Question on SB timing cover date code

[Michael L.]

guys,

I just realized that the date stamp on the timing cover for my 69 350/350 is wrong. It is a Sept 69 build car and the timing cover is stamped 7/70. My question is, is this stamp judged? Can it be seen when the car is assembled? If the answer to both questions is yes then where is the best place to look for a correctly date coded cover?

thanks,
Mike

[Joe L.]

Re: Question on SB timing cover date code

guys,

I just realized that the date stamp on the timing cover for my 69 350/350 is wrong. It is a Sept 69 build car and the timing cover is stamped 7/70. My question is, is this stamp judged? Can it be seen when the car is assembled? If the answer to both questions is yes then where is the best place to look for a correctly date coded cover?

thanks,
Mike

Mike------

While many others believe that these numbers stamped on the small block timing covers represent dates, I do not. It so happens that I'm the original owner of a 1969 with small block. My car was built in September, 1969 and the engine was manufactured in August, 1969. The stamping on my cover, which I absolutely know is original to the engine, is "1 70". There's no way in the world that this could represent a manufacturing date of the cover with an engine manufactured in August, 1969. Thus, I do not believe that these stampings represent dates.

[David L.]

Re: Question on SB timing cover date code

Mike------

While many others believe that these numbers stamped on the small block timing covers represent dates, I do not. It so happens that I'm the original owner of a 1969 with small block. My car was built in September, 1969 and the engine was manufactured in August, 1969. The stamping on my cover, which I absolutely know is original to the engine, is "1 70". There's no way in the world that this could represent a manufacturing date of the cover with an engine manufactured in August, 1969. Thus, I do not believe that these stampings represent dates.

Joe,

For many years I have believed that the stampings on timing covers were a date code (week of year & year). Over the years I have purchased several timing covers with these stampings from swap meets. Most of them were the 1969-1970 type for 8 " balancers. I also had two 66-67 timing covers for 6" balances, one had a "1 67" stamping while the other one did not have a stamping. I always thought that the plain cover was from a 1966 and the "1 67" cover was from a 1967. I still have the unstamped 1966 cover for a 6" balancer. I assumed that "1 67" represented the 1st week of 1967. This all seemed very logical as scissor jacks and bumper jacks were date coded starting in 1967.

In the late 1980's I purchased a timing cover from my local Chevrolet dealer and still have it. The GM part number is 361926 (in Gr. 0.206) and the cover (without a tab) is stamped "26". The GM box is dated March 1986. I assume the "26" stamping represents the GM part # 361926.

I guess more research is required on these timing cover stampings.

Dave

[Joe L.]

Re: Question on SB timing cover date code

Joe,


In the late 1980's I purchased a timing cover from my local Chevrolet dealer and still have it. The GM part number is 361926 (in Gr. 0.206) and the cover (without a tab) is stamped "26". The GM box is dated March 1986. I assume the "26" stamping represents the GM part # 361926.


Dave

Dave------


That answers the question. The 1969-70 small block timing cover with timing tab set for 8" balancer (which ALL 1969-70 Corvette small blocks were equipped with) was GM #3946870. So, now I'm pretty sure we know what most of the stamping represents.

[David L.]

Re: Question on SB timing cover date code

Dave------


That answers the question. The 1969-70 small block timing cover with timing tab set for 8" balancer (which ALL 1969-70 Corvette small blocks were equipped with) was GM #3946870. So, now I'm pretty sure we know what most of the stamping represents.

Joe,

Nice pick up. Why didn't I notice this? Old age, I guess.

The GM service part # for the 1967 Corvette (and others models as well ) timing cover w/6" balancer is 3885039 and is described as "double timing mark brkt". I have one of these timing covers in my collection and it is strictly a service timing cover as it has 2 tabs for different sized balancers. You brake off the tab that you don't need.

Apparently the factory installed 66-67 Corvette timing cover w/6" balancer was never sold over the counter. The GM part number must have have been XXXXX67 in the Flint and Tonowanda engine plants.

Well, the Patriots game is on.
Dave

[Mike E.]

Re: Question on SB timing cover date code

This is an earlier iteration--a 67 8" timing chain cover installed on a January 1967 350 hp motor with 31k miles. I know it to be original.

[Joe L.]

Re: Question on SB timing cover date code

Joe,

Nice pick up. Why didn't I notice this? Old age, I guess.

