Old problem revisited, rough running 8BA
 

8BA ran great on engine stand but not since installed in car. Distributor and carb. are working as they should and think problem lies elsewhere. Changes since engine was on test stand are the following: 12V battery that was on engine stand is now located behind rear seat with double 00 positive cable (engine starts immediately) had on/off toggle switch for ignition switch on test stand, am now using stock '36 ignition switch, start button on engine stand was more heavy duty than the one now mounted in my dash and now have added two fuse panels, one hot all the time, the other switchable and a 50 amp circuit breaker. The ignition switch is wired directly to the battery and not going through fuse panel. Have also added engine to ground strap. Car has negative ground and is equipped with alternator with internal regulator. Compression and vacuum good and plugs look good. No crossed plug wires. Any ideas?

Re: Old problem revisited, rough running 8BA
 

Maybe a little more info as to how it runs? Is the problem at idle, driving, acceleration. We are not mind readers.

Re: Old problem revisited, rough running 8BA
 

Won't idle, runs rough at all RPM's under no load conditions, un-driveable. I know I'm in the wrong venue for mind readers, will try harder.

Re: Old problem revisited, rough running 8BA
 

Vacuum leak?

Re: Old problem revisited, rough running 8BA
 

I think your assumption that the distributor and carb are working as they should is a bad one. I'd suspect distributor first. Is it stock?

Re: Old problem revisited, rough running 8BA
 

Make sure you have the correct coil and resister for 12 volts.
Then wire direct to resister wired to coil.
if it runs good your problem is all the mickey mouse wiring.

Re: Old problem revisited, rough running 8BA
 

If I remember right, the first problem was because of bent rods in the carb and new ones were on order. At that time the idle was fine, and ran bad above idle. Bubba had checked your distributor to be fine. You have been tutored on how to time it. As already mentioned, verify good voltage to coil, Unless you have a new carb on it, I would look there.

Re: Old problem revisited, rough running 8BA
 

When you say you have no crossed wires there is a Motors manual and the firing order is wrong,
You may want to check it with Mercury v8 49 to 53
I had it happen to me.

Re: Old problem revisited, rough running 8BA
 

is it misfiring or is it a vibration you're feeling?

Re: Old problem revisited, rough running 8BA
 

That's interesting, am using the firing order as found on the VanPelt site; will look into this further. The carb. is a new Edelbrock with new metering rods installed, this solved my over rich condition that was fouling the spark plugs. The Mallory electronic disturb. has been gone through by Bubba's and is in good working order; Bubba supplied the correct matching coil. Firing order am using is 15486372. The problem seems more like a misfire than a bad vibration.

Re: Old problem revisited, rough running 8BA
 

No vacuum leak between manifold, adapter & carb, all three ports on the carb. are blocked off. Vacuum measures 17" which am told is about right for the cam (L-100) am using.

Re: Old problem revisited, rough running 8BA
 

Have 12.6V at the battery and only 9.7V at the coil with no resistor, that can't be good!? Bubba also supplied correct resistor but said only to use it if coil overheats.

Re: Old problem revisited, rough running 8BA
 

If you by passed and went to coil direct you should have 12 colts.
Some times when going to 12 volts the resister under dash is still in use.

Re: Old problem revisited, rough running 8BA
 

No resistor under the dash, have replaced all wiring and therein lies the problem I think. Will explore why I'm not getting 12V at the coil with ignition switch on. Thanks everyone for the help.

Re: Old problem revisited, rough running 8BA
 

ballast resister, your melting down the coil

Re: Old problem revisited, rough running 8BA
 

Maybe, maybe not. What are the specs for voltage at the coil with the Mallory? What about plug wires?

Re: Old problem revisited, rough running 8BA
 

Have Taylor 8mm spiro wires. Will find out what the voltage should be to the coil from Bubba, am wondering why I don't have 12V at the coil. Will investigate tomorrow.

Re: Old problem revisited, rough running 8BA
 

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?

Re: Old problem revisited, rough running 8BA
 

I would clean the contacts in the stock ignition switch. You have 12 volts to the switch and 9 volts after the switch?

Re: Old problem revisited, rough running 8BA
 

I agree with Bill. Voltage drop thru the ignition switch. Place a jumper across it and see if it comes up to 12v.

Re: Old problem revisited, rough running 8BA
 

My older Mallory electronic distributor wanted 8 volts at the coil.

Re: Old problem revisited, rough running 8BA
 

Ground strap runs from bell housing to frame. Electronic distributor, no points.

Re: Old problem revisited, rough running 8BA
 

According to to Bubba "Mallory says you can run 12V to coil with the correct 1.5 ohm resistant coil."

Re: Old problem revisited, rough running 8BA
 

Mallory says okay at 12V to the coil with correct 1.5 ohm resistant coil.

Re: Old problem revisited, rough running 8BA
 

You could try and old dist with points, and go with 2 97s carbs.

Re: Old problem revisited, rough running 8BA
 

Contacts were cleaned when I had it apart.

Re: Old problem revisited, rough running 8BA
 

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.

Re: Old problem revisited, rough running 8BA
 

See latest post

Re: Old problem revisited, rough running 8BA
 

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.

Re: Old problem revisited, rough running 8BA
 

"36 ignition switch has key and on/off lever, yes the steering column locks.

Re: Old problem revisited, rough running 8BA
 

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.

Re: Old problem revisited, rough running 8BA
 

Ran jumper cable for coil shows 12.3V but still runs rough.

Re: Old problem revisited, rough running 8BA
 

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

Re: Old problem revisited, rough running 8BA
 

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.

Re: Old problem revisited, rough running 8BA
 

May have the wrong ignition module and coil for the distributor, exploring further.

Re: Old problem revisited, rough running 8BA
 

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?

Re: Old problem revisited, rough running 8BA
 

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

Re: Old problem revisited, rough running 8BA
 

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.

Re: Old problem revisited, rough running 8BA
 

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.

Re: Old problem revisited, rough running 8BA
 

Mallory Unilite electronic kit does,nt list one for 1953 Ford.