I swapped 3 ring damper onto my 240. Was a rebuilt unit from Damper Doctor in California. Looked first class. But the timing mark (actually a notch in the rear ring) was in a different location than the old single ring on the 240.

I filed a new mark in the 3 ring where the mark was on the old ring.

The engine has been running OK, but not perfect. I wanted to upgrade to a mechanical advance dizzy and pertronix setup anyhow, so I threw a timing light on it, BEFORE hand to see where I was. Well, turns out NEITHER mark is anywhere close to TDC. The 300 mark is about 180 deg off, the 240 mark about 140. I suspect the 240 damper had spun and the last guy to tune it just tuned by ear.

So I made a 3rd mark somewhere in the area of the TDC (not exactly easy to know for certain) Set the idle advance to about 4, and its running better than before. Seems to advance a helluva lot when I rev it up, maybe to 20 or more, just like that. But the advance will be less under a load (less vacuum), so I am happy.

But, to finally get to the point: ARE THE 240 AND 300 CRANK SHAFTS ALL DIFFERENT IN TERMS OF THE KEY SEAT FOR THE DAMPER? Or perhaps the rebuilt damper was not set correctly?

later.......

 

Help? https://www.ford-trucks.com/forums/s...d.php?t=233369

 

Yes, that thread pretty much described my experiences. But I still would like to know why the rebuilt balancer had a mark in the wrong place. I did my best to locate TDC, but its no exact science, and now there is a bit of guesswork invoved when I set the advance.