The Stovebolt Site Forums The Shop Area The Electrical Bay HEI on 66 292 revisited (again)

Well I've read through a bunch of the posts here about doing the HEI conversion, but I'm electrically challenged, so I just want to be certain I've got it ALL right before I start chopping off wires. From what I understand, I can remove the small yellow wire going to my existing coil, chuck the coil and stock distributer (on the shelf that is, not the garbage) and that's it for wires that need to be discarded. Then I drop in the 1981 6 cyl. HEI unit that I have (after alignning on TDC #1 compression) Put on HEI plug wires, and run a new 12-14 gauge wire from the backside of the ignition switch (pink) wire, directly to the pink wire that comes off of the HEI distributer. Gap plugs to 45. Time the motor.

Is this correct?

Have I left anything out?

What do I do with the wire on distrib. that's labeled "tach"?

Do I need to remove any of the existing wires that are on the starter motor, or elsewhere?

Thanks in advance! Kerry

You've pretty much got it. There seems to be some controversy over wire gauge. Some recommend 10 gauge as there are insistence were the HEI will pull enough amps to warrant it.

If you have a Tach connect it to the wire labeled Tach, other wise removed it.

If you have the full gauge dash I'd recommend removing the yellow wire from the starter solenoid. I know on my 63 it caused the amp gauge to show discharge.

Larry

At the switch, your new wire must be hooked to the start terminal and run terminal, this is how the distributor sees voltage when cranking. The old unit saw voltage coming from the starter when cranking.

When running the new wire from the switch out to the distributor, run a second small 16 gauge with it for a tachometer. If in the future if you want a tach, the wire will be ready for you, go ahead and hook it to the distributor and a tape off the end under the dash.

Joe

You have it right Kerry. Ive always tied into the pink wire which comes off the ign. term. on the switch with 12 gauge wire. Joes idea about running a Tach. wire at the same time is good, but I believe if you tied onto the start term. also, the starter would not shut down when in the run position.

Thanks guys!....So which way do I wire the ignition switch then, since we have two different opinions? I just want to make it right the first time. Really appreciate the imput!

Stay away from the start terminal on the ignition switch. On some models, there were two "ignition" terminals on the switch, I-1 and I-2. I-1 had a nickel-chrome resistor wire on it that replaced the ceramic ballast resistor from the earlier models and went to the coil + terminal during normal running. The I-2 wire was made of copper and was only energized in the start position. It bypassed the resistor wire to give the coil full battery voltage during cranking. Both of the original "Ignition" wires at the switch need to be eliminated, and a heavy wire, 10 or 12 gauge, needs to be run from the I-1 terminal to the HEI "Battery" terminal on the cap. The original I-2 wire can be used as a tach reference, if desired, as long as it's disconnected from the ignition switch. Don't connect anything to either end of the silvery-looking stiff wire that comes off the I-1 terminal. It's got a fair amount of built-in resistance.
Jerry

Thank you! This is the info that seemed lacking in all the other posts that I have read. Now I just need to go put it all together. I'm sure glad to have this website for questions like this!!!!

Well i'm not going to argue with anyone. I'm not always right but you have 2 votes for the pink wire.

That >>fair amount of built-in resistance.<< amounts to 1.8 ohms in a 6 cyl wiring harness. 1.6 ohms for V8 harness. I don't know about the '66, but on a '67 there is copper wire from ignition switch to the firewall plug/connector. The resistor wire goes from that connector to the coil. Mine actually measures 1.7 ohms.
The stock GM HEI uses less than 2 amps so there is no need for 10 or 12 gauge wire. The ign switch is fed by a 12 gauge wire and it supplies the ign, radio, wiper, heater, dash and tail lights. 10 gauge from the ign switch to HEI is like using a 1/2"garden hose to feed a 3" fire hose.
Kerry, if you are >>electrically challenged<< , then make the conversion simple. Crimp the new connector on the end of the coil wire and plug it into the HEI. You probably will have to add a length of wire for it to reach.
When I originally put the HEI on my 292 about 15 years ago, I bypassed the resistor wire and the HEI module burned out the third time I started the engine. It was a cheap flaps aftermarket module and I believe a voltage spike burned it out. I reconnected the resistor wire and removed the start wire from the "R" terminal on the starter solenoid to make sure it didn't spike the voltage when the starter load dropped.
I changed the HEI to a remote coil HEI a few years ago to give more room for the AC compressor. It is still connected through the original resistance wire. With 14 volts at the battery and 11 volts at the HEI coil at idle. About a 2.8 V drop, measured across the resistor. I've driven cars home when alternators went out and the HEI still worked down to 8.5 Volts at the battery.

