Distributor Housing Casting Numbers

[Michael B.]

I've compared a 1966 (1111153) distributor against a 1971 (1112050) and the housings appear to be identical with the exception that the 66 has no external markings, and the 71 has the number 641 cast into the housing. Does anyone know what that number means.The reason I ask is that I currently have an incorrect distributor installed in my car and I was told I could have mine rebuilt using the correct weights, springs, and vacuum; then order a new ID tag. If I proceed with that I want to ensure that the housing is the correct one for my application. Are most housings generic, or do they have meaningful external numbers cast into them?

[Richard M.]

Re: Distributor Housing Casting Numbers

I don't have the answer but I'd like to know also. They may be mold numbers and there may be a timeframe associated with their usage.....just speculation. Maybe Joe and the other distributor knowledgeable people have the answer.

Here's a document below that may help your research.....Note it was formerly a Corvette Magazine (.com) article but CM.com disappeared a few years ago but I had the article saved. Fellow member Dave Zuberer converted the html I stashed away into a pdf.

Rich

edit.....a quick glance states some of the assembled differences, in particular the 2050 was supplied with the Uniset point set(EMC) whereas the 1153 had separate points & condenser.

1066 Corvette 1111153 327/300HP W/O A.I.R. CE S TD/10/V

1971 Corvette 1112050 350/270HP All CE S/EMC TD/10/V

[David L.]

Re: Distributor Housing Casting Numbers

Michael,

I have a 1111153 distributor dated "6 A 10" (Jan. 10, 1966) with the casting number "111" on the shaft of the cast iron housing. The "111" casting in about 3" from the bottom of the cast iron housing. I can post a photo, if necessary.

Back in the 1980's I bought a 1111024 distributor dated "2 J 20" (Sept. 20, 1962) at a swap meet in NJ for my early 63 SWC (Vin # 1450). The casting number near the top of the cast iron housing was the number "41" but it was upside down. In my travels I have also seen the number "31" cast on a 1111024 distributor dated "3 K 23" (Oct. 23, 1962).

Dave

[Joe L.]

Re: Distributor Housing Casting Numbers

I've compared a 1966 (1111153) distributor against a 1971 (1112050) and the housings appear to be identical with the exception that the 66 has no external markings, and the 71 has the number 641 cast into the housing. Does anyone know what that number means.The reason I ask is that I currently have an incorrect distributor installed in my car and I was told I could have mine rebuilt using the correct weights, springs, and vacuum; then order a new ID tag. If I proceed with that I want to ensure that the housing is the correct one for my application. Are most housings generic, or do they have meaningful external numbers cast into them?

Michael------


I believe these cast numbers on distributor housings were PATTERN numbers (PATTERNS are what is used to create the sand mold for sand castings). I have always found these numbers to be quite random and I do not think they are a number which identifies a particular casting.

For an original 1966 distributor, the tach cross gear housing would not have had a hole in the end. Later distributors and SERVICE distributors for 66 applications manufactured after the early 70's do have the hole. The hole was for the mounting pin of the nylon button installed inside the housing. While not correct or original for 1966, the nylon button was a MAJOR improvement relative to distributor tach gear longevity.

[Michael B.]

Re: Distributor Housing Casting Numbers

Thanks for all the good information.

I spoke with Dave Fiedler of T.I. Specialty today about those numbers. He said he could never make any sense from them and they had no apparent consistency. With that, I'll bet Joe is right about those being pattern numbers. Incidentally, Dave told me that to build a correct 1112101 it's more than just the weights, springs, and vacuum. There is also a heavy duty main shaft. As Joe stated, Dave also told me there is a hole in the back of the tach gear housing on all housings beginning in 1971.

Richard, thank you for the link.

Mike

[Joe L.]

Re: Distributor Housing Casting Numbers

Thanks for all the good information.

I spoke with Dave Fiedler of T.I. Specialty today about those numbers. He said he could never make any sense from them and they had no apparent consistency. With that, I'll bet Joe is right about those being pattern numbers. Incidentally, Dave told me that to build a correct 1112101 it's more than just the weights, springs, and vacuum. There is also a heavy duty main shaft. As Joe stated, Dave also told me there is a hole in the back of the tach gear housing on all housings beginning in 1971.

