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Gear shift lever modifiacation [No Healey Content]

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Michael Oritt

Michael Oritt

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The gear shift lever on one of my race cars broke and though I have had it repaired--as in sleeved/welded up--I do not have confidence in its future reliability.

The transmission is a UK Ford unit, commonly used in Lotuses and Cortinas, but because of the compactness of the car's cockpit, etc. the stick must be modified from its original configuration by putting about a 30 degree angle in the straight section in order to clear the dash panel.

I have sourced a replacement which is described as "billet" and my question is whether heating and bending the gear lever in order to introduce the necessary angle would weaken it significantly. Opinions and tips solicited and welcome.
 
Others may (do) know more than I but it seems odd to me that someone would make a shift lever by cutting down a billet rather than forging it. To answer your question, I would think that it depends on the alloy it is made from and whether you plan to heat it to bend it. I assume it is steel and thus cold working it is possible, again this depends on the alloy and how far you bend it. This isn't a very useful answer so how about asking the people who make it? Too bad this isn't a " what's the worst that could happen?" kind of thing. I suppose breaking a shift lever at the wrong time could cause an accident although it was really funny when Laurel and Hardy had the steering wheel come off while driving ( or was that the Stooges?).
 
Did the one that broke break at the bend? If so, that would be the answer. There are probably ways to strengthen the bend, like putting a reinforcement wedge in, or heat treating the bent lever.
 
John Turney said:
Did the one that broke break at the bend? If so, that would be the answer. There are probably ways to strengthen the bend, like putting a reinforcement wedge in, or heat treating the bent lever.
Click to expand...


Yes heat treating is possible:

However, if you do not know the metallurgy or the proper heart treating process for it ,you most likely will stiffen the metal resulting in [ Stress Hardening ] and future breakage under stress .
 
All--

The lever that broke did so at the point of the bend which had already been welded/repaired once before. I have only owned the car--a Ginetta G4--a few years and cannot speak to the lever's history but obviously it has had hard use. I recently had the transmission converted to a dog box which allows for and invites quick, hard shifts which may account for the failure.

Today I purchased the replacement and took it to a machine shop where they may be able to increase the angle by using a press without heat. If they do have to heat it they will quench it in oil to hopefully increase the hardness. I know this is not a perfect solution and I guess I will have to keep my eye on the lever's condition.

BTW the term "billet" is often misused or misunderstood and in this case the lever was not cut from a billet but rather is made of billet steel. A google search will explain the terms' meaning better than I can.
 
Not a metallurgist but bending it without heat will cause small stress fractures that might also fail. Heating and cooling only one side should bend or straighten it, though probably not as much as you want.
 
58 special said:
Not a metallurgist but bending it without heat will cause small stress fractures that might also fail. Heating and cooling only one side should bend or straighten it, though probably not as much as you want.
Click to expand...

YEP:

What I have seen done for applications like this is to shorten the lever [ AR ] by cutting and then welding a "T" handle to the top.
 
Just my opinion it's a long time since I studied metallurgy!
Cold bending alters the crystalline structure of the steel hardens it and induces stress. I think it would be better to heat the material up to cherry red when bending. The high temperature causes the steel to recrystallize as it bends. I would let it cool slowly in air (normalizing) to stress relieve it. I wouldn't quench it in oil, this is will "case harden" the surface and tend to make it more brittle. I don't think it's hardness you need, this tends to come with increased brittleness. You need to realign the crystals by tempering/annealing. In my opinion!
It would be interesting to know why the old lever failed. I would think it probably failed at the weld which was faulty in some way rather than in the body of the material.
This might help you understand the processes involved.
https://www.youtube.com/watch?v=U6NoXTT_b48

AJ
 
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