Lucas filters heads and Bosch filter heads

Has anyone used the 200/300tdi filter head for a 2.5N/A?

For those of you not aware of the two filters heads, the old 4 (5inc top leak off) port Lucas head is commonly set up to have 1 feed in from the lift pump, 1 feed out to the injection pump, the injection pump return then goes into an input on the filter and the air/leak off pipe on the top port T’s into the leak off for the injectors before returning to the tank. So question no. 1, if I pump the lift pump diesel will come from the in and out port which would be the to and from connections on the injection pump. So when its all plumbed up, there is nothing to stop the diesel going whichever way it feels, as the Lucas CAV IP can be fed from either end (I know its not supposed to be, but there is nothing to stop it working this way – although the performance is affected) Now I have not yet taken the filter head off and had a look but, if the diesel is coming out the input to the head, then does this mean its unfiltered as its just running along the same rail?

The later Bosch style filter head has 3 in ports, and an out port, 2 of the ins are blocked off so its very simple, diesel comes in from the lift pump into a side port, and out the top port via a banjo. This is where question no. 2 comes in. Where does the air in the setup go? Surly it’s not pushed along the output to the injection pump, or do the Bosch pumps have a means of dealing with this – which would ring true as you can put a new filter on and they self bleed but I wasn’t sure at which level it did this.

So here comes question 3, has anyone used the later Bosch type with a 2.5N/A setup? I see a few problems including the issue with where does the Bosch assembly send the air.

My 300 self primes - ive had the fuel system off twice and its always started with no fuss.

I think the main problem you will have is where to put the injector leakoff.
Also, the Luycas pumps have a weedy pump to push the excess fuel back again - i assume this will also stop the fuel flowing back.

I know the Bosch setup self primes its which part of the system does the priming I am looking into. Looking at the Disco it looks like the IP takes care of it.

Injector leakoff isn't a problem, it goes to the tank.

The excess fuel simply leaves the IP as its constanty being fed by the lift pump, also I have run my IP being fed from the front and the back. If you put it in the back, it leaves via the front and vice verse.

Lift pump puts in the diesel, IP uses what it wants, excess diesel leaves the pump. Which brings me back to, what makes the diesel flow the right way? Once the system equalises it could technicaly flow any way it wants.

That where i thought the IP's return pump came in... While i was looking into veg oil usage with my old NA engine, what i gathered was that this vane pump was made of a fibrous materil, and fell apart whe the veg oil was used in it, cos it was too much hard work for it to pump. How accurate that was or not i don't know.

The Lucas CAV injection pump (and indeed almost any IP) has a metal vane pump this simply sends the diesel along to the HP metering pump.

The whole pump body is full of diesel (lubricating everything) the vane pump (fairly pathetic in terms of self lubrication) just sends diesel to where its needed, if hardly any of it is used, then the diesel coming in from the lift pump is excess and it comes out the opposite side.

If you were to change the piping around on a Lucas CAV, it would still work, so think of it as a passive component.

The biodiesel causes issues on the CAV because the main shaft has a small clearance between it and the pump body, diesel can effectivly lubricate this. Thick veggie doesn't do such a good job because it can't get in the same, the shaft wears, things can seize and break and all hell breaks loose. If you send a Lucas CAV away for veggie conversion (not the con-man one the real one) they will machine out extra lubricating grooves in the body along the shaft and change all the seals.

Anyway, the Bosch injection pump I have now learned does all the air bleeding. The filter on the 200/300tdi JUST filters, air the ferking lot goes through it - except dirt!

Clever Gerrys!

Fair enough! You know more than i do then!

Like you say, i can't see any other reason then as to what would determine the direction of flow through the filter. I have a spare one sitting here, if you want it to play with, or any parts from it, just shout!

I think i still have it anyway... I fitted the disco 300TDi one with the engine.