Thread: mustang II spring question

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I bought a used aftermarket Mustang II front clip cut from a Model A and put it on the front of my A frame. I am now putting it together and I notice that the springs have been cut (now about 9 1/2 to 10 inches tall)which I read somewhere that it is common to cut them.. Without full weight the lower A arm (stock style) points down. The spring coil then sits on the inside but is raised off the arm on the outside as the spring is not vertical between the lower arm and the tower. My expectation is that as weight is added the lower arm will approach horizontal, the spring approach vertical and will seat more evenly. I have dropped as mockup my buick v6 (no transmission) and it's not there yet. Is this normal? Wondering why in pictures that I have in a chassis book they show an aftermarket IFS with the springs seated even though no weight. Lower arm points down but I can see a bend in the spring which allows it to be seated both top and bottom even though arm is down. I cannot see how my spring will bend like that one.

You're right about the lower arm being more or less level with the ground when everything is hooked up and the suspension is loaded. When you cut a spring, you raise the spring rate of the spring and make it stronger than it was even though it may be a little shorter. It sounds to me like you are starting with the totally wrong spring for your application.

Check out this selection from the experts, 23 different springs just for the MII setup. Dial these guys up on the phone and tell 'em what you have and what you want. They can fix you right up.....
http://www.eatonsprings.com/m2coils.htm

The springs are the ones that came with it.

whatever...

I have the stock springs in my car and they are just fine as far as the suspension working, level a-arms and ride height. I have a sbc w/350 turbo which is probly heavier than the engine your using so if they are cut down they will really be too stiff.

The hard part is guessing what will work, you may find a cheap set of stock MUS II or pinto springs from a wrecking yard and use for a gauge on too much or not enough spring. Then you could buy the right set, they have very good products. I wish I could tell you how many pound springs the stock ones are but I can't find my info. Do you know where to find that info Tech?

brickman, there's no way of knowing what springs he has. If you read his initial post, he says the whole thing was bought used and cut out of a Model A. There is no way of knowing what springs the original builder used, that's why I referred him to Eaton.

If you have any circle track builders in the area, check with them to see if they have a coil spring weight checker. Looks like a valve spring pressure tester, just built on a larger scale. If you establish what weight springs you have now it should help take the guesswork out of ordering new ones.

You may want to go ahead and install all sheetmetal, radiator, etc. and have one of the racers in your area scale the front wheels to give you the exact frontend weight of the car. You will also need the distance from a-frame spring pocket to frame spring pocket with the car sitting at the ride height you want. Then you can call the people that techinspector suggested for the correct spring.

Just to emphasize Richard's point there were different factory spring rates for (abreviated example) base Pinto, w/AC, station wagon, etc. Then add the MII 6 cyl, 8 cyl, Those combos w/AC w/o, "sport" suspension, etc. Saying "factory spring" or the "ones that came with it" doesn't zero in much. As Richard said, this is used stuff, and compounding the previous owner's mistakes only complicates things.

One more thing that's a common error with MII's, guys think since they have a V8 and guess that the Pinto/Mustang was lighter they need to get the highest rate Pinto/MII spring to handle it. Very wrong. The heaviest of MII's got almost to 3400#, a Model A for instance isn't going to be close to that. Also the weight distribution was different for the Pinto/MII, their engines were nearly centered over the front "axle" centerline, in rods the engine weight is further back.

mustang pinto had about a dozen different part numbers for front springs they had different ride heights and spring rates not what you would expect