BobtailBogey Posted August 31, 2009 Share Posted August 31, 2009 Right my engine is not far from needing a rebuild but its only done 54k...... Getting quite noisy and bits of metal in the oil. So have always said when it goes im replacing with a 4.6 so what is involved and what will i need to convert my 3.5 EFi into a 4.6?? im thinking of buying a complete p38 so i have everything or would it not be much work to just get the engine?? Quote Link to comment Share on other sites More sharing options...
jonket Posted August 31, 2009 Share Posted August 31, 2009 Well, I have a 3.9L EFI and would like to convert to 4.6L. I am told I only need a 4.6L short block and use all the stuff from the 3.9L engine. The engine block is said to be the same in all engines. Only improved a little bit. And bigger bore and longer stroke. I am just starting this process. Got the 4.6L short block and still taking apart the 3.9L. Here is a good link for information about these engines. RPI Engineering Quote Link to comment Share on other sites More sharing options...
vougese39 Posted August 31, 2009 Share Posted August 31, 2009 right you will need to swap form the 3.5 timing cover,sump and oil pick up, manifold inlet and exhaust, rocker covers. but you will need to get the ecu mdified to run with the 4.6 ecu to this i would change for the hotwire system from a 3.9 or another form of ecu control wil be needed. you will also need a spacer making so you can use the crank pulley from the 3.5 as well for all the drive belt system Quote Link to comment Share on other sites More sharing options...
BobtailBogey Posted August 31, 2009 Author Share Posted August 31, 2009 So there aint much i really need from the donar car? its all swapped from my 3.5 unit? Why do manifolds etc have to be swapped? Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted August 31, 2009 Share Posted August 31, 2009 I don't agree with the above posts What you have I guess is a Flapper system ? If so then you are now looking at a Gems powered 4.6 EFI ? You have to work out id the 4.6 and the serp front end and the timing case / pumps belts / pulleys etc have enough room to fit into you landy, then if so the engine as a unit goers in, no need for changes etc. However, getting a GEMS unit happy to run isn't easy, I would suggest either a GHotwire loon and injectors AFM etc or go Megasquirt, the bonus of Megasquirt over the 3,9 hotwire is that there is no need for an exopensive fuelling chip to allow extra fuel for a 4.6 vs a 3.9, plus you can dump the dreadfull lucas stuff for modern technolgy Manifolds - well the 4.6s are prone to cracking, they are frankly pnats, you can use the 3.5 ones, the 3.9s are better HTH Nige Quote Link to comment Share on other sites More sharing options...
iomlt Posted August 31, 2009 Share Posted August 31, 2009 So there aint much i really need from the donar car? its all swapped from my 3.5 unit? Why do manifolds etc have to be swapped? As above get the hotwire system from a 3.9. i have a 3.9 ecu rpi chipped ready for a 4.6 which i could be willing to sell. I may even have the correct loom too.... Quote Link to comment Share on other sites More sharing options...
BobtailBogey Posted September 1, 2009 Author Share Posted September 1, 2009 Cool that sounds a bit better, just dropping the engine in as it is and then run 3.9 wiring just with a chip to up fuel etc.. What about the entire loom from the 4.6? would this work or would it be a pain to plumb into my 3.5 loom? Quote Link to comment Share on other sites More sharing options...
iomlt Posted September 1, 2009 Share Posted September 1, 2009 Cool that sounds a bit better, just dropping the engine in as it is and then run 3.9 wiring just with a chip to up fuel etc.. What about the entire loom from the 4.6? would this work or would it be a pain to plumb into my 3.5 loom? i carnt help you with your second half of your post. maybe someone else can. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted September 1, 2009 Share Posted September 1, 2009 Converting a GEMS unit to a Hotwire system is a nightmare in the making, anything is possible, (like nailing jelly to the wall), but for sanitys sake unless you are a sparks genuis get a Hotwire loom, ECU AFM etc ...and its plug and play as the HW loom is disconnectable from the rest of the LRs electrics / harness - and with so many 3.9s being broken a decent loom won't be much Nige Quote Link to comment Share on other sites More sharing options...
cackshifter Posted September 1, 2009 Share Posted September 1, 2009 The engine change might come as a surprise to your transmission; see Ashcrofts site re torque converter sizes, uprating etc. Also diffs might eventually hang out the white flag - depends how sympathetic you are with it I suppose, and what sort of cam you have. Nigel Quote Link to comment Share on other sites More sharing options...
task Posted September 2, 2009 Share Posted September 2, 2009 The old man currently has a 4.6 in his RRC (overfinch). This has a remapped hotwire system, X-bolted 4.6 block/serpentine (intermediate) front cover with dizzy. I'm not sure if the auto box has been upgraded but I'm fairly sure the diffs have not. It's behaved itself so far although the autobox is now getting a little tired. Just thought those details might be of help Quote Link to comment Share on other sites More sharing options...
BobtailBogey Posted September 2, 2009 Author Share Posted September 2, 2009 Im still not sure what im doing about a box etc... i might keep an auto box out of the salvage P38, Diffs might also either swap to the P38 axles or uprate my current ones. Surely instead of converting to gems or another running system, the standard 4.6 loom and running system would be cheapoer and easier to use as its already something i will have available. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 3, 2009 Share Posted September 3, 2009 Surely instead of converting to gems or another running system, the standard 4.6 loom and running system would be cheapoer and easier to use as its already something i will have available. Doubtful TBH, the loom will be pence, and the inlet manifold/plenum etc will be very little cash, as HFH says it's plug and play bar supplying it with power, virtually. Quote Link to comment Share on other sites More sharing options...
Coastcard Posted September 6, 2009 Share Posted September 6, 2009 Im still not sure what im doing about a box etc... i might keep an auto box out of the salvage P38, Diffs might also either swap to the P38 axles or uprate my current ones. Surely instead of converting to gems or another running system, the standard 4.6 loom and running system would be cheapoer and easier to use as its already something i will have available. I believe that you will find all the GEMS stuff is linked to other ECUs in the P38 (Alarms, windows, suspension and notably gearbox. etc.). As said above, to move this lot would be a sparky fiesta. If concerned about gearbox, get one from a Classic LSE which were a bit stronger. Classic boxes are mechanical, P38 ones are electronic. Quote Link to comment Share on other sites More sharing options...
BobtailBogey Posted September 6, 2009 Author Share Posted September 6, 2009 Thats a pain i was hoping that everything was away from the engine management, I dont really want an auto so im gonna have more fun making a box and clutch system work on it to. Quote Link to comment Share on other sites More sharing options...
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