Vortec V6 in a flatfender with a power Saginaw conversion.

Posting to document the build on my '42 MB. This jeep was purchased by my father in law in '78. Had a freshly rebuilt Chevy 153, SM420, Dana18 transfer case, Dana 44 rear end and a manual Saginaw conversion. Over the years it became strictly a desert toy - the alignment was so bad at one point you didnt dare drive over 25mph. I talked him out of it for use as a hunting rig 3 years ago. Got the alignment fixed, new tires, springs, shocks. Built some bumpers and ran it for a while. Wanted something with a little more power, possibly able to tow a small teardrop or similar trailer for my adventures, which lead me to look at a modern V6.

Here it is just before I started:

Here is the engine bay:

 

I traded for a 1999 Vortec V6 out of an S10. As I tore into it, I found many things that made me wonder wtf the prior builder was thinking. So far, I havent been able to use a single "plan a" for any stage, and have made it all the way up to "plan g" at one point. 1st step was pulling the hood, fenders, grill and motor and seeing what I had to work with.

 

I removed the battery tray and existing motor mounts with a torch. The rails were boxed where the new Advanced Adapters motor mounts were supposed to go, but it seemed thinner than I was comfortable with. I had some extra 1/8" plate laying around, and it sounded like a great time to play with the Plasma cutter I got for Christmas. I cut some sections and welded them over the existing boxed ends in preparation for the new motor mounts.

After that, I lowered the engine in, bolted it to the transmission shifted everything around, quadruple checked everything, bolted the fenders, grill and hood all back on and made sure everything would clear. It was tight, but everything fit.

Steering shaft vs header:



Steering shaft vs motor mount:


Once everything was in, I welded the mounts to the frame.

 

Next step was to address the power steering conversion. I pulled a box out of a junkyard s-10 for my mock ups (need a good core when I buy a rebuilt one anyway.) The old manual box was installed differently than I've seen. The upper portion of teh driver side frame horn was bent upward and the inside portion was boxed with a piece of 5/16" plate. The plate had a hole cut out of it allowing the gear box to recess into the frame and move the steering shaft as close to the frame rail as possible.




The shaft went through a hole that looks like it was just torched through the crossmember and connected to the box.


Turns out the splined clamp had only about 1/32" (only to the chamfer) of teh steering shaft. Scary as hell to know i'ts been driving 30 years like that....



My donor box was a 3 bolt mount, same as the manual, and bolted to teh original mount holes. Rather than completely re-invent the wheel, I was going to bolt the new one in its place. Good news was the pitman arm remained in the same relative position. Bad news was teh cross member was in the way. The crossmember must go for V8 conversions, but I was hoping to keep it for the V6. No such luck.

 

I built a new crossmember. Probably over did it. Built out of 2x3, .188 wall box tubing. Used some 2.5" square tubing to make a passage for the universal joint at the steering box.








The angle of the new box was just a tad off. I opted to add a 2nd universal joint to the system. Currently I have teh box, a U-joint, a short section of DD, then the original 3/4" round. I will upgrade the entire shaft to DD when I install a flaming river tilt column down the road (Maybe even on this build, if the budget allows for it)

 

Now for the passenger side frame horn. This is what the jeep had when I got it:





The top forward portion was cut off, the outside edge was fashioned out of 3/16" plate, and the huge piece of angle iron is for support I guess? For the life of me, I can see absolutely no reason whatsoever to have done this.
I cut the plate down, had some 3/16" x 2" flat stock, clamped it under what was left of the upper horn, clear back to the new crossmember. Welded it in the best I could, then boxed the inside with 1/8" plate. I had some 3" C-Channel laying around that I used to connect the two frame horns together. Tight fit, but yes, I can still remove the steering gearbox.

 

When I took everything apart for this swap, I saw some small stress fractures in the top portion of the passenger frame horn where the front crossmember connected. Most likely from the winch and bumper I built earlier this year. I am hoping this will fix that. I am contemplating cutting some 1/4" plate I have and making a plate that will run on the outside of the frame from just behind the shock mounts to the front of the horns. Probably not needed, but it doesn't stop me from thinking about it.

 

Subscribed.

 

Nice. I like the v6. It is a later 4.3 right?

 

Yes. It's a 1999. From what I read before I started, the 96-2000 are the preferred engines. This was rated at 180hp, 240 ft-lbs. engine only has 16k miles on the clock.

My welds aren't quite as pretty as some that I've seen in here, but I know they're strong.

 

So, its fuel injected. I am sure it is computer controlled. Set it up yet? I was looking to this for a replacement for my V6 225. Don't think I will do it quite yet but might in the future.

 

That may be the most messed up frame rail I have ever seen. You did a really nice job salvaging it. Your welds look great to me.

 

Yes. Fuel injected. I ran into some hiccups the last 3 years with the carb - either on too much angled ground or too much elevation change. I live at about 700 feet above sea level and can be at 6500' or more in a couple hours. Haven't set it up yet, but it all seems pretty straight forward. You need a 95 or 96 computer to do it right, and a factory modified harness will work - just tape off the leads to sensors (erg valve, rear O2 sensor, etc) you don't use. Several companies can reprogram the computer for about $200 with whatever peramiters you want - manual transmission, what to set the rev limiter at, torque and HP curves, egr delete, etc. there are multiple online sources and this is a very commonly swapped and well documented motor, so I do not anticipate any issues when I get there. Biggest issue is you need a 1" body lift to fit this tall engine in a low hood flat fender. Some people don't like lifted bodies, but I don't mind it.

Right now I'm looking at the Painless stand alone harness - I've used their kits in my 67 mustang with great results. Pricey at $850, but you get what you pay for. Plus you get a nice clean install. Right now there is a $100 rebate so I just might pick one up.

 

Thanks. I'm still shaking my head trying to figure out "Why?"

 

i have done my own "why's" before.

So, how do you get the computer to work right if you get rid of the 02 sensor. Doesn't it have to talk with the MAF to make efficient fuel burning? I would want all the fuel spark systems to work correctly to make sure I took advantage of all the attributes of FI. I have never done this, so my questions may sound ignorant.

 

You have to keep the forward O2 sensor and weld a bung into your exhaust system for it. You delete the secondary that usually is positioned after the catalytic converter. Since you aren't concerned with emissions (not even here in California) the last one doesn't matter. I'm just not sure if I want to run a sensor on each bank, or just add it after the y pipe ( I plan on running a single exhaust)

 

I actually look forward to not needing to make adjustments for too lean/rich and allowing the computer to select the optimum fuel air ratio as conditions warrant. One of the driving factors for me tackling the project. That, and the easier repairs. Just about any auto parts store stocks parts for a 99 S-10 pick up. Parts for a 1968 Chevy II (my old 153 4cyl) always have to be ordered.

 

Closed loop FI systems that adjust themselves are the answer to a lot of issues. The ability to just buy what you have, wire it up with a computer, sure saves a lot of insane work arounds to have FI. Lots cheaper too. This is cool. keep us posted on your progress

 

Motivational picture for you.