The Stovebolt Site Forums The Shop Area Engine Shop tune up on 55 engine

What would you do to tune up a 55 chevy six cylinder ? I changed spark plugs and have a pertronic flame thrower and electronic ignition. 12 volt. It runs real rough until warmed up then evens out some, but still doesn't run super smooth.

Mike,

What coil are you using (you may or may not need a ballast resistor, depending on its resistance)?
Are you using a ballast resistor?

Things to check or replace, in order of difficulty and cost:
Timing adjustment
Valve lash adjustment
Carburetor adjustment
Check/replace fuel filter
Ignition/plug wires (if you do not need them, you now have spares)
Rotor (if you do not need it, you now have a spare)
Distributor cap (if you do not need it, you now have a spare)
Run a ground wire from a screw on the distributor to head
Rebuild/replace carburetor

Thanks for the info. A good list to start with. Someone else told me I may need to adjust valves. Could be any or all of the list. Thank you!

What does a ballast resistor do and how would the engine act without one?I have no idea whether I have one or not- a real rookie here?sorry

I looked it up and yes I have a ballast resistor so not that unless it is old.

For some reason, when GM went to 12v, a resistor (called a ballast resistor) that reduced the voltage to about 9v (I think) was required in-line on the power lead into the coil. Some coils came with the resistor built in. Some (maybe all) of the Petronix Flamethrower coils have high resistance and no ballast resistor is needed.

If regular 12v points were used without the resistance, the points would burn out in a very short time.

http://www.google.com/search?q=ball...ved=0CDUQ_AUoAQ&biw=1024&bih=644

it may be that the ignition resistor is [part of] the problem if the petronix coil is also resisted, too little juice to fire properly

Bill

Hey Tim,

I don't meant to hijack the thread, but why do you suggest to run a wire from the dizzy to the head? And is there a particular screw on the dizzy, or are you just trying to ground it?

Thanks, Vince

Vince,

Just trying to assure a good ground. The Pertronix unit needs a good ground, and I guess it is possible that grease/oil might make for a sketchy ground. I think a clip screw on the distributor to a coil-mount bolt might work OK.

Definitely adjust the valves, I had the same problem on my 55 w/235 and the no. 4 intake rocker was off the valve, since correcting and adjusting valves runs like a different engine. Also I e-mailed Pertronix and they told me to remove my ballast resistor since I have the Flamethrower coil.

Larry

the instructions for pertronix is very specific in their installation requirements. Follow them to the letter, or in the one fellas case contact pertronix directly, they know for certain about their products. Rather than guessing or relying on someone elses opinion. Personally I would take the pertronix out, as I have had horrible experience with it, playing with points for the rest of my life will never equal the misery encountered with it.