I could see cutting them out of a block of 4340, but to cut the splines takes some precision and special tooling!

A second cap can't hurt!

As for overkill, I am planning to plumb mine to a Tilton pump adding a cooler!

For my telescoping 1480 splined halfshafts-

I came up by research with plans for assembling them from Dana-Splicer line

Part numbers
3-3-5141X Slip yoke female 1.562 16- spline)
3-40-1571 Slip joint male to 3.5 tube
3-28-537 Weld in yoke 3.5 tube

I also think the Mark Williams u-joints are currently the best ones available, and not cheap!

 

The cap I made is 4140, 8620 or 4340 from the scrap been. Im not going to heat treat it as its stronger then OEM with out it.

We build transmissions,rear ends, clutch's motor parts all the gears and shafts in house grinding heating are about all thats sub out. I should add no ring & pinions or spiders we do make spider blanks .

Pumping oil through a cooler is a good idea with the small volume of oil these cases hold.

 

Hi Dan,
Yes you are getting the exact same spider gears except in 17 spline. Let me know if you want to do the other cap too.
Mike

 

 

Hi guys,
I'm going touch on a few points here since a lot of GOOD questions have been brought up, rather rare these days.
Start with the basics of corvette housings. The machining is horrible from the factory. Bearing depth, cap pad height, bolt location and position is all over the place. The bearing cap pads are not flat, even, parallel or perpendicular to the carrier centerline. This is a small concern when using stock caps but with a true aftermarket cap this creates a lot of alignment issues. Since the drivers side cap takes all the stress under load I'll start with that one.
Under load, either accel or decel, the pinion forces the ring gear and carrier to the left and outward into the cap. The right side carrier bearing is forced into the housing bore. The result is cap stretch. Which it does in extreme amounts. When the caps stretches, the ring gear moves away from the pinion allowing the pinion teeth to ride high on the ring gear teeth. Also the carrier is now angled in relation to side bearing races, promoting rapid wear. Spider gears are being angled in the carrier also promoting wear. For this reason any differential would benefit from better caps.
The cap pad surface is not perpendicular to the bearing race bore. When you install a true cap you no longer have a true circle. So the first step is to machine the cap pad true to the carrier centerline.
Factory caps are tapered. Width at the top is close to .900 but at the pad it is closer to .700. Machining the pad allows you to widen the footprint to 1.00 resulting in a more stable mount. Upgrading from a 7/16 x 14 bolt to a 1/2 x 13 is just common sense due to the load being placed on it.
The right side cap doesn't go thru the stress and shock loads that the left side does so you don't have to put a steel cap on. But you can see the added benefits just from the machining.
Other areas that need machining.
New does not mean true. All carriers, including brand new, need to have the ring gear surface trued to the bearing centerline. Average amount on new carriers is .0005-.0025. Old carriers .006 is common. Same with pinion gears. The rear pinion bearing seat on the gear also needs to be trued to the bearing centerline. Normal amount to clean it up is .003-004. I don't know why a machined surface on a new gear is so bad but it is. I have seen a lot of damage on the side bearing seats of used carriers, usually due to improper bearing removal, but new carriers also need these surfaces cleaned up.
Mike

 

Pic of a spider gear blank theses are billet.

 

12 bolt conversion.
The number one reason for doing this is the increased thickness of the carrier. There is some added gain in ring gear diameter also. Why do they cost so much?
Machining. I have seen many "bad" 12 bolt conversions. Because people just don't know what they are doing. The typical method of clearancing the housing for the ring gear is what I refer to as the "drop and gouge" method. Drop the carrier and ring gear assembly into the housing and wherever the teeth gouge the housing is where you start grinding. 6 hours later it eventually clears. But now the balance weights on the carrier are hitting the side of the housing. More grinding on an already thin area.
Next the left side cap is hitting the carrier. Start grinding on the carrier. Now the ring gear bolts are hitting the housing. If you are running a 3.73 gear the ring gear bolts are too long and bottom out in the gear. If you grind too much off the housing the bottom left cover bolt will crack the boss. All this plus everything I laid out in the previous post and you will have 30-40 hours invested. Is it worth it? OH YEAH!
After seeing other people literally butcher these housings I built custom jigs and boring bars to do all this properly. No gouging, no guessing. My cap is custom made just for the 12 bolt.



Dave, you can see the radius on the cap for carrier clearance we were talking about. You can see how close the machining gets to the pinion race and the lower left cover bolt hole.

 

Also having the right equipment is important. A lathe and mill are a must. Here is a pic of my custom polisher. This one's for you Phil and Bill.

 

Are you guys using stock 12 Bolt gear sets, because I think the Tom's units are custom forged and have some machining now! Mine has pen markings with specs on the side! I might next time I am on an actual computer post up some pictures!

