Mufflers-Black?

[Michael H.]

Re: Mufflers-Black?

Patrick,

I'm hoping John will provide more details that will help us to replicate the factory blackout process, but this excerpt from a series of articles in back issues of Corvette Enthusiast says the chassis was right side up when the blackout process occurred:

"On the Chassis Line, occurs the assembly of the fuel and brake lines, fuel tank, exhaust system, installation of the engine/transmission, brake bleeding/testing, body mount shims and cushions, and chassis blackout. The chassis is upright in car position on a floor conveyor during this process." - John Hinckley, Corvette Enthusiast Magazine, December 2006 (emphasis mine)

Scott,

Something that may be confusing to folks is the terminology used to describe the two different sections of the frame conveyor system in the St Louis plant. The first section that the frame traveled down is called the "Spring & Axle" conveyor" and most of the assembly included just that. Springs and axle, etc.
For this section, the frame was loaded upside down and continued upside down until all of the control arms, suspension, steering and rear drive were installed. No blackout operation was performed in this section. The exhaust system had not been installed at this point. (at least for 63-67, and probably not for 68-69 either)

At the end of the spring & axle conveyor, the frame is picked off the line and flipped right side up before it is set on the "Chassis Conveyor".
Here is where the engine/transmission and other top side items were added, including the complete exhaust system.

The last thing that occured before body drop was the blackout process.

Years later, (I'm not sure when) the exhaust system was added to the frame before the frame was set right side up on the chassis line but by that time, I don't think any final blackout operations were performed on any chassis components.

[Terry M.]

Re: Mufflers-Black?

Mike,

That was indeed the reason for my question to Joe. I have the N11 exhaust system and wanted to understand whether it should be blacked out, or not. Unless I am mistaken, for Judging purposes, the mufflers must appear as they did when the car rolled out of the factory, not as it would appear with service replacement mufflers.

Therefore, the N11 mufflers should receive the same blackout treatment as any other mufflers on a car traveling down the St. Louis assembly line.

If this is not correct, someone please say so!

I don't judge mid-years, but you have the judging philosophy correct. If the original mufflers were blacked out -- unless you can duplicate that appearance you should receive a deduction. There may be additional deductions if the service replacement item can be detected as such.

[Tony S.]

Re: Mufflers-Black?

For judging purposes, the '65 chassis judges are looking for black out paint on the upper side of the mufflers--not the underside.

Tony

[Michael H.]

Re: Mufflers-Black?

For judging purposes, the '65 chassis judges are looking for black out paint on the upper side of the mufflers--not the underside.

Tony

They should be looking at the bottom, too.

[Mike M.]

Re: Mufflers-Black?

For judging purposes, the '65 chassis judges are looking for black out paint on the upper side of the mufflers--not the underside.

Tony

What would have been the purpose of blacking out the unseen tops of the mufflers?

[John H.]

Re: Mufflers-Black?

The first photo below shows the end of the Frame Line in 1966 - the chassis is upside-down (for the first and last time) as it enters the Frame Turnover device, which deposits it right-side-up on the Chassis Line for installation of the exhaust system, fuel tank, brake and fuel lines, engine/transmission, etc. The chassis blackout operation was done at the end of the Chassis Line, just prior to Body Drop, to hide the ugly/shiny muffler against the black background between the back of the rear tire and the back of the rear wheel opening.

The second photo shows the chassis at the end of the Frame Line in 1980 as it enters the Frame Turnover device; note that the exhaust system is in place - that process moved from the Chassis Line to the Frame Line when the catalytic converter was introduced in 1975, as the pipes no longer went through the transmission crossmember, and the converter and Y-pipe components were all BELOW the crossmember, thus more easily installed with the chassis upside-down.

The third and fourth photos describe the key elements of the midyear Frame Line and Chassis Line assembly processes.

[Michael H.]

Re: Mufflers-Black?

