Technical AV8 Late Model Banjo Spring Over Conversion

This will be my first official post. I have a question.

I am starting my 31 Ford Roadster build. I have a 1948 Columbia 2 speed axle. I want to convert it to spring over. I do not want to modify my original 31 Model A frame. I have the Havlir spring perches that bolt on top of the axle. Center to center of perches measure 51.25 inches. I have looked and looked and have not found any info on what spring to use or where to buy one. The rear springs readily available seem to be too short by a couple inches. I would be happy with just a new main leaf and reusing the old leaf pack I already have. I want reversed eye, and a spring that will lower the car 2 to 3 inches. I know using these later banjos isn't uncommon, so I was surprised not to find any tech on using them in this application. Any help would be greatly appreciated, so I can finally mock up a rolling chassis. FYI, I plan on using a 1936 front axle with reversed eye spring. Front tires 6.50-16. Rear tires 7.50-16. I plan on having the rear rims widened to 6 inches, because the late axle is wider. This is a highboy build and should have some stagger front to rear.

Thanks, Dan, Haven Hills Auto

 

100%matt here on the H.A.M.B. makes a model T spring that fits the A for those perches, check the classifieds. Should drop your car 3” without cutting The frame from what I’ve read here. Kind of wish I knew about that when I built my A chassis. Just saw a thread on this, stance looks good.


Sent from my iPhone using H.A.M.B.

 

i think you will find the 42-48 axles are a bit wide to look nice on a roadster body. most folks prefer the 35-40 size. the plain tube on the drivers side should be easy to find, the columbia side, not so easy. yours can be shortened at columbia two speed, google em up. i have one in my 34, manual shift. welcome to the hamb, lets see the car! also, the 48 axle is wide so you need a 48 spring

 

I will check out 100%Matt. Thanks. Rust Valley, yes the axle is wide. This is the problem with the spring. Parts are very hard to find and very expensive in my neck of the woods, so finding the correct Columbia is a problem. Trying to use what I have. I figured by adding 2 inches to the inside of my rear rims will make up for the gap between tire and body. Might be cheaper than cutting into the Columbia. Brookville will deliver the body to NSRA North in September. So, for now, I'm just trying to play with the chassis. It's taken me 5 years to get this far. I will post a pick of what I have started.

 

There is a taste of what I am planning. Lots of ideas are getting sorted out. I have boxes of parts I have acquired. This summer and fall will be exciting. Thanks for your help and interest.

 

If you merely replace the main leaf with one much longer, it is probable that it will fail, unless the car is much lighter than the spring's original application. The main leaf depends on the second leaf (and on and on) to provide support at a point where the moment in the main leaf is not excessive (load times the leafs unsupported length). You cannot safely lower a car (unless much lighter) by leaving leaves out; the car would become lower, by overstressing the remaining leaves. Spring steel (high carbon) is very strong, but brittle when overstressed.

Possibly you could use the original main leaf with eyes removed, and have a new longer main leaf made. But this doesn't gain you anything in lowering, since the original spring has the wrong contour.

Even with a custom designed spring, the limit to lowering could be lack of clearance between the banjo and the spring's chassis mounting hardware, and clearance between the spring and the frame rails. Note that reversing the springs eyes alone automatically reduces these clearances by about 1.5".

 

So, from the research I continue to do, I figure I need the rear spring to stretch to 48.25 inches. I was told that if my perches are at 51.25 center to center, than minus 1.5 per side for the shackle which is static at a 40 to 45 degree angle. This would be 48.25 inches compressed. The medium arch springs at Speedway say they stretch to 46 inches. I'm not sure what the Posies Super Sliders spring will stretch to, but says it will lower a stock "A" 2.5 inches. I agree if I add another longer reversed eye main leaf under the original main leaf with the eyes removed, I would still need to remove one or two leaves. Tardel had talked about how to lower a stock "A" spring. I also thought about making a longer shackle, but this could cause the spring to hit the axle. I think a "T" spring would hit the Columbia bell. From what I can gather I need a spring that is 2 inches longer compressed. I figured the aftermarket would have solved this. Maybe I am just over thinking this. I just hate to blow 300 bucks on a spring I can't use.

 

Just a thought since I dont know how much you are trying to compensate for.Could you make a spacer for each side that fits between the housing end flange bolt holes,and the bolt on spring perch? Made from say 1 inch steel plate.Drill your mounting pattern,and shape the outside so it looks good.Use grade 8 bolts.

