8.5 in rearend

Sweet_Johnny

Has A Face For Radio
Supporting Member
Oct 4, 2022
699
1,261
93
Wichita, Kansas
Thanks, I appreciate any information that someone is willing to hand out for free!
 

doood

Amateur Mechanic
Sep 24, 2020
590
804
93
0.035 pinion shim. Posting to keep track.
20240218_000202.jpg
20240218_000148.jpg
 

doood

Amateur Mechanic
Sep 24, 2020
590
804
93
0.038 pinion shim
20240218_010746.jpg
20240218_010759.jpg
 

doood

Amateur Mechanic
Sep 24, 2020
590
804
93
Please give me your opinions.

1708238096636.png
 

Streetbu

Know it all, that doesn't
Supporting Member
May 22, 2011
3,746
11,645
113
Central NY
.038 looks great to me, but take that with a grain of salt as I'm definitely no expert on gear set up.
 
  • Like
Reactions: 4 users

69hurstolds

Geezer
Supporting Member
Jan 2, 2006
8,232
17,700
113
There's only a handful of people I would consider experts. I'm not one of them. At least you're not doing a dual crankshaft timing pinion setup on a Fairbanks-Morse 8-1/8 6 cylinder opposed piston diesel engine. Those ring gears were measured in feet. Same type of mesh checking though. Just larger. And no chance of coast side mesh.

I've learned over the years that experts tend to come to a consensus that the pattern on the coast side pattern isn't a major factor. It's the drive side that matters. Obviously, you want the coast side to have good engagement, too, but it's not as critical to be "perfect" on the coast as it is the drive. I've heard and read that in different places. Again, I'm no expert. If it's important to you is all that matters.

It is my opinion that your 0.038 is the "best" of the three as far as engagement. The 0.035 seems way too close to the face, or top of the teeth, for me.

The 0.038 and 0.042 seems to me more the way to go. Although the 0.038 appears acceptable on the drive side, you seem a bit close to the heel on the coast side, but not too deep. I'd lean to the 0.038, personally out of the 3. Probably even try 0.040 and see if that nets you a tad better centering. But, I realize that's a good amount of work jacking around with all that, it's still worth the extra time now to do it, IMO.
 
  • Like
  • Agree
Reactions: 3 users

doood

Amateur Mechanic
Sep 24, 2020
590
804
93
There's only a handful of people I would consider experts. I'm not one of them. At least you're not doing a dual crankshaft timing pinion setup on a Fairbanks-Morse 8-1/8 6 cylinder opposed piston diesel engine. Those ring gears were measured in feet. Same type of mesh checking though. Just larger. And no chance of coast side mesh.

I've learned over the years that experts tend to come to a consensus that the pattern on the coast side pattern isn't a major factor. It's the drive side that matters. Obviously, you want the coast side to have good engagement, too, but it's not as critical to be "perfect" on the coast as it is the drive. I've heard and read that in different places. Again, I'm no expert. If it's important to you is all that matters.

It is my opinion that your 0.038 is the "best" of the three as far as engagement. The 0.035 seems way too close to the face, or top of the teeth, for me.

The 0.038 and 0.042 seems to me more the way to go. Although the 0.038 appears acceptable on the drive side, you seem a bit close to the heel on the coast side, but not too deep. I'd lean to the 0.038, personally out of the 3. Probably even try 0.040 and see if that nets you a tad better centering. But, I realize that's a good amount of work jacking around with all that, it's still worth the extra time now to do it, IMO.
Thank you for your thoughtful comment. I'm actually coming to the same conclusion (try 0.040). It's no problem taking it apart again. I don't want it screaming down the road. The previous ring and pinion looked so good first try this one is harder for me to interpret.


I had another learning today. With the solid spacer the shims have to go on the bearing face not the pinion shoulder. Pinion shoulder has fillet that deformed spacers (destroyed).
 
  • Like
Reactions: 1 user

doood

Amateur Mechanic
Sep 24, 2020
590
804
93
Thank you for your thoughtful comment. I'm actually coming to the same conclusion (try 0.040). It's no problem taking it apart again. I don't want it screaming down the road. The previous ring and pinion looked so good first try this one is harder for me to interpret.


I had another learning today. With the solid spacer the shims have to go on the bearing face not the pinion shoulder. Pinion shoulder has fillet that deformed spacers (destroyed).
0.040 pinion shim looks great to me. Next up, pinion preload.
20240218_130300.jpg
20240218_130355.jpg
20240218_130228.jpg
 
  • Like
  • Agree
Reactions: 6 users

69hurstolds

Geezer
Supporting Member
Jan 2, 2006
8,232
17,700
113
Looking pretty good there, IMO. I'd send it. But that's just me.
 
  • Agree
  • Like
Reactions: 1 users

doood

Amateur Mechanic
Sep 24, 2020
590
804
93
This is 0.036 pinion shim with 0.007 backlash. Just saving it here so I can view it on a big screen. I think it's a little shallow.

This process is excruciating.

20240219_192653.jpg
20240219_192600.jpg
20240219_192638.jpg
 
  • Like
Reactions: 3 users

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck Consoles Dixie Restoration Depot UMI Performance

Contact [email protected] for info on becoming a sponsor