will make no difference if you fit it or not is what i found apart from it will keep debris out of the flywheel, on all 3 engines my escort has had not one has had it fitted (i always forget) and i had no problems but if i had rememberd i would of fitted it purely for the simple reason that if theres somewhere where a stone/bit of wood etc could get in then id rather be 100% that it cant get in, mind you i havent taken any of the engines bak out again to fit it so choice is yours.
this may help you though is pulled from my friend smilers site
Engine to Gearbox mating plate
This is the standard CVH mating plate. It lines up fine and if you are using an Escort sourced Zetec no modifications are necesary. However, the Mondeo spec 2.0ltr block is slightly different. On the Escort blocks there is a cast in web on the inlet side of the engine that seals against the bell housing.
On the Mondeo, this web is missing so there is an open space as shown above. This needs to be sealed to prevent debri from entering the bell housing and rattling around at the high speed of the flywheel.
Here you can just make out a plate butt welded into place to fill the void.

And now all nice and pretty to match the shiny engine.
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rs2k powerd escort mk4.....figured id be different!
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