1961 wiring question

[petepedlar]

I need to know if a '61 Impala with a factory 348 has a balast resistor hiding in the wiring harness somewhere.


I finally have the Impala almost ready to drive....... there's a few things left to tidy up but she's really close.

I started the 409 last night. MSD ready to run. New gas tank, new rubber sections on the fuel line. I put some gas in the carb and hit the key....... it turned over and over....... not even a cough...... I checked the timing, the fireing order, test light on the coil, very weak spark at the plugs but there was spark, but the battery was getting low as it's been used for a few months testing lights, wipers and such.

Little more gas in the carb and turned it over and over...... not even a cough. I repeated everything, rechecked everything.... and tried again several times...... still nothing and the battery is getting pretty low by now....... but the fuel pump has filled the filter so we definately have gas to the carb now..... I thought maybe the starter was taking to much juice away from the ignition with the battery being low so I put a jumper wire from the battery to the coil...... this time the engine didn't even make a full revolution on the starter and it was running. I removed the jumper wire and it ran just fine. I didn't try and start it again as it was late and I wanted the battery to charge up a little.

........... I'm thinking there must be a balast resistor somewhere...... any one know if there is and where to find it????

Thanks
Dave

 

[oldskydog]

Dave,
Only the solid lifter engines came with the ballast resistor. All others had a resistor wire to the coil in the ignition/starter harness. Order a new engine harness for the 340/350 hp version and get a ballast resistor and all should be right. Sounds like maybe your original engine harness resistor wire or connector may have a problem. On the wiring diagram in the assembly manual it shows the resistor wire as a 20 ga. white connecting to the + side of the coil, into the firewall connector and coming out the inside as an 18 ga tan to the ignition sw. I believe the main harness is the same and only the engine harness is different. The service manual has the better wiring diagram and I don't have it handy but can check tomorrow.
Correct me if I'm wrong, but I remember reading somewhre that MSD's need a full 12 volts. You could probably just wire around the resistor wire if you don't want to get the correct engine harness.

 

[Dond409]

Msd

MSD ready to run needs to have 12 volts all the time.

 

[62impala409]

Can we assume that the ballast resistor used on all solid lifter engines carries more amperage at 6-7 volts than a simple resistor wire in the harness that carries about the same voltage. I realize that the purpose of the resistor is to reduce arc damage to the points. All the electronic ignition systems I have used, factory or aftermarket, require a full 12-14 volts. Leo

 

[yellow wagon]

I would agree...MSD not getting enough juice. I'd just wire around the resistor wire and you should be good

 

[real61ss]

"Only the solid lifter engines came with the ballast resistor"

Cecil,
This probably doesn't have anything to do with Dave's problem but to my knowledge all '61 348 cars had the resistor mounted on the firewall. My '61 305 had the original resistor still in place.

 

[Fathead Racing]

The problem isn't with a resistor wire or the lack of one. The problem is that when you are cranking the engine over the starter circuit shuts off current to the coil. The stock wire harness supplies power to the coil through the starter when cranking. If you don't have three wires coming off your starter you will not have power going to the ignition. Do you have an after market starter?

 

[64ss409]

The problem isn't with a resistor wire or the lack of one. The problem is that when you are cranking the engine over the starter circuit shuts off current to the coil. The stock wire harness supplies power to the coil through the starter when cranking. If you don't have three wires coming off your starter you will not have power going to the ignition. Do you have an after market starter?

Ray ran into this problem on his 60, but my 64 ign switch has current to the coil in both 'on' and 'start' positions. It will start without the full 12v coming from the starter to the coil. I don't know about 61.

 

[Fathead Racing]

Ray ran into this problem on his 60, but my 64 ign switch has current to the coil in both 'on' and 'start' positions. It will start without the full 12v coming from the starter to the coil. I don't know about 61.

I forgot about that! On my 60 when cranking with the stock starter and harness , a full 12 volts is directed to the ignition bypassing the resistor wire. The idea behind this was to give the ignition a 12 volt jolt of power for a quicker start. When you are off the start circuit power for the ignition is channeled through the resistor wire so as to not burn the points. Again I assumed that all 58 through 64 wiring was the same.

 

[petepedlar]

Thanks everyone.

I do have a newer starter with only one wire. The MSD does need a full 12 volts. There is or was no balast resistor on the firewall but I knew there had to be something....... there was power to the coil when I tested it with a test light. The test light wasn't bright because it was only getting 6 volts...... When I checked it I thought it was because my battery was low.

From what Cecil wrote I understand that it is the white wire on the engine side which changes to the tan wire on the inside of the car. If I wire around (replace) that wire I will have my 12 volts.

My hat is off to the pro's.....

Dave

 

[oldskydog]

"Only the solid lifter engines came with the ballast resistor"

Cecil,
This probably doesn't have anything to do with Dave's problem but to my knowledge all '61 348 cars had the resistor mounted on the firewall. My '61 305 had the original resistor still in place.