Yes, if you are going to an aftermarket HEI or bigger coil it will use more current and will need the 14 volts.
If you want it simple, just hook it up and drive it.
HEI
HEI coil
Engine

Richard, have you informed General Motors of your findings? They could have saved millions of dollars over the 20 years or so they put heavy wires on HEI ignition systems if they had just asked for your advice. When installing a HEI in an early vehicle, it's necessary to upgrade the wire size all the way from the fuse link connection at the starter terminal, to the ignition switch, and then to the distributor- - - - - - -just like GM did it when they went to HEI ignition! You're neglecting to consider the inductive reactance of the coil winding in the equation, which draws nearly dead-short current for a few milliseconds while the coil primary is charging between sparks. Get your facts straight before you go offering incorrect opinions.
Jerry

WOW!


Stuart

Thanks everyone.....I didn't mean to start any arguments.....just looking for good educated advice on something that I know very little about.

so will this work with 6 volts will it spark the plugs

I've never tried one on 6V, so I can't be sure, but it's highly unlikely the module would trigger properly. The whole system is designed to run at maximum charging system voltage, 14V+, and when we tried to use a HEI setup on a race car with nothing but battery voltage, no alternator, the results were pretty disappointing. Just adding a low-amperage alternator turning at about 1/2 speed with a big pulley made a noticeable difference in the performance of the ignition system.

The module has a built-in low voltage safety circuit that maximizes current flow anytime voltage drops below normal, but it's not likely a 6V system would be able to reliably trigger the module even with that circuit operating. I've got a HEI system set up in a distributor tester at school, so it would be a simple thing to just swap batteries for a 6 volt and see how well it works, if at all.
Jerry

Just a quick heads-up for anyone considering trying a HEI with 6 volts- - - - - -nope, it doesn't work. I tried using a DC rectified variable-voltage power supply on the training HEI in my distributor tester, and at anything below about 9 volts, the spark just shuts off. When (if) I get hold of a well-charged 6 volt battery I'll try again, but it doesn't look too promising. At any voltage below about 10.5, the spark gets noticeably weaker. 15 volts makes it look like a lightning strike across the plug electrodes.
Jerry

What plugs should I be using with this swap? Should I just keep the originals and gap larger, or go with a different plug? The plugs that apply to the donor vehicle are a tapered seat type, so those are out. Mine is a 66 292, the donor was an 81 292.

Also, I read somewhere that the advance mechanism should be a 10 degree......mine is a 20 degree. Should I change this as well??

The advance is probably 10 distributor degrees, which translates to 20 degrees at the crankshaft. No problem there. I like to modify the centrifugal advance (not vacuum) curve to reduce the advance by 8 to 10 crankshaft degrees, and add that much to the initial timing. It makes for better acceleration, particularly with an increased-compression engine like a 250 with 307 V-8 pistons. I takes a distributor tester to do it right, though. Use whatever plug was reccomended for the head you're using, and gap them to 40 or 45 thousandths.
Jerry

Jerry, in one of your posts above, you stated that the new 12 gauge wire be hooked to I-1 on the key switch. As long as the switch terminal stays live during cranking, that will work just fine, but some of the switches kill all circuits except start to provide full voltage to the starter. In this case, one would need to hook a new wire to the run terminal on the starter solenoid to provide start voltage, then tie this wire to the new ignition wire. Maybe you all ready said that and I didn't see it.

As far as the resistance wire being used for HEI, you might as well keep the points. With out full voltage to the module, you are missing out on the advatage of the hot spark HEI are known for. It will run, but not like it was designed to.

Our race cars and others we know of wouldn't make a full pass in the quarter mile with out a alternator. The battery just couldn't supply the required voltage. We were trying to gain HP by cutting out the alt. load! It takes 13.5 to 14 for a good hot spark. Dad has a distributor machine in his garage so we have had lots of time to test stuff. You can see a big difference in just a few volts at the spark plug ends, you can also hear it!

Heres a link to Dads book he wrote on Pontiacs. He has been racing since the mid 50's.
http://www.amazon.com/How-Build-Per..._1?ie=UTF8&qid=1227631329&sr=1-1

Joe

Joe, it sounds like you got the same racing education I did, but mine was on a real 1/4 mile, the one paved with dirt with 4 turns! We ran 11:1 compression flathead Fords on alcohol and Hydrogen Peroxide in a 34 Ford 3-window coupe. The 270 GMC's could get close, but the Fords usually won. Dad used to modify Lincoln Zephyr 12-cylinder distrributors with the BIG coil to run on the V-8s, and he supplied most of the racers in middle Tennessee with those distributors in the early and mid-50's. We ran an 8-volt battery in the race car to be sure the spark stayed hot. It was rough on points, but the coil would jump a blue lightning bolt nearly an inch long!
Jerry

Firing a plug in the open air is not near the same as firing a plug inside the cylinder under compression and proves NOTHING.

