talon90
11-08-2008, 05:01 AM
There has been a fair amount information posted as well as a fair amount of mis-information posted regarding the roof panel noises that may present on the removable roof panel of the coupe. I wanted to take a few minutes and try to corral the facts in to an easy to use post for people to reference. I will be citing the work of others as well as what I've learned along the way. If I reference a post or thread of yours and you would like it removed please just let me know.
First a little background:
The Corvette coupe has a removable roof panel. The panel is comprised of either a opaque painted polycarbonate panel or a molded transparent polycarbonate panel. The panel is bonded to a magnesium frame. The panel assembly is attached to the car using basically four pins to locate it, two sliding fit clamps and a third latch style clamp as a safety retainer. The perimeter of the frame is mated with a rubber weather seal gasket to prevent wind and moisture from entering the drivers compartment. Half of the gasket seal is on the car at the windshield top frame and b pillar halo and half of the gasket is on each side of the roof panel. These four parts come together to form the complete weather seal.
The Corvette coupe panel is a fairly complex exercise in engineering. It must fit loosely enough such that it can be installed and removed with ease. It must fit tightly enough such that wind noise, moisture and the elements are not permitted to enter the cockpit. The complexity of the design continues when you consider the fact that the side gaskets of the roof panel become the upper window frame that would normally be occupied by a surrounding steel frame that encases the window on most every other car today.
The Corvette roof panel latch handle has undergone some changes during its life. From it’s introduction in 2004 until April of 2007 the latch remained unchanged from the factory and it was a steel roller that was free to roll and move within the handle. It looks like this:
http://img.photobucket.com/albums/v610/talon_90th/C6/For%20Posting/roof%20panel/100_2681.jpg
In April of 2008 during the 2008 model year complaints of roof panel latch rattle noises were being received and a temporary fix was introduced at the assembly plant to help cure the customer complaints. It was found that by isolating the roller they could minimize and in most cases eliminate latch noise and a campaign of putting an epoxy on the current design roller while the roller was redesigned. I don’t have a photo of a early 2008 latch but it is basically the roller above with a mass of a whitish epoxy cementing the roller in place.
In June of 2008, still during the 2008 model year the newly redesigned latch handles were made available to the assembly plant and were incorporated on the line on June 10th. The new design latch handle uses a plastic roller and it is immobilized with a wedge shape that interlocks with the handle. The new latch handle looks like this:
http://img.photobucket.com/albums/v610/talon_90th/C6/For%20Posting/Latch2.jpg
A little about “noise.”
Noises in an automobile are generally perceived to denote poor quality or workmanship. One issue that we must keep in mind is that every owner is different. Each has a threshold if you will of what they consider acceptable. The roof panel being removable by definition means that it can move. Movement will contribute to sound as surfaces interact with each other. Most owners have never owned a car with a removable roof panel
Common causes of roof panel noise.
Latch handle rattle.
The latch handle design originally was a metal roller which engages a steel plate. Tolerance can allow the roller to vibrate which can produce a tapping rattle sound. Wear or tolerance in the roller itself can allow the roller to move side to side which can also tap the steel plate.
Thermal expansion.
The roof panel, the frame and the gasket materials all have a different coefficient of thermal expansion. All of these mating parts will heat up and expand at different rates. One by-product of this expansion causes to masses to try to occupy the same space and as such something must give.
Lubrication.
The gasket materials that support the removable roof panel are rubber and are prone to the effects of ozone, particle contaminants and wear. As the gaskets age they will become less compliant and less able to support the roof panel firmly and may contribute to movement and noise.
Fit.
Because the roof panel is a manufactured part it means that some allowable dimensional deviation or tolerance is going to be manufactured in. Most of this tolerance is accounted for in the engineering process but it is possible to have a component fall outside of that expected range. When this happens the parts won’t fit together as well as they were designed to fit together. A second contributor to this is an owner that may purchase an accessory transparent top that didn’t come with the car originally. These parts may not fit together perfectly. This will most commonly appear as a panel that sits too low or too high relative to the windshield frame and gasket. It is possible to realign the latch handle and the latch receiver by a simple adjustment of the torx bolt that holds each of them in place.
