Chevy full size cars 1958-1964. Pontiac, Cadillac 1958-1960. Oldsmobile - 1958. 1959-60 Olds has an X-frame with a perimeter bar added behind the rocker panel, at least the '59 88 I had had this in it. So far as I know no other GM used an X-frame. I'm still trying to get someone to explain to me what exactly is different between a hardtop X-frame and a convertible X-frame. I've had one person tell me a convert frame is specific but no one can tell me what is different about them or what parts I would have to save to make another frame into a convertible frame. EDIT: Buick used their own frames through 1960 and don't have the X, in fact the 1958 frame is a continuation of 54-57 frames. But the first and possibly second gen Riviera do have an x-frame. 1961 and up the other models use a frame similar to Pontiac and Olds. Cars with conventional frames used an added X-shaped crossmember into the 1960s, but by the mid 60's this seems to have been done away with.
I've got a fact. assy manual for the 60 Chevy. It shows the convert frame with some extra body mounts. Arms that come out and support the body. I think there were 4 extra mounting spots.
The 58 X frame according to my 58 Chevrolet Passenger Car Shop Manual shows that the hardtop and the convertible share the same frame........ If anyone's got a picture/illustration of the convertible x frame I'd give you a shiny new penny for it!!
the early 60s Chevy convertible X frame has some heavy steel reinforcements on the bottom of it. The 1974 issue of the 46-64 parts book lists the 61-64 chevy car frame part number, and says "exc. Conv." I know a guy with a 61 ragtop, it's faintly possible that I could sneak some pics of the underneath of it....and the same guy junked a 62 ragtop frame about 5 years ago, iirc.
Seems I remember the 66 Impala (hardtop) had an X frame. Had one sitting in the corner of my old shop waiting to be a lowrider, but I never got around to it...
66 impala has a perimeter frame, it would be pretty difficult to put an X in it with the floor build the way it is.
Yeah I can tell you about the Chevrolet ones... 58 X frame is by itself because it's like 2 inches shorter than 59-64. 59 and 60 are different than 61-64 in the sense that the mounts for the banana bar are different, plus the idler arm for the center link has a different bolt pattern from 59/60 to the 61/64. Wagons and el camino frames have an extra brace thingy sitting on top of the frame where it goes up to meet the bottom of the bed. Also there is a removable cross member near the fuel tank on the wagons and el caminos that are bolt in for ease in removal of the fuel tanks. In the cars, they're welded in. Convertibles have a lot of extra bracing... where it looks like they welded plates to the frame to prevent flexing. otherwise you can bolt it to a coupe with no change etc... but if you bolt a non-convertible frame to a convertible then you will be driving a pretzel in no time. Here's mine...
Ohhh good to see you've BUNNY hopped out of the BUSH for this. I thought about you long after I went to bed...............SO where is the bracing on that convertible?? Do they make it a ladder frame on any level and box in the X frame?
You going to the Asphalt Invitational, Brandy? I need to clear away the bush and get the bunny hoppin' your way. No extra braces or crossmembers on convertible frames. It's like they welded a skid plate to the frame itself along the bottom. If I can ever get the car high enough (bagged... frame sits 1/2" from the ground) I'll take pictures. Travis
Ohh that would be KILLER nice of you since I took my top off and plan on juicing it up a bit. Yeah I think I could be obliged to go to the Invitational for that.
Great input. Any thoughts on whether 61-64 GM convertible x-frames could interchange with other GM platforms (Pontiac, Olds, Buick) of similar years?
So I guess the question is, could I fix a rotted convertible frame (they always go from the rear axle back) with a new clip from any of the others?
Rusty- Yes. If the frame is solid from the rear axle and forward, that would be good to save and to weld on a new rear clip behind the rear axle location. All of the extra braces/skid plates are between the front and rear axles. I don't know what you would get for it tho. Most people look for the Canadian frames. Travis
Just trying to unload one and may get another and both rotted bad in the back, wanted to know if they could be saved or not. Thanks..
Hey, Watch out now, some of the Kunnuk Pontiacs were built on Chevrolet frames. The replacement of frame sections that are rotted or to fucked up to be straightened was once a common repair detail in the collision repair industry. When ya repair, try and just replace the rails, fish plate as necessary, and stay out of the torque box areas if possible. Gm quit the X-Member frame design in the mid sixtys, and went to the perimeter frame design in order to build a lower riding vehicle. Swankey Devils C.C.