 

If you run Lincoln brakes you will need a spacer between the spring perch and the axle. The model T profile spring the 100%matt builds is lower so you won’t need to take a bunch of leaves out.


Sent from my iPad using The H.A.M.B. mobile app

 

Why not get some weld on spring perches and put them on at the the stock "A" width of 49-1/2" eye to eye. Thinking that would be both less costly and easier than getting a special spring made. If I remember right; Matt's "T" spring is for regular width perches.

 

What Rich B said. I just did exactly that with installing a Columbia in my 29 A. Looks like you have the perches, just place them as Rich B suggests.

 

I installed a late model Columbia under my stock model a 25 years ago using my stock spring and welding stock spring perches onto the Columbia. Since the rear end is wider than the model a one it stretches the spring out hence lowering the car. I know I am stretching the spring a little bit more than it’s intent but Henry Ford built good stuff and I have never had an issue. Don’t get too excited about spring height yet Until you get the car assembled .

 

This is all good info. I have late 42-48 passenger front and rear backing plates. I will be running wide five drums. The Havlir hangers look like a quality part, and with some light shaping could be made to look like they were a cast part. The 1 inch spacer did cross my mind. I was afraid the added leverage would crack the axle flange. I hate to weld perches further inboard, because they may look out of place verses the factory look. I'm trying really hard to make the parts flow throughout the build. Being this is a fenderless highboy, I don't want the part execution to look forced. If a new Posies Super Slider will stretch that far, and thus lowering the car a little more, and still able to function, that would be a perfect world solution. I am willing to mix and match parts and get a new main leaf made, but I don't know where to have a new main leaf made, being that "A" springs have a unique curve. If I could just figure out a measurement, I thought maybe of getting a standard arch main leaf with reversed eyes made, and then heating the center of the main leaf to contour the remaining "A" leaves. As long as I didn't heat towards the eyes, the spring should still function. They do sell main leaves for 35 on up axles. I wonder if I could contour one of those with the "A" spring, being the later main leaf is longer and seems to come in various lengths. But, the later springs are wider as well, and would require some thinning. I my also figure out how to integrate tube style shocks to rear as well. I'm running a lever shock in front. Thanks for the ideas, and I'm open to more if they are out there. Planning a build is part of the fun.

 

And as far as overall ride height is concerned. I'm not too worried right now. I do want it as low as I can go without dropping an axle or cutting my frame. I figure I would sort out the rear, and see were I sit with a stock spring and 36 axle up front. I would then adjust the rake by a new front spring or tire selection. The rear spring set up will set the pace for the whole build. Thanks again.

 

I think different than most and look at it from a odd angle. I get not wanting to cut your stock frame. You also say you want it as low as you can get it. So why not just make a bolt on Rear spring hanger and mount the spring on the stock brackets behind the housing? Your body will cover the mount and it will set your car 3.5" lower than a stock Model A. No actual frame mod done.

 

You say you want the car to look traditional, and won't weld on some hand fabbed brackets. Then in the next breath say you are willing to use a Posie's Super Slider. Ha! Tradition out the window!

There is no shame in fabbing a bracket and welding it onto the axle. It is perfectly traditional. Maybe not 1940 era stuff, but neither is the axle which got you into the problem in the first place.

And another thing that threw me is your comments about heating the leaves to make them conform to the shape. You should know that as soon as you heat up spring steel it is no longer spring steel. Just a strap of good old steel, that won't spring anymore.

 

Here is my 30 Roadster on a Model A frame flat as Piss on a Plate. No kick, no custom springs, plenty low enough for me. As far as weld on brackets, all you need to make them look traditional is a Stick Welder with lot's of Slag Buggers.

 

