Tom's Aluminum Differential Case

[68/70Vette]

Sorry, Santa won't be bringing you an aluminum differential case this year. Tom had hoped to have them available the end of this year. He's now targeting for next year. I'm pretty sure he will eventually be selling them because he has sunk so much money into the project. He told me, but I don't want to say but it is in the 6 digit's of dollars.

The aluminum differential will come with an aluminum cover also.

I did buy a set of his heim joint camber rods ( part VRCCR)and also the camber rod bracket (part VCRB-MOD) that attaches to the differential case. The bracket to heim joint connect points are dropped 1 inch so the rods parallel the axles. Also, for this bracket, Tom modifies an original GM bracket. If you hold up the GM bracket and place it agains a VBP bracket, you can see the VBP bracket mounting holes are larger in diameter. This creats a possibility of a sideway shift of the bracket during hard use. In other words, the tolerances of the GM bracket are noticeably better.

 

[redvetracr]

Sorry, Santa won't be bringing you an aluminum differential case this year. Tom had hoped to have them available the end of this year. He's now targeting for next year. I'm pretty sure he will eventually be selling them because he has sunk so much money into the project. He told me, but I don't want to say but it is in the 6 digit's of dollars.

The aluminum differential will come with an aluminum cover also.

I did buy a set of his heim joint camber rods ( part VRCCR)and also the camber rod bracket (part VCRB-MOD) that attaches to the differential case. The bracket to heim joint connect points are dropped 1 inch so the rods parallel the axles. Also, for this bracket, Tom modifies an original GM bracket. If you hold up the GM bracket and place it agains a VBP bracket, you can see the VBP bracket mounting holes are larger in diameter. This creats a possibility of a sideway shift of the bracket during hard use. In other words, the tolerances of the GM bracket are noticeably better.

I was told Tom wants to sell out but he has over a million in inventory....Six figures to redesign something thats close to perfect?? He almost sounds like the Auto-Gear people, it took them three tries to get the M-22 gears right....they build billet blocks now why not a diff housing? I have a 1" block of aluminum between my diff and the camber bracket, it`s been there since 1995 and has never come loose...it does the same job as Tom`s or the VBP bracket for a fraction of the cost.

 

[mrvette]

Friggin' economy being shitty, hard to imagine much demand for aluminum diffy housing/whatever on a lo volume basis, OR a more shitty time to try selling any business.....

Wife has lost a gas station, sign shop, and roofing contractor as clients, went outta business....that hurts....another has sold just 5 bux worth of merchandise THIS WEEK, and he is in the bar supply business....freeking HOLIDAY season....and BAR supplies are hurting??

:hissyfit:

 

[68/70Vette]

I was told Tom wants to sell out but he has over a million in inventory....Six figures to redesign something thats close to perfect? I have a 1" block of aluminum between my diff and the camber bracket, it`s been there since 1995 and has never come loose...

Tom was trying to find a buyer, even before he left California. Embarrasingly enough, I never thought of the aluminum spacer block. Such an obvious thing. Tom's bracket was expensive. I could've saved some money.

mrvette...When you look at the small businesses you mentioned, it seems there's nothing in the stimulus package that really helps small businesses. Here in Cali the stimulus money is going into repaving the roads, redoing sidewalks, etc. Nothing to really create permanent jobs.

Also, the differential complete weighs pretty close to 95 pounds. A lot of that weight is the posi carrier, springs, spiders, ring and pinion. Don't know how much a bare case weighs, but an exact duplicate would weigh 1/2 as much. But because aluminum is not as strong as cast iron, an aluminum case would have to be beefier to achieve the same strength. Who knows what Toms price will be but it won't be a particularly cost effect weight savings. I'm sure it'll look a lot nicer. Particularly the cover if it has cooling fins machined into it.

 

[redvetracr]

Also, the differential complete weighs pretty close to 95 pounds. A lot of that weight is the posi carrier, springs, spiders, ring and pinion. Don't know how much a bare case weighs, but an exact duplicate would weigh 1/2 as much. But because aluminum is not as strong as cast iron, an aluminum case would have to be beefier to achieve the same strength. Who knows what Toms price will be but it won't be a particularly cost effect weight savings. I'm sure it'll look a lot nicer. Particularly the cover if it has cooling fins machined into it.

I can not claim to have ever seen one but I have been told GM had an aluminum diff for the Grand Sport race cars. I can`t imagine him investing so very much money in a differential for a 30 year old car...I can see his 12 bolt conversion as it (sort of) uses existing 12 bolt posi cases but an aluminum diff for a C-2/C-3?? seems like a poor investment for a very limited audience.