The first photo below shows the end of the Frame Line in 1966 - the chassis is upside-down (for the first and last time) as it enters the Frame Turnover device, which deposits it right-side-up on the Chassis Line for installation of the exhaust system, fuel tank, brake and fuel lines, engine/transmission, etc. The chassis blackout operation was done at the end of the Chassis Line, just prior to Body Drop, to hide the ugly/shiny muffler against the black background between the back of the rear tire and the back of the rear wheel opening.

The second photo shows the chassis at the end of the Frame Line in 1980 as it enters the Frame Turnover device; note that the exhaust system is in place - that process moved from the Chassis Line to the Frame Line when the catalytic converter was introduced in 1975, as the pipes no longer went through the transmission crossmember, and the converter and Y-pipe components were all BELOW the crossmember, thus more easily installed with the chassis upside-down.

The third and fourth photos describe the key elements of the midyear Frame Line and Chassis Line assembly processes.

Thanks John. That's just about the exact same thing I posted a few hours earlier but I've had no response so I have to wonder if anyone was buying my story.

[Terry M.]

Re: Mufflers-Black?

So then the runs going from bottom to top that I see on 1968 to 1972 had to be because the mufflers were coated before installation on the chassis. Either coated by the vendor or someplace else in the plant.

[Tony S.]

Re: Mufflers-Black?

They should be looking at the bottom, too.

Mike. That's straight from the '65 national judging chairman: black on top.

[Michael H.]

[Rich C.]

Re: Mufflers-Black?

How about some photos of muffler area from as many 63-82 'survivor' cars as possible!

'73 LS-4 454 owned 21 1/2 years

[Russ S.]

Re: Mufflers-Black?

For judging purposes, the '65 chassis judges are looking for black out paint on the upper side of the mufflers--not the underside.

Tony

Can some one go into a little explanation here as it would make no sense to have black out on the top side which can't be seen at all when it is the bottom side that is seen?

[Joe L.]

Re: Mufflers-Black?

Can some one go into a little explanation here as it would make no sense to have black out on the top side which can't be seen at all when it is the bottom side that is seen?

Russ------


All I can figure is that the top of the mufflers were painted more-or-less by "accident" when other chassis black-out was done. To be honest, I don't ever recall looking at the top of a muffler on an original C2.

However, as far as the bottom of the muffler goes I definitely remember this: back in the "hey-day" of C2's when the cars were new and seen regularly on the roads, I remember how you could tell a C2 that had had its mufflers replaced: the mufflers, easily seen when you were behind the car in traffic, were "bare metal". I DISTINCTLY recall always thinking how "funny" that looked. Of course, when mufflers were replaced at muffler shops the shops would not paint the replacement mufflers, so that's how this condition occurred.

Now, the point here is that if the mufflers were not originally painted on the bottom, there would have been nothing to "cue" what I described above when the "bare" replacement mufflers were installed. So, I am 100% sure that C2 mufflers were, at least, painted on the bottoms.

As far as C3's go, I can definitely say this: the original mufflers on my 1969 were painted on the bottom, sides, and outlet end. They were definitely NOT painted on the top surface. In fact, I still have the original left side muffler around here somewhere.

[Jerome P.]

Re: Mufflers-Black?

Russ -

Actually, the chassis blackout operation was done with the fully-assembled chassis right-side-up, in the last station on the Chassis Line, right before Body Drop, using airless spray guns fed from drums with Johnstone pumps.

There was never any "mitting" process - that fairy tale was invented many years ago by someone who had never been in an assembly plant, and "mitting" subsequently became an almost unassailable "fact" when it found its way into a JG; I've worked to erase it from everyone's memory for the last twelve years - it never happened.

What is "mitting"?

[Joe L.]

Re: Mufflers-Black?

What is "mitting"?

Jerome-----


It's a mythical process in which a worker dons a fabric mitt, dips it in paint, and uses the mitt as a paint applicator (i.e. in lieu of a brush or roller)