1963 Grand Sport Differential Build

[Gary R.]

Hi Guys,
I just finished up a '63 Grand Sport Differential and thought some of you would like to see what one looks like. These are about as rare a part as you will find. I did the steering box back in Nov for those that are interested in it you should be able to find that one here too. I am not going into who the owner is or which car this is for. Just some general pictures for those of you who get into building the old cars.


Here is what they look like. This one is not the one I built, rather it is from another forum for reference.






Here is the pinion yoke I asked Joe L about last week. It is a 1310 strap yoke.



Casting Number




Date cast




Oil deflector inside





Bearing cap bolt were setup for safety wire





HD axles were used. These are wider then any stock axle yoke I've seen and I've rebuilt all years from 63-79, including the 63 Z06's. None had an axle like this.

[Bill M.]

Re: 1963 Grand Sport Differential Build

half shaft yolks show treads but the complete unit in the beginning does not?

[Gary R.]

Re: 1963 Grand Sport Differential Build

That is correct, the complete diff is not one I built and I don't have reference on the yokes used in it. The diff I built came out of an original car.

[Bill M.]

Re: 1963 Grand Sport Differential Build

Gary I guess they tried different assemblies to see what worked best. I t looks like they were going to use cap screws and a cap similar to the big block rear half shaft retainers

[Duke W.]

Re: 1963 Grand Sport Differential Build

How is the oil deflector secured? It looks like three screws or rivets and epoxy.

I assume the oil deflector was a field modification along with the axle oil cooler to solve the problem they had with eating up ring and pinion sets.

I've always been somewhat suspicious of the aluminum carrier. Given that aluminum's thermal expansion rate is about three times that of cast iron and steel it could reduce outer bearing race interference fit in the carrier and alter ring and pinion alignment, and the higher the temperature the worst the problem.

I would imagine that differential temperatures could have easily gotten into the 250+ degree F range before the coolers were added.

It appears the carrier rear cover has a provision to mount the axle solidly to the round frame cross member rather than using a separate isolated axle mount cross member as on the production car.

Duke

[Gary R.]

Re: 1963 Grand Sport Differential Build

Bill
I really don't know if the assembled diff has original parts in it. If I recall it was going into a clone with a box frame. As Duke mentioned the rear mount and the frame was tubular.

There is a tap for an external oil cooler. The deflector is bolted through the housing and epoxied as you surmised. Stock diff temps are up there, I have seen them in the 200*f range with out a cooler. I can't say just how hot these got.

Duke has a good point on temperatures over an extended period of racing. Given a diff would probably be broken down for a PM between races might have been the reason for revisions and checked to the lash and pattern. I have the lash and preloads dialed in so for the current usage I am not concerned, if it is to run 24 hours then it should be checked, however that is very unlikely anymore.