Hei install Writeup

As promised...
Getting an HEI should be on the top of every classic jeeper's list. Not that there is anything wrong with the points and condenser ignition that powered every gasoline engine since somewhere around 1900, but for the most part, technology has yielded improvements in the last 100 years. Installing the HEI is a solid step about 65 years forward in ignition technology. Debuted in the early 70's on many GM cars, the HEI was GM's ignition of choice well into the late 80's. This means parts are in stock and available as your and anyone else's FLAPS. But enough history, lets get to the nuts and bolts of it.

A Little background on this particular project:


There is a belief that using anything but the top of the line HEI kits will "mess up the engine." I believe that refers to the distributor drive gear. The OEM gear is bronze or brass. The one on my new dist is probably steel, but I didn’t really check. I've heard of premature cam wear from the non-oem gear. I guess I could have swapped the gear from the old one to the new, but I didn't for 3 reasons. 1) I didn’t feel like doing it, 2) My jeep doesn’t see a lot of usage, so even if it wears the cam out 5x faster than the original, it will still last me a good while. 3) when/if it does wear out the cam, That means I get to do a cam upgrade.

The DUI brand is a proven unit, but my hei, brand new, only cost me $99. For the Price of the DUI I could buy 3 of the 4wd brand. I can't speak for longevity, but the only piece that’s not a stock gm style part is the distributor base itself, so any issued arising from the cap, rotor, coil, or electronics can be remedied at a FLAPS.

Now what you've been waiting for!

Out with the old...


In with the new



Tools you'll need...
1) medium regular screw driver.
2) smaller Phillips head screwdriver
3) 5/8", 1/2", and a few other wrenches.
4) Wire stripping/crimping pliers
5) timing light, (or not, as you'll see below)
5) 2 beers (4 beers for a beginning mechanic, or if your f*%&in timing light doesn’t work) I started at 10:30-ish and was done by 2:30 ish, including a lunch break, test drive, and timing light problems.

Parts List
1) New Distributor assembly, I used the 4WD hardware Billet, due to its low price. This particular one includes distributor base, drive gear, coil, cap, rotor, and igniter electronics.
2) 8mm Plug Wires, I used NAPA Belden PN: 700255. (on a hunch, I ordered this wire set which is for a 74 Pontiac with 400ci) The #2 wire ends up being a little short but works, and you would always try orienting the distributor differently if it bothers you, its fine with me.
3) OPTIONAL 30 amp 5-post relay.

SAFETY NOTE: Disconnect a battery cable to avoid live wires hanging around.

Step one is easy. Remove the distributor cap by pressing down and turning the 2 "screws" about 1/2 way around. I chose to leave the plug wires connected, and pull the cap out of the way. I also marked a positions so I knew the orientation of the cap relative to the rotor.

Step two involves first, know where your rotor is pointing. If you can remember this, and orient the new distributor rotor in the same way, it saves you from having to worry about finding TDC on cylinder #1. The loosen the distributor hold down and seen here...






Once this is loosened and out of the way, you've disconnected the distributor ground lead from the coil and vacuum advance hose , the old dizzy should pull right out of the engine block.

Step three. Remove the cap on your new distributor so you can see the position of the rotor. Now slide the new dizzy into place. Note that since the gear is helically cut, the rotor will turn slightly as the distributor engages the gear. It may take some trial and error to get your rotor back to the same position as the old one. Also be sure that distributor seats all the way down, as the oil pump is driven off of the bottom of the dizzy shaft. If necessary, the oil pump can be turned using a long regular screwdriver, until everything meets up the way it’s supposed to.



Step 4. Wiring. There are two ways to wire the hei. It can be powered directly from the old coil leads, as long as you make sure to bypass the ballast resistor. ( the original coil didn't like getting the full 12v, except when starting, the HEI NEEDS 12v power.) The resistor is usually located on the firewall like so...



To make the direct power option work, all you need to do, after the resistor bypass, is connect the wires from the + side of your original coil to the "BATT" terminal on the HEI. Bam wiring done.


To make the direct power option work, all you need to do, after the resistor bypass, is connect the wires from the + side of your original coil to the "BATT" terminal on the HEI. Bam wiring done.


