thanks scooter! i should just pm you my questions and if you are refering to mr bass... i have slacked many hours at work looking at his artwork.
Nope! Not Mr. Bass... Not sure if he's doing something like this or not. Not who I was thinking of though. Asking here is good because if you have the question then maybe someone else does. To me this place is all about sharing the knowledge. No point in keeping it a secret. Besides, my application is pretty unusual. Not only is the spring in front, but because of the way the whole car was laid out, the weight ratio of the car is different than most short wheelbased cars. Cornering and articulation may be a little different in my application than in others. Either way, hopefully someone is getting what they need from the thread...
Ford mounted the front and rear springs on all cars and pickups from 1928-41 in tension. When mounted with the chassis unloaded the spring shackles are flat to the ground then with body, engine etc. they drop to the 45* angle generally accepted as correct. This tensioned mounting eliminates the need for a Panhard bar front or rear. From 1942-48 Ford cars no longer had tension mounted springs and all had front and rear Panhard bars, this because the low-priced market demanded a softer ride and was getting it from the coil spring front and dual parallel sprung rear of Chevrolet and Plymouth. IF you do not mount transverse springs under tension as Ford did until 1941, you must use a Panhard bar on each end to eliminate sidesway.
BINGO!! Good info right there! Couldn't remember what year non pre-loaded applications started! Thanks for speaking up. That pretty much sums it up right there. I suppose you could probably run a triangulated 4-link rear suspension with a 42-48 spring as well, as long as it wasn't preloaded, as PHR mentioned above. Never seen it done. Would be curious to see it done.
To add to this: On the front-end, the type of steering that you use also comes into play. On the early drag-link setups, the drag link went from the steering box to the driver's side spindle . . . so there was no side-to-side steering load transferred from the steering box to the axle/spindle. When Ford changed to a side steering . . . or when you put a box like a Vega in an early rod, you are now adding a side load between the frame/box and the front passenger side spindle . . . which increases the need for a panhard bar in the front as well. If you're running a triangulated rear end linkage setup - then the nature of the triangulated setup helps to keep the rear centered in the car. Setups like the Pete and Jakes ladder bars are a good example. The typical 3 or 4 link setup (non triangulated) has no mechanism to center the rear. An alternate 4-link setup where the lower bars are positioned parallel to the frame rails, but the top links are triangulated, will once again keep the rear centered (have seen plenty of 9" Fords setup this way). In the end, it is all about how the suspension is designed to work -- and which suspension setup you plan to run. Just know the details of each.
ok i got my 40 spring yesterday (thanks raven61) and i am going to install the hangers this weekend(hopefully its my pops bday so we will see how that goes) i understand that the spring spreads to 48" or so, but my question is how far apart do the hangers have to be im guessing 52" with shackles and everything, is this correct or???
Interesting thread, this one - sorry to high-jack it, but I have fitted a Posies spring (above the axle) in my A roadster and it's rock hard. I've taken out 3 leaves and it's gone down an inch but is still very hard. Anyone on here got this set up and if so, how many leaves are you using? I want the car to be as low and comfortable as possible. Cheers Nick
I've got an A style rear spring in mine. Rides rough as hell. Tossed around the idea of going with coil overs for a while but it's an old-school style 'rod generally speaking. ...ah ....idunno...
hello... i have done the searches, but im just confused at what the actual measurements are. i have these measurements 1935-1936 46-1/2" perch centers 1937-1940 48" perch centers 1941-1948 49" perch centers from this thread http://jalopyjournal.com/forum/showthread.php?t=340741 and i am confused... is the 48 inches hanger to hanger, or different. am i just over thinking this??? this is what getting me confused from the thread listed above Deduct 4-5" for the shackles which leaves you about 2.5" to spread the spring eyes. When you hook 'em up the spring shackles will be parallel to the ground. When you add the weight of the chassis they will drop down to 30-45 degrees and you have a correctly installed and tensioned Ford spring.
Another cool old time set up is to use a box tube crossmember and a 40 front spring. Good ride and it looks cool.
