1975 and 1976 AIM

[Jim S.]

I was fortunate to have obtained the 1976 Corvette AIM (2 books) directly from Chevrolet Engineering. (I don't know if that was necessarily good or bad with respect to it being up to date.)

Later I was able to obtain a 1975 Corvette AIM as well. The 1975 book I had to return. Rather than copying every page from the 1975 book, I compared 1975 to my 1976 book and only copied pages that were new or different and added them to my 1976 book.

It always seemed to me that my 1976 book was missing pages. However, when I compared it to the 1975 book there were not a whole lot of pages in the 1975 that were not in the 1976.

I have always been suspicious that there are a lot of pages missing in my 1976 book.

For instance: 1976 Spark plug wire shielding.
I can find the wire routings, standoffs, and looms to hold the wires (6Y Sheet #3). But I cannot find the shielding.

Even the contents sheet (6M Sheet #1) shows an engine with bare ignition wires - no shields.

6Y Sheet #4 shows two passenger side spark plug shields. There are two revisions dated 5-8-75 on that sheet:
Symbol #1 3919807 Shield removed
Symbol #2 L.H. View removed

So unless the shielding is somehow hiding in a section that I can't find, both of my 1976 books and the 1975 that I borrowed do not have the shielding.

Jim

[Terry M.]

Re: 1975 and 1976 AIM

Spark plug wire shielding is in the U-69 (radio) option section in the earlier C3 AIMs. I don't have an AIM newer than 1972, so I can't be of any direct help.

[Jack H.]

Re: 1975 and 1976 AIM

Terry's smack dab on here! The ignition sheilding was part of the radio option. Flip your AIM to the back where RPO options are called out and you ought to find the associated shielding and 'hush up' capacitors called out there to support the basic radio feature...

[Joe L.]

Re: 1975 and 1976 AIM

I was fortunate to have obtained the 1976 Corvette AIM (2 books) directly from Chevrolet Engineering. (I don't know if that was necessarily good or bad with respect to it being up to date.)

Later I was able to obtain a 1975 Corvette AIM as well. The 1975 book I had to return. Rather than copying every page from the 1975 book, I compared 1975 to my 1976 book and only copied pages that were new or different and added them to my 1976 book.

It always seemed to me that my 1976 book was missing pages. However, when I compared it to the 1975 book there were not a whole lot of pages in the 1975 that were not in the 1976.

I have always been suspicious that there are a lot of pages missing in my 1976 book.

For instance: 1976 Spark plug wire shielding.
I can find the wire routings, standoffs, and looms to hold the wires (6Y Sheet #3). But I cannot find the shielding.

Even the contents sheet (6M Sheet #1) shows an engine with bare ignition wires - no shields.

6Y Sheet #4 shows two passenger side spark plug shields. There are two revisions dated 5-8-75 on that sheet:
Symbol #1 3919807 Shield removed
Symbol #2 L.H. View removed

So unless the shielding is somehow hiding in a section that I can't find, both of my 1976 books and the 1975 that I borrowed do not have the shielding.

Jim

Jim------


The RF shielding is in UPC "B01 to B12", sheets 35 and 36. However, I think you're just referring to the spark plug heat shielding. In that case, my copies of the 1975 and 76 AIM's seem to be the same as yours. The 1975 AIM, UPC 6Y, sheet 7 shows the shielding on both sides of the engine. It shows the GM #3817657 for the right front and left rear; the GM #3815084 is shown for the right rear; the GM #3919807 for the left front.

The 1976 AIM , UPC 6Y, sheet 4 deletes the left side view and has the other notations you mentioned. There is no other sheet that depicts the left side view and parts. The same thing is also true for 1977 and 1978. So, if there's a sheet missing from the 1976 AIM, it's missing from the 1977 and 1978 AIMs, too. The only reason I can think of for the left side shielding to have been removed from the AIM is if, at that point, the left side shielding was installed at the engine plant or if it was eliminated altogether. However, it would seem strange that only one side of the engine would have had the shielding installed at the engine plant and even stranger that the left side shielding would have been eliminated and the right side retained.

I still do not understand why the GM #3815084 shield was shown in these drawings and, apparently, used in PRODUCTION. The 3815084 was definitely used in PRODUCTION and available in SERVICE for 1963-67 models. However, it was discontinued from SERVICE in May, 1968 and replaced by the GM #3917664. I just don't understand why the 3815084 would have been replaced for SERVICE but continued to be used in PRODUCTION for years thereafter.

[Jim S.]

Re: 1975 and 1976 AIM

It is interesting that my late built (July 1975) convertible did not have the spark plug shields on the driver (LH) side of the engine. (They were on the right side.) I just thought that they were lost sometime in the seven years before I purchased it.

I mentioned previously that I borrowed a 1975 AIM and copied every page that was not identical to my 1976 AIM. (I sure wish that I had just copied everything!) I do not have a corresponding 6Y Sheet #4 from the 1975 AIM.

That means one of two possibilities: First, that the page just wasn't in the 1975 book that I had. Or second, the page in the 1975 book was identical to the 1976 page (i.e. shield and LH View Removed) and I just didn't copy it.

The revision date on the 1976 page is 5-8-75 (two months before my July 1975 convertible build.) I wonder if they might have stopped installing the LH shields - sort of a Rolling Model Change on the late built 1975s.

Jim

[Joe L.]

Re: 1975 and 1976 AIM

It is interesting that my late built (July 1975) convertible did not have the spark plug shields on the driver (LH) side of the engine. (They were on the right side.) I just thought that they were lost sometime in the seven years before I purchased it.

I mentioned previously that I borrowed a 1975 AIM and copied every page that was not identical to my 1976 AIM. (I sure wish that I had just copied everything!) I do not have a corresponding 6Y Sheet #4 from the 1975 AIM.

That means one of two possibilities: First, that the page just wasn't in the 1975 book that I had. Or second, the page in the 1975 book was identical to the 1976 page (i.e. shield and LH View Removed) and I just didn't copy it.

The revision date on the 1976 page is 5-8-75 (two months before my July 1975 convertible build.) I wonder if they might have stopped installing the LH shields - sort of a Rolling Model Change on the late built 1975s.

Jim

Jim----


I'd say it's virtual certainty that the left side shields were eliminated in 1975----it would be WAY too much coincidence that your 1975 just happened to be "missing" those very shields but it occurred for some reason other than their not having been installed at St. Louis.

In any event, I think that we have determined that the reason the left side shield diagram was dropped from the AIM is because the shields for the left side were eliminated. The thing that really interests me about this is WHY? There must have been some good reason for it but I wonder what it was. Perhaps the issue was some problem with interference with the thermostatic air cleaner "plumbing" on the left side.