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Author Topic: 69 Penske vinyl roof  (Read 4681 times)
DONCZ28
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« on: May 11, 2011, 10:21:30 PM »

In early 69 ,the Penske Camaro had a vinyl top. Some speculated ,this had a performance gain for some reason? It apears in pictures ,that they used lower trim at the bottom of this roof.  Wouldn't this have caused a negative performance gain? I also noted that Donahue drove with the windshield wipers at verticle, which could have reduced drag.
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Bruce302
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« Reply #1 on: May 12, 2011, 04:53:19 AM »

From what I have read, and understand, the vinyl roof cover was an attempt to disguise the very thin, and prone to wrinkling acid dipped roofs.
It seems to be that the vinyl actually drew more attention than if they had not been fitted.

The trim on the lower edge of the vinyll, whist not very aero, would not have been that bad in the greater scheme of things. The Camaro is a great looking car, the RS front would probably have been better than the regular grill as far as aero is concerned.



Bruce.
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DONCZ28
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« Reply #2 on: May 12, 2011, 03:06:44 PM »

I don't believe ,that it would be smart to acid dip a roof.  It's a major structural  part of a  uni body car. Convertibles have their frames reinforced.  The roof may have been lowered ,and the vinyl was used to hide welds , and body work from sectioning.  Mustangs raced at this time , had their front ends sectioned and lowered.
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Jon Mello
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« Reply #3 on: May 12, 2011, 09:44:24 PM »

At the time there was a lot of speculation as to why the vinyl tops were on the Penske cars. People suspected lots of different reasons. I think one of the stranger hypotheses I've heard was that the vinyl top covered up tiny holes which released air pressure from inside the car. I don't think I have heard anything about a lowered roof but bondo and paint can cover up welds as good as any vinyl top can. I believe Mark Donohue was the one who stated that the vinyl tops were to cover up wavy roofs because the bodies of the two team cars had spent a little too much time in the acid tank. Yes, a normal unibody structure would suffer a lot from too much acid dipping and the roof does strengthen the structure of the body. However, don't forget that these cars had complete roll cages which attached to various parts of the chassis such as the front subframe, the rocker panels, the rear frame at the suspension pickup points, the side panels just aft of the door openings and it was also welded to the inner roof structure in a number of different spots. This is what became the birdcage type of frame for the car which was much stiffer than any unibody car, especially one without a B pillar behind the door, could be on its own.

Eventually, during the 1969 season the protesting of the vinyl tops got to be so much that Penske did have to have them removed and my understand is that the wavy roofs were cut off the cars and new roofs were rewelded in place, sans vinyl. It is a good thing, since Penske's cars finally started winning races with the vinyl tops off the cars and they went on to win the Trans-Am championship that year, making it two in a row.
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Jon Mello
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« Reply #4 on: May 12, 2011, 11:19:38 PM »

I believe Bruce and Jon are right on with their responses.  Though it's been documented by members of the Penske organization in more than one place, here's a quote on the vinyl top Camaros in Michael Argetsinger's book, Mark Donohue: Technical Excellence at Speed.

"While the Penske refueling tower was causing a great deal of official concern, there was also a rustle of unhappiness over the appearance of the Sunoco Camaros.  The cars appeared with vinyl (or Landau) tops, and had the entire paddock talking.  'We were running Landau roofs because the roofs were too thin,' says Woody Woodard.  Soon after Woody came to work at Newtown Suare, he flew with Mark to Los Angeles where the new bodies were acid-dipped.  'The raw steel uni-body is called a body-in-white.  Just before it goes into the primer tank they grab it off the assembly line.  We got three and they were trucked to a chemical company in Long Beach, California, that would dip them in acid,' he explains.  'They pretty much knew how many seconds would take a thousandth off all the body surfaces.  They did the work at about 10:00 p.m.--they would only do it at night because it would put a huge cloud of blackish gray smoke in the air.  The whole body was put on a hook and submerged in the acid where it just sat and bubbled at stank.  When they came out they were hosed down, sprayed with neutralizer, and shipped to Newtown Square.  The process chemically removed--it was probably tens of thousandths--uniformly off of every steel surface.  And of course it was lighter.  The only problem was that on this occasion Mark convinced the guy to do it a little bit too long--and the roofs on all three cars were just a little bit different.' "

I chose to quote from Argetsinger's book because I believe it's the best printed record of the Donohue era at Penske Racing.

-Chad
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wrongwayron
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« Reply #5 on: July 27, 2011, 10:22:30 AM »

Amazing! and nobody has quoted THE UNFAIR ADVANTAGE.
"Another thing was the vinyl top. We were constantly repainting our cars, and it cost about $400 just to paint the top alone. So we figured that a $50 vinyl roof ought to last the entire season. Well ... actually it wasn't just a cost consideration, because we had acid-dipped the top a little too heavily, and it was wrinkled enough so that it looked bad in paint. But it wasn't aluminum or chopped full of holes as some competitors claimed."
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Jon Mello
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« Reply #6 on: July 27, 2011, 10:39:17 PM »

Thanks, Ron. I guess I was too lazy to dig my copy out.
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Jon Mello
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wrongwayron
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« Reply #7 on: July 28, 2011, 07:48:19 AM »

You're too hard on yourself, Jon. 
You've got jerks like me to do that! LOL
Besides you should have at least taken yesterday as the last FULL day of vacation and not been getting into everything that's been posted while you were gone.
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Jon Mello
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« Reply #8 on: July 29, 2011, 12:35:22 PM »

Shoulda, woulda, coulda, Ron.  Cheesy
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Jon Mello
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Steve Holmes
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« Reply #9 on: August 02, 2011, 07:32:04 PM »

Isn't it amazing, the paranoia that existed between the teams at this time, that a vinyl roof should be so controversial. Donohue also ran wide flexible piping from his engine bay through the bodywork and doors which exited into the rear wheel wells to help extract heat from the engine bay. This also gained plenty of interest.
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Jon Mello
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« Reply #10 on: August 03, 2011, 09:53:57 AM »

There was a lot of pressure to win if you were one of the factory-backed teams. That's where the paranoia and mistrust comes in. You don't want to have your opponent get any kind of advantage, real or perceived, because you could be out of a ride if your team ends up the loser.