The deduction for the shackle is less than the overall length since it is on an angle. Are you using your stock model a shackle with the 40 spring? If so the shackle is about 1 3/4; spring eye to eye (on the rear, no weight) is 46"; perch to perch is 49 1/4. The math is right, 46" spring + 2 X 1 3/4" shackle = 49 1/2" less 1/8" each side where the shackle is on an angle. From the stock numbers you can substitue your '40 spring and work the numbers, remember that in a pinch you can make your own shackle to whatever length you want, you just can't make it shorter. I think somebody mispoke in an early post on this thread, you do not want your pinion pointing up, i believe he meant to say pointing downward a degree or two. So consider that arraingement into your calculation before you weld up anything onto the axle tube ok? Again, all of this is somewhat adjustable - just get it into the ballpark for now and don't warp anything in the process or you'll be doing us a tech article on how to straighten axle tubes. Good luck, oj
I use a 'dead perch' in cross-steering applications, in which the spring becomes a 'panhard'. I've used this setup on BOTH drag link and transverse link, (and both front and rear) and have been rewarded with a precise feel of the road, with NO sway tendencies. (been doing this since 1959, borrowed the idea from an early sprint car I had, CAE chassis, CAE axle.) Novices look and say, "That side of the spring isn't working!" I smile and say, "That's why it's on the passenger side..."
Been away from the HAMB for a bit. Too much going on... Just saw this. I didn't mis-speak about the rear pinion angel, unless someone is defining "down" as the same as "up", but from a different perspective. In most cases, pinion angle should be "up". Here's a picture showing what I'm talking about. There are a TON of threads on here about when this does and doesn't hold true, though. Ultimately you have to remember that universal joints need to have a working angle to allow the rollers/needles to work/lubricate correctly. Too much working angle will cause vibration and ultimately failure. As for the spring calculations, I believe what OJ is saying (if I'm following his numbers correctly) is correct. Using a trig calcutor (like this one: http://www.1728.com/trigcalc.htm) you can find what your dimensions will be or need to be knowing that the shackles are 1-3/4" (which will be the hypotnuse) and the ideal angle should be around 45-degrees when the full weight is on the spring. The distance will come out to around 1.06" PER shackle. Multiplying this by two gives you approximately how long the spring should grow with the weight on it under ideal conditions. The 1.06" will also tell you how much it will lower with the weight on it in addition to the compression of the spring package as well. Use all that to HELP determine the kick-up and/or spring mounting. AGAIN! 45-degree shackle angle is the IDEAL, but doesn't always hold true. You could be plus or minus 5 or 10 degrees on that and still be fine. It's just a starting point. A lot will depend on the spring itself and leaves some indeterminants that can be fine-tuned by shimming the spring, and what not. Is that clear as mud? Hope I said all that right. Haven't had my first cup of coffee yet this morning. Just use the CAD drawing that I posted earlier and it will help you with a starting point.
thanks scoot that helps too... so the perches need to be moutned at 49 1/2 or??? like i said ive doen my searches but, i cant find a definate answer.
Don't like to be a naysayer...but...i've seen that inland graphic many times and cringe each time. I am a drag racer, a pinion angle like that wouldn't hookup on velcro. Might be fine for stock application but if you've got a hot rod and plan to launch it you need pinion slightly negative. Especially with the spring configuration that you are planning to use. What happens is this, when you stomp it from dead stop the pinion is physically below the axle, the pinion/driveshaft try to become a straight line with the crank shaft - just like pulling a rope tight - with the pinion in a slightly positive the pinion will try to pull downward and in effect try to lift the wheels because it is below the axle. If it is slightly negative the pinion will try to rotate up and - being below the axle - and that will rotate the axle downward smacking the tires into the asphalt. Pinion angle is life or death in a 'stock' class drag car, a modern mustang will pick up a 10th or more just giving it some pinion angle.
