Thread: Stripping, checking and re-assembling 4.0 Gems (conversion to Thor)

Hi all,

My lad has a 02 D2a with a 4.0 Thor (auto). I have a 4.0 RR Gems (taken from a well serviced running RR that had a bingle - I know the mechanic who removed the motor and he said it had been serviced by him consistently and never had an overheat and was strong - under 200,000klm too). My son is looking at stripping that motor down to have a look with a view to replacing the 4.0 in his D2a. I have never prepared the 4.0 RR motor for storage so I am assuming it may need to have the pistons removed and the bore lightly honed. Aside from a complete pull down, inspection, clean and re-assembly (with new rings presumably and he has the full head gasket kit already and he would get the heads crack/softness detected and decked to suit (lapped valves if needed and he already has the Vitron valve stem seals ready) is there anything else he needs to be considering? He would re-assemble using assembly oil on the moving parts and new head gaskets, timing gear gasket, sump gasket, rear main oil seal etc. Being a 4.0 Gems it should have brackets on the block for knock sensors (I have yet to look) but aside from TIG welding a bracket to hold the D2 Thor's crank position sensor, from memory the only other change would be to remove the GEMS timing gear sprocket and replace it with that from the Thor? Anything advice most welcome. It should be a good project for him.

Cheers

If you pull the engine to bits to replace piston and rings get it ridge lined , if he runs it n gas put in some high compression pistons