Tonawanda plant overspray revisited

[Greg L.]

Re: for 1969 L89 overspray on heads

Glad I could help Michael! I'm not sure why there would be so much confusion for so long though about the manifolds because this pic has been around since, well, 1969

I too was wondering if the pic was of a 68 or 69 even though the brochure is for a 69. However I just noticed that it must be of 69 vintage due to the smog pump not having a internal relief valve in it.

So there you have it...painted manifolds it was just like you remembered them. Now if I could only find a pic of what the paint mask line around the intake manifold looked like then I'd be set.

[Michael H.]

Re: for 1969 L89 overspray on heads

Thanks Greg. Years ago, there was plenty of confusion about painted exhaust manifolds. In fact, there was absolute rejection of the entire idea of there ever having been orange paint on these things, ever. I'm pretty sure I was the very first person to ever show a Corvette anywhere, including NCRS, in the 70's with properly painted and run/burned in manifolds. They were, of course, immediately rejected and the judge started removing points. However, I came prepared. I had factory photos of new engines that clearly showed the manifolds painted, and not just lightly oversprayed. He did eventually give back the points but still didn't believe any of my nonsense. Now, 30 years later, most still reject the idea.

I didn't notice the smog pump relief valve. I suppose I would have to know a lot more than I do about C3 to have spotted that. I vaguely remember it now since you mentioned it.

I've never had opportunity to actually see the intake manifold paint mask used for either big block or small block. I don't even know anyone that has. I'm afraid that will continue to be one of the unsolved mysteries of Corvette assy. I've made and used several that worked well and duplicated almost exactly the over spray on a 65-67 but never on a 68 and newer. I suppose they were similar.

[Joe L.]

Re: for 1969 L89 overspray on heads

Greg-----

Also, it has an SI series alternator of 1969 configuration. 1968 and earlier big blocks did not use an SI series alternator---they used a DN series alternator.

[Mark #28455]

were aluminum head engines different?

Just wondering, as the heads I have all showed equal paint along the sides (no "masking" from the exhaust manifolds being present). The 2 takeoff pairs were dated Nov 1968 and Feb 1969. The Nov takeoff was from an engine that dropped a valve and cracked one guide in late 1969.

Mark

[Dick W.]

Re: for 1969 L89 overspray on heads

The engine shown in the sales brocure was "dressed up" for a photo shoot.

In 1968 there was an internal memo sent to Tonawanda about manifold paint. It basically stated that due to increasing emission standards that the manifolds should be masked and not painted. With this being said there have been a few very original engines observed with a small amount of paint at the top edge of the manifolds. maybe 1/2" or less. I think that you will find the C-3's judged to this standard. An excess of paint like seen on the mid years will warrant a minor deduction.

[Steve Antonucci]

Re: for 1969 L89 overspray on heads

Greg,

This vac-form that was used to mask the intake(s) has also been of keen
interest to me. I still have not seen a picture of one or exactly how
much overspray was "normal".

As you probably know, it is claimed that as the exposure to repeated engine
painting processes increased, the edges of the vac-form rolled somewhat and
thus the reason for different amounts of overspray on each engine.

Does anyone know if a picture of the intake paint mask made it into any of
the articles or Corvette magazines back in the day?

Who's the keeper of the Tonawanda College of Assembly Knowledge anyway?

Steve

[Greg L.]

Re: for 1969 L89 overspray on heads

Oh great!

Just after I figured out one more of life's answers, someone changed the question.

Dick, after I posted that pic I for some reason thought to myself...I wonder if this is an engine that had special care or "make-up" for it's 10 seconds of fame? It does look quite pretty so it wouldn't suprise me if it was in fact "dressed up" for the picture. I would however tend to think that if this was the case that the lower rad hose connection on the water pump would have been painted as well and not masked off.

Would you happen to have a copy of the Tonawanda memo that explains where the masking was to be applied?

It would also be interesting to see if the 68 & 70-74 sales brochures have similar engine pics for comparison.

[John H.]

Re: for 1969 L89 overspray on heads

Steve -

I've never seen a published photo anywhere that shows the vacuum-formed aluminum intake or valve cover paint masks, but I remember watching them being used at Flint Engine in '66-'67 when I worked next door at Flint Assembly and the Pilot Line. I'd assume the vac-form masks used at Tonawanda were similar.

[Steve Antonucci]

Re: for 1969 L89 overspray on heads

John,

Any idea who either manufactured or supplied those vac-forms, by chance?
Maybe I can chase it down that way. Try to remember, it was only 39 years ago.......

Steve

[John H.]

Re: for 1969 L89 overspray on heads

Steve -

I wouldn't be surprised if the engine plant toolrooms made them on-site; pretty simple to make a splash off an intake, make a mold from the splash, and drill it full of holes for vacuum lines. The engine plant toolroom guys were pretty clever.