Cone type Sure Grip

jcslocum

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I have a cone type Sure Grip (3.23 ratio) apart to look it over before installing into my '66 Fury III. All parts look good and the cones have not bottomed out in the case. I measured the clearance (with hard wax) between cone face and bottom of the case and have right about 0.040" thousandths of an inch clearance. I have read every thread I can find on refurbishing this unit and come up with some different facts that have been posted.

My cones look like this:

2021-03-24-11-30-07-jpg.jpg


This one from a trusted member:

I'm rustyratrod from FABO. Take some modeling clay and put a piece about the size of a marble into the case half end where the cone fits into the case. Put a little grease on the face of the cone to keep the clay from sticking to it. Now install the cone into the case and press it in as far as it will go. Remove the cone and measure the thickness of the clay. I recommend machining the cone end if clearance is less than about .060". When the face of the cone hits the inside of the case, the unit becomes ineffective.

So, my cones are under this 0.060" limit recommended by Rusty. I have seen another post where the clearance when disassembled was 0.087"

I used Play-doh because that's what I had and it looks like I'm good! I have 2,2mm (0.087") clearance on both case halves.

2021-03-24-17-52-30-jpg.jpg


What I'm understanding is that at 0.040 clearance the cones are worn, what looks to be 50% (if I take the 0.087" as new) and that it will work, but not optimally with the lower spring force due to wear. This is not a DD or drag car, It's a Fury wagon that I bomb around in. I wanted a better ratio from the 2.73 that's in there right now as well as posi. My refurb thoughts are as follows:

  • Leave the cones alone and shim the springs for better operation
  • Machine the face the cones to get "like new" clearance and shim the springs
  • Leave it alone and use as is
I'd appreciate any input on what the best solution could be for a weekend queen of a car.
 

c-barge

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Since the cones haven't bottom out I'd put it back together and run it. Once the diff turns to a one wheel peel (cones have bottomed out) then rebuild it or find a better clutch SG to replace it.
 

Trace 300 Hurst

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It's a Fury wagon that I bomb around in.
....a weekend queen of a car.

It has taken 55 years to wear the cones down to 0.40. How many "years of weekends" will you get before that .40 is gone in your Weekend Queen (love that!), especially if you spend most of the time going straight-ish and not doing figure eights? 15 more years? 25?

You're right to ask the question, but if it were me.....put it back together. You'll never bottom those cones.
 

jcslocum

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Thanks to all of you for the comments!! Seems like putting it back together as is the best route.

I do wonder what the original clearance was.

Thanks again,

jon
 

Trace 300 Hurst

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I do wonder what the original clearance was.
I absolutely agree with wanting to know that original clearance, just to be able to gauge "where it was and where it is now". Hell, I'm a Manically Engineerer-er, so that sort of thing makes me tick. But I do think your Weekend Queen will be just fine with the remaining 0.40" of life. You might want to reduce the amount of smoky burnouts you do when you're "bombing around" with your new gearing. :poke:
 

c-barge

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Iirc doing donuts is what really eats up a cone style SG. Normal strait line burnouts shouldnt be too too bad. If you feel ambitious you can even add some extra springs inside the 4 main ones for a smidge extra pressure.

20200725_092141.jpg
 

Trace 300 Hurst

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Iirc doing donuts is what really eats up a cone style SG.

Other that EATING them, is anyone doing donuts in their C-Bod?

As for additional spring pressure, I'll toss in a word of caution: Excessive pressure (whatever that might be, who knows that number?) might interfere with the required differential effect and you'll end up with an unpleasant, ratcheting, Detroit Locker-type of rear end. However, replacement springs from one of the diff companies out there certainly can't hurt.

Ahh...I just stumbled on this. On that great FABO thread about reconditioning the cones, way down in the comments (post #70) I found this, written by member 19DART66: "The only thing different we use to do was to add 727 clutch springs inside the four pre load springs, a little tough on the street on corners but it kept both wheels locked together at the drag strip." So yeah....careful with too much spring pressure, but maybe just shimming the spring plates a little (.50-.60?) as was done in that How-To might be a better idea. If you read that whole thread, shims are discussed in detail.... what to use, where to buy, etc.
 

jcslocum

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I absolutely agree with wanting to know that original clearance, just to be able to gauge "where it was and where it is now". Hell, I'm a Manically Engineerer-er, so that sort of thing makes me tick. But I do think your Weekend Queen will be just fine with the remaining 0.40" of life. You might want to reduce the amount of smoky burnouts you do when you're "bombing around" with your new gearing. :poke:

I have other plans for the car including a power upgrade. So some extra burnout may be in store. I decided to order some shims to to have the option if needed.
 

MEV

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Other that EATING them, is anyone doing donuts in their C-Bod?

As for additional spring pressure, I'll toss in a word of caution: Excessive pressure (whatever that might be, who knows that number?) might interfere with the required differential effect and you'll end up with an unpleasant, ratcheting, Detroit Locker-type of rear end. However, replacement springs from one of the diff companies out there certainly can't hurt.

Ahh...I just stumbled on this. On that great FABO thread about reconditioning the cones, way down in the comments (post #70) I found this, written by member 19DART66: "The only thing different we use to do was to add 727 clutch springs inside the four pre load springs, a little tough on the street on corners but it kept both wheels locked together at the drag strip." So yeah....careful with too much spring pressure, but maybe just shimming the spring plates a little (.50-.60?) as was done in that How-To might be a better idea. If you read that whole thread, shims are discussed in detail.... what to use, where to buy, etc.
Lots of burnouts, i mean A LOT OF BURNOUTS. and a few donuts. But i run a detroit locker differential no cones or frictions to wear out ever. My donuts usually start at about 25 mph when the car snaps completely sideways and tries to kill me. We have a complicated relationship. DONT YOU JUDGE ME!
 

Fury Man Van

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Lots of burnouts, i mean A LOT OF BURNOUTS. and a few donuts. But i run a detroit locker differential no cones or frictions to wear out ever. My donuts usually start at about 25 mph when the car snaps completely sideways and tries to kill me. We have a complicated relationship. DONT YOU JUDGE ME!
LMBO.:rofl::lol:
 
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