Random MOOG Coil Spring Specs:
I put this list together tonight for a couple different Eagle related reasons. First I'm curious about making a better version of front shock coil-overs to assist tired old original springs without needing to remove the old ones (thus the 800 pound load options mixed in, which is about a third of the ideal load value). Second I'd like to make my own spring perches for use with a spacer block for an easy "body lift" that would require a spring about 17 inches free height versus the stock 15 inch but have about the same load rate. Third I'd like to think about subframe repair options that could require the one inch smaller diameter spring that I found quite a few factory options available for. I figure this list took about an hour to compile and someone else may have use for the same information.
I bolded the one I'll probably buy soon to experiment with. The load rate is the most important number, and I figure the factory Eagle at around 270 lbs/in is a little too soft for me and the 311 lbs/in was just about perfectly stiff in my past 4.2L rebuilds. That made it easy to select the one with 17 inch free height and 303 lb/in. It comes to a price much cheaper per pair too. I'm also very curious about just how stiff it would be to try the 460 lbs/in option in a 4.2L Eagle, which even happens to be cheaper yet. It may also be perfectly stiff paired with the extra weight of the 401 V8. I prefer stiff suspensions in cars like my '92 XJ or former 2006 TJ Rubicon but obviously not stupid stiff like my Scout currently is.
These advertised load numbers are only useful for comparison and the actual load rate will vary with the resting weight of the vehicle. To get the same intended ride characteristics and true observed load rate the published load rate chosen from this list has to be adjusted along with engine and AC choices. I like that this smaller coil diameter size has much more options available to choose from and a half inch change in radius is reasonable to still look like the factory coil options.
The first number in total load rating for the spring depends on the difference between load height and free height, which I didn't record. The load height for AMC coils is intended to be 9.5" regardless of the free height. The other spring I selected, Moog 5276, had an intended load height of 10.5", which is consistant with the goal of lowering the crossmember and upper control arm pivot point by an inch with a spacer block and new subframe mounting holes without changing the height of the top of the shock tower.
I don't mind making significant changes as long as the geometry stays the same as AMC originally engineered. I happen to be boxing in the old subframe with a stronger one with the same profile but an inch lower in depth. The factory strut rod bracket, crossmember, control arms, ball joints, and all the complex stuff will be in the same place relative to each other as they have always been. I've had too many shock towers rust through where they connect to the subframe so I'm incorporating new bullet proof mounting holes for the upper control arm. The only reason a new spring perch may be necessary is because of the smaller 4.09 ID coil spring and I may be just making a single CNC cut spacer block that bolts to the old shock attachment holes and adapts the old spring perch to the new coil size as well as providing new holes higher up for the original front shocks to bolt to. Long term I'd like to have the spacer block be the fast, dirty, and cheap option with a roller bearing pivot perch as another option.
Part of the motivation to provide one inch of lift is to put the front axle one inch lower under the engine. This gives me room to use the heavy duty front axle from a 2002 Chevy 1500. I already have one and it measures to about a half inch less in total width than the original Eagle axle. That is perfect to give me room for a simple bolt pattern reducer at the CV joint flanges. I'm also curious about giving clearance for the larger easier to find Jeep oil pans because I'm running low on Eagle oil pans that haven't rusted through. I'm hoping I can lift an inch at the crossmember and also lower an inch at the same time thanks to the angle of the control arms to give the same factory bumper height with just an inch of ground clearance lost. I don't actually like lifting Eagles but it may be a necessary evil that I will end up doing often in the course of rust repair. I also see another possibility of cleanly eliminating the 1" front wheel spacers I use with the deep factory alloy rims by pushing both control arms out an inch during this subframe modification.
It happens to be the coil spring from a '70 to '85 Chevy Camaro. The stiffer spring I'll probably use with my 401 V8 SX4 is from a '71 Cadillac Deville with a 7.7L V8. What is pretty cool is I then looked up those cars identified by the constant rate options I went through in this list and found additional variable rate spring options. That also shows some promise to make my car have exactly the ride quality I want in the huge range of uses I want to drive it for.
