Hello all,

If I had a great deal to snag a '94 manual D1 with a bad engine and an even better deal to grab a good 3.9 RRC engine that already sitting outside it's donor shell.

I want to make any modern improvements to the engine that I can before putting it in the '94 Disco.

I plan to use it for light to moderate off-roading, snow driving, and towing a small RV trailer.

What would you all suggest be done to the engine/recipient shell before dropping the new engine in?

 

A high lift cam shaft is a good place to start. I believe Crower makes a good one. And maybe and electronic distributor

 

Sell the engine to some one who is tired of chasing electronic gremlins and wants to take a step backwards.

Then find a cheap newer engine to upgrade...

 

Ok, I'll concede ditching the dizzy is good policy. But I'm scratching my head over the high lift cam. That's like making it more and less reliable all at the same time. Take the variability out of the ignition cycle, but cook your valves at the same time.

The smart thing to do would be to just set it right for starters. You'll have your hands full just doing that. Set a baseline. Tackle the big stuff while the engine is on the stand. Head gaskets and valley pan, mains, everything under the front cover. If I had time and resources, I'd strip the block, have it hot tanked and then bored and decked, maybe have the liners pinned while I was in there. I'd have the heads done, you could port and polish them if you have money to burn, and fresh rods and lifters.

Good luck! I'm jealous tbh.

 

The 3.9 was not plagued with all the issues that the later 4.0s had.

I would bump up the cam, replace the pump, swap the Disco dizzy in, replace the timing chain and get it installed.

 

Forget the engine, just get the NEW TerraFirma Helper Springs and your truck will ride like a dream.

 

Terra Fur Ma!

 

That's the best!

 

Live-Axle Suspension......

I get where the OP's question is coming from but even the diehard hot rod engine guys have kicked the Rover V8 into the weeds for the newer designs that are more efficient at producing nearly three times the Rover's output in stock trim.

I'm with Army, just simple stuff to clean it up and maintain reliability.

 

Thanks for your replies everyone! I suppose the best way to ensure soundness would be to just keep the mechanical parts close to original spec, unless I want to dump time and money into major mods at which point I might as well be putting a different engine in altogether.

I like the simplicity of the 3.9 so other than renewing anything I can, that leaves the distributor.

Anyone have a preference for electronic ignition? I looked into it briefly with a previous Rover but never came to a conclusion. At s glance it looks like there's:

​​​​​​Pertronix
Mallory
Davis
Are MegaJolt and MegaSquirt in that same category?

What would be the best route?

Thanks again.