HEI Installation

[Doubletrouble]

Hey guys! Well, I followed the suggestions many of you gave me. I have purchased the cast iron headers from Stovebolt and those arrived yesterday. I'm going to have to wait a bit to install them because the local muffler shop wants close to $800 to run the dual exhaust off those headers. My have things gone up in price over the past 22 years since I had to replace an exhaust system! All of this is going on my 69 C-20 pickup but the engine is a 75 version, I believe.

I also purchased his HEI distributor for my 292. He is out of town right now, so I'm hoping someone out there has done this on their 292 and can help out. His instructions state to a #10 wire from the coil + terminal to the ignition switch. I can purchase the wire and connector from the local auto parts store. I want to ensure that I am replacing the correct wire. From the pic below that is my current stock setup, I believe the wire I need to change out is the black wire on the coil's right side that leads to the distributor. The yellow and orange wire on the other side of the coil remain. The instructions also say to delete any resistor (ballast or inline resistance wire) which was use on all 12 volt point style ignitions. I don't see where this is unless it is inline under my dash. And finally, the vacuum advance line currently comes from my carb and goes to the distributor. I am assuming that this will remain the same since the engine is pretty well stock.

After I get this done, I'll work on attaching my water heater adapter for the intake...but that will be another thread!

Thanks!

Al

[Scott Webster]

The ballast resister is up on the firewall.

[Doubletrouble]

Scott, thanks for the reply! I went out and looked, both inside and outside, and am not finding the ballast resister. Can you point me to a closer location to where I might find it and what it looks like? Sorry for sounding ignorant...I can be! Thanks again for the assist!

Al

[Doubletrouble]

I've followed the yellow wire from the coil back to the starter and there was no external resistor. I then followed the purple wire back to the plug in at the firewall with again no external resistor. The purple wire is a #10, I believe and the yellow wire is much thinner. I am thinking that since the yellow wire is not #10, I need to replace it with a #10 so as to be consistent. I did meter the lines and I am reading 9 volts at both the coil and at the yellow wire connection at the solenoid. I do have 12 volts at the solenoid hot lead from the battery, as one would expect. I am still looking for an external ballast resistor...

Al

[davepl]

I'm not up to speed on 6-cylinders, but the for 8s you normally have two hot wires to the coil. One comes from the starter, and it provides a full unrestricted 12V but ONLY during cranking. You also have a second one, white in most cases, that comes from the ignition switch. This wire is itself the "ballast resistor", because it has resistance built into it.

With HEI, you do not need both. You are going to supply only one (though the second, from the starter, won't hurt anything), and it needs to be a full 12V. This means you cannot reuse the existing ignition switch wire, it must be replaced.

The easiest way to do this is to run a new wire to the "IGN UNFUSED" terminal on the fuseblock and plug it in there. Then disconnect (and optionally remove) the wire that goes to the coil from the ignition. In my experience it's been white, but in your case it looks to be orange. Either way, its the one "not from the starter".

[geezer#99]

No ballast resistor. A resistance wire comes from the ignition and is spliced together with the yellow wire to the coil and another yellow wire to the starter solenoid. You need to replace the resistance wire with a 10 gauge wire and disconnect the yellow wire at the solenoid.
You can you use the existing spot the resistance wire plugs in to the power block on the firewall or run your 10 gauge wire to an unfused 12 volt connector on your fuse block.

[Doubletrouble]

My engine wiring harness is newer and is nicely wrapped thereby preventing me from following EACH wire. Going back to the power block on the firewall, I see a purple wire that I'm assuming is the one that also goes to the solenoid but I don't see a yellow wire at that point. So I simply disconnect the yellow wire at the solenoid and then run the 10 gauge wire from that point on the solenoid to an unfused 12V connector on the fuse block (that is only hot when the ignition is on)? What relationship does the purple wire have that is connected to the other side of the solenoid?

Thanks for the information. I very much appreciate the responses!

