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Post by wally324 on Nov 6, 2014 20:13:21 GMT -5
Would someone explain the difference between a Sedan/Hardtop frame and the Convertible frame?
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Post by looney1 on Nov 6, 2014 22:51:57 GMT -5
OH, BRO !
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Post by BR[] on Nov 6, 2014 23:15:27 GMT -5
Verts are boxed, HC's and SC's are not. the vert needs the extra support since it lacks the support of the roof. they all have the same dimensions.
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Post by wally324 on Nov 7, 2014 2:25:25 GMT -5
Thanks BRO, So would it be possible to box a sedan frame to make it into a convertible frame?
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Post by mongoose on Nov 7, 2014 6:04:23 GMT -5
Sure. I've seen people box "open" frames for drag racing etc. No reason it can't be done.
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Post by wally324 on Nov 7, 2014 9:23:47 GMT -5
Thanks Mongoose, that gives me another option if I can't find a good convertible frame.
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Deleted Member
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Post by Deleted on Nov 7, 2014 9:53:11 GMT -5
I had a lot of rust in my 442 convert frame. I took it apart repaired and rewelded. This is a big job, and you must restrain the frame to keep it square while welding. I drilled holes in my shop floor and used 3/4" threaded rod to suspend the frame 30" above the floor. You will also need X temporary bracing to keep it square. No individual step is difficult, just time consuming setup as you really need a jig table the size of the full frame. You can buy the frame box pieces on the internet. www.abcperformance.net/frame%20boxing%20kit.htmlThese are not the same as the GM pieces but will get you there. I do have a convertible frame available, for $900, but I am in Atlanta, GA. This is a rolling frame with drum brakes and 3.08 rear, non-posi. |
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Post by joepadavano on Nov 8, 2014 15:48:33 GMT -5
Sure. I've seen people box "open" frames for drag racing etc. No reason it can't be done. Simply welding flat plates to the sides of an open channel frame, the way street rodders do, does NOT make a convertible frame from a HT frame. The factory used additional C-shaped pieces and welded them open side-to-open side to make a box that was about twice as wide as the channel frame. In addition, these pieces were contoured to clear the floor pan. Folks have successfully salvaged the boxing sections from an otherwise rusty convertible frame and welded them to a hardtop frame. |
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Post by wally324 on Nov 8, 2014 19:18:02 GMT -5
I had a lot of rust in my 442 convert frame. I took it apart repaired and rewelded. This is a big job, and you must restrain the frame to keep it square while welding. I drilled holes in my shop floor and used 3/4" threaded rod to suspend the frame 30" above the floor. You will also need X temporary bracing to keep it square. No individual step is difficult, just time consuming setup as you really need a jig table the size of the full frame. You can buy the frame box pieces on the internet. www.abcperformance.net/frame%20boxing%20kit.htmlThese are not the same as the GM pieces but will get you there. I do have a convertible frame available, for $900, but I am in Atlanta, GA. This is a rolling frame with drum brakes and 3.08 rear, non-posi. Alan, I go through Atlanta about once a month (by plane). Maybe I need to drive next time and trailer that home to MN. You need to post some pictures of the frame or PM me. |
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Post by Big Mike on Nov 8, 2014 19:58:29 GMT -5
Wally, you need to check out BubbaZ (a.k.a. Jeff) post on his frame repair. It's right here in the forum.
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Post by joepadavano on Nov 9, 2014 11:36:41 GMT -5
No, they won't. Again, simply welding flat plates to an open channel frame does NOT provide the same bending or torsional rigidity that the factory convertible frames provide. Yeah, it's better than the open frame, and will be an improvement under a Holiday or Sport Coupe, but it is NOT sufficient for a convertible. This is pretty basic mechanical engineering analysis of beams - the math is simple. Bending stiffness (which you need in a convertible frame to replace the missing metal roof) is provided by the top and bottom flanges of the frame rails. The factory convertible boxing sections just about double the top and bottom caps of the frame rails under the rockers, which provides about double the bending stiffness in that area. Flat boxing plates add exactly NOTHING to the bending stiffness (OK, that's an exaggeration - they add NEARLY nothing...). They are effective at adding weight if your car is too fast and needs to be slowed down, however. Keep in mind that GM was (and is) all about building cars as inexpensively as possible. If simple flat plates were sufficient, that's what the factory would have used. The more expensive formed reinforcing parts are there for an engineering reason. |
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