I'm running really rough, feels like it's running on 7 cylinders. I let the car idle, then would pull one plug wire at a time to see if any of the cylinders weren't firing. I found a couple that didn't make a difference when pulling the plug wire off. So, I put a cotter pin in the plug wire, and held it close to the plug. It would spark, but only intermittent. It seems really weak too. If I hold the pin more than 1/8" away or so, it won't spark. Even the running cylinders wouldn't arc more than 1/4" or so. Does this sound too weak? What could cause this? I have a 12 volt system, alternator, Mallory distributor (used), brand new plug wires and plugs, and a brand new coil. Thoughts?
What Flathead? That is how I check for firing issues. Works well. First be sure you have three GOOD grounds. Frame to engine, engine to cab and cab to frame. Try a another new 12 coil. Check your spark plug gap. Run Autolite plugs or NGK plugs ONLY! Install a new condenser. Install new distributor contact points. Be sure the spring tension is correct on them. Run a new coil to distributor high tension lead. Replace your contact leads and grounds in the dizzy... Rebuild your used dizzy. There that will keep you busy for a while.
Even on an old 6v system. Blue/white spark, should jump about a half inch minimum. Don't matter if it's a flathead, a roundhead, a lawnmower, or a chainsaw.
Start with the condenser. I had one go bad in the Mallory on my flathead a few years ago and it produced similar results.
My Pop always told me it's gotta shock you dam near to your shoulder, If it only gets to your elbow it ain't enough spark.
I bought this distributor used, and I don't see a condensor on the outside anywhere. Is it on the inside of the dizzy? It's a mallory 3 bolt, no box, on a 46-48 Ford Flathead. Maybe a better question is this: will it run really rough if there's no condensor? lol....
Time to take one apart and learn. They are simple. If you have any questions we will be able to help you. Good luck.
A recent Mallory will have a badly grounded (due to lacquer paint on can) and short lived condensor and points with a very short service life. Start by canning all of the above and putting in the Echlin replacements. Next...does the thing advance?
I love to learn! This is my first flathead and I've learned tons. Yes, it advances. I guess I'll tear it apart and figure it out.....
I can dig up part numbers, but they've been posted on here several times. The Mallory points I've seen wear very rapidly at the rubbing blocks and then the points fry... Once you figure out points and get good ones you should be able to get good service. Advance...it needs to come in rapidly and be donce by or not much past 2,000. Many M's have very stiff, slow advances out of the box. By the way...did you know that '32-48 Ford distributors were based on the Mallory design of points and vac brake, and that the '41-48 ones have an excellent curve???
I heard the newer Mallorys davance is more like a 350 on the spring. GMC BUBBA is always replacing the springs on the newer units. And NAPA has better points for the Mallory's. You might want to PM him. Verry smart guy! He can fix any ignition in his sleep. Im not sure about the newer condensors but the old brass ones had a waranty for life. Hell, it might be just a bad cap.
This thread is a year old,but did you figure it out? My guess is a bad condensor,like mentioned above.
Thats what my Mallory had - an OHV curve in it and it was rattling its head off at anything just over idle under load. Replace the condensor as mentioned - its a process of elimination, do the easy stuff first. Condensor, cap, wires, rotor, points. Good luck. Rat
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