Old problem revisited, rough running 8BA

Ross F-1 said:
The voltage at the (+) terminal on the coil should be 12v or whatever the battery is at; the voltage at the (-) terminal would be dropped by the coil resistance if the points are closed.

You said "Have also added engine to ground strap." The negative battery cable should be going to the block or trans bellhousing. Is that how you have it?
Click to expand...
Ground strap runs from bell housing to frame. Electronic distributor, no points.
 
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With fresh charge on battery, batt. shows 12.7V, 12.7V to starter solenoid and 12.7V to hot side of ignition switch, switch on cold side terminal shows 11.71V when switched on and 11.49V to positive side of coil and 9.8V across coil terminals due to internal resistor in coil. So question is: why am I getting nearly a full volt of drop across ignition switch when turned to the on position; I have disassembled and cleaned the contacts previously. Another curious thing is that when I flip the lever on the ignition switch to the on position it activates coil but when I turn lever to off position the coil still has power going to it, power does not completely go off until I turn ignition key to the off position.
 
When you say you turn key off do you have another switch for on and off.
The key is to lock the steering column my guess.
To get it to run get a wire with and alligator clip and jump it to coil direct,
With electronic ign you need a clean line with no add ons.
Try a new key switch with key start.
You can't be pure if the have electronic ign and 4 barrel carb.
 
George/Maine said:
When you say you turn key off do you have another switch for on and off.
The key is to lock the steering column my guess.
To get it to run get a wire with and alligator clip and jump it to coil direct,
With electronic ign you need a clean line with no add ons.
Try a new key switch with key start.
You can't be pure if the have electronic ign and 4 barrel carb.
Click to expand...
"36 ignition switch has key and on/off lever, yes the steering column locks.
 
Bypassed the stock ignition switch with push/pull switch I used on test stand, results: no voltage drop between posts on switch, when I hookup coil wire to the switch voltage drops .37V with switch on and show 11.75V at the coil. Engine still runs rough.
Will try jumper wire direct from battery to coil.
 
I don't know the history of engine.
Did you ever drive this car with this engine?
If it was rebuilt any cam changes.
Did you put the goodie on engine.
I want you to try and pump gas pedal few times and then hold half way down then start it and see if it reeves up quick.
These electronics dist. all ways pop up and as many times they do never hear a answer. That flathead will most likely NEVER SEE 5,000 RPMS
My best fix for you is put the dist. with points stock or Chevy dist. from Buba.
Good Luck
 
George/Maine said:
I don't know the history of engine.
Did you ever drive this car with this engine?
If it was rebuilt any cam changes.
Did you put the goodie on engine.
I want you to try and pump gas pedal few times and then hold half way down then start it and see if it reeves up quick.
These electronics dist. all ways pop up and as many times they do never hear a answer. That flathead will most likely NEVER SEE 5,000 RPMS
My best fix for you is put the dist. with points stock or Chevy dist. from Buba.
Good Luck
Click to expand...
This engine ran great on test stand, it had no pressure plate or engine ground strap as it now does in the car. I installed L-100 cam when I assembled the engine. I would go to the Chevy distributor right now if I didn't know the engine ran so well on test stand with the electronic. Will try starting at half throttle but am confident it will rev up immediately.
 
Do you have the vacuum wiper motor connected to the intake manifold? Bad hose or vacuum motor? Do you per chance have hyd brakes with a vacuum booster? Had a vacuum booster go bad for me.

You should not have a voltage drop across the ign switch. Use find sand paper on the contacts and then apply dielectric grease.

Also, you have run a ground strap from the frame to the motor. Is the battery grounded to the frame?
 
Bill OH said:
Do you have the vacuum wiper motor connected to the intake manifold? Bad hose or vacuum motor? Do you per chance have hyd brakes with a vacuum booster? Had a vacuum booster go bad for me.

You should not have a voltage drop across the ign switch. Use find sand paper on the contacts and then apply dielectric grease.

Also, you have run a ground strap from the frame to the motor. Is the battery grounded to the frame?
Click to expand...
Bill, I do have about a 1 volt drop across the original '36 switch and have temporarily installed a push/pull switch that shows no voltage drop but still get the rough running. All vacuum ports on the carb. are blocked off. Yes, battery is grounded to the frame. Thanks for your interest. Bob
 
I guess it didn't rev up fast?
Do you know if the dist was ever any good.
Just another thing to check.
The emitter in center of dist., make sure you have a 8 cylinder one.
It will run with 6 my guess for today. Points are your friend if you can tek you can set them.
 
Have looked closer at voltage drop across ignition switch on both the original '36 switch and the temporary push/pull switch; both switches show a voltage drop when I hook up the coil wire............is this to be expected? I had previously stated in earlier post there was no voltage drop on the push/pull but that was incorrect.
 
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