The GM service part # for the 1967 Corvette (and others models as well ) timing cover w/6" balancer is 3885039 and is described as "double timing mark brkt". I have one of these timing covers in my collection and it is strictly a service timing cover as it has 2 tabs for different sized balancers. You brake off the tab that you don't need.

Apparently the factory installed 66-67 Corvette timing cover w/6" balancer was never sold over the counter. The GM part number must have have been XXXXX67 in the Flint and Tonowanda engine plants.

Well, the Patriots game is on.
Dave

Dave------


I believe that many timing covers used in PRODUCTION were never available in SERVICE. Of those that were available, they were usually only available for a relatively short time before they were replaced with "one-size-fits-all" covers.

[Michael L.]

Re: Question on SB timing cover date code

Thanks Joe that makes sense to me. The car I'm restoring is a very original example. Although I'm not the original owner (I'm technically the third but the second owner was a close friend). When I took it apart it had many things still on it that I'm told are fairly rare to see because they are usually chucked at some point during service. Things like a radiator tag, which tells me the radiator has never been serviced, and the entire smog
system, as well as all the original ignition shielding. I'm convinced my timing plate is original and as I mentioned it is coded 7 70. At least I don't have to get a new one. Thanks again.

Mike

[David L.]

Re: Question on SB timing cover date code

Enclosed are 2 photos of a NOS 3885039 timing cover. As best as I can tell this cover is stamped "4 39". This cover is strictly a service cover as it has 2 tabs. GM # 3885039 appears in my 1967 Chevrolet Parts Catalog (Apr. 1967) and is listed for 66-67 CORVETTE (327)(exc. Sp. H/Per.) and other 55-65 Corvettes with a description COVER w/oil seal (double timing mark brkt.).

According to Chevrolet Parts History (service parts) GM # 3885039 was replaced with GM # 3928971 in Oct. 1973 which was replaced with GM # 361926 in Sept. 1977.

The factory installed 66-67 Corvette timing cover has a single tab. I can post a photo of one if requested.

Dave

[David L.]

Re: Question on SB timing cover date code

This is an earlier iteration--a 67 8" timing chain cover installed on a January 1967 350 hp motor with 31k miles. I know it to be original.

Mike,

Does you timing cover have a tab like the one in the photo below? Is it stamped "11 68" or "11 69" as the number is difficult to read.

I borrowed this photo from a fellow NCRS member from an old thread. This timing cover is stamped "34 69" which was never sold over the counter. The last two digits of the GM part number must be 69 (XXXXX69).

Dave

[Mike E.]

Re: Question on SB timing cover date code

David,
it is 11 66. It has a timing tab like the shallow long pointed one you picture.

[Michael M.]

[Joe L.]

Re: Question on SB timing cover date code

I also thought the stamp was a date code. Here’s a pic of my believed to be original ’67 300HP cover with a “4 67” stamped on it. Engine build date April ’67 (V0417HE).

Michael------


Well, it looks like the earlier covers were date coded. However, by at least 1969 that had changed to the stamping being a part number derivative.

I might add that date coding on steel stampings (e.g. timing covers) is quite unusual in the world of GM in days of old.

[David L.]

Re: Question on SB timing cover date code

I also thought the stamp was a date code. Here’s a pic of my believed to be original ’67 300HP cover with a “4 67” stamped on it. Engine build date April ’67 (V0417HE).

Mike,

Enclosed are two photos of the timing cover that I removed from my 1966 Corvette. There is no stamping. Years ago I had an identical timing cover that I bought at a swap meet (which I later sold) except that it had a "1 67" stamping. At that time I believe that the "1 67" represented a date code but now I think otherwise and that the "67" is the last 2 digits of the part number thanks to Joe L. I firmly believe that the stampings began in 1967.

Does the tab look like the tab on your "4 67" timing cover. I really can not tell from your photo.

Dave

[David L.]

Re: Question on SB timing cover date code

Since we are on the subject of timing covers here are 3 photos of service timing cover # 3812994 (sold over the counter from Aug. 1962 to Nov. 1966) which was replaced with service timing cover # 3885039 in Nov. 1966 as per Chevrolet Parts History. The 3812994 has smaller "dual tabs" (one tab is for the 4.5" hub while the other tab is for the 6" balancer).