Hmmm.... Interesting. Not disagreeing. Just hadn't heard that. Mine's adjustable, to about negative or positive 4 degrees without binding the spring. Hope I haven't mislead anyone. I can admit when I'm wrong... No problem. Sounds like I have some more reading to do... When you're running a negative angle (nose down), what rear suspension are you running? Is this on your 67 Nova, and is it parallel leaf springs?? That will be ENTIRELY different than a restrained 4-link (parallel, or otherwise).
This is what I've always followed for my 4-link arrangement... Is this wrong? I know there's a lot of arguments about rather or not pinion centerline should be exactly the same as the engine-trans centerline. http://www.rosslertrans.com/Pinion angle.htm
Here's a little something from DANA-spicer explaining driveline angle stuff. It's sort of generic. Some of these really don't talk much about what's going on with your driveline in the suspended dynamic state, though. (axle moving up and down WHILE under torsional load from the driveline) So it's not FULLY applicable to what we're doing with our cars. http://www2.dana.com/pdf/J3311-1-DSSP.pdf
I'm bumping this because it was a good thread with info I was looking for....... them BAM, it died. Where you at now Tomcantdoit?
yes, it does have alot of info on it, very useful info... i welded the perches 48 1/2 away from each other, this was the only place i could weld them, and still be able to weld on both sides, since i have a 75? granada 8inch in the back and it is not that wide (maybe like 53 inches from backing plate to backing plate). i took the spring apart all the way to the main leaf and muscled the shackles and spring into its place...very easy by the way... lets just say 70 year old greese is fun and sticky lol. i put it all back together, and i just need to take the body off again to weld the rear crossmember in there, then i have a roller again some advice for people starting their builds... get a game plan and stick to it, if you change your mind a hundred time like i have, or you will NEVER have a car, well it will take along time and eventually you will
Great info...so stated above... as I read it... you set the spring into the shackles..and the shackles are parallel to the ground...and then mount the spring into the crossmember then weld the crossmember onto the frame...this way everything should be parallel....right???...
i set the perches to the axle, checked my measurements were right on, then made sure the perches were parallel to the ground. i then made sure they were true and straight on the axle as well as the degree on the rear end was correct. i cant remember the degree, but i used scooters diagram. i then double checked measurements before final welding making sure to let the axle cool properly so i can avoid warpage. after everything was welded i put the main leaf in with it shackles and tightened everything down and reasemble the spring. unfortunaly i do not own a digital camera so i took NO pictures of this, the only thing i have from that day is in my memory and the burn on my crotch i got from the splatter. *** this maynot be the "correct" way to do it, but it is the way i did it. you also have to take into account the type of frame, rearend,wheels, tires and offset you have, because they could get in the way. i also had to move the mounts in because they might of hit my rims*** TOM
This is exactly what I was looking for. Just getting ready to remove the Deuce rear crossmember and with a Model A. This will let me dial in the ride height to keep the car just as it sits now. Thanks scootermcrad.
GREETINGS OJ!..I am a longtime oval track guy and always apply the basic laws of physics to chassis technology theory. I am not disagreeing with you on your pinion angle theory but do wish to know what causes you to believe the pinion and driveshaft want to become straight like stretching a rope?
When building a drag car, decades ago, we had a warm spring day and after months of work I felt like firing the engine just to hear it idling, maybe a whack on the throttle. It took some rigging but I remember sitting in the car with motor running and looked down at the driveshaft. I then realized it wasn't connected to the rear, I was working on the rear suspension, it was stuck up in the trans only to keep fluid from running out. The driveshaft was spinning merrily away, the car was in gear and I'm sitting there wondering what'll happen when I shut the engine off. It was hovering straight out from the trans and settleled back down in the safety loop as the motor shut down. I had no doubt were I to strat the engine again it would rise right back up to straight out from the trans spinning on the longitudinal axis like a gyrotop only going left to right not up and down. I'll brush up on my Newtonian physics tonight and see if I can't give you proper answer tomorrow, something about spinning mass but cannot dredge up his observations and laws. Like you I draw conclusions from what I see and do at the track, cause and effect kind of thing, the conclusions I have reached might be right for all the wrong reasons and I may nit be fully understand what is going on. Oj
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