65 Distributor Rebuild-Brass Button?

[Sheldon S.]

I previously rebuilt the distributor for my L79 and did not install a brass button for the cross shaft as there was no hole to put the button in. After starting the engine the tach never did work. I just pulled the dist. out and found that the cross gear teeth were no longer there nor the matching ones on the dist. mainshaft. On the newer dist.'s there is the releif hole for the brass button, should this be drilled out and a button installed or did I just install the cross gear incorrectly. I have also purchased one of the new style cross gear with the bearings to install but want to make sure I do it correctly this time. Any help greatly appreciated.
Thanks Sheldon

[Terry M.]

Re: 65 Distributor Rebuild-Brass Button?

The "newer distributors" you refer to used a plastic or nylon button originally. I am not aware of a brass button for these units, but someone may be making one.

I have found to reduce the consumption of these gears that it is helpful to reduce the end play of the distributor main shaft to about .005. Shims are available from aftermarket suppliers to accomplish this, but some measuring tools are also needed.

[Jack W.]

Re: 65 Distributor Rebuild-Brass Button?

the button you refer to (be it nylon or brass) was not present nor was a receiving hole pre-drilled in Distributors that were supplied with C2s. Both Brass and Nylon buttons for this purpose are available from a few of the usual sources, including LICS. As I understand it, rebuilding a distributor with noticeable slop in the cross-gear due to wear in the area of the distrib housing will soon result in what you encountered. While I myself did not install a button when I rebuilt my (65) distrib, many have done so by drilling a [centered] hole in the back side of the distrib housing to receive the button "lug", if there is a worn area that will serve as a guide. Some are careful not to drill all the way through, others simply do so and touch it up with some JB Weld and then repaint. I have also heard of real show-offs installing a screw from the outside in that permits adjustment of the gap / tolerence.

here's a picture I swiped from a friend's web-site showing his brass button installation:

[William C.]

Re: 65 Distributor Rebuild-Brass Button?

With care, it is not necessary to drill all the way through the housing to install the brass button, so the installation can be undectable on a C-2 when it is on the engine.

[Jim T.]

Re: 65 Distributor Rebuild-Brass Button?

Sheldon I have a 68 L79 that needs the dist shaft and tack gear drive replaced as well. Have had the parts for many years including a brass button to repair it. I have not done anything because I want to have the top piece of the distributor shaft removed from my original one and installed on the replacement shaft to keep the centrifical advance curve the same as the original. This piece has to be installed correctly on the shaft. I had an idea to clean the surface where the brass button would mate against the distributor housing and use J-B Weld to secure the brass button. One thing for sure, I will do periodic maint on the tach drive after it is back in service.

[John G.]

Re: 65 Distributor Rebuild-Brass Button?

As a point of information:
After drilling out the hole in a C2 distributor to accept the nylon button - will the thickness of the button be an issue so as not to 'over center' the driven gear with the mainshaft gear by moving it too far back? ... Along with the drilled hole does a 'well' need to be created to allow for the depth of the nylon button? . .