348 Ride Height Adjustment

Yes, you can adjust ride height using those collars. But, are your tires rubbing at the top of the wheelwell, or at some other point?

By the way, is that oil on your front shock? Is it leaking perchance or did that come from somewhere else?


Lou

 

Yes they can be adjusted, but it will throw off the handling of the car, especially if you raise the height. There are a couple of other options. You can go to a tire that isn't as wide. For example if you are running 295/45 in the rear you can go to a 285/40. The tire will be shorter, and you won't loose as much width, but it may stop the rubbing. The other option is to have the inside of the fenders rolled. Have you looked to see if you are running spacers? If you are that may be why they are rubbing. Since you are on 19"s I don't think you'll have the problem of not having enough traction. So, if you have spacers, you can either get rid of them, or go to a little bit smaller size so that you don't rub.

 

You can change ride height without messing up the OEM handling or chassis rake by:
1) set the car to factory ride height regardless of the wheels. Then decide how much you need to raise or lower to fill the wells but not rub. Say it is 25mm. Then you use the Front motion ratio as 0.7 and rear as 0.85. So if you want to lower 25mm then you take 25x0.7=17.5/1.5=11.66 turns then for the rear you lower 25mm thus 25x.85=21.25/1.5=14.16 turns. You do this even for front and rear and you will have the factory rake for proper handling but new ride height.

2) Go to a stiffer spring that prevents full travel at your road speeds. But this will change your car handling for better or worse. YMMV

 

FBB, I'm trying to adjust ride height and have a few questions:
I assume the 1.5 value in your equations is the pitch of the thread? How did you determine the motion ratios?
I'm having a difficult time getting the large collar to move. It's frozen on the shock body. Any suggestions for getting it moving. What type of tool is to be used for this?

Thanks

 

yes 1.5 is the thread pitch, MR's are in the workshop manual. Use two coil over spanner wrenches and soak the rubber that the spring sits on with pb blaster or wd-40. Still this is hard to do so I just avoid the mess and jack the car up to take pressure off the spring and use 2 spring compressor to shorten them to take pressure off the spring perches. Then they turn no problem.

 

There are at least three Service Bulletins pertaining to 348 shocks & springs, one was due to "customer complaints" about too harsh of a ride. SB# 60-23 (dated 10/10/91) states that from Assy#5765, cars were fitted with front shocks & springs 146290 & 148786 to replace previous shocks 141857 & springs 142474. SB# 60-27 (dated 12/20/93) introduces new springs F&R and R shocks to "standardize equipment with the new Spider model."
F springs 148786 change to 151881, R springs 143390 change to 148786 (so use old fronts for "updated" rear). R shocks 141858 change to 155188.
R shock absorber pad 139448 changes to 155872. This the tapered foam bushing on the shaft below upper mounting bushing.
I would suggest you determine exactly what shocks & springs you have now. The shocks will have the OEM number and a Ferrari p/n on them and the springs will either have a Ferrari p/n stenciled on the coils or paint splotches to identify spring rate or free length. If your car has been "updated", perhaps consider switching to an earlier version shock & spring combo, and adding Challenge sway bar bushings. Also, you may have to consider downsizing to F355 18" wheels.

 

Brian's comment bears further research. I have not heard this but the WSM shoew different shock and springs I believe. My stock springs say eibach and have a color band but no Ferrari part number. I'll have to look again.


*****************************************If you remove your spring to check what you have, be very careful since you will need to use a spring compressor and if it slips off the spring and is not contained by the shock body and upper mount perch a loose spring can kill you.*********************************************

This is an important time to "measure twice and cut once" because a mistake can hurt you badly.

 

I finished lowering the car 25mm. There was one shock collar on the left front that gave me grief, but after soaking in penetrant overnight it gave way. The rest of them, especially the rear were straight forward. Spring compressors were required on the front only.

While the coil-over spanner wrench I used did the job, it wasn't a perfect fit. I presume different ones should be used for the main and lock collars. Can anyone give me direction on where to obtain the proper ones?

Brian: I'm happy with the spring rate on mine, it was just sitting a bit high. My springs also have Eibach printed on them.

 

Brian is correct. Here are the TSB''s relating to the various issues (sorry for the image quality.. hope it's legible):
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