 

[Corvettes White]

I can not claim to have ever seen one but I have been told GM had an aluminum diff for the Grand Sport race cars. I can`t imagine him investing so very much money in a differential for a 30 year old car...I can see his 12 bolt conversion as it (sort of) uses existing 12 bolt posi cases but an aluminum diff for a C-2/C-3?? seems like a poor investment for a very limited audience.

Well I for one would be interested in the case. There may not be a lot of us but there are a few of us out there. Between aluminum brakes, carbon fiber drive shafts, an aluminum bow tie block, as well as a few other parts on my '69; adding an alum case would be just a part of the game for many of us. Now can we get titanium gears to go inside?

Any target pricing?

As for the grand sport cases, there was one on EBay not too long ago, recall $5000. Based on the photos I have seen, it is not a direct bolt in.

George

 

[69427]

Just out of curiosity, what's the technical holdup regarding this aluminum housing?

 

[Twin_Turbo]

For 5K and whatever is added to that you can buy one hell of a nice custom IRS based on something much better than this. I've seen a unit years ago that was a quick change unit, it basically looked like a champ type center section but it wasn't a champ unit neither was it a winters. It was an awesome looking piece though, maybe I still have an old pic.

 

[Bee Jay]

I can not claim to have ever seen one but I have been told GM had an aluminum diff for the Grand Sport race cars. I can`t imagine him investing so very much money in a differential for a 30 year old car...I can see his 12 bolt conversion as it (sort of) uses existing 12 bolt posi cases but an aluminum diff for a C-2/C-3?? seems like a poor investment for a very limited audience.

Well I for one would be interested in the case. There may not be a lot of us but there are a few of us out there. Between aluminum brakes, carbon fiber drive shafts, an aluminum bow tie block, as well as a few other parts on my '69; adding an alum case would be just a part of the game for many of us. Now can we get titanium gears to go inside?

Any target pricing?

As for the grand sport cases, there was one on EBay not too long ago, recall $5000. Based on the photos I have seen, it is not a direct bolt in.

George

Me three. I want one.
Bee Jay

 

[Twin_Turbo]

Got the pic...if you have money to burn, buy something like this:

 

[redvetracr]

I can not claim to have ever seen one but I have been told GM had an aluminum diff for the Grand Sport race cars. I can`t imagine him investing so very much money in a differential for a 30 year old car...I can see his 12 bolt conversion as it (sort of) uses existing 12 bolt posi cases but an aluminum diff for a C-2/C-3?? seems like a poor investment for a very limited audience.

Well I for one would be interested in the case. There may not be a lot of us but there are a few of us out there. Between aluminum brakes, carbon fiber drive shafts, an aluminum bow tie block, as well as a few other parts on my '69; adding an alum case would be just a part of the game for many of us. Now can we get titanium gears to go inside?

Any target pricing?

As for the grand sport cases, there was one on EBay not too long ago, recall $5000. Based on the photos I have seen, it is not a direct bolt in.

George

I`m curious...do you run a multi plate mini clutch? do you have a lightened ring gear?

 

[redvetracr]

Got the pic...if you have money to burn, buy something like this:

I know a couple of guys that had an IRS/Quick change in a Corvette race car... mounting the thing would be the problem in a street car...

 

[68/70Vette]

Got the pic...if you have money to burn, buy something like this:

I can see internal volume for a ring and pinion, but there doesn't seem to be enough space inside for a limited slip assembly. Most of the inside space of a C3 diff is taken up with the posi case, internal springs, clutch plates, spider gears, etc Is this a solid rear end, maybe a "locker" limited slip?

 

[Twin_Turbo]

posi doesn't have to be bulky if not a clutch type it can be quite small. Take a look at how small the posi case of a 9 bolt borg warner is which is a cone style posi

 

[Solid LT1]

Also, the differential complete weighs pretty close to 95 pounds. A lot of that weight is the posi carrier, springs, spiders, ring and pinion. Don't know how much a bare case weighs, but an exact duplicate would weigh 1/2 as much. But because aluminum is not as strong as cast iron, an aluminum case would have to be beefier to achieve the same strength. Who knows what Toms price will be but it won't be a particularly cost effect weight savings. I'm sure it'll look a lot nicer. Particularly the cover if it has cooling fins machined into it.

I can not claim to have ever seen one but I have been told GM had an aluminum diff for the Grand Sport race cars. I can`t imagine him investing so very much money in a differential for a 30 year old car...I can see his 12 bolt conversion as it (sort of) uses existing 12 bolt posi cases but an aluminum diff for a C-2/C-3?? seems like a poor investment for a very limited audience.

Yes GS Vettes had expiriemental aluminum cases, when one of the owners "popped" one a few years back all owners chipped in a had spare units cast/machined up to share the burden.

