Whats needed to convert a 3.9L to 4.0L
 

Hello all:
I did a quick search to look into putting a 4.0 into my currently 3.9L 1995 Discovery and didn't find anything.
I have constantly had issues with this engine, it ticks, rattles, sounds like a rod bearing is going to come out through the oil pan and is just plain annoying! I have done oil psi tests (COLD: idle 30PSI 2500RPM 14psi: Hot idle 9 psi 2500RPM 15PSI I put a new timing chain and oil pump in last year after it cracked and low oil psi light came on. I bought this rover a few years back and replaced the head gaskets at the dealer. It started ticking shortly after, went back they claimed that it was because they took the lifters out and the sludge is gone so now it makes noise... BS I was able to have them replace the lifters but it still had the tick. I have decided to just say screw this engine and get a used one (have used one 112K) the only issue is, its a 4.0. That means I need to put the new ECU in, and now I have the coil packs. Oh and no Dizzy! How big of a burden is this? Do I have to rewire the truck for the new ECU? What about the OBDI port?? Thanks guys. Also, I should mention that I have been wrenching on this rover for over 3 years and taught myself a lot with reading the RAVE and buying the Haynes manuals. I also have a general mechanic friend that helps when I have questions. JUST SO YOU KNOW IM NOT A IDIOT! LOL! THANKS! :D

So why would you go and put a totally different engine than what came in it?

Yes you would need all the associated wiring, different ECU, the 4.0 is ODB2 so everything would have to change drastically. And the used one may need a total rebuild just like the current 3.9 does. A used engine is still a shot in the dark unless you go thru it before installing.

You could scrap the 95 and buy a later model cheaper than converting the 95 to a 96 and up system.

The value of a 95 D1 does not justify such an effort. You would be spending a lot of money with no hopes of recovering it. Unless you are just bored and wealthy. And stubborn to boot.

My honest opinion. You could spend your money better with a different approach.

a 95 would be easier/more legal in the case of an aftermarket standalone ECU conversion, which would save you the hassle of getting all the OBD2 stuff.

not doubt a lot of work either way though!

Danny,
I already went through the 4.0. But your right, I think it is going to be a royal pain in the butt to convert. Plus with the price of gas, hopefully someone will be selling a 4.0 disco that is "in great shape" and then I have a parts disco. Valve, wonder if I could find one cheap... (junk yard, or who knows:cool:

For the investment in time and associated costs, you could probably buy at least one whole DI in running order if not 2.

I have a friend with a nice DII if you are so inclined. It may be cheaper than the conversion you speak of. I would not tackle it myself. You may as well gut what is in there and put in a 350 chevy or some other motor if you're going to do all that.

Or look at the D&D Fab site and give them a call. They got all kinds of 3.9's.

Just stick the intake and front cover from the 3.9 on the 4.0. Easier than trying to convert to GEMS.

What he said. I think you might need a camshaft or a gear or something to drive the distributor. People have even converted the 4.6 to distributors. Ask one of the Pauls, I bet they both know exactly what it takes to make the new engines work with a distributor.

The difference I believe is the engine management system. Both are physically the same. Just different intakes, sensors and ecu.

Or you could run 20W50 and do this https://landroverforums.com/forum/di...rite-up-48197/

Where are you located? I have a 3.9 I would trade for the 4.0 - PM me if interested