JCMC64

I got everything back together engine wise, minus the Pwr Str pump. Did the minimal wiring yesterday, tidy things up tonight, filled her with some oil and ZDDP additive, tranny fluid, hooked up battery, filled her with gas, and tried to turn her over just to get engine turning and starter engaged. But nothing. No power at all to anything, not even interior lights. This is no big deal, as I have interior completely out of it, incuding dash, and now no Front lighting harness installed as I didnt think I needed that. (do I?) So Im wondering what is the minimum wiring to install, with dash out of car, and all gauges out, just to get the starter to engage and turn the flywheel. Not even trying to actually get her started yet, just want motor to turn some. Only thing left is to find an 12v IGN power for HEI.

So what wiring do I need minimally to turn her over? thx.

JCMC64

PS...Dash harness and engine harness are only harnesses installed.

MDchanic

Big cable from battery (+) to big terminal on starter.

Big cable from battery (-) to block.

10 or 12ga wire to "S" terminal on starter solenoid, touch to battery (+) to crank (or get really fancy and hook up a pushbutton switch).

- Eric

JCMC64

Thx Eric.
I thought it was ultra simple. I will do it this evening.

How about this one- what is minimum wiring to setup to use Keyed ignition?

MDchanic

I'm not sure why you'd want to do that (it's just extra work), but you'd want the 10 (or 8?) gauge red wire from the battery to the horn relay to the ignition switch connected, the pink wire from the ignition switch to the resistance wire to the coil, the purple wire from the ignition switch to the neutral safety switch to the "S" terminal on the starter solenoid, and the two heavy battery cables as above.

- Eric

JCMC64

Ok, thx again.

The reason why I ask is after doing all the above in my first post, engine didn't turn over, everything was powerless. So I wanted to check to see if I'm missing anything minimally needed.

I didn't hook up the horn relay as the front cap is off the car, and I didn't think you needed it to just turn the Motor over. But obviously I don't know exactly what the horn relay does in this minimum scenario. I didn't think you needed it just to turn the motor over. So I guess I'm wrong...?

Ill rehook up the Front light harness too tonight WITH the horn relay, do it all correctly and see what happens.

MDchanic

You don't need the horn relay, but you asked, "what is minimum wiring to setup to use Keyed ignition?" and, by that, I thought you meant that I should trace out the way that the wiring harness transmits the power to the engine, because why on earth would someone want to connect completely new wires all the way to the ignition switch, when all they need are a couple of pieces of wire in the engine compartment?

I will repeat: To turn the starter all you need are the two heavy battery wires and a hot wire to the "S" terminal of the solenoid.

If you want the engine to run, you need an additional hot wire to the distributor's (+) terminal.
(If you had the original points ignition, you would connect the hot to the coil (+) terminal, which should be through a resistor if you want to run the engine for more than a few minutes).

There are NO other parts necessary.

The horn relay is NOT necessary, and, in the situation we are discussing, only provides a junction point for two segments of wire.

The only possible reasons why this didn't work are:

• Bad starter
• Bad solenoid
• Bad wires / connections
• Wrong connection / wrong wire.

- Eric

oldcutlass

He has an HEI so all he needs is battery + to the distrubutor and a way to crank starter which would be 12v to the "S" terminal and 12v to the large lug on the starter.

MDchanic

Whoops... HEI.

Corrected.

JCMC64

Yes, HEI.
Well both engine and front lighting harnesses are new.
They are 70' cutlass harnesses and I have a 71' cutlass. But they pinned put out almost identical by my research beforehand. ( Got them for 35 bucks each in pkg. So I was determined to make them work) only difference is on the 70 the starter wire is pink instead of purple, and other 1 is yellow instead of black or brown or whatever dark color it is on a 71'. The cables are M & H brand.

I'm going to check that the starter works first. It obviously did 10 months ago. Then going to put on original engine harness and report back...sir yes sir!

JCMC64

I jumped the starter solenoid and it turns over. I hoooked up the old engine harness , just the S wire to the starter, and key does nothing. So neither engine harness I have, the new 1 or the old 1, is working.

JCMC64

It looks like for now I'm going to have to set up an on/off switch. The original engine and lighting harness were garbage. But now it could be anywhere within the chain behind the firewall.

1) Is there a fuse to check for key ignition given the issue?

2) simple on off switch - S side of starter> to one side of switch....battery terminal on solenoid > to other side of switch. Correct?

MDchanic

Did you connect the hot wire from the battery to the horn relay to the heavy red wire to the ignition switch?

No. No fuses in the ignition circuit.


If you mean one wire from the "S" terminal on the starter solenoid and the other wire from the big terminal on the solenoid that goes to the heavy wire straight to the battery, then yes, that'll work just fine.

And using a momentary (pushbutton) switch would be advisable as compared to a non-momentary switch.

- Eric

oldcutlass

You will also need a switch in between the Battery+ on the hei and battery. If not you will have to disconnect the wire to turn the engine off. would not worry about the harness yet just to get the engine running.

