Ok I have some question, but before you flame me... I have done my research on the subject and understand the search function, but I'd just like some opinions and advice. <O</O1.) First off I started my 1931 Tudor with a 4bar setup, coil overs and an 8 inch rear end. Since then I have decided to ditch the coil over and go with the "A" spring in the back. With that being said, will the spring work with the 4 bar, or would it be worth it to change to ladder bars?? <O</O2.) removing/shuffling springs... I have read that you can do a couple things with the model a spring. One is removing ever other spring (can't remember how many tho... ), the second thing you can do is remove the top 3 springs shorten them to 12 inches each and move them to the bottom of the stack. Both of these methods, along with reversing the eye of the spring should lower the car up to 4", but hows the ride and the wear on the spring???? <O</O 3.) I also have access to a 40 spring, would this be the way to go, or is the model a spring better. I know that this might fall under preference, but there is a wealth of knowledge and experience on this site, and I would LOVE your opinions. <O</OThanks in advance<O</O Tom <O
If you already have the 4-bar set up, I'd just run that, unless you want to switch to ladders. Either will work with a model A spring. A '40 spring will take up less room inside the car because it is shorter. I usually just take springs off the top of a model A, I'm running 6 leafs in my coupe now. A Model A spring requires the shackle perches be 49.25in apart, while a '40 only requires 42.5in. These are both center to center of the axle perches.
He is correct . . . nothing wrong with a 4-bar . . . if you like the way it looks, then run it. There are different suppliers for Model A springs. A lot of guys run the narrower Posies spring (2 inches more narrow) -- it uses a center to center spring/shackle measurement of about 46.5 inches. You MUST know the type of spring you're running, what it needs in width, etc.. Also, you need to make sure you set the correct pinion angle and weld your hangers such that the spring hanger shackle bolts are parallel to the ground and the pinion angle is somewhere around 2 - 3 degrees up (depending on the type of rear-end links). I'm running a ladder bar setup (like P&J) - it locks things down quite well - so the rear end housing doesn't twist like some setups do. If you need to account for twist, then you might set the pinion angle closer to 0 degrees - knowing that it will twist UP a bit under load. Your 4-links or your ladder bars should have enough adjustment to screw with the pinion angle a bit. The Model A cross-member should be setup with the spring mounting surface parallel to the ground - with the frame at whatever rake angle you require (probably somewhere around 3 - 5 degrees). That way the spring shackle center-lines match up with the spring hanger center-lines (very important - you don't want shackle bind). If you need more info, let me know - can drop you a few pictures . . . or checkout some of my posts.
What is the advantage of running model a spring over coilovers. I ask because I just picked up a set for my 30 coupe build.
Tradition, looks and what we're all about on the HAMB! From strictly a technical perspective there CAN be a lot more adjustment and tuning to coil overs -- lots of folks run them and I have nothing against them. It comes down to what period of car you are building, what you want it to look like from the rear and what you know about setting things up. Once you've mounted a Model A spring and welded up your hangers - things are pretty much where they will be (unless you modify the spring, take leaves out, etc). Coil overs can support all kinds of spring rates, you can adjust for height, etc -- not so easy on a traditional transverse spring. A 'highboy' style coupe/roadster, etc - sure looks better to me with a banjo rear or a quick change and a model A style spring . . . but that is just me! If you're not running a traditional rear, it isn't as important to me . . . a 9 inch Ford on coil-overs seems more fitting than a banjo style rear on coil-overs. It is all about style, culture and tradition . . . the particulars of which many of us will disagree!
the 4-bar set up will not conflict with the model A rear spring except in terms of mixing genres. you can remove every other spring if you want to get your desired height. coupe and roadster springs will have 4 less leaves to start with than those for a sedan. reversed-eye main leaves are also available. the only big advantage to a model A spring over a '40 is if you are using a quickchange you will get the clearance you need. if you run the '40 spring, you will not be able to use a stock model A rear crossmember though. if you are changing out your crossmembers, you may also want to move it back and put the spring behind the axle instead of on top to get added drop.
yes pictures would help.... and yes i am changing out the cross members from a coil over bar(from tci blah) to the model a rear crossmeber, just dont have one yet gotta wait a month, all my money is tied up an intake 3 deuce intake manifold
I'm running a parallel 4-link with a Model A spring on mine. For what I was doing I needed to run the spring in front so I reversed the eyes and stuck it between the links.