Wiring option 2, which I chose is slightly more complicated, but also preferred for reliability and max fire power at the plugs. This option uses a relay to provide direct battery power, and the full 12-14 volts, to your new dizzy.
This is fairly simple, I used a Tyco/bosch 30/40a relay. Napa carries an equivalent relay, but I got mine off of ebay with a convenient pig tail.
A basic wiring diagram is available here... http://www.partsexpress.com/pe/showdetl.cfm?Partnumber=330-070


In this image Terminal 86 will be the wires that originally ran to the + of the coil.
Terminal 30 is a direct hot lead from your battery, I used 10ga wire for this.
Terminal 87 is another run of 10ga wire to the "BATT" side of the HEI.
Terminal 87a is not used, but is provided battery power when the relay is not energized.
Terminal 85 grounds the relay.

This keep the ignition from drawing excessive voltage through the small stock wiring.

Ok so you've got juice, and lots of it.


Step 5. Now you are going to run your new plug wires, keeping the order as from the old cap. Make sure you get at least the #1 cylinder, as you can figure out all the other after that. The AMC V8 is conveniently has each intake runner labeled with the cylinder number, making this a rather simple operation. I laid out the entire new wire set on the ground in order of length. I Started with the #1 cylinder and gradually worked through each one moving farther away from the dist. This is easier than comparing lengths to your wires.

Step 6. Once you've got your wires in place, and your distributor situated, go back and tighten your distributor hold down. Leave it loose enough so that you can adjust the distributor, but tight enough so that the engine vibration doesn't cause it to move on its own. Adjust the distributor to your previously established point of reference. Don't worry if it’s not perfect, it will still run. Reconnect your vacuum advance hose.

Step 7 Reconnect your battery cable, plug the original vacuum advance hose (temporarily). Then start your motor, and allow it to warm up. (note: it is a good idea to verify that you have oil pressure at this point, to confirm proper oil pump engagement.) If necessary, rotate the distributor in tiny increments until a smooth idle is achieved. If your motor will not start, recheck you plug wires, and make sure all your other connections are correct.

OPTIONAL: at this point you can go and open up your spark plug gap if desired. The HEI has a significant firepower advantage over your old stock setup, and can reportedly handle plug gaps greater than 0.050". Factory is somewhere around 0.032". I did not do this due to time constraints, but when I get the time I will probably open it up to around 0.045-0.050" range, just to be on the safe side. This is also a good time to just install new plugs, even with an HEI, I really don’t see any advantage to putting in anything exotic. Good ol' champions on mine.

Step 8. Set your timing, Hooke your timing light up. Usually there is a lead that goes around your #1 plug wire, a wire that goes to positive battery, and a wire for ground. Start your motor, and set your timing. Factory timing is 5* BTDC, on 1970's gasoline. It is probably safe to set it a few degrees farther advanced, especially if your run other than regular fuel in your jeep. Once you have your timing set, shut down the motor, and disconnect your timing light. Finally snug up the bolt for your distributor hold down. I'm sure there is a factory torque spec, but "tight" seems to work just fine.

My timing light was non functional, as I found out. I set my timing by ear. I rotated the distributor in each direction until I hear it idle a little more rough, and then picked a point that was near the middle, but slightly more retarded than advance, just to be on the safe side. This yielded no evidence or predetonation, but could have missed it due to the glasspack mufflers and the blown out exhaust gasket. As soon as possible I will set it with a light.

Step 9. Test drive your jeep. Run through the gears, and try accelerating in 2nd and 3. Listen carefully for detonation (preignition) usually characterized by a knock or ping under acceleration. If you get these symptoms, retard the timing slightly.


Initial Impressions. I haven't had a chance to drive the jeep since my install, but the jeep seems to have better throttle response, and shorter cranking times. All in all, I am extremely pleased with my HEI, and I would recommend it to anyone looking for a decent, easy ignition upgrade.

If you have any questions, I'm always on the ECJ5 forums as DrDanteIII

Enjoy!

 

Great write-up DrDanteIII!

I did the HEI upgrade on my 258 AND also did the 4.0 Head conversion on the 258! Gotta love BOTH upgrades!

