I was pondering putting a 4.3 into a disco. Emissions aside because a lot of us dont live in emissions counties... (I dont any ways) I was thinking adapters aside.... the d2 trans is electronic... it most likely communicates with the rover ECU. So if you remove the rover engine then you have a communication issue if not a total transmission problem now. Sooo.. I was just thinking... Dont use the chevy ECU. Use the disco ECU to run the chevy engine. I started thinking about the logistics of that and came up with a rough game plan. Was hoping some one could complete or shoot down the thought process. Both the vortec 4.3 and the rover 4.6 are mass air engines. Both are roughly the same cubic displacement. Why not use the 4.6 ECU, 4.6 coolant temp sensor (adapted), 4.6 mass air sensor, 4.6 O2 sensors, 4.6 everything except the fuel injectors (unless the 4.6 injectors will fit the 4.3 rail (??) Essentially using the 4.6 ECU, harness and sensors because it's not like the ECU knows what engine it's attached to. Chevy 4.3 injectors ohm out at 13.5 ohms... rovers at 14.5. 1 ohm is within spec so the ECU should not through an injector code. If you have to just add a 1 ohm resistor in each injector circuit. Since the 4.3 is a 6cyl and the rover a v8.. put a 14.5 resistor of the ends of two of the injector pigtails for two of the unused cyls so the rover ECU thinks it fired an injector that really doesnt exsist. I've been drinking a little so I cant quite wrap my mind around the ignition timing issue. I would imagine you'd put both engines at TDC #1 cyl and make the timing notch on the 4.3 crank pulley match the position of the rover timing mark pulley notch so it'd fire the 4.3 at the same time. I'm sure it cant be this easy or some one would have done it... I guess they're be a misfire or stumble when the rover ECU fired the two non-exsistent cyls in the firing order... I would imagine you could just locate 2 of the V6 cyls to wire these two pigtails back into so something always fired... hmmmmmmm..... Anyways the premise being that if the rover ECU could run the chevy metal then the transmission and all idiot lights/shifting etc should function normally, correct?

 

Keep drinking! This is going to be great! It takes a knuckle head to show us what can be done. Git er done!

 

Interesting approach, how much horse power are you looking at? My concern would be the tranny and both diffs. With only 2 spider gears, you would need to switch to lockers to strengthen the diffs and at least a large tranny aux. cooler.

 

Following your train of thought, what is pushing you to the 4.3L? Why not go with the 5.7L that actually has 8 cylinders to manage? The 4.3 is, for all intents and purposes, a 5.7L with the back 2 cyls loped off. The 5.7L will also give you more HP without significant additional fuel consumption. The beauty of the 5.7L is you can find parts anywhere.

 

hmm.. Yeah a 5.7 v8 although heavier would simplify the wiring process and issues.. also would prolly fix the ignition timing issue... I wonder what the firing order of a chevy 5.7 is compared to a rover v8? I know you can change the firing orders but only a couple different ways. If the chevy firing order is compatable with the rover firing order.. I dont see why you couldnt use the rover ecu with the chevy engine. The O2 sensors should make up for the added displacement to add fuel to the mixture for the 5.7 displacment.

I just keep thinking about these things because even though my rover 4.6 is running fine... I dont trust it as far as I can throw it. I consider every time I crank it a roll of the dice. Which is sad because I'm a dealer tech and I know engines and know what to trust for the most part mechanically. I almost got stranded last time I went 4wheelin in the mountains about 5 miles back in the forest that was completely unaccessable when my thermostat housing blew apart (got to love plastic). I was sooo lucky to have a cooler of ice with me that had melted and there was just enough lip on the t-stat to re-attached the hose to get home and used the ice water to re-fill the cooling system... couldnt get a new part local. I'd feel a whole lot safer if I had a common every day american chevy 4.3 or 5.7 under the hood that I trust and parts are a dime a dozen. I trust the rover transmission, t-case and axles... just not the engine.

 

Crap, must be getting old; I used to know this off the top of my head. The firing order is 18436572. Drivers side front is cyl. 1,3,5,7 passanger side front is cly. 2,4,6,8. This is exactly the same firing order and setup as our 4.6L.

 

With a 5.7, you would need a new tranny, t/case and lockers to handle the torque.
Got to get back to reality guys.

 

Actually, the 4.6L puts out 300 ft-lb @ 2600 rpm and the 5.7L puts out 325 ft-lb @ 2400 rpm. Not so big a difference. Furthermore, the '03 and '04 have the ZF 4HP24 transmission with the bigger fluid pump. You could beef up the TC if you want, but if the TC in a K1500 can handle it, I am betting the LT230SE can too.

 

So if the firing order is the same then the rover will fire each chevy cyl when it should just as if it was the rovers own firing order. The key is just making the chevy timing notch match the rovers clock wise for the crank sensor so the right cyls fire when they should.... if the firing order is the same then I bet you wouldnt even have to do anything. TDC #1 chevy will be the same as if TDC #1 rover so I think really then all you'd have to do is use the rover crank sensor on the chevy pulley. May could use the chevy crank sensor but you might have to adjust resistance readings. Seems easier to make a bracket to hold the rover crank sensor to the chevy pulley. Hmmmmmmmmmmm I'm feeling a project coming on.

 

I believe the 4.3 and the 5.7 make the same 245HP. The six uses higher compression.

But I absolutely love where this is going. Keep up the good thinking. Please let us know what we can do to help this thought process.