The next section will outline some of the areas that you can turn to in an effort to make your car as noise free as possible.
Paul :cheers:
First a little background:
The Corvette coupe has a removable roof panel. The panel is comprised of either a opaque painted polycarbonate panel or a molded transparent polycarbonate panel. The panel is bonded to a magnesium frame. The panel assembly is attached to the car using basically four pins to locate it, two sliding fit clamps and a third latch style clamp as a safety retainer. The perimeter of the frame is mated with a rubber weather seal gasket to prevent wind and moisture from entering the drivers compartment. Half of the gasket seal is on the car at the windshield top frame and b pillar halo and half of the gasket is on each side of the roof panel. These four parts come together to form the complete weather seal.
The Corvette coupe panel is a fairly complex exercise in engineering. It must fit loosely enough such that it can be installed and removed with ease. It must fit tightly enough such that wind noise, moisture and the elements are not permitted to enter the cockpit. The complexity of the design continues when you consider the fact that the side gaskets of the roof panel become the upper window frame that would normally be occupied by a surrounding steel frame that encases the window on most every other car today.
The Corvette roof panel latch handle has undergone some changes during its life. From it’s introduction in 2004 until April of 2007 the latch remained unchanged from the factory and it was a steel roller that was free to roll and move within the handle. It looks like this:
http://img.photobucket.com/albums/v610/talon_90th/C6/For%20Posting/roof%20panel/100_2681.jpg
In April of 2008 during the 2008 model year complaints of roof panel latch rattle noises were being received and a temporary fix was introduced at the assembly plant to help cure the customer complaints. It was found that by isolating the roller they could minimize and in most cases eliminate latch noise and a campaign of putting an epoxy on the current design roller while the roller was redesigned. I don’t have a photo of a early 2008 latch but it is basically the roller above with a mass of a whitish epoxy cementing the roller in place.
In June of 2008, still during the 2008 model year the newly redesigned latch handles were made available to the assembly plant and were incorporated on the line on June 10th. The new design latch handle uses a plastic roller and it is immobilized with a wedge shape that interlocks with the handle. The new latch handle looks like this:
http://img.photobucket.com/albums/v610/talon_90th/C6/For%20Posting/Latch2.jpg
A little about “noise.”
Noises in an automobile are generally perceived to denote poor quality or workmanship. One issue that we must keep in mind is that every owner is different. Each has a threshold if you will of what they consider acceptable. The roof panel being removable by definition means that it can move. Movement will contribute to sound as surfaces interact with each other. Most owners have never owned a car with a removable roof panel
Common causes of roof panel noise.
Latch handle rattle.
The latch handle design originally was a metal roller which engages a steel plate. Tolerance can allow the roller to vibrate which can produce a tapping rattle sound. Wear or tolerance in the roller itself can allow the roller to move side to side which can also tap the steel plate.
Thermal expansion.
The roof panel, the frame and the gasket materials all have a different coefficient of thermal expansion. All of these mating parts will heat up and expand at different rates. One by-product of this expansion causes to masses to try to occupy the same space and as such something must give.
Lubrication.
The gasket materials that support the removable roof panel are rubber and are prone to the effects of ozone, particle contaminants and wear. As the gaskets age they will become less compliant and less able to support the roof panel firmly and may contribute to movement and noise.
Fit.
Because the roof panel is a manufactured part it means that some allowable dimensional deviation or tolerance is going to be manufactured in. Most of this tolerance is accounted for in the engineering process but it is possible to have a component fall outside of that expected range. When this happens the parts won’t fit together as well as they were designed to fit together. A second contributor to this is an owner that may purchase an accessory transparent top that didn’t come with the car originally. These parts may not fit together perfectly. This will most commonly appear as a panel that sits too low or too high relative to the windshield frame and gasket. It is possible to realign the latch handle and the latch receiver by a simple adjustment of the torx bolt that holds each of them in place.
The next section will outline some of the areas that you can turn to in an effort to make your car as noise free as possible.
Paul :cheers: