1970 Corvette Q-Jet bolts

[D S.]

Re: 1970 Corvette Q-Jet bolts

Alan------

My 1969 never had any lockwashers on either the front bolts or the rear studs/nuts. Plus, the AIM's do not show that any washers of any kind were used on the front bolts or rear studs/nuts. The use of lockwashers on either the bolts or the nuts would guarantee damage to the soft aluminum or zinc diecast material on which they bear.

Thanks, Joe, for your invaluable information. I am going to remove the two lockwashers on the two rear studs.

[Jeffrey S.]

Re: 1970 Corvette Q-Jet bolts

The front bolts on my '69 are pictured below. They are "A" headmark grade 3. There is no integral washer.
Jeff

[Alan S.]

Re: 1970 Corvette Q-Jet bolts

Hi Terry and Joe,
In the 'bag' were 2 bolts, 2 thin nuts, and 2 lock washers.
Ready for some very fuzzy logic.... since the plating on the washers matched the plating on the bolts, but not the nuts, the washers went with the bolts?!?!
It made perfect sense in my small world.
Regards,
Alan

[Joe L.]

Re: 1970 Corvette Q-Jet bolts

Hi Terry and Joe,
In the 'bag' were 2 bolts, 2 thin nuts, and 2 lock washers.
Ready for some very fuzzy logic.... since the plating on the washers matched the plating on the bolts, but not the nuts, the washers went with the bolts?!?!
It made perfect sense in my small world.
Regards,
Alan

Alan------

In a GM fastening system (e.g. bolt, lock washer, nut) there is absolutely no assurance that all the pieces will be "finish-matched". More often than not, all the pieces are not so-matched.

It's not impossible that lock washers were actually used for this application. They were not used on my car and they were not supposed to have been used. But, someone at St. Louis might still have installed them on some cars.

It's also possible they were on the car when the person that "bagged" them removed them, but NOT on the car originally (i.e. some previous owner or servicer added them).

[Alan S.]

Re: 1970 Corvette Q-Jet bolts

Hi Joe,
I'm the person who bagged them. I made the change to the Holley Spreadbore a week or two after taking delivery in March of 71. That's why I'm curious... if I put them in the bag I have to think they were part of the carb attaching fasteners somewhere....
Thanks for your many replies and insights!
Regards,
Alan

[John H.]

Re: 1970 Corvette Q-Jet bolts

First from my 70 and second from a rather original car....

That's the front bolt I'm accustomed to seeing on 1970 Q-Jets on the full-size Impala/Caprice; when GM announced the Q-Jet engine fire recall in late 1969, we shut the plant down (Lordstown) for two days and changed thousands of them in-process in the plant, in the repair yard, and in the shipper's haulaway and rail-loading yard.

[D S.]

Re: 1970 Corvette Q-Jet bolts

That's the front bolt I'm accustomed to seeing on 1970 Q-Jets on the full-size Impala/Caprice; when GM announced the Q-Jet engine fire recall in late 1969, we shut the plant down (Lordstown) for two days and changed thousands of them in-process in the plant, in the repair yard, and in the shipper's haulaway and rail-loading yard.

Before the fire recall or after? If after which bolts were used?

[John H.]

Re: 1970 Corvette Q-Jet bolts

Before the fire recall or after? If after which bolts were used?

Scott -

I'm not familiar with Q-Jets in general; I only remember seeing LOTS of those bolts 40 years ago as my repairmen changed thousands of carburetors in two days. The new Q-Jets were flown in by air charters, but we re-used the existing hold-down bolts.

[Terry M.]

Re: 1970 Corvette Q-Jet bolts

Some time back there was a discussion here about the long bolts on 1970 Q-Jets and having the built in washer. I didn't read anywhere as to the headmarks on them and I assume there were more than one manufacturer of them. I have two pair of them with one pair having a P headmark and the other a C headmark. Are these the ones being referred to as being correct for 1970 Corvette Q-Jets?

