discovery 3.9 or 4.0ltrs

guinness said:

hi when i rebuild my 4.0ltr i will be using a 3.9 block can i use my 4.o camshaft from my thor engine or do i need a 3.9 camshaft.
all thr top end will be from my thor engine rockers pushrods etc,
at the moment the thor is running but i think the head gasket has gone again as loosing water and a sulpher smell from the exaust


many thanks

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vougese39 said:

3.9 does not have a point for the flywheel sensor rebuild the thor engine

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listerdiesel said:

GEMS 3.9 does have the flywheel pickup point.
THOR 3.9 has it in a slightly different position, but uses the same hole in the engine flange with a different mounting plate welded in.

3.9 and 4.0 are both 3950cc, same pistons etc etc.

Pictures below, the first two are the GEMS block, the last one is a 2000 THOR engine. The only discernable difference is the position of the hole and the size of that hole for the flywheel pickup sensor. Our THOR engine is a GEMS block with all the THOR parts transferred and the pickup mounting modified.

THOR block picture courtesy of 'OJ's DNA' on another forum.

Peter

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vougese39 said:

when the d2 was launched it was launched with the thor magneti marrelli injection system.

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listerdiesel said:

I think you'll find that the THOR system is Bosch Motronic.

Magneti Marelli may have supplied other parts but not the engine management system on the Disco 2.

As many engines are swapped between vehicles, it is very relevant for folks on the forum to know what options are available to them, including engines from other models in the Rover range(s) We bought a new 4.0 cross-bolted GEMS block from a LR dealer, stamped as such but it was no problem to rebuild a THOR top end onto it, just the pickup mount needed modifying.

Peter

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