

Is the idea to completely replace it with one of those glass bottomed CAV style filters? I saw one of these at Supercheap (a ryco) but it seems to have no priming pump - what is the priming ability of a golf stock-standard, or is there none?

If I was to simply fit a cheap plastic filter before the stock fuel filter, how would I then prime the system.

Apologies for these dumb questions - I'm keen to learn but have no experience with diesel engines.

Cheers, Iain.

[smithy010]

G'day Iain, Welcome to the forum, nice to have another dieseler.

I'm on the way to biodiesel, but not there yet.

The fiilter you currently have on your golf sounds like one of the CAV types without lift pump. If you look around, you would be able to find another filter housing WITH lift pump, but it's not essential.

CAV type elements cost about 4-5 bucks each if you buy them in bulk. They do a pretty good job of filtering. I think when i finally get some biodiesel made, i will just run the CAV filter, and of course, carefully filter the biodiesel after production.
Some guys on here (or at least one)..run two crappy cheap filters in parallel before the CAV filter, but they cost about 5 bucks each anyway, and they have about the same filter surface area to block up with crap anyway.

As brackie said, your problems will be the built up crud in the tank and lines from running petro diesel, which should clear up within half a dozen tanks of fuel.

If it's anything to go by, my plan is to run the standard CAV filter, but ALWAYS carry a spare CAV element in the car with me.

As for bleeding the system, i don't think it will be much of an issue. When you change the filters, fill them up with fuel, and just see if it will start (it may suck the fuel up automatically, and "self prime"- it's happened for me before). Otherwise, crack the banjo union at the very top of the injector pump (the one with the return line attached to it) and turn it over (without glowing) until there is no more air in the pump.

Shouldn't have to bleed the injector lines..

Cool.
Come back and chat with us Iain, the diesel forum has been a little slow of late!

[brackie]

Hi Brackie,
Cheers for the reply.

I have more questions:
I noticed in my poking around in the engine bay today that the filter in the golf has some kind of water releasing device at the bottom of the filter - is this not sufficient?

The problem with the aluminium-cased filters is that you can't see through them!

Is the idea to completely replace it with one of those glass bottomed CAV style filters? I saw one of these at Supercheap (a ryco) but it seems to have no priming pump - what is the priming ability of a golf stock-standard, or is there none?

Glass is better. The self priming valve in the VE injection pump is quite efficient, however to fill 2 filters and a glass bowl it's struggling a bit. A priming pump is kinder to the injection pump as it isn't running dry while trying to prime the system.

If I was to simply fit a cheap plastic filter before the stock fuel filter, how would I then prime the system.

The plastic filters are good value as they get out the big bits. (Mercedes used them on the 240D and the 300D of the '70s) The fitment shouldn't affect priming in any way.

Apologies for these dumb questions - I'm keen to learn but have no experience with diesel engines.

Cheers, Iain.

No mate... They ain't dumb. Goodonya for wanting to learn! Just be aware that forums will give you a wide range of opinion and the skill is to pick through it and apply the best.

[iain]

Thanks for the ongoing advice,

I fitted a plastic filter with some new clear fuel line no problems. The old line was in pretty bad condition anyway. Trouble was, I flattened the battery priming the new lines and filter. I started with a jump from my other car but I need a better solution for when I mess with the fuel system again.

Maybe I need a CAV with a primer on it. The ones I've looked at so far don't seem to have the priming function. I saw a pretty cheap (59.99) one in supercheap with a ryco filter in it - can a primer be fitted to the top of these? Any recommendations? I'll see if I can track down one of those Peugeot 505 ones...

[smithy010]

Tow starting works.

Or get a filter housing with primer pump. The one i priced at my local supercheap auto store took a CAV element, and was something like 100 bucks. A bit expensive, but if you look around (even on ebay) you'll find a good deal.

[smithy010]

140, on ebay.

http://cgi.ebay.com.au/CAV-DIESEL-FU...QQcmdZViewItem