Al

[sharpmark]

heres some more info
http://67-72chevytrucks.com/vboard/s...ad.php?t=13698

you should read both pages.
by the way in your first picture , the hei will replace the old distibutor an the coil as it has its own inbuilt coil.
hope this helps mark

[sharpmark]

Originally Posted by Doubletrouble

My engine wiring harness is newer and is nicely wrapped thereby preventing me from following EACH wire. Going back to the power block on the firewall, I see a purple wire that I'm assuming is the one that also goes to the solenoid but I don't see a yellow wire at that point. So I simply disconnect the yellow wire at the solenoid and then run the 10 gauge wire from that point on the solenoid to an unfused 12V connector on the fuse block (that is only hot when the ignition is on)? What relationship does the purple wire have that is connected to the other side of the solenoid?

Thanks for the information. I very much appreciate the responses!

Al

the purple wire is to activate the starter with the key!leave it, its important!
the wire you are looking for on the engine side of the firewall wiring block should be white and its preferable to replace this one if you can.

[sharpmark]

if you choose to go straight to the unfused point on the interior side of the wiring plug-there is a picture here that will help!
http://67-72chevytrucks.com/vboard/s...d.php?t=121515

[VetteVet]

Your answers are here.............http://67-72chevytrucks.com/vboard/s...d.php?t=148346

[Doubletrouble]

WOW! Nice references...I actually did a search but evidently had it limited so as not to find these! I'll try to get all of this done tomorrow. Sharpmark, thanks for telling me the coil goes away...I didn't realize that! I'll post when completed and let you know if any problems were had. Thanks again to all!

Al

[RichardJ]

The Purple solenoid wire is 12 gauge. As sharpmark pointed out, leave it alone and do not connect anything to it.
The ballast resistor wire is spliced into that yellow wire back along the valve cover under the harness tape. The other end of the resistor wire terminates at the firewall connector plug and should be easy to spot. Originally it was a White cloth covered wire with traces of Orange and Purple. 45 years later it looks dirty White and has frayed a little. The wire on the other side of the connector up to the ignition switch is plain copper.

Think of an automotive electrical system as you would a tree. The tree trunk carries ALL the weight of all the branches and supplies all the nutrients and moisture for ALL the branches.
Your truck has a 12 gauge wire from the battery to the alternator and regulator and then to the firewall connector. All power consummed by your truck passes through that 12 gauge trunk. On the other side of the firewall the 12 gauge branches off and only one of those goes to the ignition switch.
A 10 gauge wire from the ignition switch to the distributor would be like a 10 inch branch on a 3 inch sapling. It doesn't belong there.

The correct single connector that plugs into the HEI Battery connection is keyed with a little flag so that you can't plug it into the Tach side. If you cut a connector off a late 70's or 80's truck, you will find that the GM wire attached to it is 14 gauge wire with very fat insulation. Measure it.

Naysayers won't like that.

Try this on for size. The Battery connection terminal on the HEI splits and goes to two places. The red wire going into the coil is 20 gauge. This is in the first picture.
The three wires that go down to the module and ground in the distributor body are 16 gauge. Real killer sizes and that explains why some would suggest feeding the HEI with a 10 gauge. NOT.
10 gauge is not only unnecessary for a stock HEI, it is ill advised.

If you must do anything, take the yellow off the solenoid and replace the ballast wire with a new wire from the firewall connector to the BAT on the HEI. A 14 gauge will work fine or a 12 gauge to appease the experts.

If you want it really simple, take the yellow off the solenoid and connect the yellow you now have at the coil to the BAT on the HEI.

I've been running an HEI in my 292 with original wiring and with ballast wire in place since the early '90s. Some time before I installed the AC four years ago, I switched to an external coil HEI. Also with ballast in place.
The engine starts easily EVERYTIME and it runs down the road 75-80 mph without so much as a hiccup.

[Doubletrouble]

Thanks, Richard! Your explanation was easy to follow. I see you have a 4 speed on your 292. I have one as well with the first gear pretty much a "granny gear". I've only had to use it when I loaded the truck down with a ton of alfalfa from the fields, or a cord of wood...years ago. The only thing I wish I had on my truck is power steering. It can be a bear at times!

