I did this conversion on my van, and now i ended up changing the whole engine, box and subframe anyway, it worked, but not for long...
heres the list of what i did:
Swapped exhaust and inlet manifolds over to the TDI ones, changed the oil filter housing to the TD one as it had an oil feed for the turbo built in,
theres a small pipe going into the bottom of the block on the TD for the turbo oil return, on the NA block you need to tap out the core plug here and put the pipe in here from the other block.
reroute the water pipes through the oil cooler on the TD filter housing.
change to the TDi injection Pump.
if your TD pump is the later type with 3 black wires going to the fuel shut off solonoid, remove the shroud that is supposed to prevent access to it, remove the solonoid and replace with the older type (just one ignition live)
then put another wire from the starter solonoid wire (ignition barrel side), to the starter solonoid wire (black or black and red wire). it has a single pin plug that runs near the brake fluid pot..
this eliminates all the hastle of the chipped key problems that i ran into...
also you will need to either get a custom exhaust made or get a TD escort van exhaust which are not cheap new, the original van one will not fit the TD manifold and if it did, it will restrict and cook the engine anyway
bear in mind that the TDI engines are intended to sit slightly further forward due to the intercooler fouling the bulkhead, you can just remove the plastic part of the bulkhead which i did but you will have a problem getting anything onto the air intake because it is so close to the brake servo. it is possible and it does work but it doesnt look right.
it took me 2 evenings to do all the above without rushing too much.
it made a huge difference in performance, the following day i towed a cavalier full of spares on a trailer, with a van full of tools 10 miles to arena essex and back with no problems. unfortunately a few weeks later the head gasket and the fuel pump failed almost simultaniously so i decided on changing the lot...
if you plan on using the TD box you also need to change the subframe, linkage and gearstick because the TD box has an extra mount on the subframe, diffrent linkage, lift up reverse and a longer clutch cable.
the speedo drives will just swap straight over but you will need to swap the plugs over from the reverse light switch.
if you want to change the lot, i would recommend sourcing a whole escort TDI and just drop the lot out of the bottom with the gearstick still attached etc. this is what i did the 2nd time, hell of a lot easier in the long run. and while its out you may want to do any tweaks to the pump now if you are going to up the fuelling, because its quite difficult to get your hand down the front when its in.
the van will now easily spin up through 1st and 2nd in the dry, and its better on juice than before (unless i floor it everywhere).
all in all, i would say it was definately worth it, because if you are anything like me, the 1.8 diesel used to make me angry everytime i hit a hill! i no longer have this problem.
sorry for such a long post, but maybe this will shed some light on the subject.