Richard, thank you for the link.

Mike

Mike-------


I don't understand why the 1112101 distributor would have used a heavy duty mainshaft but I defer to Dave's knowledge and experience.

The GM #1112101 distributor used mainshaft GM #1852764. This mainshaft was also used for 1966-69 L-36 and L-68. Once-upon-a-time this mainshaft was among the least expensive of all of the Corvette mainshafts, some of which sold for twice as much. So, the 1852764 was sold as kind of a "generic" mainshaft by many Corvette suppliers. This was before folks discovered just how important having the right auto-cam was for a distributor. In fact, I have 3 NOS examples [none for sale]. I could photograph one but I really don't think you'd see any difference between them and any other Corvette mainshaft (except, of course, for the autocam).

[Michael B.]

Re: Distributor Housing Casting Numbers

Joe,

You are correct about the main shaft. That's the same number shaft that Dave mentioned and I thought he said it was "heavy duty". Perhaps he just said it was put in the "heavy duty" engines and I misunderstood him. I would love to see a picture of that shaft and any identifying numbers or markings.

I'm so ignorant about these cars I'm embarrassed sometimes, but I'm trying to learn as much as I can. With that being said, I'll risk humiliating myself by asking you to explain what an autocam is, what it looks like, and how it works.

Also, do you have a book or some other reference guide that lists what components go into different distributors? If I'm unable to locate an original 1112101 I'd like to build one but I'm not sure what weights, springs, and vacuum to use or where to purchase them. I'd also like to have a book like that on hand for future reference.

Thanks,

Mike

[Duke W.]

Re: Distributor Housing Casting Numbers

I was told I could have mine rebuilt using the correct weights, springs, and vacuum; then order a new ID tag. If I proceed with that I want to ensure that the housing is the correct one for my application. Are most housings generic, or do they have meaningful external numbers cast into them?

Most OE spark advance maps are less than optimized, so it you state what engine/transmission you have, I can give you some guidance.

Overhauling a distributor is a fairly simple process as long as the shaft bushings don't need to be replaced. The procedure is in the '63 Corvette Shop Manual and later COMs. You can save a lot of money by doing it yourself.

It sounds like the application is a '66 327/300, but is it modified? The OE 30 degree centrifugal is okay, but is lazy. If whatever you put together offers less than 30 centrifugal, that's okay. Just use more initial timing.

The OE 12" VAC is okay for Powerglide, but is a bit aggressive for manuals, so I recommend a 15" B22 for 300 HP manuals.

Duke

[David L.]

Re: Distributor Housing Casting Numbers

Mike,
Somewhere I have a Delco Remy Service Parts Catalog dated about 1971 or 1972 but I can not seem to find it right now but I did find some research in one of my notebooks that I did years ago. This may or may not help you. The cam, GM # 1966994, on a 1112021 distributor is stamped "530". At Fall Carlisle 1988 I bought a 1112021 distributor dated "0 E 7" (May 7, 1970) for $30 but no longer have it. I have (or had) the Chevrolet distributors checked in red.

Dave

[Michael B.]

Re: Distributor Housing Casting Numbers

Thanks for all the reply's.

In the past hour or so I've been messing around with the 1112050 distributor out of my 71 parts car and I've figured out what the autocam is. Prior to this I did not know that the autocam was a separate piece from the shaft itself.

Like I said, I'm embarrassingly ignorant about so many things concerning these cars.

So to properly construct a 1112101 for a 1972 LT-1, I know I need a 1852764 shaft, and a 1973437 vacuum unit. But, what number autocam, springs, and weights are used in that distributor?

Also, when trying to completely disassemble the 71 distributor, the autocam does not want to slide onto the portion of the shaft below the tach gear. Is there something I'm missing or does it takes gentle persuasion?

Thanks

[Duke W.]

Re: Distributor Housing Casting Numbers

Thanks for all the reply's.


So to properly construct a 1112101 for a 1972 LT-1, I know I need a 1852764 shaft, and a 1973437 vacuum unit. But, what number autocam, springs, and weights are used in that distributor?

Why would you want to do that? The spark advance map is set up for emission control, not performance or fuel economy. It's a joke. The maximum centrifugal is 22 and the initial is 4 according to the AMA specs. No wonder the '72 LT-1s are slugs and guzzle fuel.

