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As for the HEI mod, I've explored that rabbit hole and I've found the setup to be unreliable. Maybe if you source all old Genuine GM parts like the module and coil it will be okay, but if you build it from auto part store parts you'll be replacing modules and/or e-coils once a year... maybe 2 years if you use an non-hei oil filled coil.
I have a thread here where I posted my google search results about poor aftermarket module quality and my setups failures. I recently switched back to the stock mopar electronic ignition.
Thanks for your response M880... So The GM HEI mod is not the answer. Thanks for that. I have the Rick Ehrenberg HiRev 7500 set up for the Slant Six ( Distributor, Blue Box and assorted wiring) Maybe I will just install that. Was just hoping for the simpler GM route.
I must admit I do find these early attempts to computerizes engine controls interesting. That strange short-lived era between carburetion and OBD1. Feedback carburetors and computer controlled ignition. (I'll throw variable venturi carburetors in here too)
Regardless of the brand (Chrysler, GM or Ford) from what I've heard these type of systems ran okay when they were working. It's when they didn't work is when you were in trouble. It was a dark time for mechanics, these early systems didn't have onboard diagnostics and access to service information was limited at the time... I honestly don't think many knew how these early systems worked.
It would be interesting to mess with an intact learn-burn system... yeah I'm weird. I don't know if any of them would run right on todays ethonal gas.
I know a major design flaw of the Lean-Burn system in particular was the placement of the computer on the engine, mounting it to the air cleaner. I find it funny that today some aftermarket efi makers (FiTech, Holley Sniper, MSD Atomic 2, etc.) have chosen to install their ECUs inside the throttle body subjecting it to unnecessary heat cycling and vibration. History repeats itself...
I recall working on these cars with lean burns up until 1980. They were a problem from the start. During a service update I remember if you placed your hands around the computer portion on the air cleaner the engine would stall out. The instructor said their sensitivity to heat and cold was another problem.
Ok so I started installing the new distributor and ECU box. Think I figured out the HOT 12v and START 12v. But what about the alternator wiring and such that goes to the aircleaner leanburn junk All this wiring I want to get rid of. Its it possible
Bare with me as I look over pics of something not tangible. But.... yes you could eliminate the lean burn crap. A regular electronic distributor along with a carburetor for that engine which looks like a 225 without lean burn will work in place. The alternator has a hot wire going to the 7/16 inch nut on the bottom to power it up. the other wires without standing in front of it leaves me. Try not to lose sight of the basics of that engine. Spark which is easily gotten by the electronic distributor and of course the basic carburetor. Sorry I can't be more help.
There is 4 wires soldered together (Hot Wires) the One hot i thought was the 12v constant was the coil wire, lol. My question the Alternator wires and sensor wires as of right now. I have the Distributor in the ecu mounted and grounded ( BUT at an angle). I just want to cut and hack this old wiring and have functioning oil and coolant dummy lights and obviously the amp gauge working. PLUS the alternator working properly.
Any body have photos or wiring diagram. Patiences is key here LOL
Well Guys, I appreciate all the help. I wired in the box and the ballast resistor. The Orange wire is my white wire (no orange could be found in the store) and used the 12V relay orange. to one side of the resistor. 12v hot and positive coil to the other side. The resistor gets really hot, is this normal? Plus is charges at 15.1v now and before it was around 14.3v.
Any thoughts? Am I over thinking this stuff now? Just drive it, LOL.
Started right on the first turn of the key and smoothed out the idle even with a carb that wont work with the Vacuum advance...
Now its charging inbetween 14.8v and 15v I just re checked it... Any suggestions?
The ballast resistors get very hot. That's normal for it to be too hot to handle. As far as the charging rate 14.8 to 15 volts, it's a tad on the high end of normal but still considered normal.
Ok I know I haven't updated in a while but i guess it's time. The truck starts way better then before. Two pumps on the Go pedal and she fires right off. I know it's not a show truck or a race truck but I love it. So since the 1945 Holley doesn't have a vacuum advance port, I in my haste, bought a single barrel ford carb for cheap to install. I need to know what port is the vacuum advance on it though lol. It's a chinese carb until I can get the Ace fuel Injection system for my 2Barrel Aussiespeed intake.
The difference between ported vacuum vs. manifold vacuum is the connection leading to above vs below the throttle plates.
Ported vacuum is above the throttle blades and should only apply vacuum when off idle. (If you get vacuum advance at idle while warm your engine speed is set too high).
Manifold vacuum is below the throttle blades and will apply vacuum at idle. That is the only difference.
You can use a vacuum gauge... honestly probably even your finger to confirm which is which while the engine is running. You'll need to have vacuum advance plugged off anyway while setting initial timing.
06-03-2023, 09:43 PM
