Heated fuel filter for vegoil

[Snagger]

I bought a heated fuel filter from Sodbury. It draws 10A from the battery (so at least 120W), and if it draws the same from the alternator, should be up to 140W. That should be enough to heat vegoil for use un the 12J. The trick is the switch. The existing switch (visible in the front port) is to activate the heated when the fuel is very cold. What I need is a switch to only remove power when the fuel temperature exceeds 80 degrees. Anyone got any ideas where I could get one that would fit the housing ports?

Secondly, this filter would rplace the existing CAV filter. The only significant difference is that the injector leak-off pipe would have to route straight back to the tanks, instead of having the banjo connection at the top of the filter. I assume the banjo connection was to allow excess pressure from the lift pump to escape back to the tank?

[swag298]

Pull the existing low temp switch out and find an electric fan switch with the same thread.
For the spill return, on the injector spill rail it's the 4th injector that normally spills back to the CAV filter head right? Use a double length banjo bolt and pipe the new filter's spill line down to there. Then run a single line back to the tank. Or of course vice-versa. Double banjo in the top of the filter. (Isn't that how it's done on the CAV?)

swag

[Snagger]

The CAV has 2-in (lift pump and injection pump return line), 1 out (injection pump feed) on the main ports, and the injector leak off (from no.4 as you rightly said) going through a banjo on the top of the housing, with the tank retun line on the other side of the same banjo.

As for the fan switch - good idea, but that will activate at high temp; I need mine to deactivate at that temperature. Is there a way of using relays or other cheaply available parts to invert the switch output?

[si_guru]

As for the fan switch - good idea, but that will activate at high temp; I need mine to deactivate at that temperature. Is there a way of using relays or other cheaply available parts to invert the switch output?

I think what you need is a relay with a "normallly closed" contact. These are refered to Double Throw relays too.

http://www.maplin.co.uk/Module.aspx?ModuleNo=37526&TabID=1&C=SEO&U=SEOsearchPages&doy=search

[swag298]

With any luck the banjo bolt in the top f the CAV will be the same size as the heated one.
As for the switch. Say the existing one switches on as temp drops below 4 degC, (Just a guess.) reversing it using relays would only mean that it would stay on at anything above 4deg....with no high temp cut-out.......and it would switch off if the fuel temp was below 4deg.
A good car parts place would be able to match the switch. Whether there are any that would switch as low as 80deg is another matter.
Maplin or RS would be the next place to try.

swag

[Snagger]

Thanks for the link Steve - £1.79 isn't going to break the bank, either!

[Snagger]

With any luck the banjo bolt in the top f the CAV will be the same size as the heated one.
As for the switch. Say the existing one switches on as temp drops below 4 degC, (Just a guess.) reversing it using relays would only mean that it would stay on at anything above 4deg....with no high temp cut-out.......and it would switch off if the fuel temp was below 4deg.
A good car parts place would be able to match the switch. Whether there are any that would switch as low as 80deg is another matter.
Maplin or RS would be the next place to try.

swag

Thanks Swag.

The new housing has 4 ports -3 in around the edge (one blanked, one occupied by the switch at the moment), and one outlet (on the top). That presents me with a small problem, as I have one port too few on the new housing unless I remove the switch completely, run the leakoff staright to the tank, or join the leak off and injector pump return lines before they get to the filter.

As for the switch, I'll try VWP.

[callum]

you should be able to get a switch from rs. reversing it is difficult. i had the same problem when i got the wrong switch for my fans, cut off rather than switch on. my dad spent ages trying to sort it, but eventually had to give in and get the right switch.

my engine (isuzu), and possibly tdi's too, has a switch ike that to tell the glow pugs not to bother going on if the engine temp is high enough. i'm not sure what the cut off temperature is for that though. may suit your needs.

[Geobloke]

I read somewhere that when temperatures are lower than 10degreesC a diesel (either standard or Bio) preheater works wonders for protecting injection pumps and injectors and also improves the efficiency of a diesel engine. Any truth in this?

