Putting together one of my beater disco 2s for the crotch goblin. Something he can beat up and I'm not out anything.

I have a 03 with 8x,xxx miles that is in the dreaded dowel pin mis alignment range. No paperwork to support or service work to tell if the engine has ever been changed.

Motor has carbon issues and some stuck valves, which is why it was parked and sold for scrap to me.

I have a 4.0 from an 01, approximately 150k. Head gaskets beyond gone. The plan is to inspect 4.6, if there's no abnormal looking oil pump wear and the cover fits properly I'll likely chance the 4.6 swap along with new cam/lifters/spare heads

If not my plan B is to pull the rotating assembly from the 4.6 and install it in the 4.0. 4.6 cam, rods and crankshaft. I'd use the 4.0 pistons for more compression as we're stuck running high octane anyway.

As of now I don't have nanocom to sync the 4.6 ECU.

Will I have any issues with check engine lights with a higher compression 4.6 engine/cam on the 4.0 stock ECU?

Thanks ahead of time..

 

I’ve heard of people upping the compression that way. As you know, people often put the complete rotating mass from a 4.6 into a 4.0. I think it’s a bit more experimental to do what you’re considering. I can’t see why the ECU would know any difference as far as throwing a code. The higher compression might give you other issues though (but it still might be worth a try).

 

About the only issue I'm worried about are check engine lights...I really hate those.

 

It's been done with no issues upping the compression, I'm not sure the ECU even needs to be flashed or synced to run with no codes. I may be wrong on the ECU but fairly certain they are similar enough to not cause any issues with functioning O2s

 

I'm pretty sure you will get a LT fuel trim error running a 4.6 on a 4.0 ECU, but why not run the 4.6 ECU if you have two complete trucks?

 

The 4.6 is SAI. I'm pretty sure with a nanocom I could sync the 4.6 ECU to the 4.0 disco, I'm not sure if I could delete the sai

 

Mine is 4.0 block, 4.6 internals but using 4.0 pistons for higher compression and still running the 4.0 ECU with SAI. I just use the 4.6 air intake and haven't had any fuel trim codes. You could get the ECU re-flashed by Tornado Systems but its pretty expensive and requires shipping to/from UK.

 

I honestly won't bother reflashing unless cels are an issue.

The 4.6 block is crap. Got the radiator out and did most of the removal today, found a cracked timing cover right above the crank pulley. Good news is the engine (no heads) spins nice and freely by hand so fingers crossed there's no scoring on any of the main/rod bearing surfaces.

Hope to get the 4.6 the the rest of the way out tomorrow. Start on the 4.0 tomorrow. Fingers crossed the 4.0 is in much better shape upon tear down.

 

Nanocom cannot turn SAI on or off but a testbook can. Testbook could reflash any ECU to any other program. The other alternative is get a non-SAI 4.6 ecu/bcu combo (pretty rare for a D2, I know they exist I just have never seen/had one) but since @gecko951 has validated no CEL go for it. 4.0 block should be lower probability of sleeve slip.

 

I'll be looking closely at the sleeves on the 4.0. I'll take the heads off before I pull the engine to verify. I plan on install pins in the cylinder while out so long as it looks good