Ok. Lets clear the air here. I do want a traditional styled AV8. I don't want to stick weld or gas weld just any old part that will work. I'm 33 as of today, and I hate that I'm a "millennial", but I have resourced about all the info I can on trying to figure out how my idea can work. That's why I'm here. All of our hot rods are different, and that's what makes them cool. For me, I want a very refined execution of a pre 1950 Ford hot rod. I have many reasons for wanting what I want. Without explaining the whole build, I was hoping to just solve the rear spring problem. I understand that if you torch a spring, the steel is compromised. I also know that hot rodders have been torching their springs for years, and if done properly in the right spots it can be very effective. My 66 Mustang has the front springs torched, and the ride quality was not sacrificed. The springs are not mangled and haven't failed since I did it 16 years ago. I agree the Posies Super Sliders are not "traditional" but it is just an option. I'm here looking for a more traditional approach. I'm am willing to have a completely new spring made if it comes to that, but I don't know who can build what I want. Back in 1949 it was very possible for a spring to be custom made. So lets stick to trying to find a solution to the problem in the spirit of a post war hot rod but refined to todays standards. No billet, no L.E.D.s, no radials, no base clear paint, no small block Chevy, no T5 trans. Just a clean northern built hot rod. This will hopefully be shown at Autorama in Detroit some day when finished. I have sourced almost all of the rare and hard to find parts, now is the time for engineering and mock up. I don't want a cookie cutter magazine rod bought from all brand new parts. However I know I'm limited as to what is available and what things cost. I love all the ideas and suggestions and all will be taken into account. I may mix and match or come up with a completely new idea that others can use. Innovation is part of hot rodding. My box is pre 1950 tech other than MIG or TIG welding. Thanks for all the info guys.

 

I think welding on a nice spring perch you made yourself at the correct spacing is actually more traditional (pre 1950) that bolting on a perch ordered over the internet. Keep the stock A or T spring. I'm sure it's been done a thousand times.

 

I figure I can weld on the tubes, but can I weld on the flanges. Like if I wanted to gusset the hanger to the flange for support. Just an idea. I like options.

 

Something like this?

 

Have you contacted Martin Spring in Kalamazoo? Looks like they're close to you.

The reason I ask is that years ago, when I built my roadster, I had a local (Orlando) spring shop make a new A main leaf with reversed eyes to my length and height specs. They then fitted the remaining stock A leafs to it. I think we used six. It was easy/peas with their experience and the right tooling. Still on the road after 33 years.

 

This could be a workable solution, but let me enhance with a couple of suggestions:

1. Adding spacers will increase the stress significantly on the backing plate flange and associated bolts. The inner end of the spacer (nearest to the banjo should be machined to fit firmly against the axle housing; the vertical load will be absorbed here, rather than creating an enormous moment to be absorbed by the long mounting bolts. Spacer could be aluminum. Could be made a bit long, trim length later if spring eye with shackle bottoms out against perch on full bump. (Alternately, the bottom of the perch could be built up with weld, and machined to bear on axle housing, rather than the spacer.)

2. If there's room, enlarge the backing plate and flange holes, and use larger bolts. Do not drill so large that you're compromising the strength of the flange local to the bolt hole. Use large diameter thick washers beyond the backing plate (inside drum) if they will fit.

 

I did not know you could weld to the backing plate flange. This could be useful. If I used a weld on type and used a gusset to support the hanger into the flange I would be confident it wouldn't move, and it could be placed at the stock measurement as suggested. Also I have not contacted Kalamazoo Spring. That is another solution. Thanks guys. All of this information gives me plenty of homework. I like the brain storming here.

 

It sounds like you want to do things right so get the earlier, narrower axle tubes. It will not look right if you use the wider ones.


Sent from my iPhone using H.A.M.B.

 

I could swap the left side tube easily, but the right side tube is the Columbia. From what I researched it costs over $1000 to have the Columbia bell shortened an inch or so. That cost does not include the bullet proofing and restoration or building of the shifting mechanism. Columbia 2 speeds are very hard to source in good condition. Mine is low miles, tight, and unmolested. And most of the Columbia wizards are in California and Texas if I remember right. There might be a guy in Tennessee. Shipping out west and trusting that it would ship without damage does not seem cost effective compared to a custom spring or custom mounts. I get the axle is wider than stock, so I hope the added 2 inches of inner rim will make up the difference. 7.50-16s will fit to a 6 inch wide rim.

 

An acquaintance of mine restored a historically significant unique British sports car. He sent the steering box and all the period correct Dzus fasteners (had much thicker heads than currently available) off to a reputable chrome plater. Got back half the fasteners and no steering box. Never even took pictures of the box, so had no idea if it was from a Wolseley Hornet or an Armstrong Siddeley Hurricane or ? So, I wouldn't blame you for being reluctant about shipping those axle pieces off for machine work.

As for the wheels, you can add the two inches, but also can remove the rim center, and relocate it to give even more back-spacing. Or find a 6" rim with an ID matching your center and weld them together with the required back-spacing. (Probably not feasible if wires.)
.