Pertronix spark plug gap on a 170

[TucsonHooligan]

What is it ideally? I know its not stock, its shorter, but damned if I can find it anywhere.

 

[Harte3]

Ideally will depend on what your engine considers "ideal". You might start with the stock gap as a baseline and experiment going up and down from there in small increments and settle in on what seems to be the best to you.

 

[fordconvert]

Points systems tended to be 35. Electronic systems (pertronix included) seem to start around 45. Depending on compression and several other factors some get to around 80 (stock 75-89 HEI's on Oldsmobile motors come to mind). Most of the time you dont see much over 50-55 for fairly stock street type of motors.

 

[FalconSedanDelivery]

is about it with a Pertronix conversion in a stock dist , Two reasons, one , unless you upgrade the coil AND wires you will overtax the secondary and have problems, with spark crossover and two the stock cap diameter has limits ( the reason the Durasparks are bigger in Diameter ) I suggest .040 with just a pertronix added, .045 if you have pertronix and a better coil and wires.

 

[fmartin_gila]

I used the Pertronix I and the matching coil with it. I set the gap on the spark plugs at .045. Seems to do just fine with that setting.
Fred

 

[LaGrasta]

My Pertronix set-up is at .55. Is there any downside to running it this big?

 

[x21]

I think thats what I was running in my 200 - a 55 gap. Had the Pertronix I Ignitor and 40,000 volt 'flamethrower' coil.

 

[fmartin_gila]

Next time I have a reason to pull the plugs, I will try a bigger gap.
Fred

 

[ludwig]

Well, g*d (aka Dennis Schjeldahl) says that you run a colder plug and a larger gap with Pertronix. He recommends .55 and that is what I have. The advantage is a fatter spark to get better ignition/combustion.