Misfire?

My '52 has felt like it was randomly missing cylinders for some time now, and on a half-educated guess I decided to look at the distributor.

When I opened it up I found the breaker points looked a little the worse for wear (but not obviously destroyed), the cap contacts were slightly blackened, and the rotor contact looked like it had seen better days. So I figured I found my culprit, and ordered a distributor rebuild kit from Bob's.

Replacing the parts seemed easy enough, but I ran into trouble when it turned over but wouldn't start. After a little tinkering I realized the breaker arm probably wasn't in the correct position, so I adjusted it until the engine started reliably. Which is great, but...

The engine is obviously unhappy. It's got an extremely pronounced rhythmic sound and feel, and the whole car vibrates along with the rhythm of the engine. Here's what I'm talking about:

I haven't done anything to any other component of the ignition system. Am I looking at a misfire? Did I somehow create a timing issue? I made sure all the ignition wires seemed securely in their sockets on the distributor cap.

I'm learning as I go with this car, so I'm no garage veteran. Google didn't seem much help because all it wants to return is articles about timing chains and OBD II codes.

I feel like I just kinda broke my Roadmaster.

Recheck your firing pattern.

Also, if possible, run the engine in a darkened environment and watch the plug wires for sparks where they touch any metal, or each other or even at the caps on the plugs. Give your eyes a few minutes in the dark to adjust first. Any little blue lights on those wires will mean it's time for replacements. If you want to buy a another year or so, then buy some wire loam at Walmart, the small size loam is perfect for encasing and isolating the spark plug wires. And it was less than $5.00 a few years ago.

avgwarhawk, are you suggesting that I might have swapped one (or more) of the cables in the wrong positions on the cap? I could certainly check that. I thought I was being careful...

The wire are only two years old or so. I wouldn't think they'd be failing yet, but I suppose I could check.

Then after checking the wiring like Chris suggested, I would clean and gap the spark plugs. How old is the gas in the car? What, if anything did you put in the gas on the last fill up?

How is the coil? Can be checked with an ohm meter,just google it.Check for frays or cracks in the point lead wire to the coil,can not have any shorts,ballast resistor ok?Pull A plug and see what kind spark it has,nice big blue jump,or weak, yellow arcing, on the side?Sounds like it is missing due to weak spark,is the points gapped correctly with A feeler gauge? Just some thoughts Mark M

Check as JohnD suggested. New wires are no guarantee. When I did my '38 about 1-1/2 years ago I replaced the wires. I bought a set pf reproduction wires. A while back it started missing. Sure enough the "new" wires were arcing to the head. Making up my own set of wires using good quality solid core wires cured the problem. New doesnt always mean good.

"After a little tinkering I realized the breaker arm probably wasn't in the correct position, so I adjusted it until the engine started reliably. Which is great, but..."

Did you just straighten so the contacts are parallel or did you vary the gap? Clean the contacts with lint free tissue and brake cleaner, set with a feeler gauge cleaned with the same. I don't have the specs for you engine, but the point gap is probably around 0.015" and the dwell is around 30 degrees and should not vary more than a few degrees with varying RPM. Sad, but I have received substandard and DOA ignition parts from 'Buick suppliers'...get points and condenser from NAPA auto or Rockauto (Standard products). And of course set timing, be sure of the firing order, function of the vacuum advance, condition of plugs and wires, substitute a known good coil ...

Willie