I have to dig out the case I was planning to use! But was going to use an 3.70 code 1969 big block HD unit I have somewhere!

I also am throwing spec and info up, because of the comradarie thing between enthusiasts! I going to do most of the clearancing because it doesn't seem like guys what to do all of that labor intensive work! And I know it is hours of grinding! Many gear ships don't want to take the responsibility of doing the case grinding! They will assemble and tune! Minor things like true the cap surface or thread them for the larger bolts! Out here the old Pepe shop was taken over by Toms and when Tom's moved to Idaho, an outfit called the Gear Shop moved in! I haven't talked to them yet to see if any ex-employees of Pepe or Tom still work there! I also know the grinding is what people don't want to do, unless you just need therapy!

 

Here is link https://www.google.com/url?sa=t&rct=...ExmbA39J1pDVSg

 

Why not just REM it? or are you doing both now mike??

 

Like safety glasses gloves face shield chair.

 

The Tom's Ring & Pinion 12 Bolt units definitely have different part numbers than the GM passenger and truck ones that he sells! I want to compare dimensions on these!

 

She is wearing glasses, sitting on a chair, and I'm not going to force her to wear gloves if I won't wear them myself.

 

Doing both now Paul, including shot-peening the housing and cover.

 

I have not blown it out yet... running 160 tread ware tires on 10" rims and still spin the tires at 70mph by just smashing the peddle.
Are you also Cyoring everything as well?

Have you had anyone putting down more power than me yet that you have built a Super 10 like mine for? I would like to know what power range these will start blowing out at...

 

A new housing would be required to use standard 12 bolt components.
The link I posted has pictures of everything Tom has machined.
It would definitely be a big project to do correctly and I'm sure would be quite expensive.

 

I wish I could cryo and rem all of them but I only do it at customers request.Doing two builds right now with everything.
I think Alan Rothman makes more power and torque than you. 660/700. Picks the front wheels up on launch. Runs constant 10.5 in a heavy car. One person definitely does with a 540. He blows the tires away over 100 mph but doesn't drive like you. So far no one has popped one yet so I really don't know how much they will take. I'm pretty sure it's the carrier that will give first.

 

I think what I wrote caused some confusion! Yes if you used conventional 12 Bolt stuff (no machining) you would have to use another non-Corvette 12 Bolt case! What I was trying to convey was I think these Tom's ring and pinions were made to minimize the case grinding and fitting!

But Unlike these great and knowledgeable shops that are on here sharing, I am not anywhere near their level! If I had one of them in my backyard where I could drop it all off, I would consider that just to get it done! Shipping stuff like this has always made me nervous! I don't trust the Post Office and UPS to get heavy boxes anywhere safely or not losing your package, unless you really pack things heavy duty and pray a lot! ! Plus these are rare parts and I feel strange having them go far far far from hom, into the care of strangers that I don't know! But I can tell Tracdogg is a really good guy and outfit! And I am warming up to the others on here! I am just beginning, and I am hoping locally that that Gear Shop still has an old employee who used to build these! Take the project as far as I can intelligently, because I do things pretty precisely and take my time go as far as I can to save some on the labor cost and to help the turn around time! Or maybe once I get to the point to pay someone, I would seriously consider tracdogg or supercharged and others that I am seeing as very knowledgeable guys!

Basically for grinding! I wasn't going to stick gears in and see where they hit and then grind caveman style! I was going to reference from a 10 Bolt case and together ring and pinion and measure that in comparison to the 12 Bolt posi and ring and pinion and approach the grinding by measurement and some patterning! I don't have a lathe but I do have some milling experience and equipment! No where near a professional! But they are my parts, so naturally no one will spend as much quality time with them, as I would!

Ps on my initial post, I was amazed by the sat in place distance the ring gear was sitting up on the posi case shoulder from the Bolt posi surface! Even if I refrigerated the posi case and heated the ring gear, it seemed no where close to slip down the posi case shoulder and onto the surface of where it should mate! It looks to me like you have to use quite a force to press that on and my initial thought without measurements was how is that gear going to handle that! It is a stout piece! I should measure and double check things, because It has been sitting around for years, but maybe someone plucked an unmachined one by accident, a long time ago! I bought this unit when I bought my full aluminum GM performance Small Block (Race Bow tie Wet sump unit) IMSA block basically capable of 800hp! I had the 10 Bolt built for the 500hp 355 cube long Rod engine I was running! I was planning on the highest normally aspirated small block in the history of my neighborhood!

 

Wow... with stories like that I feel safe.. and I am happy i went with the lighter 10 bolt.. the whole reason i stayed 10 bolt was the mass weight and the rotational weight.. in that aspect the 10 bolt kicks the 12's ***.. and if it is built like you and I built mine, it seems good for upwards of 850hp i believe which is out of my range,,,, For me this means better lap times and 1/4 mile times.. cool... thx!!!