Of course, '55-'57 Chevy ragtops had an "X" member in addition to the regular frame. What a pain to run duals through without having a rattle somewhere! In '65 when the X frame went away, the convertibles got a fully boxed frame for extra strength, instead of the C channel that all other passenger cars got. That's why so many convertibles (in this part of the world, anyway) have punky frames; no one bothered to stick a garden hose in the acess holes to wash the dirt out.
Tri year Pontiac's are the same damn way.........and they trapped moist dirt as well as other debris. Sadly.
This is an old thread but since I am the X-Frame expert and have been studying them for the past 9 years in preparation for writing an academic book, I thought I would correct a couple errors concerning applications. First Fact... the style frame in question was never called an X-Frame by any General Motors division. The engineering designer called it a "Cruciform" frame and the commercial term is a Tubular-Center X Frame. Each division had their own name for it and Chevrolet called theirs the "Safety-Girder Frame", which in itself is a whole different story. Second Fact... the Tubular-Center X frame was originally exclusively designed for the new 1957 Cadillac Eldorado Brougham while toying with the idea of converting the other models to a unibody. But at the last minute, they ported the design with a few changes over to the other Cadillac models. That out of the way, here is the lineup: 1957-1964 Cadillac (1965 Fleetwood Series 75 limousine was a 1964 carryover except for commercial models) 1958-1964 Chevrolet 1961-1964 Buick (1958 was X-Braced; 1959-1960 Buick had a K frame under the front floor area) 1963-1970 Buick Riviera 1958-1960 Pontiac 1958-1964 Canadian Pontiac (they were Chevrolet chassis and drivetrain with Pontiac panels) Oldsmobile did not use this style frame but for 1959-1960, did have a pseudo-hybrid version with wide stance side rails. Hope this clears up some questions? Eric Huffstutler (Reverand Eric, The X Frame Cleric)
As far as interchangeability, each General Motors division had their own design which means, different lengths, wheelbases, widths, kickup heights, etc... With convertibles, they used a reinforcement plate stitch welded to the top and bottom of the rails between the tunnel and kickups. Some call them "fish plates". Eric Huffstutler (Reverend Eric, The X Frame Cleric)
The convertible bodies also had extra reinforcing in the rocker area, eh? The additions to the frame weren't enough...something to consider if you are planning to cut the roof off of one of these cars, or use the frame under something else
Product diversification...not 'all your eggs in one basket'.... water heaters are a stable commodity product
The A.O.Smith company pioneered the forming methods used to produced auto frames and in fact were the largest producer of GM frames for quite a period , the water heaters a new d grain silos and boilers etc came later . There are some very good write-ups on the net , quite a company !
Let me answer the second question first. A.O. Smith has always done more than build vehicle frames. In 1921, they made high-pressure tanks for use in oil refining. In 1927, they developed a method for welding large-diameter steel line pipe for transporting natural gas (pipeline). In 1933, developed a method of fusing glass to steel and introduced the first large, single-piece glass-lined brewery tank. This lead to a patent for the glass-lined water heater which they began manufacturing in 1939. It didn't happen overnight and only increased production when unibody construction took over as the industry standard, killing off the need for automobile frames. As far as the three different frames? Some label what are called "seamless" frames either California or Canadian and both terms is a misnomer. Example: 1958-1964 Chevrolet X-Frame Manufacturers 1.) A.O. Smith Co. - built reinforced frames for convertibles from 2 “C” channels welded together 2.) BUDD Corporation – built frames for sedans and hardtops from 2 “C” channels welded together 3.) Chevrolet – built frames for sedans and hardtops from an extruded steel tube at the Flint, MI stamping plant. This has become known as the “seamless” frame. Frames delivered to various assembly plants depended on who ran out first and who had frames available. The seamless frame also had a different style center tube than the welded ones. The seamless style had no specific state or plant they were used. Some think the "California" moniker came from California's safety regulations and how the bumper was attached to the various frames with the seamless being chosen. (a story for another time). For 1958 Chevrolet, the convertible and sedans used the same exact frame except for the extra welded on plating. There were no extra attachment brackets. The sills were built larger and boxed like a side rail and the cowl was double walled. Lower door post heavier and underbody bracing also made heavier. GM knew of the design shortcoming before going into production but hedged their bet with the extra reinforcements. For 1959, they added an additional verticle flange inside the rocker and extra mounts (with extra floor braces) for the convertible. But as far as the sills being different between the convertible and sedan models, there were none that I know of. BTW... this design is not new. The 1935-1950 Fiat 1500 series had a nearly identical layout. There were other cars and even a Jeep that used the cruciform style frame over the years. If you have questions, please ask. Eric Huffstutler (Reverend Eric, the X Frame Cleric)
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