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2.5NA Deisel into a 2.25 S3


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Since we took the 2.25 apart and found wear in the bore needing a £120 rebore we thought we'd look at the 2.5 that was also in the back of the truck when we got it.

We have mounted it to an engine stand and sorted out the starter motor and wiring, all was going well, with the engine turning over and stuff, and an exhaust section bodged on to just run it with when we came to the fuel system.

The lines appear too short to reach the position of the pump on the 2.5

The fitting to the pump are wrong - the feed is doneish, we swapped for the 2.25 connector, but the return/drain is totally wrong and requires some new bits.

I though that the feul systems were compatible, it would appear not at the moment - any one have any suggestions.

The aim was to run the engine up and see if it ran OK, if so we would then drop that into the S3. At the moment it looks like we would need to ruin the feul system for the 2.25 to check it.

I also note that the engine mounts are slightly different, the left side (looking out the windscreen) looks fine, just needs a swap, but the side under the injector pump is totally different, it looks like we would need to alter the chassis engine mounting.

So Q's,

1) What engine mount modifications are needed, I thought it was a straight drop in

2) Can we bodge a feul line onto the injector pump inlet, running a gravity feed, bypassing the feul pump, and also blanking off the spill/return line from the pump to get it running on the stand.

3) Would we need some of the bits from the 90 2.5NA feul system to make this work (or go and buy the correct fittings) or is there some knack needed to get it to work?

I thought the swap to a 2.5NA was a no brainer, but it seems to be fighting us, so any information or pointers to pages about swapping for the 2.5 would be appreciated, I can't seem to find any pages on google, loads about going to perkins and 200tdi etc

Someone one here will have done it so some detailed information would be appreciated before we go back to the 2.25 lump and pay for a rebore.

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Silly thought, is it a 2.5 a Landy engine, not Sherpa? Fuel pump should be in the same place as 2.25. There may be an imperial/metric issue but not length...

Engine mounts, can you not take them off the 2.25 and fit to the 2.5, chassis mods shouldn't be needed. Blocks are the same. Gravity into injection pump should be ok, hang a plastic coke bottle from Neils roof rafters. Another bottle connected to the spill/return off the injectors/pump will do. Just plumb up using washer hose to get it going. There shouldn't be much return fuel at idle.

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Catflap has the 2.5TD engine in. Apart from the exhaust system, fitting is the same as the 2.5N/A.

Sherpa lump is easier than the 90 one, due to the position of the injector pump. You need to modify the fuel lines anyway, so use the appropriate ends and connect with 8mm I/D fuel pipe. The job seems complicated, but isn't really.

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I originally fitted the Sherpa engine to catflap. The two fuel pipes to the filter housing were too short, so I extended them with 8mm fuel pipe. These are low pressure, so the chance of leaks are minimal. I take it you are referring to the lift pump and not the injector pump?

Any modifications to the chassis etc are covered in catflaps thread on the members vehicles section.



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looking at doing this mod.Got a 2.5 nad in my 90 going to put it in my s3 been told to cut the mount off the o/s (drivers side) and weld a 90 mount on i can use everything off my 90 to do the job (clutch cover engine and chassis mounts accelerator pedal fuel filter air filter) but will need a s3 deisel downpipe and clutch plate , also looking at using a tdi heater plug relay but its a job to do!

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Ahh a few minutes to reply.

The lines that are too short and wrong end fitment are to the left hand side of injector pump and the right hand side. I think left is input (as when the pump was upright on 2.25) and right is spill return.

The fuel lift pump is a bit of an unknown since it wasn't there! We had to remove the one from the 2.25 block and fit that in anticipation of things fitting.

Catflaps problem with the drivers side mount is what I thought when I looked at it.

All in all, we have now decided that on a cost-benefit analysis we are going to use the 2.25. It means stumping up the £120 for the rebore but we are sure we will get it all back together and running after that.

If anyone is interested in a 2.5NA in the Fareham area (PO13), however it is missing:

lift pump

starter motor


broken flywheel housing

broken inlet manifold

probably going to have a series 3 oil filter adaptor :)

we have a spare injector pump too, although I am very unconvinced about the condition of it.

The engine is free to turn (we had the starter motor turning it over) but don't really know if it is a runner.

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