C3 Race Car Build

[Oneball]

4hrs later and diff is setup. Followed Tom’s Differentials video on YouTube rather than the dial gauge method.

 

[Oneball]

Tops painted in epoxy primer.

 

[Oneball]

Toasty this afternoon. Rear spring split.


Lower leaf shortened


Reassembled and bush thingies pressed in




New clamps made.



And fitted.

 

[Forrest Gump]

Is that a new spring? How much did you shorten it?

 

[Roscobbc]

Is that a new spring? How much did you shorten it?

And why?

 

[Oneball]

Yes it’s a new HD/gymkahna 7 leaf spring.

It’s now about 40mm so about 20mm more clearance each side.

I moved one hole in by enough to provide the same end to hole dimension as stock and then drilled the central hole by half the amount the other way.

 

[Oneball]

And why?

Just gives a touch more wheel/tyre to spring clearance.

 

[Roscobbc]

Interesting - my 18" rears are on 9" wide rim with 5" (rather than 4") inset (keeping F/R track the same as stock). Ends etc of the 7 leaf spring fit comfortably inside the wheel rim (sway bar linkage didn't - have removed it) didn't need to use an offset trailing arm with the 18" rims - however with a 285/40 rear tyre having quite a 'square' section as such it does 'kiss' the chassis very lightly when cornering hard as the trailing arm or stock rubber pivot bush flexes.

 

[Oneball]

Interesting - my 18" rears are on 9" wide rim with 5" (rather than 4") inset (keeping F/R track the same as stock). Ends etc of the 7 leaf spring fit comfortably inside the wheel rim (sway bar linkage didn't - have removed it) didn't need to use an offset trailing arm with the 18" rims - however with a 285/40 rear tyre having quite a 'square' section as such it does 'kiss' the chassis very lightly when cornering hard as the trailing arm or stock rubber pivot bush flexes.

But I’ll have a 15inch rim and with longer link bolts the spring end will be about an inch lower in relation to the wheel. So right on the rim.

This spring has had the end ground and it’s close.

 

[Roscobbc]

As you say 'very' close indeed - stock 4" wheel inset?

 

[Oneball]

A 10” wheel with a 4” backspace will give me two inches wider which I reckon will work just right with the flares. Need to ask a few people’s advice before I decide on wheels though.

 

[Oneball]

Stuck the tops on today as they’ll need to be there for the cage being made.




Think I may have to permanently fix some of the roof and header rail trim prior to the cage going in as some of the screws won’t be accessible.

Front hubs on. The procedure for doing the hub nuts up just doesn’t feel right, the only thing really keeping the nut on is the cotter pin but there we go.

 

[Oneball]

Front wheels on, still not happy with the driver’s side wheel bearing but will see how it is after a run.


Diff now finished. Just waiting for a drill bit to plumb in a cooler to the case and I’ll be able to get it back together

 

[Oneball]

Think I picked the hottest afternoon to sort the diff. Case drilled and tapped for oil cooler lines.



Backlash set.


And engagement pattern.



Also had a look at the driver’s side front wheel bearing this morning before work as I was up at 5am. Pretty sure the spindle is toast and has run the inner race at some point in the past.

 

[Daytona Vette]

Hi Tim
Any ideas for the Bolts and lock Tabs for UJ to rear wheel, the High Tensile Bolts stretch, what do you Racers do other than wire tie the Nuts, anything to stop the stretching?

 

[Oneball]

Hi Tim
Any ideas for the Bolts and lock Tabs for UJ to rear wheel, the High Tensile Bolts stretch, what do you Racers do other than wire tie the Nuts, anything to stop the stretching?

I’m just using a new set of standard bolts and lock tabs. Will see how it goes. There’s probably an ARPbolt that could be used that maybe stronger don’t know.

I use threadlock for a lot of things. Loctite 248 comes in a stick so is easy to use and can be broken with heat if needed.

 

[kentvette]

That's an impressive engagement pattern you have there! As I said, not such great memories for me - or should I say my long suffering "diff guy"!

 

[Daytona Vette]

I’m just using a new set of standard bolts and lock tabs. Will see how it goes. There’s probably an ARPbolt that could be used that maybe stronger don’t know.

I use threadlock for a lot of things. Loctite 248 comes in a stick so is easy to use and can be broken with heat if needed.

Thank you Tim

 

[Roscobbc]

High tensile bolts are fantastic - ideally installed on race engines using a 'stretch' gauge' rather than torque wrench. ARP nuts 'n' bolts are amazing and one area where the Far East hasn't dominated supply. People talk about aviation grade fixings - the ARP stuff as we'll possibly use of our cars is well ahead of aircraft related equipment. Amazingly if you look at the catalogue you'll see even higher grade nuts 'n' bolts that will typically be used on multi thousand horse power drag racers.

 

[Roscobbc]

Oneball - perhaps explain the rationale of going with diff cooling on your Vette for us mere mortals?