2.5TD and 200TDI fuel pump differences

[Landy7]

Hello all,

4 years ago I swapped my 2.5td engine for a 200tdi (disco). I roughly followed this guide: http://www.glencoyne.co.uk/tdiguide.htm

Coming to the fuel filter housing, I did not have the housing from the 200tdi so I used the present 2.5td fuel filter housing. From the guide:

Quote

If converting an older diesel Defender you can use the old type filter, but you will need to blank off the unused ports.  The Disco filter only has two - in and out (marked with arrows for direction of flow). 

So I blanked the unused ports and connected it all up, we are now 4 years later and no problems at all with this setup.

Now recently I heard from someone that the 2.5td uses a lucas cav fuel pump and the 200tdi a bosch one and that you need to use the correct fuel filter housing because of the 'front pressure'. I always thought that the fuel filter and it's housing don't matter, it just filters the fuel in and out, you also have the fuel lift pump behind it so .. is there something I'm missing? Would it be a good idea to source a 200tdi fuel filter housing after all?

 

Edited September 13, 2020 by Koen110

[Mo Murphy]

I'd imagine that if anything was going to be damaged, it would have been by now !

Changing the fuel filter housing should be a straightforward task and still should be plenty around if you want piece of mind.

Mo

[western]

The older 2.5TD & 200tdi use the same fuel lift pump, ETC7869, It's the injection pump & injectors that are different, TD has a CAV unit whereas the 200tdi has a Bosch unit. 

[Arjan]

We swapped the 2.5 N/A many, many years ago for a 200 Tdi and the fuel filter never gave problems.

Could be true on paper / theory but in the real world...

 

[Robert Davis]

Agree the the advice was referring to the injection pump verses lift pump..

Only the 2.25 still used the older style CAV IP that fit into the "distributor hole" of it's petrol counterpart.

When the 12J was introduced LR switched over to the Bosch IP, but kept the same early CAV Lucas style sandwich filter that was used on the 2.25.

The 200TDI used the later spin-on style filter that was also used by the 300TDI.

I believe all the lift pumps were the same from the 12J to the 200TDI.

The only real difference in the fuel routing was the return line on the 200 and 300TDI verses the earlier diesels.

On a 200TDI the spill-over line joins with the return line and goes straight back to the tank. On the 2.25, 12J, & 19J, the spill over line goes to the top of the sandwich filter via one side of a banjo with the other side to the tank.  The return line from the IP then enters the inlet side of the sandwich filter.  In theory. any trapped air is supposed to rise into the banjo and get pushed out and back to the tank.  This theory is flawed because the fuel loop allows the trapped air inside the filter to get sucked back into the feed and back through the IP again and again.  The routing makes the sandwich filter more difficult to bleed.

The 300TDI introduced a sedimenter that will trap water and particulate.  Installing a sedimenter on an earlier vehicle will trap water and particulate that will otherwise end up in the filter.  

To make the sandwich filter easier to bleed on all models:

You can join the spill over line to the IP return line and send it back to the tank separately as long as you plug up the inlet port on the sandwich filter where the IP return line was connected.  The same is true of the banjo, but if you don't have a second plug, you can still join the spill over line to the IP return line and let it go back to the sandwich filter as long as you substitute a solid bolt for the banjo bolt.   in this way, any trapped air is prevented from entering the filter and cycling back around.