Broken distributor rotor

Hotrodvideo

Senior Member
Anyone ever buy a distributor rotor from Mac's for a 59AB engine and had it break in half?? I did today. I know it turned ok in the dizzy before I installed it, I was able to turn it by hand from the back with the crab cap on.

I think I'll buy another one from Napa this time.
 
I had one break on me but it is because I did not put the crab cap on properly. Now I just pull the whole distributor, work on it, put it back together and then put it on the engine. It is hard to be sure everything is aligned properly when you try to just pull the cap.
 
On the subject of 59A, or 21A distributors... I just had a (crab) cap failure. The cap & rotor were sourced from one of the 'usual' suppliers (mentioned above) that we mostly all use. The cap looked like a piece of crap from day one, and its pre-mature failure only confirmed what I suspected all along.
Bottom line, I bought another cap & rotor from a local, independent parts store. It came in an SMP package (Standard Motor Products), it's USA-made, has brass contacts, and is a beautifully made part. I should have done this in the first place.
 
On the original subject... You mention 59AB, and you mention 'crab' cap. I hope you are aware that the rotor for a 59AB is NOT the correct rotor for a 'crab' cap. If you try to 'mix', like a 59 rotor, with a crab cap, something is SURE to break.
You MUST have the 1942 rotor, with the 1942 cap. 59A (45-48) rotors are different.
Just a thought....
 
I bought the '42 thru '44 crab style cap and the '42 thru '44 rotor which according to Mac's are supposed to work together. The '46 and later rotor is different so yes I'm aware of that. I had the entire dizzy together on the bench and spun it by hand to makes sure that the rotor was okay in the dizzy and that they cap fit and then I put it on the engine and when it wouldn't start, I took off the cap & noticed the broken rotor.
 
I friend brought me a 46-48 dist with the 2 piece cap with new cap and rotor from Mac's. I installed new points and cleaned up the dist, put on the cap with the narrow gasket and rotor. Just turning the dist by hand you could feel the rotor hitting the ***'s, I took a used original rotor from my stach and it worked perfect. Just srugg your shoulder and say, that's what you get nowdays. Walt
 
I friend brought me a 46-48 dist with the 2 piece cap with new cap and rotor from Mac's. I installed new points and cleaned up the dist, put on the cap with the narrow gasket and rotor. Just turning the dist by hand you could feel the rotor hitting the ***'s, I took a used original rotor from my stach and it worked perfect. Just srugg your shoulder and say, that's what you get nowdays. Walt
Not so Walt ,i have good fitting USA made caps and rotors from Borg-Warner with brass contacts.Some times its a problem with the axiel movement of the dist shaft. There are shims to be used in some to take out the play in these shafts.If the shaft moves too much to the front towards the cap the rotor moves with it and can hit the contacts.Each individual dist must be checked for this. ken ct. Theres not a lot of room in there as you know.:)
 
I bought a new Echlin rotor from Napa, I took the dizzy off the engine and put the rotor on and spun it around and checked the cap fit and everything else. I put the complete dizzy back on the car and it started right up. The rotor I got from Napa is identical to the one Mac's sells, in case you were wondering.
 
I bought three sets of points from NAPA (Echlin) marked made in the USA. One set was good. In one set the right points plate was shorted out to where the other piece screws in. In the third set both plates were shorted.
 
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