The best distributor for a LT-1 is an unmolested an 1111069 from a 327/365, but you can probably get close to that with what you've got plus a ten dollar spring kit, a ten dollar B28 VAC, and a whole lot more intial advance (no charge).

Duke

[Michael B.]

Re: Distributor Housing Casting Numbers

Duke,

The more I'm learning, the more I'm questioning going the "original" route on the distributer. I just purchased this car and it's got a lot of stuff missing and/or incorrect, i.e. fuel pump, water pump, master cylinder, missing A.I.R. system, TCS system removed, etc.. Since it's an LT-1 with a/c, I would like to get back as close to "original condition" as possible; at least appearance wise.

I'd like the car to run as well as possible, but I'm not really concerned with maximum performance these days. However, if I can improve performance with different weights, springs, and vacuum unit, etc., while keeping the original appearance; then that's probably the route I'll go.

If I were to build a distributor to the 1111069 curve using my 71 housing, what components would you suggest other than the B28 vacuum? And where would I order them?

Also, the main shaft and lower bushing in the 71 distributor were both badly scored. To use that housing it's clear the bushings would need to be replaced. Is that something done by a specialty shop/machine shop or can I DIY it myself with the proper tools?

Thank you for your input.

[Duke W.]

Re: Distributor Housing Casting Numbers

Bushing replacement, if required, should be done by a competent machine shop since they need to be align bored to about .001" clearance after installation.

You can build your distributor with just about any cast iron tach drive base and intenal components, and get the spark advance map dial-in with a new VAC and aftermarket spring kit. Then you just buy the correct number band. There are recent threads on the subject, as there have been on finding B28 VACs, which are becoming scarce, but apparently are still available in the Airtex brand from any retailer that carries Airtex. So you need to do a little research in the archives.

Some guys with a correct AIR pump gut the internals and plug the lines. It's not that hard to have everything look original in NCRS judging, but make internal modifications that can't be seen to make the car perform better and use less fuel.

The TCS can be installed, but essentially non functional and will not cost you anything in Flight judging, but might cause a PV failure.

Duke

[Joe L.]

Re: Distributor Housing Casting Numbers

Joe,

You are correct about the main shaft. That's the same number shaft that Dave mentioned and I thought he said it was "heavy duty". Perhaps he just said it was put in the "heavy duty" engines and I misunderstood him. I would love to see a picture of that shaft and any identifying numbers or markings.

I'm so ignorant about these cars I'm embarrassed sometimes, but I'm trying to learn as much as I can. With that being said, I'll risk humiliating myself by asking you to explain what an autocam is, what it looks like, and how it works.

Also, do you have a book or some other reference guide that lists what components go into different distributors? If I'm unable to locate an original 1112101 I'd like to build one but I'm not sure what weights, springs, and vacuum to use or where to purchase them. I'd also like to have a book like that on hand for future reference.

Thanks,

Mike

Mike------


The autocam is the oddly shaped piece attached by brazing to the very top of the mainshaft. These were always available ONLY as an assembly with the mainshaft. The mainshaft, itself, was pretty much the same for all 1962-74 Corvette distributors except TI.

Yes, there exist references which do list the components used for every Corvette distributor. For the 1112101 here are the original components of note. The remaining components were the same as all other Corvette distributors of the period (i.e. cap, rotor, points, etc.)

SHAFT, with autocam-------GM #1852764 (stamped 210)

CAM--------originally GM #1965890 replaced by GM #1967002 (stamped 530 CCW or 528 CCW)

SPRINGS-----------GM #1939480

WEIGHTS----------GM #1881371

VACUUM CONTROL----GM #1973437

BREAKER PLATE-----GM #1876641


ALL of the above parts are long-since GM-discontinued. The above parts are pretty much "what makes a 1112101 a 1112101". However, while that's what's original to your car, I agree with Duke that a 1112101 will not make for well-performing engine.

Below are photos of the GM #1852764 shaft:



DSCN3038.jpgDSCN3039.jpgDSCN3040.jpgDSCN3042.jpg

[Joe L.]

Re: Distributor Housing Casting Numbers

A few more:


DSCN3044.jpgDSCN3045.jpg