Front Springs - Fifth Set Still No Luck-Help

[Keith B.]

I have now purchased a set of NOS front springs for my 67 small block 3851100 from Dr. Rebuild. After installation I lowered the car and presto-- The same ride height as the other 4 spring variations (28 inches from center of the wheel well to the floor). Again I do not have the bushing washers on the car, the car is sitting corectly on the frame, the spring is in the proper slot in both the spring well and the A-arm, the car will bounce freely up and down. When I compress the spring with a spring compressor I lower the car and can get the correct Z score that corresponds to a fender to floor height of 26 inches. I do not have the radidiator, the seats, or the front bumpers on the car but I dont believe the weight will be enough to get it to sit 2 inches. The car cannot be driven -- but the cars weren't driven at the factory and the cars didn't sit too high. What can I do. I took an old spring cut off a full top coil put it back in in the car and I never got it under 28 inches. With each spring I have gotten the same ride height within 1/2 inch. I need help-- Big time. Everything I can think of has not worked. Please help if you can.

Thanks
Keith

[Larry P.]

Re: Front Springs - Fifth Set Still No Luck-Help

Can you get a similar car and measure everything? Try to determine exactly what is differant and what isn't.

Larry

[Harmon C.]

Re: Front Springs - Fifth Set Still No Luck-Help

I think when you get done and everything is installed and you drive it the results will make it set lower. Maybe not 2"s but at least better. If you jack up a Corvette and remove the tires and replace them it will set higher till you drive it.

[Bill W.]

Re: Front Springs - Fifth Set Still No Luck-Help

install the springs weight the car down with sand bags till its lower than you want it. let it sit a couple weeks. make sure ALL the bushing bolts are loose and well lubed. I hope they are rubber. if you tighten them with the car low that will help. when you drive it a few miles it will settle about an inch,orleave it parked it will settle on its own. if the rear is to low that will affect the front also.yes the seats, rad. and bumpers DO make a difference...Bill

[Duke W.]

Re: Front Springs - Fifth Set Still No Luck-Help

Because of the Corvette's relatively high front roll center the wheels camber postive on rebound (suspension droop), and the track narrows. When you set it back down on the ground the tires bind up, and the car will not settle to normal ride height.

In order to achieve normal ride height as a minimum you have to roll the car back and forth several times while turning the steering wheel back and forth. The shorter the distance you can roll it, the more cycles you have to do in order to unbind the tires and get the suspension to settle to near normal ride height.

Duke

[Mike McKown]

Re: Front Springs - Fifth Set Still No Luck-Help

Keith:

I have casually read all the posts on your problem from the first time you brought it up. I forgot what all the responses were and what you had checked so if I repeat something, please overlook. I know someone told you to check the ride height as prescribed in the shop manual. This is taking a dimension from the inner A-arm pivot to somewhere on the outer end of the control arm (I forget exactly where it is. Look in the manual). After you have taken this dimension, you now have ONLY Three

possibilities as I see it:

The ride height dimension as prescribed in the manual IS NOT to spec. You need to look at the frame and front suspension components.

The ride height dimension as prescribed in the manual IS to spec. You have a body problem, my friend, and a serious one (or the front frame horns are bent way up in the air and you have a big time strain on your radiator support).

Give us a dimension from the bottom of your number 1 crossmember (under the engine) to the floor, the end of the front frame horn to the floor and the top of the wheelhouse dimension to the floor. While you're at it, the dimension from the front of the frame rail (the straight portion) to the floor. Measure within 1/8 inch and you will be close enough for some relative figuring.

Mike

[Keith B.]

Re: Front Springs - Demensions

Ok.
First I have 7.75 x 15 Bias Ply tires on stock rims.

Front cross member lip to floor 10.5 inches(front just below where the brake line attaches to the front cross member and the brakets attach for the bumpers)

Bottom of steering knuckle to floor - 7 5/8 inches

Bottom of frame horn (end) to the ground 14.5 inches

Wheel house (Fender Lip center) to Floor 28 1/4 inches

Frame to floor 9.5 inches(where the frame turns inward toward the engine right at the rear of the body mount -- closer to the rear of the car.)

Would appreciate others measurements if available

Thanks for the help

Keith

[Wayne W.]

Re: Front Springs - Demensions

Take a look at your springs. Are they straight or do they curve?

[Keith B.]

Re: Front Springs - Demensions

They appear to curve slightly at the top. When I compressed the spring using a rod through the shock tower the car comes down giving me a correct "z" score and a ride height of 26 inches at the wheel well. There just doesn't seem to be enough compression on the spring. I can insert my index finger in to the first knuckle on the 4 coils at the bottom. The car moves freely and bounces when pushed on simulating driving.
Keith

[Wayne W.]

Re: Front Springs - Demensions

If these springs are installed correctly they will be curved. It is common for them to not be installed with the top of the spring in the correct position at the top. This produces a straight spring and a increased ride height.

[Mike McKown]

Re: Front Springs - Demensions

Keith:

Re: Dimensions on your Saturday post.

I have measured another car and am trying to draw a comparison for you. You gave a dimension of 7 5/8 for steering knuckle to floor. What is the dimension from the center of the lower arm pivot bolt to the floor? This is with weight on the springs and not pulled down with a spring compressor. I'm guessing from other things said it is 10 1/8 inches but I would like to know. I believe the manual says this difference should be 3.5 inches + - .5.

The pivot bolt on the comparison car sits at 9 1/2 inches with a wheel well height of 25 5/8 inches. Your tire radius is 1/8 taller than mine so given same tires, mine would measure 25 3/4 at the wheelhouse, still 2 1/2 inches less than your car.

It appears that leaving any design/manufacturing tolerances out of the picture, your inner pivot bolt centerline would have to be 2 1/2 inches higher than mine. Is this correct?

Other than something here, the only other thing might be that the shafts and bushings on your control arms are bound up, even without the end caps. You said you had a radiator and coolant missing (maybe forty pounds and maybe a 30 pound battery). Put a 70 pound sand bag on the front of the car. May move it a half inch.

Best I can do for now.
Mike