On a related note I think its amusing that someone recently bought tired old four cylinder springs to "lower" their six cylinder Eagle. When you lower a vehicle you need to increase spring rate to decrease how much travel your suspension moves as you hit bumps. It would make more sense to buy a much stiffer spring with a higher load rate then cut down the free height if you want to lower your car. Being stiff is better than being floppy and smacking the bump stop in a jolt at every pothole.
AMC COIL SPRINGS
Moog 3140: 1490 lb load rate, 0.65 bar, 14.94 in height, 276 lbs/in, 5.02 in ID: $66.79
Moog 3112: 1591 lb load rate, 0.68 bar, 14.38 in height, 307 lbs/in 5.02 in ID: $70.12
Moog 3156: 1690 lb load rate, 0.68 bar, 14.92 in height, 311 lbs/in, 5.02 in ID: $63.89
SORTED BY COIL DIAMETER FIRST THEN PRICE PER PAIR SECOND
Moog 2278: 868 lbs, 0.60 bar, 11.00 in height, 435 lbs/in, 3.42 in ID: $76.79
Moog 5230: 1884 lbs, 0.60 bar, 18.25 in height, 251 lbs/in, 3.62 in ID: $60.79
Moog 5244: 2124 lbs, 0.64 bar, 17.75 in height, 315 lbs/in, 3.63 in ID: $66.99
Moog 5370: 2022 lbs, 0.64 bar, 15.94 in height, 357 lbs/in, 3.63 in ID: $68.79
Moog 5256: 2174 lbs, 0.64 bar, 17.91 in height, 315 lbs/in, 3.63 in ID: $76.99
Moog 5234: 2025 lbs, 0.62 bar, 17.81 in height, 297 lbs/in, 3.63 in ID: $78.79
Moog 5272: 2279 lbs, 0.65 bar, 17.99 in height, 327 lbs/in, 3.63 in ID: $78.79
Moog 5374: 1957 lbs, 0.64 bar, 17.17 in height, 317 lbs/in, 3.63 in ID: $79.79
Moog 5032: 3125 lbs, 0.75 bar, 16.44 in height, 460 lbs/in, 4.08 in ID: $45.79
Moog 5276: 1981 lbs, 0.65 bar, 17.05 in height, 303 lbs/in, 4.09 in ID: $49.79
Moog 5006: 2480 lbs, 0.68 bar, 16.88 in height, 355 lbs/in, 4.08 in ID: $62.79
Moog 5030: 2900 lbs, 0.71 bar, 17.05 in height, 419 lbs/in, 4.08 in ID: $62.79
Moog 5044: 2360 lbs, 0.68 bar, 18.06 in height, 334 lbs/in, 4.08 in ID: $62.79
Moog 5332: 2308 lbs, 0.65 bar, 18.25 in height, 298 lbs/in, 4.09 in ID: $63.79
Moog 3226: 834 lbs, 0.51 bar, 17.25 in height, 134 lbs/in, 4.04 in ID: $64.79
Moog 5330: 2300 lbs, 0.67 bar, 18.52 in height, 306 lbs/in, 4.09 in ID: $65.79
Moog 3224: 719 lbs, 0.51 bar, 16.39 in height, 134 lbs/in, 4.04 in ID: $68.79
Moog 5378: 2062 lbs, 0.67 bar, 18.51 in height, 294 lbs/in, 4.09 in ID: $69.79
Moog 5376: 1886 lbs, 0.67 bar, 17.92 in height, 319 lbs/in, 4.09 in ID: $76.89
Moog 5278: 2083 lbs, 0.65 bar, 17.50 in height, 298 lbs/in, 4.09 in ID: $77.79
Moog 5270: 2550 lbs, 0.70 bar, 17.94 in height, 362 lbs/in, 4.08 in ID: $80.79
Moog 5268: 2450 lbs, 0.70 bar, 17.62 in height, 370 lbs/in, 4.08 in ID: $82.99
Moog 5282: 2810 lbs, 0.71 bar, 17.50 in height, 411 lbs/in, 4.04 in ID: $106.99
Moog 2203: 515 lbs, 0.47 bar, 15.42 in height, 95 lbs/in, 4.25 in ID: $60.79