Beefing the Frame

[Deleted User]

I was thinking the other day of all the stuff I should do when the car goes into the welder's shop (for the MII install). Since I am considering a 4 link rear suspension, I understand the frame would have to be "beefed" up, maybe "z'd" or something. My question is....if I build supports that run underneath the body, would they have to be tacked or welded to the underside of the body or not? If I didn't, would there be vibration or rattling noises to drive ya crazy? Or would you just make crossmembers and such slightly less height than the top of the original frames so it wouldn't touch the body underneath?



I've not had to deal with a unibodied car before.



Jay

mrsbojigger

Good morning Jay,

You may want to check out what was done at www.egbertsstreetrods.com/hudson.htm.

They are using a 4-link suspension on that Hudson. It can give you some ideas since they are the professionals. Also, I am definitly going to be beefing up the under carriage of mine. I am using a complete Camaro front clip which ends about mid way on the crossmember. From that point back all the way to the rear spring clip I am going to run a u-channel. Actually a u-channel with 1/2" flanges for welding. The front clip and the rear clip will be connected to make a complete "frame". This u-channel will be of the same gage as the outer unibody frame. It will not be as thick as the Camaro clip but it doesn't have to be because of the unibody. I will be welding it to the floor. The logic is 2-fold. First, when it is welded to the floor it is now part of the unibody and adds strength. Secondly, with a long span of light sheet metal like this it can spring up and down under normal road conditions like a giant guitar string vibrating. I know you can't see but trust me it but it does happen. What about "z"ing? Do you mean "C"ing? Here again check out the Egberts car. I can explain a lot. I had to "C" my frame on my convertible since it is so low. I just welded sheet metal plates on both sides of the frame. Rodders do this all the time.

What happened to the parts that run lengthwise to hold the emergency brake cables? They went into the trash. It was a Rube Goldburg setup anyway. I am using a late model Chevy truck S-10 emergency brake system. Much cleaner.

Have fun and Peace,

Chaz

rambos_ride

mrsbojigger wrote:

Good morning Jay,
You may want to check out what was done at www.egbertsstreetrods.com/hudson.htm.
They are using a 4-link suspension on that Hudson. It can give you some ideas since they are the professionals. Also, I am definitly going to be beefing up the under carriage of mine. I am using a complete Camaro front clip which ends about mid way on the crossmember. From that point back all the way to the rear spring clip I am going to run a u-channel. Actually a u-channel with 1/2" flanges for welding. The front clip and the rear clip will be connected to make a complete "frame". This u-channel will be of the same gage as the outer unibody frame. It will not be as thick as the Camaro clip but it doesn't have to be because of the unibody. I will be welding it to the floor. The logic is 2-fold. First, when it is welded to the floor it is now part of the unibody and adds strength. Secondly, with a long span of light sheet metal like this it can spring up and down under normal road conditions like a giant guitar string vibrating. I know you can't see but trust me it but it does happen. What about "z"ing? Do you mean "C"ing? Here again check out the Egberts car. I can explain a lot. I had to "C" my frame on my convertible since it is so low. I just welded sheet metal plates on both sides of the frame. Rodders do this all the time.
What happened to the parts that run lengthwise to hold the emergency brake cables? They went into the trash. It was a Rube Goldburg setup anyway. I am using a late model Chevy truck S-10 emergency brake system. Much cleaner.
Have fun and Peace,
Chaz

The mechanical back-up were a nice feature for the era - and I've heard many folks on the forum running stock braking setups that they have hit the mechanicals more than once! But with a modern dual piston system and a good ebrake backup the mechanicals are not really needed.

That being said I looked underneath at connecting the original front sub-frame to the back "frame" rails on the 49. I don't know guys because of the shape of the floor pan and without channeling the floor I can't see how you could get a beefy enough piece of iron up there without affecting your ground clearance - there are too many horizontal stiffners *and the front and rear floor pan* running underneath that would require cutting out or around in my opinion.

You can see Eggberts 48 had extensive (=expensive) mods done to the floor pan and rear tub areas to make it work.

