Distributor question

[Mike E.]

Trying to get a 67 roadster running for the first time since 1979. (It's a very rare one--it's a small block, and not 435 hp). (Original HH motor--California smog, 300 hp). In dropping the distributor in, I had a bit of an issue with aligning the rotor--the whole of of the distributor turned, even when it wasn't supposed to. (The football-shaped piece at the top of the shaft is loose on the shaft--and even I know that it's not supposed to be.)
As I think about brazing that back to the top of the shaft, I'm assuming that it's position on the shaft is critical to the timing. It's almost impossible to tell how it was related to the shaft from looking at it--any suggestions?
Thanks!

[Joe L.]

Re: Distributor question

Trying to get a 67 roadster running for the first time since 1979. (It's a very rare one--it's a small block, and not 435 hp). (Original HH motor--California smog, 300 hp). In dropping the distributor in, I had a bit of an issue with aligning the rotor--the whole of of the distributor turned, even when it wasn't supposed to. (The football-shaped piece at the top of the shaft is loose on the shaft--and even I know that it's not supposed to be.)
As I think about brazing that back to the top of the shaft, I'm assuming that it's position on the shaft is critical to the timing. It's almost impossible to tell how it was related to the shaft from looking at it--any suggestions?
Thanks!

Mike------


Yes, the auto cam is not supposed to be loose on the mainshaft. However, I don't think it really matters how it's oriented to the mainshaft. The only POSSIBLE "indexing" features of the mainshaft are the hole for the drive pin which secures the distributor gear and the "blade" for the oil pump drive. I don't think that either of these are related in any way to the orientation of the auto cam. So, I think you can braze it on at any position.

[William C.]

Re: Distributor question

To amplify on Joe's comment, the autocam on the top does have a relationship to the distributor drive gear to provide the proper positioning of the vacuum advance can, but it's not that big of a deal, if the vac can interfeers with the proper timing adjustment, (usually by hitting the intake manifold before proper base timing can be reached) just pull the distributor, pull the pin out of the bottom gear, rotate 180 degrees, reinstall the distributor and you will be "good to go"

[Joe C.]

Re: Distributor question

To amplify on Bill's comment. The distributor shaft, of which the autocam is a part, is indexed in a precise and specific manner, when the autocam is brazed onto the shaft. The orientation determines proper alignment of the rotor electrode relative to the dimple in the dist drive gear. At this point, there is one and only one way to determine correct alignment when brazing the autocam back onto the shaft..........................the rotor electrode must be clocked EXACTLY in the same position as the dimple in the drive gear. THIS WILL ONLY APPLY IF YOU KNOW , FOR CERTAIN, THAT THE DRIVE GEAR WAS INSTALLED PROPERLY BEFORE THE AUTOCAM SEPARATED FROM THE SHAFT. The gear must be installed in the proper orientation on the shaft, but that is only determined by the orientation of the rotor from a correctly oriented shaft/autocam assembly.

If all of that sounds confusing to you, then it is probably safe to assume that your distributor drive gear was oriented properly BEFORE the autocam separated from the shaft. If that is valid, then install the rotor, align it's electrode exactly with the dimple on the drive gear, mark the orientation of the autocam, and braze it in that position. The most that can happen if the autocam is installed in a random fashion, is that the distributor orientation can be off by up to [360/13]/2 = 13.85 distributor degrees (27.7 crankshaft degrees)