1963 distributor shields

[Richard G.]

1) Magnetic or not?
a. Of the three examples, I have, all the stainless tops are non-magnetic and the stainless sides (front and rear) are magnetic.
b. The rivets retaining the grounding clips and the mylar insulator are magnetic steel. All appear to have been chromed plated at one time.
c. All of the grounding tabs are also magnetic.

Rusty top rivet shown below;



2) Distance between the attaching slots for the side shields, where they drop down is;
a. b. Both Middle and Late examples are 15-3/8 Center to center.




3) Distributor top side thickness
a. The Early shield is .021
b. 4) Forward grounding tabs
a. Early; Tab is straight, with four puncture points at both the top and bottom.
i. No identifying letter stamping could be found on the tab.
ii. iii. No Carb and FI holes

Early


Mid


Late


b. Middle; tab straight, with four puncture points at the bottom.
i. ii. Top is smooth and may have possibly been shortened or cut off.
iii. c. i. ii. 5) Carb & FI punched holes;
a. Early; Lacks the Carb and FI holes in the back.
b. Middle; Lacks the Carb and FI holes in the back
c. Late; Has the Carb and FI holes in the back



6) Weight;
a. Early; 21.6 oz.
b. Middle; 23.2 oz
c. Late; 24.2 oz

7) Differences of the Overall width @ widest point.
a. Early; 18-1/2.
b. Middle; 18-3/8
c. Late; 18-3/4

Measured from outside to outside in this area;



8) Wrinkles at the right and left sides or the top where it has been folded down.
a. Early; wrinkled
b. Middle; smooth
c. Late; smooth.

Early wrinkled area;


Smooth




9) Spot welds
a. All have 17 to 20 spot welds on the front face. Somewhat random spacing.


10 Radius at the ends
a. The early shield drops faster at the area above where the vertical shielding attaches.

Early shield in the foreground. Also a good picture that indicates the difference in the wrinkled areas.
Little difficult to see both shields. (Shinny is difficult to photograph).


Same area traced onto cardboard to help visualize the differences.



Input and comments welcome
Rick

[Edward J.]

Re: 1963 distributor shields

Rich nice work, just another thing to add to the 63 list of changes. GM must of had a couple of suppliers ?? some of the changes were subtle.

[Chris D.]

Re: 1963 distributor shields

Rich,

Great write up.

My mid march car has a known original shield that seems to have an early ground tab on a middle design shield (.024" top, no wrinkles).

I took a peak at the AIM and only find records of the early shield and tab numbers. Later changes after August '62 are not captured in my copy.

The AIM shows the tab (clip in GM speak), rivet, and backup washer as separate part numbers in the AIM. Does this mean the clip attachment was a St. Louis operation? If so, it suggests the change between the early and middle clip configuration could be independent of the early and middle shield.

Is anyone aware of a part number change between early and middle shields? Thin gauge with wrinkles almost sounds like they went to production with prototype tools and material.

Gotta love those first year running changes.

Chris

[Jim L.]

Re: 1963 distributor shields

FWIW.... The early distributor shield on my '63 (#3493) is smooth in the area shown which has wrinkles. It does have the clip with two sets of four puncture points, tho.

[Loren L.]

Re: 1963 distributor shields

Start with a copy of Amgwert's story on C2 shielding circa 1986 or so. Continue with a measurement of the grounding clip rivits - 3/8" diameter are real - .030/.032 are repro.

[Frank D.]

Re: 1963 distributor shields

Interesting stuff, my May 63 car came to me without shielding and I am running the LICS repro stuff; which, by the info here, is for a late car - I don't recall that they offered any other repro options (e.g. early car, etc)...

[Richard G.]

Re: 1963 distributor shields

Early;
The head of the grounding clip and the Mylar retaining rivets (on the early shield) were the same @ .236 (nominal)

Mid
The head of the grounding clip and the mylar retaining rivets (on the mid shield) were 236 to .245 (nominal)
I believe these both started as the same rivets. Under magnification the heads of the grounding clip appear to have been struck harder and have some flattening to them. Kind of splitting hair here.

Late;
The head of the Mylar and the grounding clip retaining rivets were .245-.248 (nominal)

For all intents and purposes the rivets, on the shields I own, could be considered the same rivets. Easy to see why manufactures would offer the late shield as a reproduction. It could be stamped using the same late mold, as later C2's, and just drilled for three Mylar rivets instead of two.
Rick

[Loren L.]

Re: 1963 distributor shields

The shield I received with #10706 when I bought it in 1972 has 1/4" diameter metal headed rivets in the top shield and 3/8 diameter rivets in the grounding clip - the top is Stainless Steel, as is the grounding clip. The rivets in the top shield and the mounting clip are magnetic, as are the front and back sides of the shield. The clip is the one with the four projections facing the air cleaner at the top and bottom.
I personally have never seen a clip with the top four projections missing - I would wonder if it would even make contact with the air cleaner/plenum.

[Richard G.]

Re: 1963 distributor shields

Loren;
The shield I called middle;
I suspect the top of the grounding clip has indeed been lobed off. If it has, they did a super clean job. It is significantly shorter than the others.
It also has the "D" sideways between the rivets. I have never had it on my car, you may be correct (cut off) and will not even touch the air cleaner. You got me thinking on this issue. LIC sells replacement tabs for $10 and they include the rivets.

All three grounding clips are Magnetic. The early shield grounding tab appears to have some rust on it. Cheap stainless will rust. Right now I am not sure if it is chromed or cheap stainless.

One rivet is missing on the top of the early shield, the hole is .160 (nominal in size). I suspect GM used a 1/8 or 5/32 rivet. I plan on making replacements on the lathe out of 303 stainless. If you look close I can see where they seem to have been hit with a different punch than the top rivets. I am only guessing the diameter of the rivet head will vary by how hard it is hit. Possibly different operators preferred different settings? Or they used different head sizes. I just don't know.

[Edward J.]

Re: 1963 distributor shields

I wonder if changes were done to grounding clips around the time FM radios were available. my mid March car has the one 4hole clip on bottom with a slightly rounded of top with a D.

[Richard G.]

Re: 1963 distributor shields

Yes, I believe that is the general consensus.

You mean like this one? It also has the sideways "D".



Rick

[Edward J.]

Re: 1963 distributor shields

Rich, yes your picture is what my car has for a top shield. sorry my explanation was not very good.

[Richard G.]

Re: 1963 distributor shields

Ed;
Frankly, I was under the impression that the tab may have been modified because I have never seen another like it. Although the cut would have been nicer than anything I could have come up with. Good to know there is another and what general timeline it fits. Our knowledge has changed considerably from "Its a 63 if it has three rivets on top". Now I know that statement isn't even completely true.

In general it appears they widened the attachment screws for the vertical drops and raised the sides for more room for the wires to bend.

One has to view the 63 Corvette like modern software. It's coming out on this date no mater what, and we will fix the faux pas
later.

I wanted to add to the thread what the interior of the rivets look like between the early shield and all the others.
Notice, the lack of the washer. The later rivets are also bored on one end. I have read where they are sometimes identified as tubular style rivets.
Note; My early shield obviously had water setting inside it at one time.

Early;


Late and Mid shields;



I wanted to thank everyone for their input. Much appreciated.
Rick