The CJ Build – HEI Ignition Upgrade for the 258

HEI upgrade

Getting rid of the duraspark once and for all!

Now, I was honest with myself, and thought the current ignition (duraspark) system was just total JUNK that had to be ditched somehow. At this point, I thought it was a good idea to figure out some OTHER type of ignition system, something more simple and easy to troubleshoot…because the duraspark system was obviously NOT easy to troubleshoot, having so many wires and in so many locations that it makes the engine compartment look more like a rats nest than a place where something should actually OPERATE. I decided on getting an H.E.I. system for the Jeep…for 1 reason at first

ONE wire ignition hookup.

How cool is that! Now that was the first reason, other than the obvious reason of the duraspark not doing ANY spark much less a ‘dura’ spark… also, the other reason was that HEI apparently is a huge upgrade in throttle response due to the fact of higher voltage going to each spark plug (around 40k volts per plug instead of the measley 15-20k volts from standard ignition system).

To get the HEI setup… look for a distributor from a Chevy C-10 Pickup with a 250cid 6-cylinder. Something in the 1980 range, or early 80’s will work great. The systems on these trucks is a unified ignition that contains the coil and all ignition modules RIGHT in the distributor….only thing you need to do is hook up a 12v hot on start/run and you’re in business! Also, you’ll need to get a drive gear assembly from an AMC v8 distributor to get it to fit in the 258, but it’s an easy deal to set up. OK, so I got it and put it in there… here’s what she looked like after the H.E.I. install:

MUCH nicer… got rid of the old coil, ballast resistor, about 9 extra wires in the split loom and another box under the hood… It’s ALL GOOD Baby!

You can see some wires coming into the top of the distributor here…the red and yellow and brown wires…well, they’re self contained, they come from the ignition module in the bottom of the distributor and hook into the coil in the cap of the distributor.

Now that the HEI is installed, it’s time to figure out what the TDC (top dead center) of the compression stroke on the number one cylinder is… to do that…I just used a trick that I heard my dad or someone tell me a long time ago I think. I took some cork that I bought at lowes and plugged up the number 1 cylinder, and then used my big breaker ratchet with the monster socket on it to turn the crank until the cork popped out…there’s my compression stroke…now I had to figure out where the TDC was for it… just looking at the notces on the timing marks told me that I was there, and then when I went back up to see the number one cylinder, I could see the top of the piston! VOILA!

Ok, now that I have TDC on the compression stroke, now what?

Well, now it’s a matter of getting the rotor put on the distributor and seeing where that thing is, and picking that “SPOT” to be the number 1 cylinder reference when you put the cap back on the dist., that spot is where you will hook the number 1 cylinder spark plug wire. Then the firing order is 1-5-3-6-2-4, so just hook up the other wires to the right number in the firing sequence, starting on the number one and counting clock wise around the distributor till they’re all hooked up.

Time to put in the rest of the spark plugs after gapping them to .050″

Almost ready to fire her up… just a few more things to do.

Right now it’s all about figuring out the timing setup on this beast…so since we’re at the number one cyl and all that like I mentioned above…it SHOULD fire up and at least somewhat run a little bit…even if it’s real rough. So I leave the distributor vacuum advance line OFF to do the timing…. I’m ready to try to fire it up!

Primed the carb (starting to wonder about this carb every time I look at it, from all the bad stuff I’ve heard and read about the Carter BBL, makes me wonder what I’m gonna have to spend money on next) Ok, I crank the engine and…. nothing, zilch…the big “O”. WHAT NOW?

I get my wife and have her come and turn over the engine while I’m holding the sparkplug on the number 1 cylinder against the engine block to see if I get spark (holding it by the plug boot by the way) and YEP, PLENTY of spark… so what gives? I am getting next to nothing… when I turn over the motor…it gurgles for a second or two and then fizzles out. I pour down about 1 oz of gas and try it again… same thing. Ok, so now I look down the throat of the carb and turn the throttle, since I know I put some fuel in the float bowl… lets see if it’s squirting anything….

NOPE…the carb is either fouled and gummed up, or something else…well, how could it be anything BUT the carb at this point…I’ve tested the spark and know my timing is close enough to provide at least temporary running abilty… gotta be the carb. So what do you know, its time for the NEXT upgrade… Geez this is getting old…I just want a running Jeep!

Continue On With The Motorcraft 2100 Carb Swap Upgrade…

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