JCMC64

Ok. Progress. Got key ignition to work. You have to have battery juice to the ignition thru the horn relay, though i get that any method of connecting the battery assesory wire to the front lighting harness + red horn relay wires would have worked fine too. Got fuel to the carb, So now I just gotta find an ignition 12vdc for the dizzy And hope I got the dizzy lined up right. Taking a break to eat. Will update more later. Should have her fired up later tonight. Thanks for the input guys.

JCMC64

Got her started last night. She sounds great. Used a hard +12vdc off horn relay with a quick disconnect to shut off engine. Now I need to find the right 12vdc keyed ignition.
What is the correct 12vdc for the HEI pwr to use off the original correct 71' harness?

Video of it starting:

You Tube

MDchanic

The big heavy pink wire from the ignition switch.

- Eric

JCMC64

Hey Eric,

I figured out that (remember Im a rookie here) that you need keyed ignition power, that when key is on, power is always at Distributor and when key is truned off, no more power at Dizzy, thus car shuts off.

At one point the motor was only firing when I had key all the way actuated even though I thought I had tested it right before hand.
So I knew it was wrong power immediately. So I just jumped wire from horn relay directly to the dist, and had a quick disconnect to stop motor as Old cutlass said.

So the pink wire is from ignition switch, I see on schematic going through fuse box to + side of std coil...and then another branch going off somewhere that I cant quite make out on the blurry schematic I got off line in the CSM. I see one part going to Fuel gauge pod, pwr for the lamps? is this right?

oldcutlass

There is 1 wire that feeds from the starter "I" terminal to the coil, and 1 wire from the bulkhead connector on the firewall. The "I" terminal is for the start, and the bulkhead wire is for run. Now the caveat here is whether you still have a resistance wire from the bulkhead, you cannot use this wire as the HEI needs full battery voltage to operate correctly.

MDchanic

The big pink wire goes from the ignition switch, splits, one part goes through the fuse box, where it powers the gauges, the transmission kickdown switch, and the signal lights, and the other part goes through the firewall connector to the resistance wire to the coil.

You can either splice right into the big pink wire right after the ignition switch and pass the wire through the firewall (crude but effective), or carefully unclip the terminal from the resistor wire from the outside half of the firewall plug, remove the resistor wire from the terminal, remove the resistor wire from the harness, attach the terminal to a new piece of wire, reinsert the terminal in the firewall plug, and rewrap the new wire into the harness (artistic, but there's no turning back if want to go back to points).

It's up to you.

- Eric

JCMC64

I took the power off the coil pair as you suggested Eric, the brown wire in the pair, solder it onto HEI harness plug wire, used heat shrink on it, then wrapped it with real harness tape. Alls good in the hood. Heres a better video (havent played with timing or tune, idle at all yet):

MDchanic

Looking good!

Just to be clear, you didn't use the resistor wire that connects to the coil (+) terminal, right? Because that's not enough voltage, and will cause problems later.

Looks like it's coming along great!

- Eric

oldcutlass

X2?

Octania

to address the original question- the MINIMUM wiring to turn a motor is ZERO- you can turn it mechanically, e.g., using the drive wheels thru the transmission.

To use the factory electric starter, one needs a ground and positive cable, and a wire to the S terminal on the solenoid. Technically, that S wire can be done w/o if you use a screwdriver or whatnot to make that connection.... not recommended though.

JCMC64

Got ya, I think Im good, but can you please explain why this is above?
On the schematic out of CSM, it shows the pink wire off the IGN splitting as you already noted, then going through firewall paired with a yellow wire.
Does this wire have some sort of resistance built into it? I see on schematic that there is black lines drawn over the pink wire going to the coil indicating it is unique. Thx.

krooser

If that's a fresh engine with a flat tappet cam I wouldn't be messing with starting that engine until you have a cooling system hooked up and you can run it for at least 20 minutes at a steady speed to break in the cam.... goosing the throttle sounds cool but you are not doing your cam any favors.

MDchanic

Sure.

The technical term for it is "bassackwards engineering."

Basically, you want the engine to be able to start even under adverse conditions, such as when it is very cold out (thicker oil, harder to turn over, draws more power from a battery with already-decreased battery output due to low temperature).

It would be nice to be able to bump up the voltage at times when it's cold and the engine is hard to turn, but, of course, you can't, because a cold battery puts out less power than a warm one.

The solution is to do something simple, but not obvious: If you design the coil to make a strong spark on the voltage you would get when turning over an engine full of thick oil at twenty below zero with a low battery, you can easily reduce the voltage to the coil at other times when you do have enough power.

Thus is born the ballast resistor, in use in cars since at least the 1930s (and probably earlier, but that's not my area of expertise).
The coil is designed to make a good spark with about 8 volts input.
When you turn the ignition switch to START, the "S" terminal of the starter solenoid is energized, pulling in the coil, which closes the circuit between the starter and the heavy battery wire, pushes the starter drive gear into engagement with the flywheel, and makes a connection between the Heavy battery cable and the "I" terminal of the solenoid.

