7029207 carb question

[Greg L.]

I just came across this p/n carb but the date next to the p/n is 0468. Is it not odd that a 69 carb was dated mid Feb of 68?

[Joe L.]

Re: 7029207 carb question

Greg-----

The 7029207 carburetor was manufactured for many years as a SERVICE carburetor for many 1968-69 applications. The "8" likely refers to 1978 or 1988. The carb may even still have been in production as of 1998, so it might even represent that year. '207' carbs manufactured in late 1978, early-to-mid 1979, late 1988, and early-to-mid 1989 work out real great for 1969 L-46 owners; they can get a much newer carburetor with "correct dates".

[Joe L.]

Addendum

By the way, there is a way to discern a 1969-era '207' carburetor from a later-manufactured one even if the "dates" look "correct". How? Well, original, 1969 era carbs will have a plastic fast idle cam; later produced SERVICE carburetors (well prior to the first "confusion" year date of 1978) usually have a metal fast idle cam. I don't think that the plastic style cam is even retrofittable to the later carbs. It may be possible, though.

[Greg L.]

Re: Addendum

Thanks Joe, I knew that the 207 carb was a service replacement but I had no idea that it was produced for so many years...must have been a good one!

[Clem Z.]

the early plastic fast idle cams were too light

and the fan wash would blow them back on to fast idle. i guess the extra cost of metal was too much for the GM bean counters at first.

[Mike McKown]

They also cracked-Recall *NM*

[Jim B.]

Re: the early plastic fast idle cams were too ligh

These fast Idle cams made of blue green plastic were replaced in a safety recall in 1969. All 1968 and 1969 corvettes were involved that had the quadrajet. The recall notice stated that they were subject to cracking and would fall off and jam the linkage sometimes in the open or WOT position. My letter is dated Aug 7 1969. As an original owner of a 1968 I have the letter.

Jim Boudreaux
#38390

[Mike McKown]

I believe this was ALL quadra-jets, not just Vett *NM*

[Joe L.]

Re: the early plastic fast idle cams were too ligh

Jim------

I never received a recall for my 1969 with Q-Jet. If I did, then I must have ignored it (which is highly unlikely I would do) because my original carb still has the original plastic fast idle cam on it to this day. I did have to repair some small cracks with epoxy, though. This I did about 15+ years ago. The carb has not been used on my car in more than 15 years, however.

The original cam on my car was an "off-white" plastic cam.

The original cams were discontinued in July, 1969 and replaced for SERVICE. However, the replacements were also plastic. They continued to be available and used in SERVICE until the mid-1980's. The replacements were color-coded. For manual transmission applications they were blue or blue-green. For automatic trans applications they were red.

I don't think that the metal fast idle cams, which did appear later on SERVICE 68-69 carburetors, were ever available seperately in SERVICE and I don't think that they are retrofittable to carbs originally equipped with plastic cams. I could be wrong ob both scores, though.

Was the fast idle cam on your 1968 replaced under the recall? If so, what is the configuration of the replacement cam?

[Jim B.]

Re: the early plastic fast idle cams were too ligh

Joe

Yes, the cam was replaced by warrantee service with a metal cam. I drove my car for quite a while with that Carb/metal Cam but I haven't had it on the car for a while either. I need to get it rebuilt but am afraid to let it go. It is a 7028219 Carb which I have never found anywhere for sale.
One of the reasons I bought a late 68 instead of a 69 which were in the showrooms at the time, was that they offered a 5 year 50K mile bumper to bumper warrantee on the 68 but not the 69. Maybe they limited the recall to warranteed cars??? Chevy was wierd back then as I recall.
It is funny that the bearing that the cam rides on is also plastic and the same color, blue-green, and they didn't replace that, only the cam itself. The color you quote agrees with my configuration as I have a 327/350 M22 convertible.

[Joe L.]

Re: the early plastic fast idle cams were too ligh

Jim-----

So, the replacement cam on the car now is blue-green? If so, are you sure it's metal? I've never seen a metal cam that was color-coded. The blue green cams that replaced the original in July, 1969 were plastic. I have many NOS examples with the part number on them.

[Jim B.]