Cool frame setup Scooter! Looks like you're a bit ahead of me . . . but we're working toward the same goals - just takes too much time and too much money. My problem is that I have 3 projects going at the same time . . . but I like em' all!
I hear ya' brotha! I have entirely too many things going on in my life to move this along as fast as I would like as well. It's blown apart for finish and paint (FINALLY!), but now I just need the time to even spend spraying!!! GAH! I will be happy to see this back in the rolling state and the frame, real axle, and all the suspension parts look a MILLION times better than in these pictures! Hope the pictures help someone...
Glad to help man! The setup will work behind as well, I just didn't have the room for a large kickup that would go over the axel. And because of how it's setup I had to add a couple leaves and reverse the eyes on the main leaf as well. Should ride like a dream though.
in his best old man from coming to america voice... ah ha ah ha ah ha!!!!! your on to something, didnt even think of that
lol nice scooter!!!! gotta watch that movie tonight.... and i don't know why there are so many damn smiley faces on my post??? i don't remember putting in those, only like 3. lol
I have another question for the experts out in HAMBland... what is the measurement from the center of the rear axle to the center of the rear cross member, for both the model a spring and the 40 spring??? thanks TM
All depends on your spring hangers. Once you know where the axle needs to be (based on the body, wheel wheel position, etc), and you know the spring shackle centerline location, then you know where the centerline of the cross-member needs to be. The cross member is mounted so the spring surface is parallel to the ground - which is what your shackle bores should be as well (on a straight spring). Are you using old hangers, buying them or making them?
i might make the hangers or buy them from doctorz at socal, just not sure yet, still gotta go to my family friends house and get the 40 spring. im gonna go to my pops house where the car is tonight and check all that. thanks again doctor z, scooter, bored&stroked, and all the others who answered my questions very helpful
Mine are modified So-Cal hangers. They put the spring right where I wanted it. Do you still need the center to center dimensions for the A spring? I think you had asked before and I put up a CAD drawing with dimensions. Hopefully that helped a bit.
These dimensions will hold true for a STOCK Model A spring. They may vary slightly depending on how many leaves are in the spring and how broken in it is. Also, with the spring shackel mounts they may vary +/- 1/2" from what I've seen.
Just so you know, the dimensions that ScooterMcRad posted are for a stock Model A spring - showing the stock spring hanger widths. A lot of people will use the 2" narrower Posies Model A spring (29-31R-C) - which has a spring shackle bore center-line measurement of 46.5 inches. Their standard Model A spring uses a 48.5 width. A 40 rear spring will be somewhere around a 44" shackle mount width. Make sure you know what spring you'll be running before you set this stuff up.
thanks scooter!!! yea i am going to choose the best of the two, but it looks like im gonna go with the 40 spring, since i dont have to tear up the floor boards, but that could change. ahhh these cars are never finished.
That is correct! Sorry! I should have pointed that out... That is very important to note. I will put a note with the picture so it doesn't confuse anyone! Thanks for pointing that out B&S!
i miss c9... He would of been all over this with awesome pics and advice. Im not saying that this advice sucks, im just sayin i miss c9, after searching his posts about his 30-31 roadster. Rip c9
i have another question... since i am using the 4 bar and spring in the back, do i need a panhard bar???? edit: the search function returns mixed feeling on this, and im sure this question will to. so, im just going to run one since i have one.
I knew this would show up eventually. I've seen them run both ways. Because the spring is transverse it helps elliminate side to side movement that is offered in a typical 4-link arrangement. The spring has been put in extreme tension which is working with the weight of the car to center itself between the shackles. It may not work as well with a later spring (non-bell shaped) because it doesn't require as much pre-load as the Model A. The Model A spring has a HUGE shape change when pre-loaded properly and it works in favor of the suspension design. A panhard bar will also work and there is a well-known builder here on the HAMB that used it on one of his builds and it worked just fine. A later spring was used with the configuration. Since I'm using a Model A spring that offers an extreme amount of centering capabilities I'm not going to run a Panhard bar. I'm not ruling out the idea of using one 100% though. Going to see how it does. In theory, unless I'm planning on hard corner on low-profile tires, it won't move enough with an A-spring in it's compressed state.
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