72 with a/c coil spring replacement

[Michael B.]

I removed the body from my chassis yesterday beginning my first body off restoration. The car has 84,000 miles on it and I'm wondering if I should replace the front coil springs when I rebuild the front suspension? If so, what vendor supplies the most correct reproduction springs?

Zip offers a spring they claim is an exact reproduction but the spring rate is listed as 430 lbs. whereas the original 3931824 spring had a spring rate of 264 lbs. Likewise, Paragon's spring has a spring rate of 474 lbs.

How would these higher spring rates affect the car concerning ride height and comfort?

Corvette Central offers replacement springs they claim are correct but they are shorter and have fewer coils.

Anyone have experience with this?

Thanks,

Mike

[Terry M.]

Re: 72 with a/c coil spring replacement

I removed the body from my chassis yesterday beginning my first body off restoration. The car has 84,000 miles on it and I'm wondering if I should replace the front coil springs when I rebuild the front suspension? If so, what vendor supplies the most correct reproduction springs?

Zip offers a spring they claim is an exact reproduction but the spring rate is listed as 430 lbs. whereas the original 3931824 spring had a spring rate of 264 lbs. Likewise, Paragon's spring has a spring rate of 474 lbs.

How would these higher spring rates affect the car concerning ride height and comfort?

Corvette Central offers replacement springs they claim are correct but they are shorter and have fewer coils.

Anyone have experience with this?

Thanks,

Mike

The answer to your ride height & comfort question is a resounding YES!

I have no experience with any of those replacement springs, but based on what I have seen on restored cars some or all of them will result in an exaggerated ride height. I hope others will be able to offer their direct experiences for your edification.

[Tom L.]

Re: 72 with a/c coil spring replacement

My'72 LS5 w/ a/c car has sat low since I got it, front and rear. When I went through the front end of it the springs that were in the car were original (even had the tags on them) and they also had 1/2" spacers under them. I decided to try a set of Moog springs because of the low height, figured I had little to loose. After getting it on the ground it still sat low, but not lower so I left them in. No idea why. If you want the number of the springs I used I can get them, I stored the originals in the moog boxes, Good luck!

[Edward J.]

Re: 72 with a/c coil spring replacement

I would say if the original springs are the same length. Reuse them and if the car sat level .my 72 air car sets so nice with the original springs, even after after I restored my car 10 years later.

[Michael B.]

Re: 72 with a/c coil spring replacement

Thanks for the responses so far.

I'm going to call some local spring companies on Monday and inquire if they have the ability to test my springs when I remove them. If they aren't able to test them I'll rig up something to test them myself. If the springs still have the original 12 height, and test to anywhere close to the original 264 lb. spring rate I'm going to reuse the originals.

With all the replacement and reproduction parts available these days I didn't anticipate finding correct springs would be such trouble.

Mike

[Russ S.]

Re: 72 with a/c coil spring replacement

If your front sits at the correct height now, there is no need to test them. Re-use them.

[Richard M.]

Re: 72 with a/c coil spring replacement

I absolutely agree to reuse your original springs if they are physically and mechanically sound. Over the last 5 years I have had nothing but trouble when using reproduction springs, BOTH front and rear. My best result was a set of GM NOS F41 HD front springs on a originally equipped L71 F41 BB '67 as prior changes used later C3 bigger beearing hubs, bigger diameter spindles, PS only steering arms and BB progressive coil springs, likely to soften the ride for a prior owner. I set everything back to stock.

The reproduction "short" easy to install coils are merely F41 HD replacements which are larger wire diameter and fewer coils for ease of assembly. The result could be a much stiffer ride.

The last C2 chassis I restored included using 'alleged' exact replacement stock front springs resulted in noticably higher(1"+) ride height which required a painstaking removal after restoration completion to cut half of a coil from each end to get to specified stock ride height per AIM specs.

Pain described...

HERE and

HERE and

HERE

Rich

[Edward J.]

Re: 72 with a/c coil spring replacement

I agree with Rich original spring give a much better ride and as it is the Corvette ride was never that great

[Michael B.]

Re: 72 with a/c coil spring replacement

To update.

