" Hope it dies whine on his test drive tomorrow."
???? 

Greg B wrote:

Definitely a fun project.   I enjoyed doing mine when I did both an 8" and 9" at almost the same time.  Most of the parts came from QP too.   Looks like your pattern may be a touch deep, but it surely doesn't suck.   I tried looking it over well, but I'm probably not the best judge of internet pictures at the moment. 

If you want to make an easy tag for it, head on down to Wally Mart and use their dog tag machine.  You can write all the particulars and ratio  on it.   That's what I did.

 
This was the best pattern I could get.  I'm deeper than the 1.029.  It was the only way to get the pattern near the center.  They are QP gears so I'm not confident on how they machined.

He installed them last night and will test drive today.

He said it has a whine on acceleration.  Which in theory could be the pinion being to deep.  He's thinking he ordered his axle shafts to long. 

I could not center the drive and coast side without going deeper with the pinion.  I tried to move the back lash from .007-.010 on every shim thickness I tried.  Ugh

TKOPerformance wrote:

RTM wrote:

He said it has a whine on acceleration. Which in theory could be the pinion being to deep. He's thinking he ordered his axle shafts to long.

I could not center the drive and coast side without going deeper with the pinion. I tried to move the back lash from .007-.010 on every shim thickness I tried. Ugh

A couple thoughts:

First, not sure how he's hearing a whine on acceleration.  I'm not sure I've ever heard a rearend make noise on acceleration.  I've heard them absolutely howl when coasting.  Typically on acceleration there's too much other noise going on.

Second, what gears did you use?  Were they used?  Because when setting up used gears what I've always followed is to essentially completely ignore the drive side.  Additionally, you may get a goofy pattern where its centered root to tip, but not heel to toe, and the pattern may run off the edge of the gear on the heel on one side and the toe on the other.  That's fine for used gears.  All that's really important for quiet operation of a used gear set is that the pattern is centered root to tip on the coast side.  
 

 

Brand new gears from QP.

TKOPerformance wrote:

I would verify the whine myself.  If you had a good pattern (pattern I see in the pics looks good), and proper backlash I can't see how they could whine on acceleration.  The only other thing I could think to check would be runout of the carrier (ring gear mounting surface).  Some gears are inherently noisy on the coast side, but I've never heard gear whine on the drive side.  I'd wonder is there was a whine from something else that he is just now hearing because there was a change made to the car.  Does the car have an auto or manual trans?  

 
He's sending it to QP to let work on it.

https://youtu.be/nVb5WRUfM7Y

Best video I have seen on pattern.  I’d call your pattern good.  I’d maybe put the pinion in a little deeper.  Looks like your drive pattern was further out than your coast.

I've never put much faith in using the pinion depth tool, etc.  Maybe in a factory setting that works, but every rear I've ever set up I ended up doing by good old trail and error starting with the factory pinion shim, checking the pattern, and making adjustments as needed.  I own a really nice (and expensive) pinion depth tool, but after trying to use it twice I came to the conclusion I wasted more time monkeying with it than I did changing shims and running patterns.  The tool didn't generate the right shim for a good pattern either time, so I simply stopped using it.  I just make setup bearings so its easier to change shims, but on an 8" or 9" its even easier, because you don't even have to touch a bearing to change the shim, and there aren't shims to set backlash.  

I would never advise opening the BL up more than max spec.  On a car that will see highway use leaning toward the wider side is advisable, because the heat of use will shrink it somewhat.  In a drag only application I'd go the other way to reduce windup shock from a hard launch.  

See if the bearings have a name on them in the install kit.  If they aren't Koyo, Timken, SKF, or another brand I recognize I wouldn't use them.

There are very few companies that actually make gears, so if its a small company my guess is the gears are made in China and they stamp the company's name on them.  The equipment to make and lap gears is pretty expensive, so doubtful a small local company would have it.  

Honestly the diff would put me off too.  The biggest issue with stuff from China is the metallurgy is often suspect.  I'd probably just toss the whole setup on eBay and let someone else take the risk.  

QP upgraded his gear set for free.  I can only guess they did so because they couldn't get much better of a pattern than I had gotten.

Ya, what does the upgrade include?

I have two 9” differentials on facebook marketplace for $80 each. Both are good ones. One is a 2.75 and other is 3.0.  Both a single track 28 splines. Also have a nice set of Ford original 3.50 gears. I doubt I will be needing any of this stuff.