1980 Gymkhana Rear Spring

[David H.]

Re: 1980 Gymkhana Rear Spring

Dave,

The Spring Research Institute claims the spec on the leaf thickness is 0.228”. Joe and I went with 0.229” based on another person who measured an actual main leaf back in 2010.

Gary

Gary

Seems like people are not the only things that get bigger as they age!

Dave

[Mark K.]

Re: 1980 Gymkhana Rear Spring

Gary,

I measured each of the leaves individually. They all measure .235. The liners measure .020. All measurements were taken close to the center bolt,
to minimize the effects of wear. The main leaf and leaf #2 are flat at the ends. Leaves #3-7 all have the same sharp bend at the end. Leaves #8
&9 are also turned up, but at a lesser angle. See the attached photo.

Mark

Mark100_0247.jpg

[Gary B.]

[Joe L.]

Re: 1980 Gymkhana Rear Spring

Mark,

Thanks for the measurements. If you add up 0.235” x 9 and 0.02” x 8, you get 2.275”. That must be pretty close to the assembled thickness. Maybe Dave’s measurement of 2.545” includes some rust/corrosion.

It’s interesting that there are two shapes of the turned up ends. I hadn’t heard of that before.

Gary

Gary----


Dave's measurement includes the liners.

[Gary B.]

Re: 1980 Gymkhana Rear Spring

Joe,

My calculated thickness also includes 8 liners. I think the difference between a real measurement of the assembled thickness and a calculated measurement is caused by stacked things being thicker in total than the sum of the individual parts. You can really get things to have zero gaps between them. Plus, the paint thickness isn’t taken into account with the leaf thickness given by the Spring Research Institute.

Gary

[Gary B.]

Re: 1980 Gymkhana Rear Spring

Mark,

I was fortunate enough today to be able to look at a copy of the GM engineering drawing for GM spring 14021604, dated Mar 14, 1979. It contains some interesting information. First of all, it confirms that all leaves are 0.228” thick +/- .005”. Also, it gives the assembled thickness of 2.169”, which is consistent with 9 leaves of 0.228” and 8 liners of 0.018” thick. But note that the 2.169” thickness is a design spec. It could be thicker than that if all leaves are 0.005” thicker than the 0.228” nominal spec, and because of the paint thickness.

Finally, the GM drawing shows the use of two “clips” or bands that surrounded leaves 1 thru 5. The bands are located 13.91” from the center bolt to the center of the band (clip). The attached shows a cross section of the spring/clip.

Gary
249F52BB-7876-4CA6-9877-1C218D2FCFFD.jpg

[Mark K.]

Re: 1980 Gymkhana Rear Spring

Gary,

Ok so my measurements weren't too far off, given paint & corrosion. Did the spring you looked at have the clips? My spring does not have them.
Any ideas for a source for the clips?

Mark

[Gary B.]

[Gary B.]

Re: 1980 Gymkhana Rear Spring

Mark,

According to the GM engineering drawing for GM 14021504, leaves 1 and 2 do not have upturned ends. Only leaves 3-9 are upturned. And those 7 leaves should have upturns like the one shown in the right in your photo.

Gary

[Brad Hillhouse (37766)]

Re: 1980 Gymkhana Rear Spring

Gary - If you think a 1981 FE7 rear spring would be the same as 1980, I can provide photos of the spring clamp from two different very low mile 1981s. One STL, one BG. Let me know if they would help

Brad Hillhouse

[Gary B.]

Re: 1980 Gymkhana Rear Spring

Brad,

The production part number for the FE-7 spring was the same, 14021604, for 1980, 1981, and 1982. So, a 1981 spring will have the same clips/bands as a 1980 spring.

Gary

[Gary B.]

[Gary B.]

[Ronald L.]

Re: 1980 Gymkhana Rear Spring

Gary,
Any suggestions on getting aprorper rated FE7 spring? AN does anyone have an accurate stencil?

I've seen - working on an 82 that has a yellow stencil, original or replacement?

[Gary B.]

Re: 1980 Gymkhana Rear Spring

Gary,
Any suggestions on getting aprorper rated FE7 spring? AN does anyone have an accurate stencil?

I've seen - working on an 82 that has a yellow stencil, original or replacement?