C1 Dual Point Distributor Rebuild

[Donald H.]

I would like to restore/rebuild my distributor which is a 1110891 dual point. I have searched this forum, looked in the ST-12 and other documentation that I can find and am unable to find much info specific to this type distribution. The ST-12 has good exploded view of the tach drive FI version, and I found a rebuild article for rebuilding a single point tach drive, but I have not found much for this 891 as far as rebuild, exploded view, etc.

My questions are:

Does anyone have any good instructions for rebuilding this distributor?

Are the small parts that I see listed for the regular vendors mostly generic and would fit this distributor? e.g., shims, seals, felt washers, etc.

Is there any harm in replacing the ID tag as far as judging? I have attached a photo and the original is sort of beat up. Is it better to keep the original or replace it with a new one that is easier to read and looks new?

Thanks,

Don

[Bob B.]

Re: C1 Dual Point Distributor Rebuild

Don,

It's easy to drill out the rivets for the tag. Unless your tag has the wrong date, that's also easy to restore. Take 0000 steel wool and buff the entire surface of the tag. You don't need to remove all the remaining paint. Then spray paint the whole surface black, let dry and buff with 0000 again but only the raised areas and the lettering. Your tag will look nearly new.

If your distributor has a lot of play, you'll need to remove the rivet at the bottom and put in a shim. Then use a replacement rivet or make one out of a correctly sized nail. Just be sure to secure it - you don't want it coming out when the engine is running!

Take the oil tube off and there is a wick inside. Pull that out. Clean the wick in solvent and let dry. Soak the whole distributor in carb cleaner for a day and get all the goo out.

Polish the oil tube and all the clip and screw hardware off the distributor. The clips are black spring steel and probably will turn out great. Paint the distributor black as it was. When you reassemble, soak the wick in oil first and you'll need a piece of dental floss to pull it back through.

While you're at it, get one of the single-wire Ignitor electronic ignitions and you won't have to worry about points. If you don't have an original cap, the AC Delco one is the next best.

You'll have a distributor that looks new and you'll have your original tag. The replacement rivets are available at any Corvette parts house. Here's a pic with one distributor I restored next to one that looks like the before of the first one.

Good luck!

Bob

[Tom P.]

Re: C1 Dual Point Distributor Rebuild

THERE IS NO NEED TO DRILL OUT THE RIVETS! They can be punched out from inside!
I made a special punch just for this purpose years ago. I made it from a length of 1/8in steel rod. I reduced the diameter on one end of the rod to fit into the rivet holes by grinding down on a fine wheel. Then I bent the small end just enough to reach the rivets holes from inside the dist bowl. One or two firm taps on the home made angled punch and the rivets come right out and can be saved if desired.
I'll try to remember to post a picture of my home made punch tonight.

[Donald H.]

Re: C1 Dual Point Distributor Rebuild

OK. I measure the end play and it was .018 and the ST-12 says it should be .002 to .007 so I punched out the lower gear pin. I will order a set of shims tonight.

I also found a small felt button that was in the very tip end of the upper distributor shaft (see picture) under the rotor. Anyone know the purpose of this?

Can I just clean this with brake cleaner and reuse? Does it need to be oiled.

Can I reused the gear pin or should I replace?

[Donald H.]

Re: C1 Dual Point Distributor Rebuild

THERE IS NO NEED TO DRILL OUT THE RIVETS! They can be punched out from inside!
I made a special punch just for this purpose years ago. I made it from a length of 1/8in steel rod. I reduced the diameter on one end of the rod to fit into the rivet holes by grinding down on a fine wheel. Then I bent the small end just enough to reach the rivets holes from inside the dist bowl. One or two firm taps on the home made angled punch and the rivets come right out and can be saved if desired.
I'll try to remember to post a picture of my home made punch tonight.

Heh Tom,

I couldn't see that the rivet holes when all the way through they are so small. But once I took the shaft out and with you note, I found the holes and used a very small allen wrench and small hammer to punch the rivet out. As you say to easy

I also posted a photo that shows the felt pad that was under the rotor. And with the shaft apart, I found a shim/washer on the shaft under the cam assembly. Is this all there is to this distributor? This shim/washer and then the shims at the gear end?

Thanks,

[Tom P.]

Re: C1 Dual Point Distributor Rebuild

I think you've got it all.
Now the critical thing is side-to-side movement of the shaft in the bushings. If it is negligible, I'd leave it alone.
I personally like to shim all my distributor gears .005-.007, preferably close as possible to .005.
I believe the felt pad is an oil wick. just wet it with motor oil.

[Donald H.]

Re: C1 Dual Point Distributor Rebuild

What points and condenser should I use?

I've read a thread about NAPA parts by Duke Williams, so I think the correct parts for my dual point distributor would be Echlin points CS7860 or CS786, and condenser Echlin RR174.