As for wide flexible piping, I don't think I ever saw anything like that in use on the '69 Penske cars. I believe it was just holes lined up with one another between the doors and the quarters. If you've got a pic or two of any piping, I would love to see it.
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Jon Mello
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wrongwayron
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« Reply #11 on: August 03, 2011, 10:06:38 AM »

I agree with there NOT being any piping, just the front to rear wheel well holes. As for the mistrust: THE UNFAIR ADVANAGE read is great; especially when Mark is talking about "The Red Light Kid", Chief Steward Dave Tallaksen.
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Steve Holmes
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« Reply #12 on: August 03, 2011, 05:01:58 PM »

You guys are right! I just went and checked, and as Jon has said, the Penske cars just had large holes that lined up through the bodywork, there was no piping involved. Apologies, it seems I was attempting to fabricate a new story!
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wrongwayron
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« Reply #13 on: August 03, 2011, 06:05:43 PM »

I have got no problem with you keeping the rest of us on our toes. 
But I cheat: I attempt to look it up first... and I still make big mistakes.
So when I doubt I refer to Jon.
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Jon Mello
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« Reply #14 on: August 04, 2011, 03:01:02 PM »

Steve, you got me excited that maybe I missed something. I certainly don't know it all and love to see and learn about new details.

Ron, if I'm your safety net, you are in trouble!  Grin
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Jon Mello
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« Reply #15 on: April 01, 2012, 12:22:40 PM »


At the time there was a lot of speculation as to why the vinyl tops were on the Penske cars. People suspected lots of different reasons. I think one of the stranger hypotheses I've heard was that the vinyl top covered up tiny holes which released air pressure from inside the car. I don't think I have heard anything about a lowered roof but bondo and paint can cover up welds as good as any vinyl top can. I believe Mark Donohue was the one who stated that the vinyl tops were to cover up wavy roofs because the bodies of the two team cars had spent a little too much time in the acid tank. Yes, a normal unibody structure would suffer a lot from too much acid dipping and the roof does strengthen the structure of the body. However, don't forget that these cars had complete roll cages which attached to various parts of the chassis such as the front subframe, the rocker panels, the rear frame at the suspension pickup points, the side panels just aft of the door openings and it was also welded to the inner roof structure in a number of different spots. This is what became the birdcage type of frame for the car which was much stiffer than any unibody car, especially one without a B pillar behind the door, could be on its own.

Eventually, during the 1969 season the protesting of the vinyl tops got to be so much that Penske did have to have them removed and my understand is that the wavy roofs were cut off the cars and new roofs were rewelded in place, sans vinyl. It is a good thing, since Penske's cars finally started winning races with the vinyl tops off the cars and they went on to win the Trans-Am championship that year, making it two in a row.

The author that mentioned the holes in the vinyl roof was being hypothetical,  theorizing on a what if for what advantage a vinyl covering could provide. As it is if Mark stated in his book that they dipped the bodies than that is probably a key reason for putting vinyl on About 13 or so years later the theory of relieving aerodynamic air pressure was evident on World Superbike championship motorcycle fairings. Secondary benefits would be as Penske stated. The cars sure were noticed. Vinyl roofs would make the roofs look the same for little relative effort. And both men were being factual. Wink
Last thing, vinyl is way lighter than metal, and probably equal in weight to the weight lost by dipping. The main idea though, is the solution to the waves was cheap, fast, and simple.
S A
« Last Edit: April 01, 2012, 01:15:10 PM by Shadow Ahead » Logged
Jon Mello
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« Reply #16 on: April 01, 2012, 06:44:57 PM »

Since we are talking about the Penske vinyl tops, I guess we should at least have a picture.  Cheesy

This picture below is of Donohue's car at the first race of the '69 season. If you compare it to the ad
below it, you will see that they made no attempt to copy the top and trim the way the factory did it.


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Jon Mello
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« Reply #17 on: April 02, 2012, 07:06:53 AM »

Whaddya talkin about? The vinyl's black ain't it? Grin

S A
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Sixteen Grand Sedan #56
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« Reply #18 on: April 02, 2012, 11:46:54 AM »

The coverage area of the top on the Penske car is different than on that of the production car. The production car vinal top extends below the back window yet stops short of the drip rails on the side.
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Robert Lodewyk
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« Reply #19 on: April 02, 2012, 04:07:28 PM »

   I remember Richard Petty's  Plymouth Road Runner having a vinyl roof about the same time in Nascar. I may have a photo in my archives
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Jon Mello
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« Reply #20 on: April 03, 2012, 09:31:17 AM »

Mark, here is some info on the Richard Petty car you are talking about.
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Jon Mello
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« Reply #21 on: April 05, 2012, 07:55:43 AM »

interesting triva Richard Petty ran the 1968 Daytona 500 with a mystery black top Roadrunner

quote from a NASCAR site
"It's become folk-lore that the car had a vinyl roof. That's not the case. It was textured black paint. Call it the golf ball theory of aerodynamics. The "pockets" in the textured paint were supposed to capture air, which would allow the passing air to move more efficiently over the car at speed. Think about it as air sliding against air, instead of air sliding over the sheet metal."

During the race, the roof began separating from above the windshield frame.

Some said it was acid dipped or aluminum roof 

They duck taped down to finish the race

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