I'm in the process of building a 1922 Chevrolet 490 chassis for The Race of Gentlemen The original springs have a reputation of being much too hard/harsh, so I'm looking for a softer modern rear spring to cut (the 490 uses quarter elliptic springs) and use in their place (Banjeaux Bob is building one as well, so I know he'll appreciate this info too ). The springs are 1 3/4" wide, the longest rear spring is roughly 31" long, and the longest front spring is roughly 24". Soooo, in a perfect world, I'm looking for a pair of rear springs that are over 62" long, have 7-9 leaves. Any and all help is greatly appreciated, as always- thanks! Bill
Yep, let's see pics. 7-9 leaves is gonna be pretty stiff. Without seeing it, a rough idea would be to use the top leaf with spring eyes and maybe the next 2 largest leaves, eliminate the rest. If you need the overall height of 7-9 leaves for mounting, use a spacer.
^^^^^ something like what he said, would be my suggestion, or Go to a spring shop and make a new spring or maybe just a new main leaf.
I figured that a spacer to eliminate some of the pack would help. Will pop out to the blast furnace... err, I mean the garage, snap some pics, and be right back... unless I'm overtaken by the heat (it's 9pm and still 90 outside)
Okay, my pc won't let me download the pics- will try to find some on the net and share them. One thing to understand is that there are no eyes on these springs; they are flat on both ends with a hole through each end to mount them in the spring pockets and on the axles. Also, the front springs are 1 3/4" wide... and the rear are 2" wide- shame on me for assuming that front and rear were the same width...
Gotta love the guys on MTFCA- someone posted some 490 chassis pics on coaltown kid's (man I miss him being on the HAMB) thread about his 20's sprinter! Here are the pics:
I can see why those would be too stiff! I'd remove what leaves possible with the way they are made. Slick them up and separate them with some sort of plastic sheet. Of course this is as old as the hills method but it does work. Worth a try.
Let's put it this way- if I step onto the rear bumper of a modern pickup with leaf springs, my 240lbs will lower things about 4-6 inches. When I stood on the chassis of the 490, nothing moved... even when I hopped up and down on the front or rear crossmember.
Check out the springs they use on boat trailers,they use 3-4 leaves, maybe there is something close to what you need. Bob
They give a hard ride because they had to make them massive enough to keep the axles located with no additional help. Running single 1/4 elips per side all alone, isn't really a good design for that. Start taking leaves out, without adding additional arms/locater assemblies and driving is gonna become... interesting...IMHO. What you need is a real suspension...not this poorly thought out, OEM money saving mashup. Didn't really work then and its not suitable for much now...
Wonder what it is like riding is a restored stone stock Chevrolet 490? What was the total number of them produced? All 15 Million plus Model T Fords got around real well in all types of places, so did everything else Henry built 1928-48 with the same basic spring setup Bob
Leaf springs of anytype {except one leaf] when new start out lubed an smooth,old there ruff ,not lubed,not smooth ,so stiff. Add that to often we make car into a lite hotrod an some try to just use the same old spring adds up to extra ruff ride. If spring is cleaned up an lubed it helps,but if car is now not near as many lbs. as it was,well the springs may need redsigning or at lest there rate changed by fewer leafs in stack.
Thank you for the replies guys! Bob, I've never ridden in a stock 490- will ask the VCCA guys about the stock ride. This will be a period build, so completely redesigning the suspension is out. May look at friction shocks, but not much more (I don't expect to be doing anything about 50mph anytime soon, or running a slalom course ). What I was hoping to find, was a modern spring with a softer ride that I could use... after purchasing an auxiliary trans for the car, my funds are getting thin. And yes, I know that adage "do you want cheap or safe", but was wondering if I might find something in the salvage yard that I could trim to legnth instead of having to have them made.
Dana- I hear you- this thing is pretty light body-wise, but the frame is pretty heavy. I can walk a T frame around by myself with ease, but this one takes some effort to move... the extra weight is either in the spring pockets or the thickness of the frame (my little Capt. Obvious moment there). Will see what a little lube and a few less leaves does.
The cheapest and easiest solution to try first would be removing one or more alternating leaves. For a piece of steel of a given dimension, all will have the same stiffness regardless of whether it was made in 1922 or 2002 and regardless of whether its dead soft or glass hard. IOW, just using something newer doesn't mean the spring rate will be softer. For a quarter elliptic spring where you're not changing anything other than the number of leaves, the spring stiffness is going to change in a direct ratio to the number of active leaves. IOW, if the spring has 8 leaves and you remove 2 leaves, then the spring will be 6/8, or 3/4 as stiff as original. If you removed 4 it will be 4/8 or 1/2 as stiff as original. As others have mentioned, get the leaves slicked up and put liners between them. Otherwise, interleaf friction can make the spring 2 or 3 times as stiff as it would be if everything is able to slide easily. What you're seeing now when you step on the chassis is interleaf friction making the spring pack act more like a solid beam rather than as a spring.
metlmunchr, Thank you for the further explanation- alot of what I was thinking, but didn't know how to say (this first week of school has been a killer on the brain cells)! Part of the reason for substituting newer springs was to get leaves that were in better condition, and by doing that, relieve some of that interleaf friction. I will start with the stock leaves and remove some, grease away, and see how things go. Nice thing is, I've been able to find a few springs already, that if I want to experiment with them, they will fit nicely! Will let you know how things go, and please chime in! Thanks again, Bill
It would, no doubt, add a lot to the labor factor but I remember seeing a thread by Mike Bishop (AV8) on heavy massaging leaves for a smooth ride. Radiused and chamfered ends, grinding, sanding to almost the point of polished. Together with liners made from polyethylene (kids snow sledding sheet) and eliminating leaves might do it for you.
Er...how close? Used to pull one or two leaves out of the 7-9 leaf vette rear springs, gave a better ride in a Model A.
Unfortunately, no progress as of yet- the school year started (I teach middle school band and chorus), my daily driver died, etc... On a good note, I just spent my last weekend camping as a cub scout leader, EVER !!! Now, don't get me wrong, I love the scouts, but Mrs. Yankee and I have lead dens for the last 8 years, so I'm really happy to get some of my weekends back, along with one free night a week With spring break and summer coming soon, I will be able to get back on the 490 and will post updates.
Thanks Bill, I'll look forward to it. Would you happen to know if later Chevy stub axles are interchangeable with those in a 490 type axle beam, please?
Whatever happened with this, Bill? I am really taken with the idea of a 490-based racer for TROG. Also, it might be worth noting that Chevrolet itself seems to have recognized that springs alone weren't ideal for locating the axle, as the 1923 cars have wishbones like a Model T.
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