1963 356B Timing and End Gap Issues

[jmsnyder]

I'm working on a friend of mine's 356B Super 90. Basically it just wasn't running very well and needed a basic tune up. One of the carbs was pretty trashed so I rebuilt the carbs, replaced the cap, rotor, points, plugs, oil, all the basic tune up stuff. Everything I took off was definitely in need of replacing.

Anyway, when I got everything back together, The timing was jumping all over the place and it was impossible for me to set the static timing. I took the distributor (022) apart and one of the springs had come off. I put it back on and although slightly better, the timing was still erratic.

To confirm it was a timing issue, I bought a cheap, but highly rated, knock-off 009 distributor for $35 from Amazon and it came the next day. I put that in and was easily able set the static timing to around 8 degrees BTDC and dialed in the carbs for a perfect idle.

The issue I'm facing is with the advance. When you apply the throttle, the engine revs up to 2,000 rpm and stays there. While watching the timing with the timing gun and slowly building up the revs, the advance seems to come on as it should until all of the sudden the TDC mark on the pulley disappears and and the revs stick at 2000 RPM. When this is happening, the throttle is in idle position, and the TDC mark on the pulley is at the very bottom, 180 degrees from where it should be. There is no pining or anything like that. It will stay there until I manually retard the timing. When I do that, the RPM comes back down and the engine will stall unless I take the timing back up to the initial 8 degrees or so before it dies.

I can't figure out for the life of me what would cause this other than just the fact that it's a cheap knock-off distributor.

Just for the record, I did confirm the point gap and try several combinations of caps and rotors I had laying around.

One more thing, when I was checking to see how well the rotor snapped back to the static timing setting, I noticed the main pulley moved slightly. Interested, I moved it in and out by hand only to find out how much play there is! I did a rough measurement on the pulley and it seems to have a full millimeter of end play. It's not just the pulley either, when I move the pulley in and out, the distributor rotor rotates back and forth several degrees.

I did some reading on both problems and didn't find any definitive answers. I read that excessive end play at the pulley means a broken crank but I'm pretty sure it would run MUCH worse or not at all if that were the case.

Any Ideas? Thanks.

[jmsnyder]

Forgot to mention, I ordered new springs for the old 022 distributor but I would still like to solve this mystery.

[JT912]

Is the carb linkage getting stuck on something? Did you balance the carbs?

[apsal]

its a broken crank, sorry to report.

[peter leinberge]

Based upon my limited experience, of the several cranks I've snapped, if it broke , especially in the center, when pulling or pushing on the crank pulley you'll usually hear a "clunk".
It might just be worn thrust bearing or bad end play. (keep fingers crossed!)