If you had problems getting an HEI to work on battery voltage (12.5) in a race car you should have consulted someone that knows something about that application. As I know a stock GM HEI uses less than 2 Amps, it doesn’t surprise me that DUI has a race version that works on less than 3 Amps.

From their web site.
DUI Performance Distributors.


“Our Racing D.U.I. Distributor is capable of turning 9000 RPM's Amperage draw off the battery is minimal as the Racing D.U.I. only pulls 2-3 amps, whereas other aftermarket ignition systems draw 10 amps or more. For those not running an alternator, this prevents the battery voltage from dropping too quickly.”

Get over yourself, Richard- - - - -some of us have real-world race experience. Spending time reading the websites of people who are going to solve all your problems by selling you something is a fool's errand. I've used, and discarded a bunch of DUI's products. They don't work in the real world of racing! Rant all you want- - - -I'm not interested in listening.
Jerry

RACE car engines aside.

The originator of this thread wanted to put a STOCK HEI in a STOCK 292 truck engine.
Good spark plugs will fire with a points ignition in the 10,000 to 14,000 volt range, depending on compression and fuel mixture.
Good spark plugs will fire with a HEI ignition in the 10,000 to 14,000 volt range, depending on compression and fuel mixture.

Bad spark plugs will require a higher voltage in order to fire, but most stock points coils can fire up to 18,000 volts.
The biggest advantage of HEI ignitions is that they will fire bad plugs more reliably and you don't have the replace the points on a regular basis.
Anyone that doesn't have a problem setting the point gap/dwell and timing will tell you they noticed no difference when changing an engine to electronic ignition on a stock engine. The one thing that is most notable is that they can't remember when they did the last tuneup.

The originator of this thread also said that he was, "electrically challenged".
It may seem like a simple task to some of you to change the stock wiring, but you are not there showing the guy how it is actually done. You are telling a guy to cut up his wiring harness and you don't have any knowledge as to whether he is capable of putting it back together the way you envision it.
Leaving the resistor and the original wires as they were has the single advantage in that it has the greatest chance of being successful.
If a guy knows enough to make this change without problems, he wouldn't be asking here in the first place.

I have to disagree with the " notice no difference when switching to HEI". Mine and everyone else I have changed over idles much better, starts easer, and gets better fuel mileage. Thats why we change them over. Maybe the low voltage has something to do with your no difference! And as far as sound and site of the spark gap making no difference, if you can see it on a bench in open air, how could it not effect it under compression? Its true both systems can fire a plug, but a HEI will do it easer at lower speeds and at higher rpms with out jumping around. They are rock solid on a distributer machine. A points distributer is always bouncing around a degree or to. Dad and I have a machine in the garage and have seen it time and time again. Thats why we change them over, and thats why they run better.

As far as the wiring goes, here it is again.

Back of key switch,
1) new 12 gauge wire from Ign. terminal to HEI
2) if the ignition terminal drops voltage when in start position
see number 3.
3) second wire from starter relay post (R)run or (I)ignition. This terminal is active when starter is engaged.
4) tie both new 12 gauges wire together at some point and run to the HEI

Sounds pretty easy to me. Please e-mail me if you need more help Kerry3.

Well I finally got an hour or two to put my HEI in the truck today............works like a charm! Could be my imagination, but it does seem to run crisper. Either way, I'm sure it is an improvement over the old points ignition. Thanks for all the info, and input, on how to do this! It really is easy as hell. Hardest part was getting the oil pump cog lined up with the distributer shaft. Finally stuck a straight edged screwdriver down there and turned it to match the dist. and it fell right in! Now on to my next project........power brakes!

Glad to hear its running OK, and I bet it is running a bit better! Joe

kerry3:

Wow, I feel like I just ran a marathon, after reading all the posts on this thread. I have done the HEI conversion on several of my 4-5-6 Chevy trucks with factory 283/327 V8 engines and feel it is a great improvement for a number of reasons. In any case, I am glad to hear you were able to do the conversion successfully.

I have converted many of my 4-5-6 Chevy trucks to power brakes, utilizing the factory power brake booster assembly, while retaining the factory drums on all four corners. It, too, is a great improvement. That coupled with a power steering conversion, makes these trucks a true joy to drive/operate. Although I am a "stocker", in every way, I do like these improvements and since power-assist steering and power brakes were available as factory/dealer-installed options, I am comfortable in not diminishing the factory fit/finish and preserving the vintage quality of the period-correct 4-5-6 Chevy trucks in my collection.

In closing, congratulations and let us know how you progress with your power brake conversion.