Is a stock model A frame strong enough to handle a mild flathead without causing any problems? I've heard they would bend like wire, I've heard they would handle it fine. Which is it?
box the frame and weld in the crossmembers and you will be fine. adding a center X or K member would help too
yup! but i suggest you make or install a beefier center crossmember when you pull the old one out. you'll also want to update the rest of the drivetrain and brakes. it's also not a bad idea to weld the crossmembers in so they aren't only depending on the rivets.
What about welded crossmembers, added (and welded) center K memeber and no boxing plates? By not adding boxing plates, you save a hundred pounds or so, and that matters when you have an engine that only puts out 100 - 130 horsepower. But is it safe? I just have to ask - anyone remember that argument between Boyd Codington and Bluebear about this?
Add a few braces here and there ,,look at a 32 frame that should give you an idea of where they thought issues would occur with a V-8 ,,no need for a major rework of the frame
Yes I do ,Looks like Blue bear one by default ,That was a shame that Boyd would not let him do what he wanted ,Sometimes you have to learn the hard way .Believe it or not its eaier to build a A frame out of 2x3 square tube than boxing a stock A frame.I d box it ,Adds strength .and x members add strength
A stock standard Model A frame flexes like crazy, that's what it was designed to do. That's why Model A doors can pop open in certain conditions. You can get away with out boxing if you weld the crossmembers in and supply some K or X bracing, but really... Boyd was right. They're 80 years old, they're pitted, fatigued, full of bolt and rivet holes, and they've most all had cracks welded up. Do ya wanna risk it? BTW: a flathead is not so much about HP, it's about torque, you know, that stuff that twists frames. Box it. I've just done mine, and I'm real glad I made the effort.
i have a friend that built his first coupe back in 1962, unboxed frame with a smallblock chevy and it stills gets driven around from time to time. like alot of things, you can do it, the real question is why would you? there are alot of places i would look at shaving weight before i thought about not boxing the frame or welding up the cross members you could easily increase engine performance to compensate for the 80 pounds boxing plates will cost you, the only reason i can really see anyone not boxing their frame is because they don't want the h***le involved.
In the Tardel/Bishop book the 32 K-member is utilized to act as a transmission mount and to brace up the frame. This is for a motor of 100 to maybe 150 horse power but not recomended for much more than that. Ol Codington probably knew someone that built a model A with higher horse mill that broke a frame going down the road. I've seen some pretty rust frames right where the old banger rear mounts go and thats where they break. The K-member will brace that so that if it does crack you'll likely see it before it falls into two pieces.
Depends on the "year" of the car you want to build. Have you seen this?; http://www.jalopyjournal.com/forum/showthread.php?t=422635 I like to see a forties build,all old parts and Ford stuff. Cloth covered wiring..etc..(not one part from Speedway) I build new Model A frames,so I'm around those all the time.
I am going to run a stock 8BA flattie with my model a frame. I boxed it in already and am designing and x member for it. Its better to be safe then sorry!
exactly what von rigg fink said box it and x member it nice pict, I like people who post picts so for those who dont know what were talking about now have a visual good luck with your frame big mac
Well...they made the frame rails deeper in 32 so that difference will be hard to copy. Thing with a 32 as well is that the design lasted for exactly 1 year. The FIRST year Ford had to deal with the V8! Then Ford got serious about torsional strength with the X member frames that followed and I'm sure the surprising torque of the V8 had something to do with it...along with the longer wheelbase. I think a good A frame will hold the weight and horsepower, but I wonder how enjoyable the car will be compared to how it would be with a solid foundation.
I meant for a fully boxed frame, and I'm probably off by 40 pounds. I was just moving the boxing plates I have cut for my model A frame in the garage, and it sure as hell felt like 100 pounds when I picked them up, but that might have been my New Year's day hangover . . .
I have a good set of A rails that I'm putting a flattie on, and not boxing it. Maybe 150 horses won't be a problem on the street. The old round-track guys boxed them because they were sliding sideways all weekend on a rutted dirt track. The A frame was designed to flex. A partly boxed, or poorly boxed frame would be more prone to cracking than a stocker.
I'll be boxing mine, at least up to the firewall, and will have some type of X- or K-shaped crossmember, that ties in to the front boxed frame. But, I've seen plenty of rods at shows that have unboxed frames. I saw one guy who tore off the front p***enger side body mount at the base of the firewall.... my guess is the body didn't like all the flexing the frame had happening. Just not what I want on my car. It's boxing for me. JMHO, Pete
Y'all kill me. I dare someone in hamb land to build a non-boxed frame,un dropped axle, 21 stud V-8 roadster.No fenders and painted a old Ford color.
a 20' stick of 4"x3/16" is 51 pounds, with welds, minus tappering ends your probably around 40-45 pounds to box a model A frame
Boxing a frame is such a small step to laying a good foundation for a hot rod. I don't understand why guys try to avoid it. Even if I were building a banger powered roadster, Id box my frame.
I don't think anyone said it can't work...just that it would be so much better if you DO go thru the extra trouble! Now if your going for a true 40's build and all stops are out...different story entirely! Bet you even end up with a retro cool and totally Traditional "Roadster pinch"! (Clean frames too BTW...NICE!)
I'd think that boxing the frame would be prudent but it appears that Chris didn't box his latest effort or at least hasn't boxed it yet. http://www.jalopyjournal.com/forum/showthread.php?t=422635&highlight=v8 I think that a couple of factors are involved though and one is that the car still would need buggy springs on both ends with wishbones that allowed it to move up and down a bit. The other would not be overdoing it on the horsepower.
I have never seen anyone ever do this, but how about welding a second set of original frame rails (swapped side to side) inside the original frame rails ? Sort of like this [] . Instead of just boxing it, it would make the frame rails twice the width along the whole length, and improve torsional stiffness much more than just boxing. The original sideways bend in the rail would need to be reversed for the inner set of rails, but obviously the taper along the rails should match perfectly. Any opinions on this ?
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