Tommy,
I'm sure you're right, of course. I did a quick check of the piss poor 61 assembly manual illlustrations without reading what few notes are left on the incomplete pages. Although it doesn't show in the illustrations, it specifies that the RPO 572 (305 hp) stater harness 2979832 installs the same as RPO 580/590 (360hp/340hp) harness which is part number 2979833. I don't know what the difference is between the two harnesses since they are one digit off in part number, but It must have a ballast resistor, although it is not shown in the illustration nor called out in the parts list. ????
To simplyfy things I think this statement is probably correct: Only the 250 hp 348 engine did not have the ballast resistor. All optional 348 engines and the 409 had the ballast resistor. Still not positive on the 280hp, but it is an optional engine so maybe it had the BR.
To confuse things even more, the service manual doesn't have the typical wiring diagrams, but has them broken down by system and does'nt cover all options or configurations. There is one diagram for the 3x2 carb engine noted RPO 573 only which shows a ballast resistor. The RPO 573 was actually 573A for the 280 hp and 573B for the 335/350 hp. There is no diagram for the RPO 572, 580, or 590 which all used the BR. ???????
I know my 61 which was a 348 does not have the ballast resistor so it must have been a 250 hp since it doesn't have the coil on the firewall.
It's truly a shame that whoever copied the assembly manual from the original GM files, didn't see fit to copy the whole page with the legends and notes on the lower part. Those notes have a lot of great info on changes and when they occured as well as part number change history. A good example of what might have been revealed is on RPO 490 Sheet 3.00, item 8, Carburetor 3797698 which is the 3270 AFB . The item 9 just below it is blank indicating that it was a part number that was removed at some time in production. The legend and notes would have given more info.

 

[Fathead Racing]

You may find that the actual voltage through the resister wire is up to at least 9 volts, just less than 12. You will have voltage to the coil when the key is in the run position. Check and see if there is any voltage to the coil when you are cranking the engine. Be careful about jumping 12 volts to the coil through anywhere but the run start circuit, you may find that you can not shut the engine off when you turn the key to the off position.

 

[oldskydog]

The lo perf engines used 1.8 ohms resistance and the hi perf (solid lifter) use .3 ohms resistance on the seperate resistor types. According to the 61 service manual, the resistor wire should be 1.4 to 1.65 Ohms.

 

[petepedlar]

Only the 250 hp 348 engine did not have the ballast resistor. All optional 348 engines and the 409 had the ballast resistor.

Cecil, my car would also back up this statement as it was a 250 HP 348.


Dave

 

[petepedlar]

You may find that the actual voltage through the resister wire is up to at least 9 volts, just less than 12. You will have voltage to the coil when the key is in the run position. Check and see if there is any voltage to the coil when you are cranking the engine. Be careful about jumping 12 volts to the coil through anywhere but the run start circuit, you may find that you can not shut the engine off when you turn the key to the off position

Before I disconnect the resistor wire I will check it with a voltmeter to find out for sure. I think by the way the engine reacted it cuts the voltage by quite a bit..... like I said earlier the engine cranked and cranked and did nothing.... but with 12 volts to the coil the engine didn't even do a full turn on the starter before it was running.

If I just replace the resistor wire with a normal wire, power will still be shut off with the ignition switch...... but you are right if that new wire is not switched properly the engine would not shut off.

Dave

 

[oldskydog]

Dave,
It sounds like you have no ignition from the starter to the coil, like Ray said. The original harness provided current through a 20 ga dark green from the R solenoid on the starter to the + side of the coil for starting. Once the key is released, that circuit is dropped and current is provided through the run circuit by the 20ga white resistor wire to the + side of the coil. If you only have one wire on your starter, I don't see how you would have any spark on start, as you described. Somehow you need to get switched power to the coil either through the starter R term on a stock starter or maybe from the single terminal on your starter as long as it is disconnected when the starter is released. Did your aftermarket starter come with any wiring instructions?
There was a difference between the 6 cyl cars and V8 car wiring in 60,..not positive if 61 was exactly the same. On Ray's car, as I recall, it was originally a 6. The 20 ga white resistance wire ran all the way to the starter R term instead of going to the + term of the coil directly. Starting current was provided from the R term on the starter via a 20 ga green to the + term on the coil. Visually the difference is the 6 cyl harness only had one dark green wire to the coil, whereas the V8 had a white and a green on the coil +.

 

[Brian Thompson]

Dave-

When I re-wired my harness, I completely removed the resistir wire back to the plug and put a new wire in it. Haven't had any problems.

 

[Fathead Racing]

Dave,
It sounds like you have no ignition from the starter to the coil, like Ray said. The original harness provided current through a 20 ga dark green from the R solenoid on the starter to the + side of the coil for starting. Once the key is released, that circuit is dropped and current is provided through the run circuit by the 20ga white resistor wire to the + side of the coil. If you only have one wire on your starter, I don't see how you would have any spark on start, as you described. Somehow you need to get switched power to the coil either through the starter R term on a stock starter or maybe from the single terminal on your starter as long as it is disconnected when the starter is released. Did your aftermarket starter come with any wiring instructions?
There was a difference between the 6 cyl cars and V8 car wiring in 60,..not positive if 61 was exactly the same. On Ray's car, as I recall, it was originally a 6. The 20 ga white resistance wire ran all the way to the starter R term instead of going to the + term of the coil directly. Starting current was provided from the R term on the starter via a 20 ga green to the + term on the coil. Visually the difference is the 6 cyl harness only had one dark green wire to the coil, whereas the V8 had a white and a green on the coil +.

Yep Cecil, you are correct. My car is a 6 cyl chassis. I changed the wire harness when I installed the 348. After I put in a mini high torque starter that only had 2 wires and no provision for suppling juice to the coil on crank I installed a diode that would only supply power but in one direction while cranking, thus the cranking/start circuit would supply 12 volts to the coil while cranking but would not back feed the circuit.

 

[real61ss]

Cecil,
I think you are correct about the 250 horse 348 not having a resistor. I had a '61 Impala 348/250 4 speed parts car while I was restoring my blue '61. I've sold the car now but I have some pretty detail photos of the car, after looking at those photos, it did not have a resistor.
I know......We got two different conversations going on here!!!!!

 

[rstreet]

Cecil:
I believe I have a 61 manual available to me but am not sure of the date. It might be the one that would have been issued in Aug/Sept(first edition).
robert