cbushrun

Hey guys, my first post so please be gentle!

I converted my Jeep CJ5 to a carburated 4.3 a few years back. At the time it had a MSD mechanical advance distributor and I've been wanting to swap it out for a HEI, vacuum advance disty for better gas mileage.

I changed it out over the weekend. I first turned the motor over until the rotor was pointing towards the #1 post on the disty. I then removed the MSD disty and installed the new HEI disty and played w/ it until it slid in place and the rotor was pointing towards the #1 post on the cap.

It started relatively easy but I cant get it to idle. below 1200 RPM it starts to crap out and I have to feather the throttle to get it to run smooth.

I'm not that familiar w/ HEI ignitions. It looks like the cap can be installed/rotated in different positions around the base. Is there a certain position the cap needs be on? I have the "nose" of the cap (where the wiring goes into the coil) pointed toward the back of the engine bay and the vacuum canister pointed in that direction as well. That puts the #1 cylinder post (on the cap) at about 4-5:00 o' clock when you are looking into the engine bay.

I didnt think an engine could run if the disty was 180 out, but I would like to confirm that, does anyone know for sure?

If so, does anyone have any ideas on what else it could be??

Chris

cbushrun

1Gary,

Thanks for the reply....that has to be the best, fail safe way of knowing I'm at TDC and the one of the things I like about Chevy motors is there are only 3 value cover bolts!!

After thinking a bit about your recommenation to have the oil pump shaft's slot lined up front to back I was wondering how could that be??How could you know where to put the shaft?

I've been hung up with where the #1 post is on the disty andif I understand the concept, its not to worry about the disty or the shaft, just be 100% sure #1 is at TDC, line up the shaft so you dont have to guess where the slot is, get the disty seated. Then just make sure the rotor is facing the #1 plug wire and the firing order is right.

Thanks again....Im looking forward to trying it this eve!!!!

cbushrun

Gary...so I removed the valve cover, turned the motor over by hand and checked #1 for when the intake closed and then stopped at 0 degrees. I then took the cap off and the rotor was pointing at the #1 post. Needless to say I was hoping to see something different...

I didnt have a lot of time to dig into last night, but do you recommend taking the disty out, aligning the shaft slot front to back and slipping it back in? If it still runs poorly should I take it back out and try turning it to the next tooth??

The difficulty is I changed carbs at the same time, from an Edelbrock 600 (too big and crappy off-road performance) to a Motorcraft 2100 2 bbl and I'm trying to isolate the problem between the carb and the disty. The carb is freshly rebuilt and I cant detect any vacuum leaks.

Any other ideas??

cbushrun

Hi GAry,

Thanks again for the suggestions.

So I found a vacuum leak from the carb to manifold gasket and got that fixed. I wasnt able to spend a lot of time on it after I fixed it as it got late. It is running better and I was able to get it to idle around 1000 RPM....but when I go to cap the vacuum line it immediately dies.

COrrect me if I'm wrong, but I need to cap the vacuum advance at the carb, for the disty to set initial timing, right?

Any other suggestions?

Regarding the holly and such, I mainly looking for off road performance and decent gas mileage w/o learning a whole new carb. I hope I dont ruffle and feathers, but I've heard Qjets are very touchy and I need something less complex, even if I sacrifice potential performance. Going lean isnt a bad thing, I dont need the speed in a Jeep : )

cbushrun

Gary,

Thanks again for the help. I found a vacuum leak from the carb base gasket and replaced the gasket. It helped the idle but was still having issues. I sprayed some more and found the carb has a leak in one of the shafts.....

It wasnt the disty after all. Thanks again for the help!!!