I took the frame down to the local car wash today and got it cleaned up quite nicely. After power washing the front end I noticed there are spacers underneath each front spring. So that pretty much ends my indecision on replacing the front springs. Now the question is which replacement spring is the best choice.

Mike

[Tom L.]

Re: 72 with a/c coil spring replacement

Spacers? I'm real curious about them since I found some under my springs. Not sure why they were there but the were. Perhaps we can compare notes when you have them in hand. I saved mine, just have to find them.

[Richard M.]

Re: 72 with a/c coil spring replacement

Mike, Is this a SB or BB car?

I would recommend you attempt to locate a NOS set of springs based on the following information. If not, you may encounter ride height issues when the car is completed.

A larger image here....http://www.gmpartswiki.com/getpage?pageid=52275

[Michael B.]

Re: 72 with a/c coil spring replacement

Tom,

It will likely be a week or two before I have the springs removed but I'll take some photos of the spacers as soon as I get them out. The lower ball joints were replaced at some point, and my guess is the spacers were installed at that time.

Richard,

My car is a small block that had 3931824 springs. If I could find NOS springs I'd snap them up in a New York Minute.

Mike

[Richard M.]

Re: 72 with a/c coil spring replacement

Richard,

My car is a small block that had 3931824 springs. If I could find NOS springs I'd snap them up in a New York Minute.

Mike

Mike, I understand now. I just did some searching and found no 3931824 springs anywhere, not even used. It may be that a prior owner added the spacers simply as a precaution thinking the springs may have sagged over the years. Maybe they're not necessary. It's entirely possible yours are good. But make sure before you consider using them that they are originals. Are there ID tags still there? Maybe they're old non-GM service replacements.

I would take some measurements, coil wire diameter, overall length, etc and find the spec for 3931824 to verify what you have, including a spring rate test if you can get that done locally. If they are proven original, you may want to consider using them after restoring and cleaning. If they're badly pitted or out of spec, time for more ideas. Yes you could go for the Eaton replacements, and you may have to, but you may have cut them so you don't end up too high.

Joe Lucia may have a NOS set in his "unavailable-for-sale-stockroom" for spec and measurement comparison. Joe has a 30,000+ parts collection in his NOS parts museum and is a great resource for information. If he sees this and has some info to share he'll likely respond.

Rich

[Michael B.]

Re: 72 with a/c coil spring replacement

There doesn't seem to be any decent choice for replacement front springs for my 72.

I spoke with Eaton Spring today. They show their MC 1400 spring to be the replacement spring for 72 small block cars with, or without air conditioning. It's an inch taller than the original spring and has a spring rate of 500 pounds. When I told him the specs on the 3931824 factory spring were 12.08 inches tall, with a spring rate of 264 pounds he said he didn't believe it and I must be mistaken. He admitted he did not have the data for this spring in any of his cross reference material.

On to Corvette Central. They show item 572052 as their replacement spring for a small block with air conditioning. However, this "stock" spring has a spring rate of 474 pounds. When you look at their Gran Touring spring the description says it's heavier than the standard spring which they say should have a spring rate of 294 pounds (not the 474 lbs. they sell).
The fellow at CC said he didn't have anything lighter than the Gran Touring spring which is advertised as heavier than standard.

On to ZIP. Zip sells item SU1022 which they describe as an "exact reproduction" of GM 331316. It's got the right dimensions but the spring rate is 430 pounds. GM 331316 replaced spring 3931823 which had a spring rate of 250 pounds.

It seems all the replacement springs are substantially stiffer than originals. I'm wondering if there would be a change in ride height with the ZIP spring? Also, how much would the ride and handling be affected with a 430 lb. spring as opposed to the 264 lb. original?

I'd really appreciate hearing from anyone who has installed any of these springs.

Thanks,

Mike

[Edward J.]

Re: 72 with a/c coil spring replacement

Mike, Did you check your spring heights yet? My 72 springs were not measured, but I just put the springs side by side to see if they where the same height, as they were, so I cleaned them and reinstalled them car sat perfectly( might be worth a try)), Don't give up on them yet. If you decide to replace I would scour the internet and all sources, there were a lot of small block A/C corvettes build in 72.