Keep up the great work and keep us posted! :tea:

~Boodie

 

Great write up!! This needs to be in the Tech section.


What brands of stuff did you guys use? I hear stories of cheep ebay crap messing up the engine. I hear the spendy stuff is a waste of money, you can get stuff less expensive and it works just as good.

 

EDIT: Hmmmm, I dont think my engine compartment looks like that much of a mess in person...

 

Well, I'm not done yet. I'll let you know.
Thanks!

 

You could just slide this in with a one-wie hook-up .

 

R) The "high voltage" sticker is a nice touch - as if the original weren't.

 

Write up complete!




I think, If somebody wouldn't somebody mind going through and spell checking/grammar correcting it I would appreciate it.



Did you know there is a 10,000 word limit to an individual post? I had to cut out some lines of test to comply! wow.

 

Outstanding !!!! Write up !!!!!!!!

 

UPDATE.


After receiving several warnings about the new drive gear, I decided to investigate further. There is anecdotal evidence of the new drive gear being made for hardened steel, and causing premature wear on the factory cam gear. there was one account that stated the cam gear wore out in less than $50 miles. There was also a person that said they have been running the new gear for 3000 miles without incident. It was recommended that I swap the original AMC dizzy dear in place of the new one.

To test the relative hardness of the gears, i grabbed a file from my tool box. While the AMC factory gear was easily scratched, the new gear seems to be significantly harder. Also concurrent with what i had read, the machine work on the new gear seems to be a bit rough. I then decided to swap the the gear over just to be on the safe side. The gear is secured to the distributor, for both the new and old dizzy, using a pin that can be easily removed with a small punch. I swapped the gear from original on to the new HEI easily. I then re installed the HEI as before. Hopefully this mean disaster averted. Even if I was going to be fine with new gear, and it was easier to spend 15 minutes swapping gears now, than 10 hours replacing the cam gear later.

FWIW,
-Dante

 

Excellent Write up DrDanteIII ! :tea: Good stuff!

 

Thanks for the compliments. I just had a hard time finding info for any HEI swap aside from a DUI unit, and thought that it would be nice to have another resource for the next guy who wants to do one.

 

Really? I find the HEI write ups all over the place.....hmmmmmm. Maybe I'm admitting to being on the internet too much...I've said too much.

http://myweb.cableone.net/wdohrn/hei.htm

http://www.4x4wire.com/jeep/tech/electrical/hei02/


http://www.crtperformance.com/html/jeep_amc_hei_s.html

http://www.bustedjeep.com/projects/hei.asp


http://www.junkyardgenius.com/ignition/jeep/HEIcompair.html (write up about the gears eating up the cam shaft)

And on and on.....

 

I have participated in a few forum threads with Junkyardgenius about the issues he mentions, as my jeep came with a DUI from the PO.

Many of his claims appear valid, especially about the cheap aftermarket HEI conversions. Hardened gears, wrong profile, incorrect advance curve, etc. Regardless of the fact that he seems to have a real axe to grind. I've read enough posts over the years to believe some of his claims may have a basis of truth.

Anyway, I investigated further, reading DUI's website, and even going so far as to contact them by telephone, and speaking with one of their techs concerning the issues raised. From my research, I came to the conclusion that DUI had addressed EVERY SINGLE issue JYG had raised.

When confronted by the evidence from DUI, his response was pretty much a shuffleing of feet, and a grudging admission that DUI "might be ok".

I suspect this is part of the reason you pay so much $$ for the DUI as opposed to all the cheap aftermarket clones out there. In addition to quality parts, extra bearings in the dist, NEW housing, etc., DUI also custom tunes the advance curve to your engine. Seems like in this case you might get what you pay for. At least now I have some understanding of why the thing is priced so outrageously.

I would just encourage folks to do their research, and make an informed decision that you are comfortable with. Engines aren't cheap.

:tea:

 

updated:

2 years on and my HEI 304 is still running strong. It starts and stays started better in the winter, and the throttle response is better. Its been 100% reliable.

 

I have had mine in about 3 yrs. No problems so far.

 

JYG says that the GM HEI was designed to be vertical but it seems to me that Buicks always had the distributor installed on an angle.