4.0 conversion questions

I would like to convert my 4.0 to run a carb, but can't find any useful information on a few things. The two main things I have questions about are the intake and ignition.

I was wondering if there was any company that makes a carburated intake for the 4.0, or should I try and modify the intake to accept a carb ( by an adapter plate or machine work if neccesary). I found info on using a 4.2 intake but that sounds like a pain.

And about the ignition, I was thinking of using a HEI system. How involved would this be? Is using the distributor from a Chevy straight six the only way, or does anyone make a drop in HEI system.

Thanks for any info.

i dont' know much about the swap other than there is no benifit. realy why are you trying to do this

I've got to agree - it's a lot of work for a negative benefit.

The EFI used on the 242 is a solid system - why ditch it? Even with the ChryCo controller (1991-2005,) it's still pretty good - and better than nearly any carburettor.

HEI? Again, why? The RENIX and ChryCo systems put out as much spark energy (or close to it) as the Delco HEI does, so again, it's a lot of work for nothing. That, and I don't think the Chevvy distributor would fit (but I'd consider either a Chevvy I6 or an Even-Fire V6 for the swap.)

I know I've talked about adapting the GM-Delco HEI/DIS to the AMC 242, but that was in the interest of tunability. The three coils will make for a higher spark output than the single coil ever will, I'd be retaining fuel injection, and I'd be picking up parts availability, programmability, and tunability in the bargain. Way much better than a step backwards.

So, I'd have to ask again - why are you doing this? It seems like a step backwards to me...

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Just a thought. I would like to clean up the look of the engine bay and the easiest way to do it would be to get rid of the rats nest of wiring that the renix system need to let the engine run.

I know that FI is much better off road, but the complexity of it just turns me off.

I don't know what I want to do with my MJ now that I am not driving it daily, and I am just exploring different thoughts.

carbing it should not be one of those options just not worth the visual gains you get

LazarusMJ said:

Just a thought. I would like to clean up the look of the engine bay and the easiest way to do it would be to get rid of the rats nest of wiring that the renix system need to let the engine run.

I know that FI is much better off road, but the complexity of it just turns me off.

I don't know what I want to do with my MJ now that I am not driving it daily, and I am just exploring different thoughts.

Click to expand...

I agree with the guys above. And, what will you do about emissions, if that's a concern? Really, there's nothing wrong with the Renix system. It works well, can tolerate some changes in fuel, air and timing, AND it's OBD 1 instead of 2. And, at least here, emissions is less strict for mine than for later models. If you want to clean it up, you could do some custom wire-looming and custom vacuum line routing using metal brake line.

Well...

If you've got your heart set on carburettors, I'd fab up an intake manifold and go with side-draughts to clear the hoodline.

There's not a lot of wiring to the RENIX ignition setup, so no trouble there.

As far as that "mess" of wiring, I've got a couple restomods in the pipeline where I'm going to tackle that mess anyhow. I'll let you know how I do - but it will take a couple years for me to get to it...

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If you want to clean up the appearance, convert the 4.0 to use propane.

For the best carb setups as well as EFI setups for the 4.0L, check out

http://www.cliffordperformance.net

I believe they will be a supporting sponsor shortly.

You'd still have to have some wiring. I think it was just people being lazy when they finished the electrical - which is why I'd like to clean it up.

I don't have any trouble with the system - I think it works well. I just don't care for the appearance - and that's what I'm going to fix. I'm also going to delete the bulkhead connectors in favour of Amphenol locking round connectors, and re-arrange the wiring into "subharnesses" to make troubleshooting and servicing easier...

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