I guess if you just have the money and time to burn or are going to run some 500hp+ monster motor setup and flogg it at the race track every weekend those mods will be needed - but for not for a daily driver or weekend warrior IMHO!

mrsbojigger

Hi Dan,

As you know everybody has a different way of doing things. This is my way of doing things. My funds are very limited being an Artist. Its feast or famine. My income has dropped about 60% since 9/11. No kidding! I don't arbitrarily make changes since money is the key. I think them out before using them. You and I discussed this pre-engineering thing before. We are both all for it. I am limited to just hand tools but I do all the work on my chassis myself. The only "high dollar" tool I have is a little 110 volt mig welder from Datona Mig. I keep it cheap. My Hud is going up on the rotissary this winter and with the help of your great photos I will be doing the floor pans, trunk pans AND the connecting of the frame rails. It WILL work. By the way I made my own rotissary with just the cost of the square tubing that I got from a salvage yard.

Have fun and Peace,

Chaz

P.S. Dan, I'm reading a great autobiography of Raymond Lowey. His thought process on mechanical and design aesthetics was phenomenal.

[Deleted User]

Hey Chaz......how'd you hook your car on a rotisseire? Where are your mounting points? I'd love to be able to make one of those, it would make life so much easier. Did you strip the car to lighten the weight? My is so complete, I'd hate to have to do that. But the drivetrain (except the rear end) is coming out soon. Seems to not be much use to anyone for a flathead, so I think mine may go to the scrap heap! Or melted into boat anchors! lol I was looking in the latest Custom Rodder mag and they have a 49 Plymouth that the guy used tubing to make a custom x-member to beef up his frame in the middle (and you could make weld tabs to periodically weld to the floor). I haven't looked yet, but is the rear frame rails a "c?" or boxed? I gotta get my 4x4 blocks out and get mine higher up on the jackstands.



I think for now I may just go with dearched leaf springs in the rear to keep the cost down.



Anyway, would love to see your rotisserie.



Dan, as always your tips are great. I appreciate everyone's helpful tips and tricks.....this is a excellent forum!



Jay

rambos_ride

mrsbojigger wrote:

Hi Dan,
As you know everybody has a different way of doing things. This is my way of doing things. My funds are very limited being an Artist. Its feast or famine. My income has dropped about 60% since 9/11. No kidding! I don't arbitrarily make changes since money is the key. I think them out before using them. You and I discussed this pre-engineering thing before. We are both all for it. I am limited to just hand tools but I do all the work on my chassis myself. The only "high dollar" tool I have is a little 110 volt mig welder from Datona Mig. I keep it cheap. My Hud is going up on the rotissary this winter and with the help of your great photos I will be doing the floor pans, trunk pans AND the connecting of the frame rails. It WILL work. By the way I made my own rotissary with just the cost of the square tubing that I got from a salvage yard.
Have fun and Peace,
Chaz
P.S. Dan, I'm reading a great autobiography of Raymond Lowey. His thought process on mechanical and design aesthetics was phenomenal.

Boy can I commiserate on the funds issue! My job right now pays me 60% less than I made then as well - and I have to have more skills...

I didn't mean to imply that a sub-frame connection couldn't be done without channeling the floor out but there could be some minimal ground clearance degredation - but there are always trade-offs and with customization you never really know until you do it the first time.

For my own build I have been trying desperately to not leave anything hanging lower than originally was designed and without hacking the floor pans - at this point I have succeeded but still have the remainder of the exhaust system to figure out a way to get bigger exhaust and mufflers and maintain those tolerances - I may not be able to...

Sweet job with the rotisserie! I wish I had the space to have utilized one of those. My car would never rotate under my carport! But, prepping the underneath and ALL the repair work would have been so much better!

Yet again I am forced to admit "tool envy" :rolleyes: - I know you are "shop challenged" as well - but I swear my next house will have a shop and enough room to do things right!

What's the name or ISBN on the book - might make an interesting read....

mrsbojigger

Jay,

Here are some pics for you. The rotissary that I will be using on the Hudson is the one that I used on the 47 Ford frame. I am modifying it to include wheels/brakes for moving about and the L-shaped frame attachments shown in the proceeding pics.

NOTE: My storage space is at a minimum. The horizontal supports are bolted into a U-channel at each end so the complete rotissary can be completely dismantled and stored in a space no deeper than 18".

mrsbojigger

pic 2 of how to attach car;

mrsbojigger

pic 3 of how to attach car

Unknown

With the '53 Wasp, I had Mark Williams in the northwest bend up a couple of box tubing rails for the rear. I don't know if they're still in business but they were pretty big in the drag racing manufacturing scene in the 80's. They may still have the measurements.



