63 springs

[Steve D.]

Front

Old springs .565" wire diameter, 15" high, 8 coils

Replacement springs .6" wire diameter, 17" high, 13 coils

Can anyone identify the replacement springs? I thought I was ordering the progressive wound springs for 64 and later.

Rear

Old spring__ bottom leaf 10.25" arc height (floor to underside of spring)
New spring__ bottom leaf 5.5" arc height

New spring is supposed to be standard not heavy duty. Any clues here?

Also, the new spring was shipped with the UPS label taped on the spring: no box, no wrapping. The edges of the liners are torn in numerous places. Anybody else have this experience?

Steve

[Gary B.]

63 rear spring

Steve,

I can tell you a couple of things about your new rear spring. First of all the spring steel stock that was used to make your original 63 spring is no longer available as a standard thicknes. So, what spring makers typically have done is to use thicker standard stock for each leaf. This, of course, results in a significantly stiffer spring. I know of one repro spring with a stiffness 40% higher than an orignal 66 spring and a free arch that is 8" instead of 10.0". In order to compensate for the thicker leaves and stiffer spring, spring makers must reduce the free arch in order to get close to the original ride height. Herein lies a problem. If the new free arch is too large, the car will ride too high since the increased stiffness will prevent from spring was deforming enough. This phenomenon is the bane of many people who have replaced their original rear spring with a repro spring. You should read my articles in the Restorer from a few years ago for more details about original and repro rear springs for 63-77 cars.

Gary

[Steve D.]

Re: 63 rear spring

Gary

Thanks for your comments. Can you give me the Restorer volume# reference for your article ? My membership started in early 02, so if it's before that I'll have to hunt it down.

Steve

[Jack H.]

See Noland Adams'....

Complete Corvette Restoration & Technical Guide, Vol 2. In the rear of the book is a rather complete specifications section. If memory serves, you'll find a table for front suspension that nails the dimensions and coil characteristics of each of the various springs used during '63-67 for various applications including number of active coils, length, diameter of steel, windings, Etc.

[Gary B.]

Re: 63 rear spring

Steve,

These are the articles and issues:

“Leaves of Spring or 1963-1977 Standard Suspension Rear Leaf Springs. The Corvette Restorer, Vol. 26, No. 3, 12-16, 2000.

Restoring a Mid-Year Rear Leaf Spring: Combining the Best of Old and New. The Corvette Restorer, Vol. 26, No. 4, 32–35, 2000.

1963-1977 Standard Suspension Rear Leaf Springs Revisited. The Corvette Restorer, Vol. 27, No. 2, 16-17, 2000.

I'm not 100% certain that the issue years are correct.

Gary

[Duke W.]

Re: 63 springs

Steve - why are you replacing the springs?

Duke

[Steve D.]

Re: 63 springs

Duke

In the front, I thought I would be upgrading to progressive wound springs.

In the rear, I have some metal loss (on the main leaf and some of the others)where patches of rust remained stuck on the liners during disassembly and sand blasting. I didn't know how much was significant.

Steve

[Craig S.]

Re: 63 springs

Steve - you may want to consider the option Gary mentions in his article, restoring an original spring and possibly replacing the bottom leaf only with a repro leaf which is slightly thicker, leaving original scalloped secondary leaves. If you feel yours is too corroded, there are many used ones out there for reasonable prices, you should be able to get a used 9 leaf for no more than $120 or so, probably far less at shows etc...Craig

[Steve D.]

Re: 63 springs

Craig

I thought that would be one of my options when I ordered the new spring. But with the difference in the amount of arch on the new main leaf, is that still possible?

Steve

[Gary B.]

Replace just the main leaf? Absolutely. *NM*

[Duke W.]

Re: 63 springs

I wouldn't characterize progressive springs as an "upgrade". The switch to progressive springs was done along with rubber cushion body mounts and other changes to improve NVH. It was a matter of engineering judgement at the time, and I'm not aware of any modern cars that use progressive rate springs.

I don't think changing to progressive springs on a '63 is going to make any material difference in ride, handling, or NVH. If the original springs have not lost signficant material due to corrosion, clean them up, apply a rust resistant coating and reuse them.

As far as the rear spring is concerned, it's tough to tell without inspecting the spring. A good way to determine corrosion damage is to weight the leaves and compare to new, but I don't know of any specs. If the spring has lost no more than 10 percent of it's mass, it's probably okay to use; 10-20 is iffy, and more than 20 percent is probably not serviceable.

Problems with "reproduction" springs seem to be endemic, and you're going through it now. My recommendation is to do everything possible to restore and reuse the original springs.

Duke

[Steve D.]

Re: Replace just the main leaf? Absolutely.

Gary

I'm trying not to be too slow here, but are you saying that I can replace the old main leaf that has a 10.25" arch with the new main leaf that has a 5.5" arch ?

Steve

[Gary B.]

Replace just the main leaf

Steve,

The 5.5" free arch on your repro spring sounds very low to me. I would recommend talking with Mike Eaton at Eaton Detroit Spring about a repro spring that has an arch closer to your original spring and using that main leaf. Note that it is very unlikely that anyone will sell you just the main leaf. You'll have to buy the entire spring and use just the main.

Gary

[Steve D.]

Re: 63 springs

Duke

I don't think the metal loss of total spring weight would even approach 10%. There are patches where there may be a rust gouge of 1/16" or more. There are a couple of these on the main spring near the center, and on a few of the other lower leaves.

Steve

[Duke W.]

Re: 63 springs

I think the springs are fine. Fix 'em up and use 'em and send the repros back. You save the hassle and can use the funds for other purposes.

Duke