AZmopar Posted February 26 Report Posted February 26 Hello! What front suspension modernizations have been successful on these early to late 40’s Dodge/Plymouth/Desoto’s replacing the kingpin setup? Thanks! Quote
andyd Posted February 26 Report Posted February 26 Not a lot............the "best" replacement I have seen in 50 yrs playing with my 1940 Dodge was the complete replacement from the firewall forward with rectangular tube then either a Mustang 2 or better still, XJ6/12 jaguar complete front suspension/steering BUT either of these two involve a LOT of work & fabrication........I've had my 1940 Dodge since 1971, in 1973 I installed a 318 Poly & cast iron Torqueflite.........and over a couple of years I updated the front end/suspension & steering.........from the late 70's its used a 9" narrowed Austin 1800 rack & pinion, home brewed Valiant/Alloy tube steering column, Oz PBR 11" vented disc brakes, firewall mounted booster & dual circuit master cylinder, 1941-54 Moog cast iron upper control arms, stock 1940 lower control arms, stock 1940 spindles, 1941-54(actually 1962 Australian Chrysler Royal) Stub axles, a 1" thick adjustable Heim jointed sway bar with nylon bushes and relocated upper shock mounts.........it handles & steers o/k .........if I was doing it again......well I'm 70 now so that won't happen.........lol..........I was 17 when I bought the car, 19 when I hotrodded it......lol...........anyway heres a couple of pics..........regards from Australia......Andy Douglas 2 Quote
AZmopar Posted February 26 Author Report Posted February 26 Beautiful car, Andy!! That’s quite the evolution! I’ve heard of folks doing the Mustang II front end but I’m really trying to keep it all Dodge. I’ve tried to mock up all the different Mopar k frames but each would require a ton of fabrication. But, I think I’ve come up with a workable all Dodge solution. I’m retaining the ‘41 lower control arm, and using a Dodge Aspen/Plymouth Volare upper control arm, spindle, caliper, rotor, and sway bar. For steering I’m using a manual rack from a Dodge Omni. The biggest fabrication so far is grafting the Aspen lower ball joint mount to the kingpin fork on the 41 lower control arm. Also, making a bracket to mount the Aspen upper control arm bracket to the 41 upper control arm mounting pad. I’m still mocking it up but it’s looking very promising so far! I’ll post some pics once I can shrink them down below the 3mb limit lol - John 2 Quote
Sniper Posted February 26 Report Posted February 26 How far off the ground is that lower control arm going to be? an inch? Will it hang lower than the scrub line? 1 Quote
AZmopar Posted March 11 Author Report Posted March 11 The lower control arm is still in its factory mounting location. I’m not expecting any clearance issues there. Quote
Sniper Posted March 11 Report Posted March 11 1 hour ago, AZmopar said: The lower control arm is still in its factory mounting location. I’m not expecting any clearance issues there. I don't think you know what a scrub line is? Basically, if you run a string fromt eh bottom of a rim to the other rim bottoms nothing on the car should hang below that. This is so that if you get a flat nothing digs in and puts you out of control. As high up as that spindle is sitting tells me your chassis is going to be hanging down low. Quote
AZmopar Posted March 11 Author Report Posted March 11 Ahhh gotcha! I wasn’t familiar with that term but I understand it. As I’m mocking it up, nothing appears to be below or at the bottom of the rim. I mocked with a 15” wheel that I plan to use. I still have more tweaking to do before I commit to this idea but so far I think it’s going to work and be safe. I’ll take some actual measurements from key points and see where it’s at. The kingpin and the proposed spindle differ in height by 2.5 inches if I remember right. I took all the height difference from the bottom, so yes it’s going to sit lower, which is ok with me. But yeah, I’ll keep checking ground clearances as I work through the idea. Thank you! Quote
kencombs Posted March 11 Report Posted March 11 There is also another ''scrub' term that is even more important IMO. Scrub radius, the arc the wheel area in contact with the road describes when turned off straight ahead. It's primarily influenced by kingpin inclination and a vertical line through the center of the tire. Ideally the tire would rotate around a single point. Very few modified vehicles do though. Wheel offset and tire diameter can change that. From past experience I can tell you with certainty, a large scrub radius really messes with the driving feel and tire wear. Quote
OUTFXD Posted March 11 Report Posted March 11 On the topic of modernizing suspension... Anyone know of a similar front spring to ours that is a might bit stiffer? Even after putting new shocks on, she is mighty soft riding. p.s. 1946 Plymouth Special deluxe Quote
Sniper Posted March 11 Report Posted March 11 1 hour ago, OUTFXD said: On the topic of modernizing suspension... Anyone know of a similar front spring to ours that is a might bit stiffer? Even after putting new shocks on, she is mighty soft riding. p.s. 1946 Plymouth Special deluxe I am not going to say Ford Aerostar Springs LOL I said I put on my 51 or like 997 lb per inch? I just looked the specs up the other day somebody asked me about the Aerostar Springs which I'm not saying LOL 1 Quote
FarmerJon Posted March 11 Report Posted March 11 (edited) On 3/11/2024 at 5:22 PM, OUTFXD said: On the topic of modernizing suspension... Anyone know of a similar front spring to ours that is a might bit stiffer? Even after putting new shocks on, she is mighty soft riding. p.s. 1946 Plymouth Special deluxe " Precision Springs" are made in USA # SP08160 Also available from MOoG, but are more $ and like all mOOg parts now, are made of Chinesium. May drop stance a little, I cut 1 coil before installing them, so I dont know. I like the stance and ride, but they are a bit too short of a spring and bang around over larger dips. (Once cut) Went from this: to this: Edited March 14 by FarmerJon 1 Quote
p15-1948 Posted March 12 Report Posted March 12 (edited) I used Coil Springs for a 48 Plymouth I used to own and a 65 Marlin my granddaughter now owns. They can make them stock, change ride height, or change stiffness. My granddaughters Marlin we went with standard height and +30% on spring rate. Coil Spring Specialties is located in downtown St. Mary's Kansas. It's been a lot of years, so I can't remember what we did on the Plymouth Edited March 12 by p15-1948 2 Quote
OUTFXD Posted March 16 Report Posted March 16 On 3/11/2024 at 3:42 PM, Sniper said: Aerostar Springs like 997 lb per inch? Out of idle curiosity, do you know what the spring rate for stock springs are? (1946 Plymouth P-15 or other applicable vehicles) Quote
Sniper Posted March 16 Report Posted March 16 No idea, service manual doesn't say and the parts manual only shows a standard and heavy duty option, no rates given. 1 Quote
p15-1948 Posted March 17 Report Posted March 17 4 hours ago, OUTFXD said: Out of idle curiosity, do you know what the spring rate for stock springs are? (1946 Plymouth P-15 or other applicable vehicles) You might check with Coil Spring Specialist above, since they make springs stock, higher rate, and lower rate they should know that information. 1 Quote
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