The rails were welded to the crossmember at the front edge of the rear seat as well as directly to the perimeter frame in the rear. We also added a tie in from the perimeter frame just before the kickup.



By using this setup, it kept the costs down. We used a ladderbar/coilover setup which really worked well and allowed us to put 12" slicks under the rear. If anybody sees a rose/purple '53 Wasp Brougham out there it probably came out of my shop in Reno!

[Deleted User]

Just kinda curious what your planning on doing to the car to need to brace the rear? My dads 49 has a narrowed rear and 31"x13" slicks with the stock frame rails moved inboard and 33" ladder bars, but he has a full cage, and hammers the car on a weekly basis. If its just a basic hot rod you probably would not need a lot of bracing but if you plan on hammering it a six point bar system could be some cheap insurance. You can't really compare work done on any other period car because of the frame vs. unibody issue, but the unibody structure on a Hudson is very strong, remember you even have an extra frame rail running outside the rear tires! I know from building my 47 that its a whole diff. set of rules when you mess with the unibody car vs one with a full frame.We would be glad to pass on any knowledge gained through our experience if you need it. http://groups.msn.com/HudsonEssexTerraplaneBulletinBoard/hudsonspeedparts.msnw?Page=2

[Deleted User]

harcoequip:



I was thinking about what bracing would be necessary to install a 4 link set up in the rear (for airbag suspension) mostly for lowering effect. I will probaly run 3.08 gears in the rear, so its more for economy rather than a drag car. Not that I wouldn't get on it on a long empty bit of highway (which I probably will do!). Some have thought here that you would need to beef up the rear frame to handle a 4 link, but I'm not sure anyone has actually done it, so I don't know that there are any examples out there. Any suggestion you might have would be greatly appreciated. By the way......nice pics! :-)



Jay

rambos_ride

harcoequip wrote:

Just kinda curious what your planning on doing to the car to need to brace the rear? My dads 49 has a narrowed rear and 31"x13" slicks with the stock frame rails moved inboard and 33" ladder bars, but he has a full cage, and hammers the car on a weekly basis. If its just a basic hot rod you probably would not need a lot of bracing but if you plan on hammering it a six point bar system could be some cheap insurance. You can't really compare work done on any other period car because of the frame vs. unibody issue, but the unibody structure on a Hudson is very strong, remember you even have an extra frame rail running outside the rear tires! I know from building my 47 that its a whole diff. set of rules when you mess with the unibody car vs one with a full frame.We would be glad to pass on any knowledge gained through our experience if you need it. http://groups.msn.com/HudsonEssexTerraplaneBulletinBoard/hudsonspeedparts.msnw?Page=2

:cool: Sweet Pictures! - I knew some big-ol fat tires sitting within the original sheet metal would look cool!

Makes me wish I had more time, money, tools and shop to work in because when the trunk pan was cut out on my 49 would have been the time to do something like that...oh well maybe my next Hudson...

[Deleted User]

I'm using coils in the front right now for costs reasons. Eventually I'll change to airbags which can be done with only having to mount the shock outside the coil. The MII should drop the front 3-4". I am thinking about airbags in the rear if I can figure out an economical set up. Looks like I'm going to have to do some frame work on the ourside rails, so if I don't have to go too crazy, I'd like to find an airbag set up for the rear to get it low. If it looks like its too costly now, I'll just go with some dearched springs and/or lowering blocks for now. Its interesting to me that harcoequip's Dad just mover the stock frame inward and is stomping a narrowed diff! Makes we wonder if a 4 link with airbags may not require and beefing, justmounting mods. I don't know, but since our "chief" appears to not be coming thru with that article on his Hornet, I'm just looking at alternatives.



Jay :-)

[Deleted User]

I talked a little with Dad about your plans and he feels that it if all your frame rails are solid you don't need a bunch of extra bracing. The frame structure of a Hudson is one of their claims to fame. A little side note 33" ladder bars are the correct length to attach to the stock Hudson crossmember so no extra cutting would be required since you don't plan on narrowing the rear!

Also, thanks for the kind comments, Dads car is torn down right now for paint and a new engine. It will finally be solid yellow (color on the firewall) and is getting a new 500" mopar with Indy aluminum heads. I get his old 440 with a couple of improvements. He had a best of 11.24 sec. @ 119mph and my ride will be about 400lbs lighter so were are hoping for two 10sec Hudsons! We will keep everyone up to date on our progress.