Modifying a 4.0

[vangremlin]

On HorsepowerTV this last weekend, they did a project to upgrade a 4.0 L engine to produce 242 horsepower.  Biggest things were a new aluminum head and a new camshaft.  They tried to modify a fuel injection intake manifold to work with a TBI and had poor results, so they pulled off the TBI and stuck a carb on there. 

Could be some useful info on modifying a 258.  Here is the link to the episode

http://www.powernationtv.com/episode/EP2015-14/project-242-amc-jeep-six

[carnuck]

I saw that. They didn't sync the TBI correctly. I would have the Jeep EFI running in less than a week (less before my accident)

[txjeeptx]

I watched the show,  and thought they left out a key piece of information in using the MPI manifold with their modification for a square-bore TBI/carb. They didn't mention what they did to block off the injector ports. Just a quick shot of what they turned on a lathe to block off the injector ports would have been nice. If it was a part they purchased rather than made, they should have included info about who sells them. You can see that they did not TIG weld the injector block-off plugs into the manifold, they have bolt heads, indicating to me that they are parts that are inserted into the injector bungs to block them off. Where do you find fuel injector bung block offs? Nothing mentioned. Otherwise, the show was cool, if not a shameless plug for the new aluminum head.

Edit: I know you could just leave the injectors in the fuel rail and they will seal off the holes while they are not in use for injecting fuel, but the guys on the show had some sort of clean little plugs that they used to block off the injector bungs so they did not have to leave the injectors and rail in place. And the plugs do not look like they just tapped the injector bung for a plug - it looks like something that could allow them to reinstall injectors if they wanted to go that route in the future.

[eaglefreek]

The bung plugs are available online. Powerblock or Power Nation or whatever they are calling it these days, is a big infomercial. If a company doesn't pay them to promote their product, they're not going to mention it. I would have rather seen the stock MPFI used, but there would be no financial incentive to do so. A before and after in a vehicle with the factory EFI would have been a more real world test.

[carnuck]

Exactly! I ran my '84 J10 with a 4.0L (Renix) with a carb on it (I made a quickie adapter out of a plate of aluminum) but the brake booster was in the way so I didn't take it on the road like that. Later I got a Hydroboost setup (which is smaller and stronger than the vacuum one) but UPS lost my steering parts for 6 months so it wasn't ready to go to Ouray, CO in '02 for the Full Size Jeep invasion. Instead, I took my 4 banger TBI 5 speed '86 Comanche that we lifted and converted to 4x4 the day before the trip (I had been up for 72 hours by the time it was done, took a shower and we hit the road. I had to stop in Colorado for a 12 hour nap and then we carried on)
   Off topic again (Squirrel!) I have an HEI distributor and LPG carb for it now. It currently has an HO motor in it but the modified to LPG Renix intake has pipe plugs screwed into the injector holes. I will be leaving the injectors in the current intake and set up so I can quickly convert to gasoline if need be. I just need to add the TPS for fuel injection to the LPG carb and add a TVS cable for the AW4 (I didn't take the LPG system off the Canadian Jeep so it may have that already)
   I have an AC compressor for onboard air, and may have a dual alternator setup later on. Power steering. Waterpump and fan from a Grand Cherokee. Nothing fancy schmancy in my J10 (to speak of) AW4 (which can shift even without power) and Rubicon NV242 OR  (RokLok) tcase with 4:1 low range, Dana 60 rear and D44 Ford front with 4.10s for now, but I'll have to regear later for the BIG tires I'm putting on.

Now I'm wandering again. The reason for my LPG is it's cheap here if you get it in bulk. $1.65 a gallon and it's 110-130 octane so it LOVES compression (to a point) It's dead simple once hooked up. A diaphragm kit in case of major backfire popping the regulator (which takes 20 minutes to overhaul with a screwdriver and practice) HEI dist is one wire. One wire alt or a modded 10SI GM alt pushing 90 or more amps. Like the much vaunted mechanical diesels, only 1 wire to run everything and even a couple flashlight batteries can keep it running a long ways once it's running.