Or I see an NOS tune up kit on ebay for my distribution with Delco parts, points D103P and condenser D203

Thanks,

[Christopher R.]

Re: C1 Dual Point Distributor Rebuild

The lower gear goes back on the shaft only one way. There is a dimple on the gear. The dimple needs to point the same way as the rotor.

Here's a good article on distributor rebuilding.

http://www.tispecialty.com/articles/article6.htm

[Donald H.]

Re: C1 Dual Point Distributor Rebuild

The lower gear goes back on the shaft only one way. There is a dimple on the gear. The dimple needs to point the same way as the rotor.

Here's a good article on distributor rebuilding.

http://www.tispecialty.com/articles/article6.htm

I had found the article. I did read and will use some of it, but it is specific to later distributors. After closer look, I do see a very small dimple on my bottom gear.

[Rod K.]

Re: C1 Dual Point Distributor Rebuild

I think you've got it all.
Now the critical thing is side-to-side movement of the shaft in the bushings. If it is negligible, I'd leave it alone.
I personally like to shim all my distributor gears .005-.007, preferably close as possible to .005.
I believe the felt pad is an oil wick. just wet it with motor oil.

Tom,

What would max side to side clearance be and where would one find bushings for these distributors if they're needed? Are they possibly the same as later style?

[Tom P.]

Re: C1 Dual Point Distributor Rebuild

Rod,
I have ZERO specs for side-to-side movement of a shaft. But, when a dist is disassembled, and the shaft is inspected in the area where it turns in the bushings, you can get a very good idea real quick about how much, if any, wear there is between the shaft/bushings. If the shaft is nice and smooth, or at least doesn't have really noticeable grooves, then it is probably OK for re-assembly as is. For me, the side-to-side movement has become a "feel" thing as a result of comparing a dist that is known to have almost zero wear and go from there. I have no source for bushings, but there are a few replacement shafts out there. For a seriously worn dist that needs professional rebuilding, I use the same person that John DeGregory uses which is Don Baker. He's the best source I know for a rebuild. No email address is available for him, his phone is 815-498-9522.
Unless there is a major problem with a dist, I do all of my own rebuilding/refinishing.

By the way, the distributors that I have found to have the worst wear are tach drive (NON-FI) versions. It appears they have the worst wear at the lower shaft/bushing interface as a result of the tach gears becoming worn/damaged/broken and the metal particles dropping down between the shaft/housing and working in between the shaft and lower bushing. I've seen some pretty badly worn shafts out of these tach drive distributors. Since the FI distributors have their own direct oil line feeding them, it is rare to seen worn or damaged gears in an FI dist.

[Edward M.]

Re: C1 Dual Point Distributor Rebuild

What points and condenser should I use?

I've read a thread about NAPA parts by Duke Williams, so I think the correct parts for my dual point distributor would be Echlin points CS7860 or CS786, and condenser Echlin RR174.

Or I see an NOS tune up kit on ebay for my distribution with Delco parts, points D103P and condenser D203

Thanks,

I am doing a functional rebuild (no cosmetic changes) on a 56 dual point for a friend.

Don't mess with the D103P points unless you can find a set that were actually manufactured in that time frame. Double check the actual part number and make sure it matches.

The later replacement points (also D103P) are junk. My friend sent me a set of these to use, and they really are flimsy. I aksed him to locate a set with the correct part number as specified in 1956, or get the NAPA points. He found a set of Delco points with the correct part number. They will work out just fine.

These distributors are easy to rebuild, just check the clearances as others have indicated. Good luck on it, and let us know how it works out.

[Stuart F.]

Re: C1 Dual Point Distributor Rebuild

The pin holding the gear on the shaft: Is it a "roll pin"? If so, it can be reused. If it is a solid tappered pin, it can be reused if you are careful when you remove it so that you have enough material to "peen" it over again. Even then, I prefer replacing solid pins with roll pins as they can be used over and over as long as they fit tight. They also make for a neater installation.

I have not done one of these for a long time, but I recall that back in the day, it was hard to find anything better than a dual point for performance. I'd tried Mallory's, and W & H Dual Coils, etc., but nothing was as simple and consistent performer than the old dual point with a good coil.

Stu Fox

[Donald H.]

Re: C1 Dual Point Distributor Rebuild

The pin holding the gear on the shaft: Is it a "roll pin"? If so, it can be reused. If it is a solid tappered pin, it can be reused if you are careful when you remove it so that you have enough material to "peen" it over again. Even then, I prefer replacing solid pins with roll pins as they can be used over and over as long as they fit tight. They also make for a neater installation.

I have not done one of these for a long time, but I recall that back in the day, it was hard to find anything better than a dual point for performance. I'd tried Mallory's, and W & H Dual Coils, etc., but nothing was as simple and consistent performer than the old dual point with a good coil.

Stu Fox

It is a solid pin. I have ordered parts and did order a rolled pin to replace.

Thanks,