No offense guys, but y'all need to get out from behind the computer and come to some NCRS meets. I know there are a lot of people who think the Internet is the greatest thing since sex, but you have to get out and lay hands and eyeballs on real Corvettes if you want to do a good job restoring your car.

[D S.]

Re: 1970 Corvette Q-Jet bolts

No offense guys, but y'all need to get out from behind the computer and come to some NCRS meets. I know there are a lot of people who think the Internet is the greatest thing since sex, but you have to get out and lay hands and eyeballs on real Corvettes if you want to do a good job restoring your car.

No offense taken, Terry, and I can't agree with you more but that is what these posts and threads are for and doing. The photographic submittals really help us where words can't. Certainly there are going to be differences of opnion and that is a good thing because we can understand and see that there were various different applications on the same year Corvettes. None of us has seen each and every Corvette Q-Jet in 1970 or any other year so one has to assume there will be differences.

Question: In that first close-up photo of the Q-Jet and bolt....is that part of the carburetor bolt hole exposed to the left of the bolt? Would that maybe explain why Q-Jets in 1970 received the built-in washer bolts? Were the Q-Jet holes in ensuing years smaller due to a tooling change?

[Terry M.]

Re: 1970 Corvette Q-Jet bolts

It sure does look like part of the hole in the top plate is exposed. I'll try to look at it more closely this afternoon if the owner is around the car. It is a 1969, about sn/ 30K -- which makes it later in the model year.
I thought the photo was better focused than it is here, it is the same A headmark that was posted earlier, and I would expect the same kind of configuration under the head that was posted and Joe Lucia commented on. That said, I am not going to ask the owner to remove a bolt for us -- that is over the top in my opinion.

Edit add: The car got a Bowtie sign-off here, so it might show up at Concord. I haven't asked the owner his plans because the sign-off was not an enthusiastic "two thumbs-up," in all four areas, and he is a little put-off. I don't want to meddle in those affairs in which I don't have a dog in the hunt. \

[Joe L.]

Re: 1970 Corvette Q-Jet bolts

All-------


Attached is a photo of a known NOS example of a GM #9419047. This is the bolt that GM says was used for later 1971 through 1981. This is a later SERVICE example (the only way to absolutely know the part number of the vast majority of parts), so the headmarking will likely not be period-correct, at least not for earlier C3's. However, the configuration, specs, and finish of the bolt ought to be correct. This bolt is 3-11/16" in length.

[Terry M.]

Re: 1970 Corvette Q-Jet bolts

All-------


Attached is a photo of a known NOS example of a GM #9419047. This is the bolt that GM says was used for later 1971 through 1981. This is a later SERVICE example (the only way to absolutely know the part number of the vast majority of parts), so the headmarking will likely not be period-correct, at least not for earlier C3's. However, the configuration, specs, and finish of the bolt ought to be correct. This bolt is 3-11/16" in length.

Joe, Is that a dark gray, or even black finish? It looks like it, but sometimes photos can be deceiving.

[Joe L.]

Re: 1970 Corvette Q-Jet bolts

Joe, Is that a dark gray, or even black finish? It looks like it, but sometimes photos can be deceiving.

Terry-----

It is a very dark gray, almost black, phosphate finish. Black phosphate is also the finish specified for the 9419047 bolt.

Was this bolt used on every later 1971 through 1981 Corvette? That I don't know, but it's the bolt that GM specified for every later 1971 through 1981 Corvette.

[Clem Z.]

Re: 1970 Corvette Q-Jet bolts

Terry-----

It is a very dark gray, almost black, phosphate finish. Black phosphate is also the finish specified for the 9419047 bolt.

Was this bolt used on every later 1971 through 1981 Corvette? That I don't know, but it's the bolt that GM specified for every later 1971 through 1981 Corvette.

the bolts i have a dark grey but not black looking like the ones in the picture. also mine are used so that could make a difference