pinion depth, how close does it have to be

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65TerrorCuda

65TerrorCuda

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Setting up some new 8.75 489 gears, it seems like 2 thousandth of pinion depth is the difference between too deep and too shallow. What's the typical range? Setting up used gears wasn't this fussy.

I had the pattern perfect but noticed the lash had closed up a thou. Dammit. Setting it back to 8 thou threw the pattern off again.

Does anybody enjoy this job lol
 
65TerrorCuda said:
I got er good, but at 7 thou. Ring gear says 8-10, can I still run it at 7?
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Yes that's fine. I have an old drag racer friend that sets them up at zero and wears the back lash in. He's been doin it that way since the late 60s. Never had a failure.
 
65TerrorCuda said:
There is, 2.771 I think. Lemme go look

2.770

Ended up at 41 thou shim. 42 was too deep and 40 was too shallow. Not much room for error.

I just tried different shims until I got there. No depth gauge, just several hours of work
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The number on the pinion is nothing but a guide to get you close. Sometimes you're dead on using that number. Most times, you're just close. Sounds like you got it zoomed right in.
 
RustyRatRod said:
The number on the pinion is nothing but a guide to get you close. Sometimes you're dead on using that number. Most times, you're just close. Sounds like you got it zoomed right in.
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I'm not proud but it took another solid 5 hours to get it all done today including the spacer preload.
Zero lash that's wild! I'd be interested to hear the break in procedure if it's any different
 
65TerrorCuda said:
I'm not proud but it took another solid 5 hours to get it all done today including the spacer preload.
Zero lash that's wild! I'd be interested to hear the break in procedure if it's any different
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He had none other than stage and go. lol He's almost 90 now. I've learned a lot from him. Some "not to do" things, too. LOL
 
My 741 case was a little tight on bask lash. After a few attempts I gave up and left it a little tight (used gears) No issues. Just drove up to NH and back this weekend all good.
 
RustyRatRod said:
He had none other than stage and go. lol He's almost 90 now. I've learned a lot from him. Some "not to do" things, too. LOL
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That's another question I had, is it safe to do a test rip before break in is complete. Now I know. Sounds like a cool dude! Don't use lathe while drinking beer... I'll leave her there!

Kendog 170 said:
My 741 case was a little tight on bask lash. After a few attempts I gave up and left it a little tight (used gears) No issues. Just drove up to NH and back this weekend all good.
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That's about how I did my used gears last time. Had a slight whine at certain speeds but the price was right lol. Glad you got er done right!
 
65TerrorCuda said:
Alright, so I just needed more resistance against the gears to get a good read. And more yellow grease. 8 thous full send.

Thanks guys!
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What did you do exactly to get the side load (I'm assuming that's what you mean by resistance) against the ring gear to get a good read on the pattern?
 
65TerrorCuda said:
That's another question I had, is it safe to do a test rip before break in is complete. Now I know. Sounds like a cool dude! Don't use lathe while drinking beer... I'll leave her there!


That's about how I did my used gears last time. Had a slight whine at certain speeds but the price was right lol. Glad you got er done right!
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If WL ever broke in a gear set, I never knew it. I've seen finish a setup, pull the car on the trailer, tie it down and go racin the next day. And win.
 
VSTwister said:
What did you do exactly to get the side load (I'm assuming that's what you mean by resistance) against the ring gear to get a good read on the pattern?
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I wedged a prybar between the ring gear and 3rd member and leaned on it a bit. Most important was not to use too much of that marking compound. It's a bit tricky

RustyRatRod said:
If WL ever broke in a gear set, I never knew it. I've seen finish a setup, pull the car on the trailer, tie it down and go racin the next day. And win.
Click to expand...

Just finished the break in period, works great. Still need to do a full throttle hit. Definitely gunna be a spill the beer moment, 3.91 feels crazy compared to 3.23
 
PXL_20250904_033608563.jpg


and don't forget to remove the pinion nut before pulling the yoke
 
65TerrorCuda said:
I wedged a prybar between the ring gear and 3rd member and leaned on it a bit. Most important was not to use too much of that marking compound. It's a bit tricky



Just finished the break in period, works great. Still need to do a full throttle hit. Definitely gunna be a spill the beer moment, 3.91 feels crazy compared to 3.23
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Yeah I love some low gears. I ran a 3.91 in Vixen for a short time. It was a real hoot, but with just 13" tires it really spun the engine at highway speed so I put the 3.23s back in. That's ok though, cause the 4.11s and T5 five speed and taller 14" tires are in the works. lol
 
RustyRatRod said:
Yeah I love some low gears. I ran a 3.91 in Vixen for a short time. It was a real hoot, but with just 13" tires it really spun the engine at highway speed so I put the 3.23s back in. That's ok though, cause the 4.11s and T5 five speed and taller 14" tires are in the works. lol
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That should be sweet! I can see why people go overdrive or 5 speed with the low gearset. It's addictive.
 

65TerrorCuda said:
I wedged a prybar between the ring gear and 3rd member and leaned on it a bit. Most important was not to use too much of that marking compound. It's a bit tricky



Just finished the break in period, works great. Still need to do a full throttle hit. Definitely gunna be a spill the beer moment, 3.91 feels crazy compared to 3.23
Click to expand...
You must've had the right stand stand or really large vice to put it in. That's been my issue before.
 
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