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Gmagno

Cut & Shorten 240Z Steering Column in Race Car

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Help and advice needed please.

 

I have searched everywhere and cannot find any info on this process. I want to shorten the steering column/shaft 3 inches for taller drivers. I have seperated the column, the top half is spring loaded, the inner shaft is male spline and connects to the bottom female shaft, 2 piece setup. Common sense tells me I need to cut the space between the dash mount and steering wheel. Worried about not getting the spring back in place properly after the cut/weld. I really don't want to screw this up since these columns are not off the shelf and not cheap. I just need someone to tell me its possible, or not. Thanks in advance for the help.

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You want to do the exact opposite to this taller driver who had to get an extension to keep the wheel close enough with the pedals as far away as practical. For mine it was all about getting the seat and driver back for better weight distribution.

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12 hours ago, 260DET said:

You want to do the exact opposite to this taller driver who had to get an extension to keep the wheel close enough with the pedals as far away as practical. For mine it was all about getting the seat and driver back for better weight distribution.

 

Seat is all the way back, even modified/removed metal to extend further back that stock.

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I have the answer. Just need to think about it, give me a minute.

 

Edit:

 

So as others have suggested other methods such as a flat wheel or inverted wheel, thinner seat, reclined seat, would be much easier.

 

Early Z assembly

A6D09B0C-6C70-40A7-B5D2-4D82A3BCF6B2_zps

Column to firewall

D13D5BD8-2617-491C-AE04-DCE88E3673C6_zps

Internal shaft

6CB2451E-6230-4FCE-80C8-748F7A02998F_zps

The outer tube

F41559BD-5466-4400-95B7-719FF1FB3AA3_zps

Bottom seat of the outer tube

BE4EA6F9-A4A1-4A5C-8860-2D38E9DCC08B_zps

Inner tube with spring.

 

So the inner tube is a mostly hollow tube that ends right where the steering column attaches to the dash. The outer tube is two parts with one being the upper portion that attaches to the dash, and the lower portion that extends down and has a bellow that attaches to the firewall. Internally there is a shaft that comes through the fire wall. In case of an accident the bottom bellow crushes and the assembly slides away from the driver if that is the greater force or if from the other side the assembly is retained and the hollow tube slides up through the hollow portion. 

 

You would be compromising the safety by shortening the length it has to collapse. If that is not a concern then in theory you could section the inner and outer tube of the upper portion. The splines of the shaft only engage at the bottom of the upper inner tube so unless you wanted to also go about manipulating that it would be better to cut it out of the upper portion. The concern would be as you guessed, getting them welded inline perfectly. If they were off you would have binding issues come up as the top is retained by a sprung c-clip. You do have a bit of room with the springs on both sides, but you may feel some binding. You also would run into issues with retaining the steering lock and the blinker mount. Your steering wheel would also get quite close to the dash with limited room for the steering mounted accessories.

 

With that said there are a bunch of ways to line up tubes and weld them straight, there is the budget, 90* channel with pipe clamps. Or more high tech methods like 3d printing a brace to line them up.

 

58A0B357-728F-4B16-9AF1-899A17DBADCE_zps

 

I ended up cutting the bottom portion to fit a power steering setup. So my problem was welding the shaft, which now in retrospect I have very limited collapse as it widens at the bottom of the splines although I accounted for some of that by retaining the collapsible portion of the donor column as well. It took a few tries to get it to the point you couldn't feel bind, much more difficult, but possible.

 

Long story short, you could do it. The question is the balance, as it was built around that setup to a point, once you move that you may need to modify the dash and the controls, and at that point you get into "making a new column is easier than trying to modify the old column."

 

 

 

 

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I just turned upper mount other way around. It's not symmetrical.

And yes spline shaft can/have be shorten. I did't because my cross member is bit further. I only did shorter bush to connect shafts. Out of icehockey puck🤣

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