Tach drive Distributor shaft seized to Cam weight base assembly

[Tom L.]

Hi all, recently I had noticed that the engine in my '72 was idling rough and when hot it didn't turn over too well as if the timing was too far advanced. Using the "90% of all carburetor problems are electrical" rule I dove into the ignition system. I quickly found that the Cam Weight Base assembly was seized to the main shaft in the fully advanced position. Kind of explains what was going on.

When disassembling the main shaft from the Cam Weight Base assembly it only took a few taps to separate them. The mating surfaces were dry. Back in 2009 I rebuilt the distributor and my guess is that I just lubed the shaft with motor oil, probably my mistake. So my question is this, what type of lube should be used and how should it be applied? Thanks!

[Duke W.]

Re: Tach drive Distributor shaft seized to Cam weight base assembly

I find it hard to understand how the cam assembly could seize to the mainshaft since those mating surfaces have little load. Carefully check the mating surfaces for galling. If evident on the mainshaft, but not too bad chucking it up in a lathe and knocking down the high spots with some medium to fine grit paper might do.

If the cam assembly has any galling a small ball hone like used on brake wheel cylinders should knock down the high spots. Mate them dry and make sure they move freely, but have essentially zero wobble.

As far as grease is concerned I still have some old GM 1960954 distributor and starter motor grease that I use for the grease well, mainshaft/cam assembly mating surfaces ,and tach drive gears, but a full synthetic like Mobil 1 is probably okay to use.

Duke

[Tom L.]

Re: Tach drive Distributor shaft seized to Cam weight base assembly

Thanks, that's what I figured. Both mating surfaces cleaned up nicely with a scotch-brite pad soaked in lacquer thinner. When I slid one over the other, without oil, everything moved freely and there was near no detectable wobble. Will re-assemble and get it back running now.