C4 1986 Aluminum Torque Arm - What if made of steel? READ!

[Fiddler's Gold]

Corvette Friends,
I have a problem to share with you. The previous owner of my modified 1986 did not properly engineer a suitable support for the new T-56 that was installed & meshed to my Dana44.
(I own a 1986 Corvette) The support plate was weak and subsequently there was considerable play & lack of stability with the tranny/driveline. Well, BOOM, the little plate cracked at the weld junction with the aluminum torque arm coming from the differential that should attach to the tranny. I would like to have a beefy aluminum housing built around the tranny and then welded and bolted to the aluminum torque bar, but cost & availability of a professional aluminum shop is at question. My neighbor (mechanic and welding professional) can only weld steel in his shop and had plans to drop the aluminum bar, template it out and construct a new one from steel with a new steel support housing around the tranny.

My questions are the following:

(Please keep an open mind as this is just speculative)

1. What would happen if this new torque bar & support housing was constructed from steel?

2. Would I experience any considerable loss of rear balance or control or would it simply be a weight consderation? (this is what I am most concerned about) Anything to worry about??????

3. Was aluminum originally used for its weight reduction &/or oxidation-reduction properties?

4. Will there be any additional problems to consider?

Weight is not an issue at this point since the steel design in question will not add that much weight to the overall & it is acceptable.

Anyone have any insight or education into this?
(My thoughts
Steel has a bunch of advantages over aluminum inherently in the following regard : Fatigue (2x more than AL), Hardness, Flexion/Elastic modulus, Density (3x more than AL), strain rate, thermal expansion (1/4 of AL), etc. I know that AL is a fabulous material - but my options are kinda limited. Can someone with engineering experience with this as at pertains to this piece on a Corvette chime in?

Thanks!
Andy

 

[69MyWay]

Andy,

I don't think steel will hurt, just weigh more.

The F body used a torque arm as well in the third gen cars. My thought is you get a F body torque arm for that style trans, get your stock vette one, go to a welding shop and have them figure out how to make a new one that has the F body head on one end and the Vette tail on the diff side.

 

[Fiddler's Gold]

Thanks Chris

I was slightly concerned about the moment arm and the CG problems that might be adjusted with the movement of the torque arm. I have been calculating the torque/rotational adjustment & moment forces using simple physics and feel that the steel structure & potentially increased weight would offset the delicate balancing of the in-line drive but not enough to nor not far enough out of line to negatively affect the rolling axis nor the CG too much. Looks like the F bodies torque arms are made from stamped steel and the aftermarket occassionally from stainless/zinc. Was thinking of replacing the entire existing aluminum torque arm and then constructing a new arm out of steel with channel plates and stainless steel G8 fine thread bolts.
It should work ok as long as my dimensions & angles are in proper alignment with the differential mounting.

Thanks & I would be REALLY interested to hear anyone else's take or opinions on this (informed or uninformed)

Thanks!
Andy

 

[vigman]

Why not kill more birds with a bigger stone

Put in a 6 speed ( ZF ) and use the factory Torque tunnel/ mount.. that will also fix your speedo problem.. and not make it such a clap trap. As well as solving your interior problems!

Re design is fine.. but more often than not.. what you found in your car is the result.

Not enought time... not enough money.. not enough experience ( pick any two)

In a stock setup at least parts are available not a one off custom.

In the case of a REAL Grandsport ( or other RACING legend..) then fab is fine IF YOU HAVE THE TIME & MONEY! You can't go to the local Vette wrecking yard and get what you need.


The ONLY other exception is being Chris's next door neighbor!

 

[Fiddler's Gold]

Vigman

Yeah, well unfortunately don't have the extra $3k to put into a new ZF6 --- so if you can find a home for this new T56 and get me a ZF6 for free, then cool. No disrespect, but this is where I am right now. I didn't choose to be here, but that is the way it is. I need more constructive advice. I will get this working and working well. It will be engineered and designed using templates, CAD design and professional installation.

Thanks for the support as always, Vig! You are the best.

Andy

 

[vigman]

Ok plan B

What about a wrecking yard?
Is 1K out of range?

OK if that doesn't work....and it was ME!

I would do Chris's suggestion of grafting the two together, I think the steel I beam might be a bit over kill for the application..

I'm sorry, I have no other suggestions!

Vig!

 

[Fiddler's Gold]

PICS COMING TOMORROW!!!

Well my friends...
We designed a fabulous I-beam type of steel brace with G8 bolts and custom welding. In the middle of the custom braces, will be a HD stainless steel flat bar that runs the entire length of this new torque arm. This thing could handle the torque of a monster truck. Not too heavy - yes heavier than the aluminum piece but not too heavy. At least I don't have to worry about flexion or cracking now. hehehe ;-) Talk about dropping in a 406 with juice?
hehe I could handle a couple of twin engines with this setup.



I am going to have this torque arm rewelding & then sell it or keep it in case I (or the next owner) ever wants to go back to a 4+3 or a ZF-6 setup.

I WILL POST PICS OF EVERYTHING TOMORROW!!! THANKS!
Andy

 

[-=Jeff=-]

Hey Fiddler..

Check this Picture, it is a custom bracket ont he back of a 4L80E to fit into a c4


Here are the websites with pictures

http://bowtye8.tzo.com/hovmovies/pics/directories/tom87vette/ http://bowtye8.tzo.com/hovmovies/pics/tom4l80etn.htm http://bowtye8.tzo.com/hovmovies/pics/tomspicsb.htm


Maybe that will help too

 

[Fiddler's Gold]

DAMN IT FEELS GOOD TO BE A GANGSTA

Thanks Jeff.
I think we got this one WHIPPED.

More pics to come today.Thanks for the info!

Andy

 

[Enuzio]

Modulus of steel

Corvette Friends,
I have a problem to share with you. The previous owner of my modified 1986 did not properly engineer a suitable support for the new T-56 that was installed & meshed to my Dana44.
(I own a 1986 Corvette) The support plate was weak and subsequently there was considerable play & lack of stability with the tranny/driveline. Well, BOOM, the little plate cracked at the weld junction with the aluminum torque arm coming from the differential that should attach to the tranny. I would like to have a beefy aluminum housing built around the tranny and then welded and bolted to the aluminum torque bar, but cost & availability of a professional aluminum shop is at question. My neighbor (mechanic and welding professional) can only weld steel in his shop and had plans to drop the aluminum bar, template it out and construct a new one from steel with a new steel support housing around the tranny.

My questions are the following:

(Please keep an open mind as this is just speculative)

1. What would happen if this new torque bar & support housing was constructed from steel?

2. Would I experience any considerable loss of rear balance or control or would it simply be a weight consderation? (this is what I am most concerned about) Anything to worry about??????

3. Was aluminum originally used for its weight reduction &/or oxidation-reduction properties?

4. Will there be any additional problems to consider?

Weight is not an issue at this point since the steel design in question will not add that much weight to the overall & it is acceptable.

Anyone have any insight or education into this?
(My thoughts
Steel has a bunch of advantages over aluminum inherently in the following regard : Fatigue (2x more than AL), Hardness, Flexion/Elastic modulus, Density (3x more than AL), strain rate, thermal expansion (1/4 of AL), etc. I know that AL is a fabulous material - but my options are kinda limited. Can someone with engineering experience with this as at pertains to this piece on a Corvette chime in?

Thanks!
Andy

Hey...Andy

If it were my car, I would have the neighbor fab it up, and take it to truck spring shop for heat treat and enjoy. The modulus or stiffness of steel is roughly three times that of aluminum. I like the idea.

Enuzio