[P00DLE]

hmmm we just used to dilute it with a little white spirit cant remember the ratio and then chuck it n the tank neverhad any issues with it that im aware off.

[Snagger]

This heater is a Land Rover option for severe climate conditions. I think it's primarily to prevent diesel waxing in the filter, but may also have some protective effects on the pump as you say, Guy.

I'm hoping that it'll get hot enough to allow me to use vegoil in normal UK conditions. The 12J uses a little less fuel than the Tdi, and the outside temperature won't be as low. I'll also be adding some thermal insulation to the filter, housing and pump line. Sine the VOW2 heaters on ebay (specifically made for using vegoil in large engines) only draw 160W, 120W for a comparitively small diesel engine should be sufficient. I'll use straight diesel in cold conditions to be safe.

Thanks for the info, Callum.

[discodrew]

Just bumping this one up a bit as I've not had access to the forum for over a week :(

Why not wire in an on/off switch to the dash and use a fuel temp meter?
then you could see on a dial what the temp is and manually switch the heater on and off?

this then gives you the option to switch the heater off when using straight diesel, as you dont want that at 70 odd degrees.

Just a thought

andy

[Snagger]

The heater would be selected by a dash switch for that very reason and to reduce power consumption, but I'd prefer not to clutter my facia with too many instruments - I already have the SIII speedo and the combined water temp/fuel quantity/oil temp unit, plus battery condition and oil pressure guage in the centre panel.

[Converse]

I was tempted by one of these filters on ebay but it only raised the temp to 10oC - enough to stop waxing of ordinary diesel but not sufficient for SVO.

[Snagger]

I was tempted by one of these filters on ebay but it only raised the temp to 10oC - enough to stop waxing of ordinary diesel but not sufficient for SVO.

That is probably because the cutoff switch in the housing (as pictured) is calibrated to 10oC, rather than the heating capacity of the unit. As I said, it draws 10A, which will mean 140W with the alternator providing power. The VOW2 (and various other units on ebay) made for vegoil conversions all draw between 120 and 160W, but are made to accomodate engines with larger capacities (and fuel flow) than ours. I think it should work with the thermal switch bypassed, but I may need to temporarily fit a guage, as per discodrew's suggestion, to see what the fuel temp stabilises at when in use.

[Converse]

That is probably because the cutoff switch in the housing (as pictured) is calibrated to 10oC, rather than the heating capacity of the unit.

Damn - I knew I should have bought it. I'll follow this thread with interest to see how you get on.
I'm currently using a 50/50 mix of dinodiesel/ bio diesel and the 2.25 seems to love it - it literally purrs along!
Problem is the guy that has all the support to produce biodiesel is selling it at 90p litre. I was planning to process my own but the cost of shipping methanol is exorbitant. The batch I've just made worked out at £1.30 litre!
I'm determined to use either SVO or biodiesel if only to thumb my nose at all those who offer criticism for driving a gas guzzling 4x4

[Snagger]

Damn - I knew I should have bought it. I'll follow this thread with interest to see how you get on.
I'm currently using a 50/50 mix of dinodiesel/ bio diesel and the 2.25 seems to love it - it literally purrs along!

It's good to hear that your pump and injectors tolerate it unheated. I do have concerns as CAV pumps are less resistant than the Tdi Bosch pumps to hydraulic damage, and the 12J/19J engines use CAV pumps which are probably similar mechanically to the 10J's CAV. The injectors are certainly the same.

I'm not certain yet that the heater will work, but for £1 at Sodbury, it's worth a try. I'll need to splash out a little on a relay and some pipe unions, but it should all come in at under £10.

I'll get it fitted and try to measuer the fuel temp once operating. If it reaches over 60o, I'll try running on increasingly strong proportions of vegoil, starting from 50/50 and working up. I'll PM you when I get it operating on 100% (may take some time;) ).

[Converse]

http://www.bio-power.co.uk/exchanger.htm

Found this link for making a heat exchanger