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Lash is a bit big unless you plan on being hard on it. Is that measured at the tightest spot? I like to check in at least 4 places.
8 3/4 742 case setup questions
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vintage chromoly
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Only one spot cranky. I'll set the indicator back up and try 4 spots.
The recommendation is .080 to .012.
What do you recommend for a hot street car?
Also, what gear lube and viscosity do you think?
The recommendation is .080 to .012.
What do you recommend for a hot street car?
Also, what gear lube and viscosity do you think?
vintage chromoly
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What do you think of the pattern?
Ok?
Ok?
vintage chromoly
Well-Known Member
Checked the lash at 4 spots.
I have .010, .010, .009, .011
I have .010, .010, .009, .011
And sure grip additive.
vintage chromoly
Well-Known Member
I have a 4oz. Bottle of friction modifier I plan to add.
Guess I'm O'School on that $10 for it, just me. Yes you can add it later. My dad bought a 64 Olds Starfire convert with posi. We were out riding around and he went around a tight corner at low speed and it felt like we ran up a curb. Huge clunk, took it back to dealer several times to complain. They said there was bulletin, were told to put an additive the factory supplied. Didn't totally fix problem but much better.
Coronet 500
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Like the backlash, I like to check pattern at 4 spots around the full ring.
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What brand are the gears? Richmond likes the pattern to be closer to the toe or the inner end. They also like the 90/140 but I've always used 80/90 in my stuff. I've also used STP as an additive but short term, you really don't need it unless you experience chattering or clunking. Were you able to take a measurement from the center line to the pinion? The pattern looks decent but to me, they never look right lol
vintage chromoly
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Motive gears cranky.
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Did a build sheet come them for pattern and BL? It's been over a year since I did a set of Motives but I usually shoot for .008 BL but I doubt .010 will make much difference if any. And sometimes the ring gear is marked for what the BL should be....
vintage chromoly
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The pinion is marked for depth on the gear itself.
The instructions say between .008 and .012 for backlash.
I set up the pinion at the number on the gear and the pattern was way off. It took a .040 shim to achieve that depth.
I put a .090 in and achieved the pattern in the pictures I posted. Cass, who sold me the gears said to start with a .090.
To be fair, I'm measuring from the split of the carrier bearing to the back of the pinion. I'm assuming that the flat surface in the case where the carrier bearing cap parts is the center of the carrier. Maybe a bad assumption, as the pattern was falling off the teeth by 50%
The instructions say between .008 and .012 for backlash.
I set up the pinion at the number on the gear and the pattern was way off. It took a .040 shim to achieve that depth.
I put a .090 in and achieved the pattern in the pictures I posted. Cass, who sold me the gears said to start with a .090.
To be fair, I'm measuring from the split of the carrier bearing to the back of the pinion. I'm assuming that the flat surface in the case where the carrier bearing cap parts is the center of the carrier. Maybe a bad assumption, as the pattern was falling off the teeth by 50%
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The split is not always dead center but of the ones I've checked....which ain't many haven't been off more than .005". My set up tool is an older Pro Parts that I bought from a buddy after he used it one time. I borrowed it for at least 10 years before he finally asked if I wanted to buy it. Sure! I had already set up dozens of rears in that time. Thing is, the pattern never really looked right to me so I just quit checking it after testing several rears to see how they acted. Have only had one rear that had a slight hum to it and you had to listen for it.....
vintage chromoly
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Thanks again cranky!
Much appreciated.
Would you adjust my setup any more given the pattern I have in the photos?
Much appreciated.
Would you adjust my setup any more given the pattern I have in the photos?
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That's a tough one to call from someone who really doesn't go by what the pattern says......
Needs more pinion shim. Pattern is up towards the top of the tooth, nreds to go down into the root further.
Doug
Doug
vintage chromoly
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Added .003 more shim and then .006 more shim. I think the pattern was the best with .093 shim.
We shall see.
I bought a nice, made in the USA, inch pound dial torque wrench to set the pinion preload. I had to put .052 worth of shims on the small bearing to get 25" pounds of preload.
I made a pinion yoke holding tool from some 1/4" plate steel and an old 440 rocker shaft.
We shall see.
I bought a nice, made in the USA, inch pound dial torque wrench to set the pinion preload. I had to put .052 worth of shims on the small bearing to get 25" pounds of preload.
I made a pinion yoke holding tool from some 1/4" plate steel and an old 440 rocker shaft.
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