Having purchased a 63 corvette previously taken apart by someone else; when placing the body on the frame, I had questions about the proper placement of body mount shims. Is there someone that can tell me how this process was done at the factory and what I might do at home to double check my work?
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Re: Body mounting and shiming
Hey Tim, Nice to see you on the discussion board. Dominic told me that you were working on the white beast trying to get it finished. I can't help you with your question but you might want to get a hold of Chuck Gongloff and see if he has any information from his '63 fuelie convertible that could help you. My '69 is off being painted and I hope to have it back soon. It has been out of the garage way too long for me. I totally stripped the body of everything before it left so it is going to take some time putting it back together. Let me and Carl know if you need any help. Even though my '69 needs to be put back together and Carl has Deb's '66 body off the frame I am sure we can squezze some time if you need it.
Rich -
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Re: Body mounting and shimming
Ken, sorry it took so long to get back with you on this subject. When I purchased my 63 the body was already unbolted from the frame and shims were missing. After painting the car, I placed the body back on the frame, leveling it up as best I could with body shims. I think I did a good job but wondered if there was a way to recheck my work and mabie adjust if necessary. It has become clear to me lately that what I should have done is to level the frame prior to body placement and measure the difference side to side at each body mount location and shim so each mount is level with the adjacent mount. In short, what I'am saying is that the difference is in the mounts welded to the frame, and the placement of shims will make the mounts level side to side. All of the bodies are made in a mold so they are allready flat side to side.Comment
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Re: No shims
Ken,
You mentioned no shims after '63. Ummm, you sure about that?
MikeComment
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Re: Body mounting and shimming
Ken, Do you know the procedure that was used at the factory for body shimming? How was it determined how many shims went to each body mount prior to the time the body met the frame? Keep in mind that the frame was already marked with chalk indicating how many shims to use before the body placement.Comment
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Re: Body mounting and shimming
The rubber cushions for the body mounting were part of Chevrolets Engineering's effort to reduce NVH (noise vibration and harshness) and this continued through the years. The variable rate springs used in '64 and up base suspensions were part of this effort, too. I think Noland's book may discuss this, but I recall reading somewhere that St. Louis used a special gage fixture to determine the number of shims required at each point. Though I can't speak from direct expertice with '64 and up cars, I believe that shimming continued in '64 and beyond, as the purpose of the cushions was to provide harshness attenuation and equal and proper compression of the cushions was important to this goal. Proper shimming limited the torsional and bending "preloads" that were placed on the body to acceptable levels. Excess preload when combined with normal sevice stess could potentially cause structural problems (cracks or even fractures).
As an interesting side note, over the year's '63s have often been considered to have better handling and development potential because of their more rigid structure. Though later mid-years rode better and were less subject to squeak and rattle gremlins, the cushions reduced both bending and torsional rigididy, two paramaters which are, today, acknowledged prerequistites to handling excellence.
DukeComment
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Re: No shims
Thanks Ken,
Now I'm a little smarter. I didn't know there was such a thing as a Corvette without cushions ('63). As far as I know 'shimming as required' is applicable to all years of cars, have a look at the threads above.
MikeComment
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