C2 Dist Restoration - Is button Redundant?

[Glenn B.]

Just in the process of restoring my 67 distributor. The tach drive gear housing is worn quite deep in the typical fasion (see photo). I purchased a nylon button to compensate. I was getting ready to drill the housing, but on closer inspection of the new drive gear - I am questioning the wisdom of this.

The old drive gear had a hollow center - you can see the "pin" remaining in my housing corresponding to the hollow region in the gear. The NEW drive gear has a bronze cap on the end - not hollow. So I am wondering if I am better to have the new gear ride on the "pin" that remains (and maybe fill the well with JB weld) - Verses drilling the housing and having it ride on the nylon button?

Anyone have any thoughts on this?

http://i157.photobucket.com/albums/t69/gbindley/Distributor/SNV30977.jpg

http://i157.photobucket.com/albums/t69/gbindley/Distributor/SNV30980.jpg

http://i157.photobucket.com/albums/t69/gbindley/Distributor/SNV30981.jpg

[Joe L.]

Re: C2 Dist Restoration - Is button Redundant?

[quote=Glenn Bindley (43555);352904]Just in the process of restoring my 67 distributor. The tach drive gear housing is worn quite deep in the typical fasion (see photo). I purchased a nylon button to compensate. I was getting ready to drill the housing, but on closer inspection of the new drive gear - I am questioning the wisdom of this.

The old drive gear had a hollow center - you can see the "pin" remaining in my housing corresponding to the hollow region in the gear. The NEW drive gear has a bronze cap on the end - not hollow. So I am wondering if I am better to have the new gear ride on the "pin" that remains (and maybe fill the well with JB weld) - Verses drilling the housing and having it ride on the nylon button?

Anyone have any thoughts on this?

http://i157.photobucket.com/albums/t69/gbindley/Distributor/SNV30977.jpg

http://i157.photobucket.com/albums/t69/gbindley/Distributor/SNV30980.jpg

http://i157.photobucket.com/albums/t...r/SNV30981.jpg[/

quote]

Glenn----

You really don't need the nylon button with the type of replacement cross gear you're using. I would remove the "pin" that has formed due to the wearing effect of the original cross gear, though. That "pin" is going to do you no good, at all, and may very well do harm. So, I'd remove it by grinding it down to the level of the surrounding worn area. Then, install the new cross gear as-is.

Actually, this type of replacement cross gear is designed to be used with a set screw that's installed by drilling and tapping the housing (and centered on exactly where your "pin" is now). Then, the set screw is adjusted after installation of the cross gear to take up any end play. However, I think you can use it without the set screw and it will work fine.

[Glenn B.]

Re: C2 Dist Restoration - Is button Redundant?

Thanks Joe, that explains the diff between the gears.

Given that both gears are the same length , I presume I just shim it on the far end with additional washers? Is there no concern that the gear will now sit deeper in the housing?

I definitely prefer to avoid drilling through the housing if I can.

[Timothy B.]

Re: C2 Dist Restoration - Is button Redundant?

Glenn,
The thrust on the small driven gear is inward. If this gear sits to far in the housing the same thing as before will happen and you will be replacing parts again. If you are carefull, install the brass bushing and get a drill bit the same size as the ID of the bushing and drill (using the bushing as a guide) to remove the pin that's formed. This will also give you a center start to drill through the housing for the brass button which is what you need to install. It's very important to drill through the housing straight.

I think (double check) the drill size is 3/16" to go through the housing for the brass button and if you install it you will find it's necessary to remove the washer that goes on the driven gear. If you want to drill for the hole, then mill the housing so the button sits flat then you can use the washer behind the gear.

[Joe L.]

Re: C2 Dist Restoration - Is button Redundant?

Thanks Joe, that explains the diff between the gears.

Given that both gears are the same length , I presume I just shim it on the far end with additional washers? Is there no concern that the gear will now sit deeper in the housing?

I definitely prefer to avoid drilling through the housing if I can.

Glenn-----


I think that you will find that the thickness of the brass button on the end of the new gear exceeds the thickness of the integral steel button on the old gear. If so, I think the additional thickness will make up for at least some of the wear in the housing.

My previous advice was based on the fact that I thought you wanted to avoid the need to drill the housing and you've confirmed that. There are still several ways you can go:

1) drill and tap the housing for the set screw I described earlier. After the set screw is adjusted to take up the end play, fill the outermost portion of the hole with JB Weld. You may need to grind some off the head of the set screw to get sufficient clear depth in the hole. Then, sand off the excess JG Weld, paint the housing, and no one will ever know the difference. You can use a tool available from Paragon to ensure a properly centered hole. The tool is very moderate in cost;

2) Using the Paragon tool, drill a hole in the rear of the housing but do not drill all the way through. Drill just deep enough to accommodate the length of the pin on the rear of the aftermarket brass bushing.You may even have to shorten the bushing's pin, but this will cause no problem. Install the bushing. You may have to remove the washer from the gear shaft;

3) Do as the above but drill all the way through. Fill the outer portion of the hole with JB Weld. Sand and paint;

[Gerard F.]

Re: C2 Dist Restoration - Is button Redundant?

Glenn,

Take a look at this post post from the archives:

https://www.forums.ncrs.org/showthre...+gear&uid=5608

Exact same situation with my 67 distributor a few years ago. What I wound up doing was cutting off the little mounting ears of the nylon button (not all the way) and found that it fit perfectly in the worn depression in the housing. I put it in by putting a gob of grease on the end of tach drive gear. Worked great for about 2 years and 5000 miles, twice judged.

Recently my tach cable broke, and I changed the cable and housing.
When I took the tach gear and housing out, I could not find the nylon button. Either it came out when I removed the gear, or it disintergrated.

So I used one of those tach gears with the thicker bearing surface, greased it up well with Sly-Glyde. Found that it works just as good without the button. Just don't tighten down on the gear housing, leave it a little looose.

I have another nylon button now. If I have any trouble with the tach drive, I'll put it in like I did two years ago. However as long as the tach needle stays nice and smooth, I think I'll leave it as is.

[Gerard F.]

On second thought

Glenn,

If you have the distributor off the car, try cutting the ears off the nylon button and grinding down the point in the housing a bit. Then test fit the nylon button to the housing. If it fits nice and tight to the housing, then epoxy it to the housing.

This will keep it from moving everytime you want to throw a little grease to it.

Otherwise try it without the nylon button, I think the head of the new gear is larger in diameter then the worn depression in the housing.

[Joe L.]

Re: C2 Dist Restoration - Is button Redundant?

Glenn,

Take a look at this post post from the archives:

https://www.forums.ncrs.org/showthre...+gear&uid=5608

Exact same situation with my 67 distributor a few years ago. What I wound up doing was cutting off the little mounting ears of the nylon button (not all the way) and found that it fit perfectly in the worn depression in the housing. I put it in by putting a gob of grease on the end of tach drive gear. Worked great for about 2 years and 5000 miles, twice judged.

Recently my tach cable broke, and I changed the cable and housing.
When I took the tach gear and housing out, I could not find the nylon button. Either it came out when I removed the gear, or it disintergrated.

So I used one of those tach gears with the thicker bearing surface, greased it up well with Sly-Glyde. Found that it works just as good without the button. Just don't tighten down on the gear housing, leave it a little looose.

I have another nylon button now. If I have any trouble with the tach drive, I'll put it in like I did two years ago. However as long as the tach needle stays nice and smooth, I think I'll leave it as is.

Jerry-----


Now, this presents another possibility. I was not aware that the nylon button was the same OD as the typical worn area in the housing. Inasmuch as you have found that it is, it might be possible to remove the retaining stem from the button and, then, "impale" the button on the wear-formed "spike" in the center. The "spike" would then serve to retain the button from any sort of lateral movement. The thickness of the button would then more-or-less "restore" the worn area in the rear of the cross gear bore.

[Gerard F.]

Tach Gear Study

Here's a picture of 3 tach drive gears:



The one at the top is my original, bunged up along with the distributor shaft.

The middle one is an older replacement which I installed two years ago with the modified nylon button and a new shaft. The brass button is shown to the left, I never used it since you need to drill a hole (and I think pull the shaft to install it).

The lower one is a current new replacement like the one I have in now without any button. Note the difference in the thickness of the bearing surfaces as well as the thickness of the nylon button next to the original.

Here's the three again with a head on of the original and the nylon button:



The diameter of the nylon button is slightly larger than the wear hole. However, the retaining ears on the button fit within the wear hole and around the little point at the center of the wear hole. If you trim back the retaining ears, it fits nicely in the hole. Only problem is holding it in place, when you remove the gear to lub.

My conclusion:

If you have one of the new replacement gears with the thicker bearing surface, you may not need the nylon button. Mine works fine leaving it a little loose, but I only have 400 miles on it.

If you have an older gear with a thinner bearing surface, use the modified nylon button, but glue it in.

What do you think?

[Glenn B.]

Re: C2 Dist Restoration - Is button Redundant?

Jerry, I never realized there were some many variants of the replacement parts.

My eaten drive gear is same as your original, my repalcement gear is same as your second photo - with brass end, but exact same length as original.

My nylon button is black, with a much longer tail than yours.

I ended up doing the following....

1) Drilled off the "tit" using a 3/8 bit - which fits snugly in the cable coupling - which I used as a guide.
2) the 3/8 bit removed the tit and nicely locates the centre, then carefully drilled a small pilot hole (1/8) straight through
3) The button is at least 1/8 larger diameter than my wear hole. I found that one of my dremel "grinder" bits was almost the identical diameter to the nylon button. I pushed the shaft of this bit through the pilot hole and attached my dremel tool from underneath. The pilot hole just fit the bit shaft, and holds the bit in X-Y position. I then ground the housing down to appx thickness of the button.
4) Needed to shave the diameter of the button with a file, and cut back the shaft of the button, and finally drill the hole out to the shaft size of the button.
5) pressed the button in - with some JB weld in the hole. It sits just a little proud - maybe 1/32 - may not need the washer between the gear and the coupler.

Here's a couple of pics.

http://i157.photobucket.com/albums/t69/gbindley/Distributor/SNV30988.jpg

http://i157.photobucket.com/albums/t69/gbindley/Distributor/SNV30991.jpg

Hope to finish the project next weekend....