Al

[blue 72 gmc 4x4]

That price to do the exhaust seems pretty steep to me. I don't think it cost me that much to do mine although I may be wrong as it was 3 yrs ago I had it done.

[JointTech]

I just paid $650ish to midas to install headers, a header bolt kit, run dual exhaust off the header and they had to whipup a spacer for the power steering pump. The welds are ugly as hell. I provided the hedman headers and Cherry bomb vortex mufflers. I thought it was a bit steep but metal aint cheap these days.

[Doubletrouble]

ARGGGGGHHHH!!!! I went out and bought the new wire and connectors per the referenced post above. The NAPA part numbers were spot on. I came home and disconnected the wiring harness from the firewall and found the ignition wire. I removed it (it was a bit of a pain) and installed the new wire with new connector. Replaced the plug and fastened it down. I ran the wire (for now) along the existing wiring harness and gave myself ample length to hook into the new Langdon HEI distributor. I put the appropriate connector on that end and tested it to ensure that it would fit onto the spaded connection. It did. I disconnected the yellow wires at the coil and at the started solenoid. I removed the coil and removed the old distributor. I rotated the engine to TDC on the compression cycle.

The new distributor slid right in! It took a couple of times to engage the oil pump, but it finally went. It was evident that my stock metal gas line was going to be in the way of the new cap. I knew I would have to make another trip to the parts store to get some gas line and clamps. I went to change out the plug wires...dummy, the existing plug wires won't fit! They are a different fit at the distributor...much smaller.

So much for finishing this job today. I have to go to work soon. So tomorrow (I'm off work) I'll go to the parts store and get appropriate plug wires and some gas line. I was really disappointed in that I didn't see that before I started the job, but oh well. This is part of being your own mechanic! Any suggestions on plug wires would be greatly appreciated, if they make a difference!

Al

[blue 72 gmc 4x4]

What's smaller on them?? The connector?

[Doubletrouble]

Blue, that is exactly the problem. I can bend the brass connector part to fit around the nipples on the cap, but the rubber boot is about twice the size on the original wires than for the HEI. They won't make any type of a seal.

Al

[Scott Webster]

Originally Posted by Doubletrouble

Scott, thanks for the reply! I went out and looked, both inside and outside, and am not finding the ballast resister. Can you point me to a closer location to where I might find it and what it looks like? Sorry for sounding ignorant...I can be! Thanks again for the assist!

Al

No problem. I guess some don't have one from what I'm reading here, but my truck used to before I swapped in this engine. Ones I have seen were a small white ceramic block with a coil inside and two tabs on the outside.

[blue 72 gmc 4x4]

Huh..you dont want that! Go to touch something and get lit up! Probably be better just to get new wires anyways since you put a new dizzy in it. I know after a while the wires get old, core's crack and can make you're truck have a miss. Thats what my 69' was doing, but the wires were ONLY 25 years old

[Doubletrouble]

I'll hit NAPA in the morning and hopefully have everything done by noon. I'll post a pic of the final product when done. I'm pretty pumped to get it done and see how well she runs with the upgrade.

Al

[Doubletrouble]

Got the job finished this morning after getting new plug wires and some 3/8" gas line to replace the original. As I said before, the original metal gas line was in the way to get the new distributor cap on. I gapped the plugs at .060 and started her up. She didn't even hickup before firing up! I then set the timing at 12 degrees and she simply purrs! I took her out and holy crap! The power she now has and all without any hesitations or sputtering! I can't believe I waited this long to make the conversion!

Below are some pics of the finished product. I ended up leaving the original ignition wire within the harness and simply wrapped the new white wire (12 gauge because there was no way a 10 gauge would fit!) into the wiring harness. On the other end, I wrapped the two yellow wires within the harness as well.

Anyway, thanks for all of the help! This was a job well worth every penny! I can only imagine how much better gas mileage I'm going to get (was getting 7 to 9 mpg) with as great as she runs!

Al

[blue 72 gmc 4x4]

Its amazing how much better stuff runs with a good spark huh?!

[sharpmark]

good onya mate!!
its always a good feeling when you do something yaself and it has a happy ending!!!!!