Re: the early plastic fast idle cams were too ligh

Joe

No, I guess I am not a great writer. The cam is metal and is annodized in color. The bearing in the shaft that it rides on is blue green plastic, left over from the original cam.

Where did you get the older plastic cams?? I would like to have one to put mine back to before the warrantee work.

Looking at the time, I think we both need a life.

Jim B.

[Michael H.]

Re: the early plastic fast idle cams were too ligh

Joe,

I think you have it exactly right. I well remember the campaign on the plastic cams in 1969 and I'm sure the original AND the replacement cams were plastic, not metal. (I still have several, somewhere, and still have a few of the special installation tools that were supplied with the new cams) I don't remember the color codes but the color was used to identify the application and would have been different on the replacement cam. The campaign continued for over a year and included the 68 and 69 model years. The problem was just as you described. The plastic material on the original cams became brittle in just a few months and the cams were breaking, falling into the linkage and causing a possible WOT condition. The new replacement cams were made from a different material that supposedly eliminated that problem.

It's possible that a newer metal replacement showed up on new cars a few years later but the original campaign only included plastic as I remember.

Also, as you mentioned, this campaign included ALL GM cars equipped with Q-Jet carburetors. Owners received a notice in the mail that looked like an old IBM card, instructing them to report to any Chevrolet dealer for the required modification.

[Jim B.]

Re: the early plastic fast idle cams were too ligh

I have the original letter and the original carburetor as modified by the dealer and they definitely put on a metal Cam in Aug of 1969.

[Joe L.]

Re: the early plastic fast idle cams were too ligh

Jim-----

Well, this is all very perplexing. As I mentioned, the original fast idle cam on my 1969 manual transmission application carb is an off-white (now, more yellowish) plastic cam. The same cam was supposed to have been originally used for 1968 Corvette carbs.

In July, 1969 GM replaced this cam (and, the cam for automatic trans applications) with another plastic cam. These cams were color-coded as I previously described. I was not aware that any original 68-69 cams were color-coded. I know, for sure, that the one used on my car was off-white; as I mentioned, I still have it.

It would seem reasonable to assume that the reason that GM replaced the original cams for SERVICE in July, 1969, was due to the problems associated with the original cams (which, apparently, prompted a recall previously unknown to me). However, what surprises me is that they replaced yours with a metal cam. As I mentioned, the July, 1969-released SERVICE replacement cams were plastic. These cams continued to be available in SERVICE until the mid-1980s when they were discontinued. It's hard to imagine that GM would have replaced the original cams under a recall campaign with metal cams and then continued to sell plastic cams in SERVICE for many more years.

In addition, as I mentioned previously, I don't think that the plastic and metal cams are directly interchangeable. If the plastic cam is replaced with a metal cam, then several other parts have to be replaced, too. Of course, they may have changed all these parts as part of the recall campaign.

I would have expected that if the plastic cams were deemed unsafe so as to prompt a recall, then the SERVICE part would have changed to a KIT which would have included the metal cam and whatever other parts were necessary to install it on a carburetor originally equipped with a plastic cam. To continue to sell a SERVICE part that had been "decredibalized" through a recall would have been foolish. And, if the plastic cams had been improved to eliminate the defect, then why not just use them for the recall campaign?

It is possible that at the time that your car was retrofitted, the improved design plastic cams were not yet released. So, the only repair option would have been the metal cam along with the other parts necessary to make it work on the carburetor. In this sense, the metal cam would have been an "interim" design. I can find no record, at all, of its availability in SERVICE. So, if available, it was available to dealers as a special SERVICE item only for the recall campaign.

One of the reasons that the metal cams are not easily retrofittable to carbs originally equipped with the plastic cams is that the metal cams are much thinner in cross-section than the plastic cams. The metal cams are about 1/8" to 3/16" thick whereas the plastic cams are about 5/16" to 3/8" thick. The two different types require a different cam follower and other associated parts.

Does the metal cam on your carb have any number stamped on it?

Also, in answer to your question, I don't recall where I got the cams I have. I picked them up "somewhere along the way"---perhaps when they were still available from GM. However, these are the REPLACEMENT plastic cams, not the originals as used for 1968-69. As far as I know, and as evidenced by the original cam that I still have on my original carb, the originals for, at least, manual transmission applications were "off-white".