• The "I" terminal is connected directly to the coil (+), so while the starter is cranking (which lowers the voltage, even when it's not cold out), the coil gets full voltage directly from the battery, with nothing in between.
• When the engine fires and you release the key, the solenoid pulls back, and the "I" terminal is disconnected.
• At this point, with the key in the RUN position, current flows through the pink wire, through the firewall plug, and into the resistor wire (the ballast resistor).
• As it travels through the resistor wire, its voltage is reduced, under the typical load of the coil, to about 8 volts, which is what the coil needs to operate properly.

Why not run the coil directly off of the battery all the time?
Because if you do, the coil will overheat and be damaged.


So, the coil is wired directly to the battery while cranking and through a resistor while running.

The problem in HEI installations is that while the coil in a points system was designed to run on 8 volts, the HEI system was not. They found an electronic solution to the old engineering problem of having a hot spark at a low voltage but not overheating at a high voltage, and designed it into the HEI, so cars with HEI could do away with the resistor wire and the connection to the "I" terminal.

This is a good thing, unless you want to retrofit the new HEI to a car designed for the older points system. The HEI wants 12 volts, but the resistor wire can only give it 8.
The solution is to run a regular wire, as I described above, in place of the resistor wire.
If you don't then you will have rough running, hard starting, and random stalling problems, and you will be unhappy.

This is one of the reasons why many of us say, "Just leave the points alone - they work fine."

Make sense?

- Eric

JCMC64

Its got 200 miles on the rebuild, cam already broke in long before I got the car. Thx.

JCMC64

Pretty much get this everything to this point...though is "I" the same as the "R" labeled on my solenoid? I get the "S" operation fully, and now understand the "I" more, if the "I" is synomonous with "R" as that is the other terminal labeled on my solenoid.

Here is where I have a question. I get what your saying here, but:
1) is there a physical resistor in this line, or how is the voltage actually physically lowered in this line? I get that its after the firewall and between the coil+
2) when I measured the voltage on the yellow wire under simulation, it behaves exactly as you describe in write up above. But the brown wire always stays exactly at the battery voltage, around 12vdc or whatever it is at any given time. Why didnt it drop to 8 volts? Obviously Im missing something here.

Understood. Not designed for 12 volts, rather for 8 volts.

Get the theory perfectly, but it isnt happening like that on my setup so far.

Understood

Get it, but still have above questions.

Totally understand, makes perfect sense, keeps 12vdc to the HEI instaed of 8vdc...but still my question.

Get it, 8vdc no good for HEI.

Yes, all is very clear, except my question why its not duplicated on my car, the brown wire at the coil+ which is the resistor wire measures 12vdc all the time while ingnition is in run.

Thx for taking the detailed time to answer Eric.
Jim

MDchanic

Okay, Jim,

Yes, it is. I, R - all those little letters look the same to me - My mistake. Sorry.


The wire itself is a resistor. It's Nichrome instead of copper.


You're missing a load.
If you measure it when connected to a coil and points (or to the HEI), it will be 8 or 9 volts. With no load, it's a full 12 volts.
Picture a garden hose: You open the valve at the house just a little bit, and close the hose nozzle. You walk away from it for a few minutes. You come back and open the nozzle - for a second, it sprays hard, like it's on all the way, but then it slows to a dribble because the valve is mostly closed.
Same thing - if you had a gauge at the hose nozzle, it would have read full pressure with the hose closed, but the pressure would have dropped rapidly once the nozzle was opened, because of the resistance of the valve further up the line.


You're welcome!

- Eric

JCMC64

Ok. Got it. Makes good sense. Thx again.

JCMC64

MD...I wanted to do a better tap into pink ign wire for HEI pwr. I have the fuse box apart for another reason and was wondering if its ok to tap it here, want to know if its ok to solder a pwr wire run to the Dist from back side of the fuse panel pink wire here. I dont want to remove resistor wire, or any cut in dash wiring, so since I was cleaning it all up anyways, thought about just soldering a 12-14 gauge wire here to, run it throught the FW, and to the batt side of HEI. Thx in advance.

MDchanic

Yes, you can do this, just be sure to solder the wire to the "hot" side of the fuse, rather than to the fused side, or you will keep blowing INST fuses.

I would recommend 12 gauge wire, as I believe that's what the factory used.

- Eric

JCMC64

Got it. Thx. I noticed that point when I was studying the schematic (and when I took apart the fuse box and saw the layout for the first time. Seeing inside of fuse box for yourself first hand and analyzing it add another dimension so the schematics) Glad you verified that for me.

JCMC64

MD...just to be sure (though I spent my due diligence on this...just to triple check!), the fused side is the side of the tranny switch\Fuel gauge - two smaller pink wires in pic. And the hot side is the thicker pink wire connected to longer metal tab. Correct? Thx.



Spot to solder the pwr for HEI-