How many here are ready to make depositis of $500 for a HD differential case fabrication? 35-40 buyers making deposits would get a project done to completion.

I think a "top drop" differential like Mark Williams or Strange Engineering use in drag racing would be a better product and much stronger.

Heck! even the C5/6 guys need a better differential than GM made for their cars, my C6 Z06 buddies are having trouble with differentials when they mod cars for 40-70HP increases.

Here is a link to a 63 Gran Sport restoration, must be nice to have $$$ Link: http://www.racingicons.com/gs/chassis.htm

 

[69427]

Also, the differential complete weighs pretty close to 95 pounds. A lot of that weight is the posi carrier, springs, spiders, ring and pinion. Don't know how much a bare case weighs, but an exact duplicate would weigh 1/2 as much. But because aluminum is not as strong as cast iron, an aluminum case would have to be beefier to achieve the same strength. Who knows what Toms price will be but it won't be a particularly cost effect weight savings. I'm sure it'll look a lot nicer. Particularly the cover if it has cooling fins machined into it.

I can not claim to have ever seen one but I have been told GM had an aluminum diff for the Grand Sport race cars. I can`t imagine him investing so very much money in a differential for a 30 year old car...I can see his 12 bolt conversion as it (sort of) uses existing 12 bolt posi cases but an aluminum diff for a C-2/C-3?? seems like a poor investment for a very limited audience.

Yes GS Vettes had expiriemental aluminum cases, when one of the owners "popped" one a few years back all owners chipped in a had spare units cast/machined up to share the burden.

How many here are ready to make depositis of $500 for a HD differential case fabrication? 35-40 buyers making deposits would get a project done to completion.

I think a "top drop" differential like Mark Williams or Strange Engineering use in drag racing would be a better product and much stronger.

Heck! even the C5/6 guys need a better differential than GM made for their cars, my C6 Z06 buddies are having trouble with differentials when they mod cars for 40-70HP increases.

Here is a link to a 63 Gran Sport restoration, must be nice to have $$$ Link: http://www.racingicons.com/gs/chassis.htm

Got no problem with the deposit. It's the unknown balance amount that scares me.

 

[BBShark]

I can not claim to have ever seen one but I have been told GM had an aluminum diff for the Grand Sport race cars. I can`t imagine him investing so very much money in a differential for a 30 year old car...I can see his 12 bolt conversion as it (sort of) uses existing 12 bolt posi cases but an aluminum diff for a C-2/C-3?? seems like a poor investment for a very limited audience.

Yes GS Vettes had expiriemental aluminum cases, when one of the owners "popped" one a few years back all owners chipped in a had spare units cast/machined up to share the burden.

How many here are ready to make depositis of $500 for a HD differential case fabrication? 35-40 buyers making deposits would get a project done to completion.

I think a "top drop" differential like Mark Williams or Strange Engineering use in drag racing would be a better product and much stronger.

Heck! even the C5/6 guys need a better differential than GM made for their cars, my C6 Z06 buddies are having trouble with differentials when they mod cars for 40-70HP increases.

Here is a link to a 63 Gran Sport restoration, must be nice to have $$$ Link: http://www.racingicons.com/gs/chassis.htm

Got no problem with the deposit. It's the unknown balance amount that scares me.

$500 will buy you the billet to machine it from (if you get a good deal). That's just the diff housing, no cover.

 

[69427]

Yes GS Vettes had expiriemental aluminum cases, when one of the owners "popped" one a few years back all owners chipped in a had spare units cast/machined up to share the burden.

How many here are ready to make depositis of $500 for a HD differential case fabrication? 35-40 buyers making deposits would get a project done to completion.
..............................
IHere is a link to a 63 Gran Sport restoration, must be nice to have $$$ Link: http://www.racingicons.com/gs/chassis.htm

Got no problem with the deposit. It's the unknown balance amount that scares me.

$500 will buy you the billet to machine it from (if you get a good deal). That's just the diff housing, no cover.

In my case, I'm already using the late batwing, so no fancy cover needed, but I'd definitely have to have an indication of what the final housing price would be before I jumped on board.

 

[69427]

Just out of curiosity, what's the technical holdup regarding this aluminum housing?

Well, the costs have been discussed so far, but are there any technical reasons this can't be done by someone with a CNC type machine (and a decent design shape)?

 

[redvetracr]

Here is a link to a 63 Gran Sport restoration, must be nice to have $$$ Link: http://www.racingicons.com/gs/chassis.htm

that website is a hoot...as if anyone with a GS (or any other Corvette race car with significant history) is ever going to race it in (real) competition....I find the whole aluminum diff thing sort of overkill as I can think of quite a few things that would give someone a "bigger bang for the buck" than an aluminum differential housing...