Thanks for the answers bgh, vintage68, and chicane67 on my question regarding pinion shim ranges. Very helpful! graemlins/thumbsup.gif

So, my pattern looks pretty decent, using 31/1000 shim and 8/1000 backlash. Maybe slightly more to the face than to the flank on both drive and coast side.

On the drive side the pattern marks the half of the tooth towards the toe. On the coast side its centered heel-to-toe. I have read that heel-to-toe is less important than face-to-flank.

I am tempted to go 2/1000 thicker on the shim. But, if you were setting up your first diff, would you err to the loose side (pattern slightly towards face) or the tight side (pattern slightly towards flank)? What is the downside? Will one sing, while the other break? I'll err towards singing vs. breaking if given a choice.

Thanks again for the very helpful answers so far.

I should clarify - if I put in a thicker shim to get the pattern just a tiny bit more to the flank (on both drive and coast), it will also get closer to the toe on the drive side. And, since it is already on the "inside" half (towards the toe) on the drive side, I'm not sure if I want it further towards the toe. That is why I am debating on adding another 2/1000 or not. Thanks.

If this is a performance set-up and drive is already slightly 'toe' with coast centered.....I'd call it a day.

If you were to add 0.002" it may make drive too deep.

If you open up lash a little, it will bring both patterns out. I dont thgink you need to make a depth change based on the information you have supplied. I normally set the pattern with the drive side slightly off center towards toe with coast centered.

Also, the pattern should have good root-to-tip tooth contact.... any 'hard' line close to the root of the tooth should be screwtinized.

Trial and error, along with a lot of patients is always the best way to set up a set of gears. Try the .002 thicker pinion shim and see how it looks. If it was better before then switch back. You will sleep better knowing that you tried it and you won't be wondering if it might have been better with a thicker shim. graemlins/thumbsup.gif

Trial and error... you ain't kidding! smile.gif

Here are the results for the 33/1000 test...


33/1000 - Both drive and coast spots got smaller but better. Does that make sense? And, the coast side is now slightly off center towards heel. Drive, as before, is on toe half.

Should I flip a coin between 31 and 33?

Thanks again for the helpful insight.

It's hard to say without seeing a picture, but I'd say that if the coast pattern moved off center to the heel side then you should go back to the .031 or maybe a .032. Did you try changing the backlash to see if it got better?

Two pictures on the way!

I'm also setting up a 12 bolt with 4.10 gears at the moment, can u email me your pictures of your final setup so I can compare with mine. BIG color pictures have gotta be better than black & white ones from manual.
thanks
mailto:badnshr@msn.com

Sounds like it is starting to go too deep. I'd go back to 0.031"

A 0.001" change isnt a whole lot to justify, unless you are like me and just want to be exceedingly picky.... smile.gif

[ 03-09-2003, 11:01 PM: Message edited by: chicane67 ]

billyd - I'm figuring out a way to post them here... stay tuned!

chicane67 - thanks for the responses. The problem, of course, for someone new to this is I don't know when I am being picky and when I am neglecting something important. But, I guess that is all part of the learning process. smile.gif

Be picky.......money doesnt grow on trees when things brake!

Interested in some pics on how it turned out.