Hoping someone out there has a 1940 Chevrolet Convertible or can help with questions? I am seeking some photos of the original frame and possibly a couple of measurements. Any help appreciated! Eric UPDATE See updated post below dated February 5, 2016 ... thanks!
I will assume you mean the top frame. I bought a CD of the Fischer body manual that includes the section on the convertable top from Chevs of the 40s. It is a reprint of the original GM books and it is available from a lot of the usual car book sites. It shows detail pictures of the frame and mechanism. Chevs of the '40s sells a lot of the parts for the top also.
No, actually I am talking about the chassis frame which is a massive overbuilt one year only design for the 1940 convertible. The frame apparently has not been part of the various manuals so need pics and measurements.
Nearly 5 years ago I made this post and no one has attempted to answer it so, I am bringing it back to the top. There was no 1939 Chevrolet convertible in the USA but was an export model to Australia and Holden added their own X brace member to it. In 1940, Chevy reintroduced the convertible in America but it had a poorly engineered, overbuilt chassis which by GM's own account, failed and was not strong enough. It was an oddball with the look of an armature cobbled frame and not shared with any other GM car or model. For 1941 they went with a more traditional X. But strange is the fact that nowhere in the 1940 Chevrolet Shop Manual does it mentions nor illustrate the convertible and what literature the car is illustrated in does not mention the different chassis used. Only a body shim chart seems to exist from a service bulletin and then the drawing is not 100% accurate to the production vehicle. My question is wondering why this mysterious chassis design was used. Who designed it and why (other than being a convertible)? Why not use a simple X brace as Holden did to the basic boxed 1939 frame which was similar in design for 1940 - or one that GM already had in use? And any photos or illustrations of it would be greatly appreciated! Eric Chevrolet-Holden (Australia) added X to 1939 Chevy Convertible chassis and a poor stitched picture (seeking better) of underside of a 1940 cabriolet (convertible) for comparison.
Ray, I have been gathering information the past 6 years for an academic book about the design and development of x-brace (cruciform) chassis frames. They have been used on vehicles almost as long as they have existed and still used today on the London Taxi. The 1940 is an oddball used on one model for one year only and seems like a waste of money designing it... and why in the first place when Chevy had other simpler layouts and fixes available that GM, and other companies, had been using for years. One easy fix being seen in the Aussie built 1939 Chevy convertible. So to answer your question, yes, I would like to know more about the 1940s origin, rational, who ordered the design since Coyle was a penny pincher, etc... Thanks Eric
If you want pictures of the frame, you might try Ron Francis, of Ron Francis Wiring. 1-800-292-1940 He used to own a 1940 Chevy Convertible, and he featured it in a lot of his advertisement. Don't know if he still has it or not, but he may have some old build pictures, etc. Good luck.
Thanks X... I am always seeking better bare chassis photos of unaltered frames but not as much as trying to solve the puzzle about this 1940 oddity. Even in the Chevrolet Engineering Facts book for 1941, they admitted that the '40 design was a failure and so used a more traditional X brace for '41 on the convertibles. GM Heritage has been great providing me with copies of those pages but have nothing on record about the '40 that I am seeking info about. Someone on another thread pointed out how the design layout was not structurally sound so again, why did they even bother if this was a disaster on various levels using a huge cross brace, doubled up (stacked) side rails, X (or K) legs do not align up, and used a huge flat plate to tie it all together? Eric
Here's are 40 Cabriolet frames and a 46 convertible frame for comparison. A friend has a 47 Olds convertible and the actual X-member is heavy I-beam construction not open pressed 'C' section. The Olds is large open 'C' channel whilst the Chevy is closed 'Top hat' design.
The yellow chart I posted myself years ago and the ones below it in b/w is the 1941 replacement chassis. The topside of the 1940 looks like this:
Eric, I've had my '40 convert for 36 years, soon to go into it's 37th year under my care. It has had an MII ifs on it for the past 25 years or so, otherwise the frame is pretty much original. It's held up pretty well and I never belabored the fact that is was a one year only frame design. What can I do to help you? Charlie
Thanks for the lead. I sent Charlie Chops 1940 a PM and see he is here every day, and offered to help with his own 1940 Convertible, but still have not heard back yet... Charlie???
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