Coil spring identification
Thread Starter
Pro
Joined: Jan 2008
Posts: 631
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From: WEST MILFORD NEW JERSEY
Coil spring identification
Took these springs out of my 66 big block. can you tell me if they are the correct springs for this application.
Thanks,
Wes
http://i289.photobucket.com/albums/l...e/DSC02171.jpg
http://i289.photobucket.com/albums/l...e/DSC02170.jpg
Thanks,
Wes
http://i289.photobucket.com/albums/l...e/DSC02171.jpg
http://i289.photobucket.com/albums/l...e/DSC02170.jpg
Le Mans Master
Joined: Sep 2003
Posts: 8,812
Likes: 2,029
From: eastern NC
It looks as though someone may have welded a spacer to the spring to add a little lift to the front end.
I've never seen a factory spring done like this, certainly not a Corvette... but then I've not seen everything either.
As inexpensive as new springs are I would certainly start with new ones instead of these.
Good luck... GUSTO
I've never seen a factory spring done like this, certainly not a Corvette... but then I've not seen everything either.
As inexpensive as new springs are I would certainly start with new ones instead of these.
Good luck... GUSTO
Safety Car
Joined: Feb 2003
Posts: 4,068
Likes: 27
From: St. Joseph Mo
Strictly speaking the spring on the bottom w/9 coils will have a higher rate (#s per in.) than the spring on top w/11 coils. Installed height being the same on both, the bottom spring will have more preload than the top in order to offset the added weight of the AC system (evap., condenser, compressor, etc.). They also will operate at a higher stress (#s per sq. in.)
The OP's springs has had a spacer added to shorten the installed height and the increaseed preload will result in a slight ride height increase.
BB AC springs are not the same as SB AC springs.
The OP's springs has had a spacer added to shorten the installed height and the increaseed preload will result in a slight ride height increase.
BB AC springs are not the same as SB AC springs.
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
The spring on top (#3851100, variable-rate and progressively-wound) was only used on '64-up small-block cars, with or without A/C.
The constant-rate parallel-wound spring on the bottom was only used on big-block cars - #3888250 without A/C, #3888251 with A/C.
No Corvette ever used anything like the springs shown in the OP's photo.
The constant-rate parallel-wound spring on the bottom was only used on big-block cars - #3888250 without A/C, #3888251 with A/C.
No Corvette ever used anything like the springs shown in the OP's photo.
Drifting
Joined: Feb 1999
Posts: 1,808
Likes: 28
From: CA central coast
I've also seen reference to a 427 spring with 7 coils, 12.8 inch free height, 5.1 inch OD, and 0.68 rod diameter (not sure if it was used in '66, possibly only stock in 1967 and sold for replacements in earlier big block cars)
Standard springs had 12 coils with about 0.16 inch lesser rod thickness, free height of 15.4 inches.
But, there is some controversy over springs, and I've seen a post by someone who ordered the '66 restoration package from GM and said the specs in that package were a bit different, at least for small block springs.
Drifting
Joined: Oct 2008
Posts: 1,936
Likes: 92
From: Rochester Hills Michigan
The spring on top (#3851100, variable-rate and progressively-wound) was only used on '64-up small-block cars, with or without A/C.
The constant-rate parallel-wound spring on the bottom was only used on big-block cars - #3888250 without A/C, #3888251 with A/C.
No Corvette ever used anything like the springs shown in the OP's photo.
The constant-rate parallel-wound spring on the bottom was only used on big-block cars - #3888250 without A/C, #3888251 with A/C.
No Corvette ever used anything like the springs shown in the OP's photo.
The spring on the top is 3888250, not 3851100. It looks just like 3851100, but it is longer.
The spring on the bottom is 3888251.
Bill
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Team Owner
Joined: Oct 2000
Posts: 38,897
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From: Washington Michigan
I can't locate my spring drawings - I'm going from my notes; let me know if this sounds correct:
3851100 is .600" wire, 16.8" long, 195#-295# rate.
3888250 is .600" wire, 14.26" long, 195#-295# rate.
3888251 is .573" wire, 17.15" long, 224# rate.
Drifting
Joined: Oct 2008
Posts: 1,936
Likes: 92
From: Rochester Hills Michigan
3851100 is right.
3888250 is 17.35 long.
3888251 is right.
My data comes from Chevy drawings.
Bill
Thread Starter
Pro
Joined: Jan 2008
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From: WEST MILFORD NEW JERSEY
Coil springs
Well I was able to find a set of NOS GM 3832518 springs. The free standing height is approximately 12.5 inches tall with 7 coils .I literally got them for real cheap. Thanks to all that responded
Heel & Toe
Joined: Oct 2010
Posts: 23
Likes: 0
From: Ham Lake Minnesota
Chrislyn-
I just purchased the same pair of NOS BB springs with the 12.5" free height. Did you get yours installed and how did the car sit for height? Just wondering as whenever I've installed new springs in other projects the car seems to sit higher than desired.
Also wondering if anyone has any info in the free height difference mentioned in this thread (10.8 v. 12.5) for the 3832518 springs.
- Do they function the same?
- It would seem that the taller FH would cause the car to sit higher after installed.
Just wondering if I can do anything to ensure I get my desired height (stock or a little lower (its a F41)) before install...not really interested in doing this twice
Thanks,
Gary
I just purchased the same pair of NOS BB springs with the 12.5" free height. Did you get yours installed and how did the car sit for height? Just wondering as whenever I've installed new springs in other projects the car seems to sit higher than desired.
Also wondering if anyone has any info in the free height difference mentioned in this thread (10.8 v. 12.5) for the 3832518 springs.
- Do they function the same?
- It would seem that the taller FH would cause the car to sit higher after installed.
Just wondering if I can do anything to ensure I get my desired height (stock or a little lower (its a F41)) before install...not really interested in doing this twice
Thanks,
Gary
Drifting
Joined: Feb 1999
Posts: 1,808
Likes: 28
From: CA central coast
Chrislyn-
Also wondering if anyone has any info in the free height difference mentioned in this thread (10.8 v. 12.5) for the 3832518 springs.
- Do they function the same?
- It would seem that the taller FH would cause the car to sit higher after installed.
Just wondering if I can do anything to ensure I get my desired height (stock or a little lower (its a F41)) before install...not really interested in doing this twice
Thanks,
Gary
Also wondering if anyone has any info in the free height difference mentioned in this thread (10.8 v. 12.5) for the 3832518 springs.
- Do they function the same?
- It would seem that the taller FH would cause the car to sit higher after installed.
Just wondering if I can do anything to ensure I get my desired height (stock or a little lower (its a F41)) before install...not really interested in doing this twice
Thanks,
Gary
Noland Adams' C2 bible says the free height of the F40 spring is 10.84.
The same book has a chart in the rear that shows a variety of spring free heights, but nearly all have the same "working height" of 8.56 inches (exceptions: the 1967-only non-F40 and 427 are both listed at 9.98 inches). Yet my 1976 parts book does not show any unique spring part number only used for 1967, so go figure!!!
The front end "at-rest" design height was likely meant to be nearly the same for all appropriate factory spring choices, regardless of free height, but if you install a spring with a large mismatch (like a 427 spring 3888250 for a 327 car) you may end up with a noticeably taller front end. OTOH, there is only one HD spring (3832518) listed for F40 (63-65) and the same spring was used for F41 (66-67, up to 71, actually), no matter which engine you have, so I would expect a small block car with an F40/41 suspension to sit a little higher in front than a big block car.
Last edited by waynec; Feb 19, 2011 at 07:00 PM.
