Suspension Problems

[fixitman]

Carl, Attached are the coil spring tables from the early 260Z FSM. The tables show both front springs to be identical. For a non-A/C car like mine, the free length and installed height is 14.9" and 8.7", respectively. Both rears are also identical with a free length and installed height of 15.4 and 8.7", respectively. I have to confirm the shop installed the springs in the correct locations.

The part numbers on the Nissan receipt indicate that the springs are Euro Stage 1. Possibly, I could have a spring rate test done sometime to determine if they are actually Stage 1 or 2.

As for the Bilsteins, if the part numbers are P30061 and P30062, they were purchased in March 1984. I don't have an old Bilstein catalog to confirm the numbers. Does this date make the shocks the low pressure gas type? Do you have an old Bilstein Catalog to confirm the part numbers?

According to the FSM, the rear is at the correct ride height but the front is still high by 1.4". The weight of one seat, carpet and all interior panels has yet to be added but I don't expect this additional weight to change the front ride height very much.

Fixitman

SpringData-FSM.pdf

[Carl Beck]

Carl, Attached are the coil spring tables from the early 260Z FSM. The tables show both front springs to be identical. For a non-A/C car like mine, the free length and installed height is 14.9" and 8.7", respectively. Both rears are also identical with a free length and installed height of 15.4 and 8.7", respectively. I have to confirm the shop installed the springs in the correct locations.

Thanks for including the pages - Will read the data to me over the phone, so I must have recored the last one incorrectly. Nonetheless, the difference in OEM vs Euro rear springs - only accounts for 0.7in increase in rid height.. The original picture you Posted looks like the car was sitting 3 to 5 inches higher than it should.

Could be - the shop had torqued the lower control arms down, with them suspended in the air. Could be something else was done wrong. Either of which they corrected when they swapped the OEM springs back in.

The part numbers on the Nissan receipt indicate that the springs are Euro Stage 1. Possibly, I could have a spring rate test done sometime to determine if they are actually Stage 1 or 2.

Sorry - you did say Stage I. I may be calling them Stage II because the Stage I springs for the 240-Z's are 12% stiffer than OEM. The Stage II springs for the 240Z are closer to the 140 lbs/in... So when I see 140lbs/in I think Stage II. That may not be the case for the 260Z -

If you can get an accurate measure of the wire diameter used in the Eupo Spec. Springs - we can get pretty close to what they would measure out to be. You have to find someone that has a coil spring measuring machine to get accurate measurements. The Coil Spring Measuring machine will be able to hold the spring in place, then compress it to 80% of its free length - then take load measurements as it is compressed an additional inch or two.

Call Race Car Development shop's in your area - and you might find one with the necessary machine to measure the coil spring rates..

As for the Bilsteins, if the part numbers are P30061 and P30062, they were purchased in March 1984. I don't have an old Bilstein catalog to confirm the numbers. Does this date make the shocks the low pressure gas type? Do you have an old Bilstein Catalog to confirm the part numbers?

If you bought them in 84 they are the low pressure type - no one was building high pressure gas shocks as OEM replacements then. The newer high pressure gas shocks can have 100 to 200 lbs of lift - and they will set a very light weight 240-Z from 0.75 to 1.5 inches higher by off loading that much weight from the springs.

According to the FSM, the rear is at the correct ride height but the front is still high by 1.4". The weight of one seat, carpet and all interior panels has yet to be added but I don't expect this additional weight to change the front ride height very much.

But the FSM also says that if the bumper height isn't correct - you move the bumper up/down.

We may never know exactly what caused the rear of your 260Z to be sticking up so high after the original installation of the Euro Spec. Springs

FWIW,

Carl B.

[fixitman]

After checking the the springs against the shop manual, the shop had to reverse them. As a result, the front bumper is now only 0.60" higher than factory spec; the rear bumper is 0.90" higher than spec. Considering that a little more weight from a few more bits have to be added, I think the ride height will be fine in the end.

I also spoke to Bilstein in CA this morning. They don't have any information on early Z applications anymore, not even the part numbers. But they did say that Bilsteins have always been low pressure gas shocks. Consequently, Bilsteins should not raise the ride height.

The attached photo was taken after the springs were reversed today. Damn, it looks good, if I do say so myself.

Fixitman