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-   -   mopar 8-1/4 ring and pinion pattern (http://www.hotrodders.com/forum/mopar-8-1-4-ring-pinion-pattern-127867.html)

Goldduster360 11-08-2007 05:36 PM

mopar 8-1/4 ring and pinion pattern
 
1 Attachment(s)
I am in the process of setting up a set of motive 3:55's for my Duster. The pattern looks OK but it doesn't really look exactly like any of the pictures I have seen for set up good or bad. What do you think?

http://www.hotrodders.com/forum/atta...id=25391&stc=1

charger528 11-08-2007 08:16 PM

no expert but it looks like the pinion is good its centered with the ring gear.
I think the ring gear needs to be shimmed or adjusted to go Little deeper into the pinion it seems to be riding a little high on the teeth.

but like i said not a expert have never set up gears on a 8 1/4

i have only done 8 3/4 gears (with removable carriers) all of which seemed to in-gage a little deeper and had a broader pattern.

richard stewart 3rd 11-08-2007 09:46 PM

Hi, 360
Charger is correct, you need to shim
the pinion some, if it were just for a
daily runaround family car, it would be
ok where it's at, but for comp. you should
only have about half of the tooth covered
from the tow up.
Take care,
rich

Goldduster360 11-09-2007 08:33 AM

Thanx for the inputs guys. I will add a small amount of shim to the pinion and see what happens, that was my suspicion that the pattern was a little high too, especially on the coast side.

Goldduster360 07-16-2008 05:35 PM

final pattern
 
3 Attachment(s)
Here is my final pattern with pinion bearing pre-load at exactly 25 inch pounds, backlash is .010" plus or minus .0015". I monkeyed with the pinion depth quite a bit and actually ended up within a couple thousands of original shim thickness of .072" from where I originally had it. Adding shims made the pattern too narrow and ran off both ends of the gear. Subtracting shims put the pattern more towards the tow and was very pie slice shaped. I tried .064 shim stack and kept adding until I got back to where I am at (.074). Pattern changed a tad after pressing on new bearing and installing new crush sleeve. I did mike the set up bearing and compared it with the new one, they were within .0005". I did this by placing the bearing face down on a flat surface with the bearing cup on top of it and measured the distance from the bearing cup edge facing down to the flat surface. I am not thrilled with this pattern but I guess this is as good as it's going to get. When I run a tighter backlash the pattern develops a sharper point on the heel end and moves closer to the toe. Coast looks ok in my opinion. These gears are designed to run at .008 to .012" backlash setting. They are basically at the max lash limit now. If I run tighter the pattern gets lower and pointier. Should I just button it up and forget about it?

richard stewart 3rd 07-17-2008 12:46 AM

Hi GD360
I've been looking at your patterns & I
think you need to do some more adjusting
check the link patterns against yours.
Rich

http://precisiongear.com/pgtechpatterns.htm

Goldduster360 07-17-2008 06:00 AM

richmond patterns
 
I also found some nice examples of actual gear patterns instead of illustrated pictures like everyone always shows. I think my pattern falls in between the second and the last one shown. What do you think?

http://www.ricks2k.com/info/instruct...gandpinion.pdf

Also, my pattern seems to look close to the second and the last example shown here:

http://www.drivetrain.com/ringpinioninstal.html

You will notice it says to either decrease pinion depth as in example #2 or to increase backlash as in the last one. My contact is fairly centered though, they show them closer to the tow than mine. Thoughts? I am at a loss what move to make next. I am thinking go for maximum allowable backlash, it's at 10-11-1/2 depending on where I check it. I would imagine you can go a tad over max if it's within .002" in a couple spots.

Edited in:
And here is another pattern link, this guy went through about the same amount of effort as I did and his pattern ended up looking like mine. Maybe some are just not going to be perfect?

http://www.chevelles.com/forums/show...pinion+pattern

Goldduster360 07-17-2008 05:51 PM

one more ring gear pic
 
2 Attachment(s)
I ran the pattern one more time and took a really clear pic of it. I think the pinion is sitting a tad deep. Maybe .003" too much?

Edited in: I got a response from one of the techs at Motive, the manufacturer of this gear and they said it did not look good. They agree with me that I need to remove some pinion shim to get it right. Back to the drawing board :thumbup:

Goldduster360 07-20-2008 08:41 PM

Removed only .004"
 
5 Attachment(s)
Well, I tore into it Friday night, pressed off the new bearing without destroying it but did wipe out one of the shims. Was still able to mike the ones I took out, they were at .073" total not .074".

I decided to try .069" again. Also, I paid very close attention to my backlash adjustment, checking, then rechecking and rechecking again in several spots. I made sure the carrier bearings were properly loaded and also torqued down the caps before taking a pattern. I suspect maybe a sloppy set up job was giving me inconsistent results before the last "final assembly".

Before applying gear marking compount I coated all the ring gear teeth with a light coat of gear oil(applied with a slightly oiled paper towel and spread it on each tooth evenly without having it be runny) Kind of oiled it the way you would the outside of a gun barrel.

I used a block of wood wedged between the outside of the ring gear and the differential housing and spun it over only twice. Could not believe how much difference .004 thousands of an inch made!!!! Please check out the attachments. Backlash is set at .008-0095" I think it's good to go....

Goldduster360 07-23-2008 07:19 PM

Motive's Blessing
 
Just got a response from one of the reps at Motive and they say the pattern looks good now. Guess I am good to go. :thumbup:

Goldduster360 08-03-2008 08:20 PM

Too Shallow
 
2 Attachment(s)
Just for the heck of it I pulled out .003" from the shim stack and took another pattern. As I suspected it was too shallow validating both mine and motives take on my final pattern. Here is what .066" worth of shims looks like versus the .069" that were shown in previous post. Same backlash setting of .008".

Take note on how the drive side took on a half moon/top of tooth shape while the coast side devoloped an odd shaped pie slice pattern. All it took was .003" in the wrong direction to really mess up a good pattern. So if you go back through this thread you can see what .004" too deep looks like versus .003" too shallow looks like.

I hope this helps anyone searching for info on how to set up gears. Judging form only a couple responses on this thread with hundreds of views I am assuming there are allot more people looking for advice than giving it when it comes to setting up gears........

Mike H 08-03-2008 08:40 PM

You have to remember a Motive gear will never look like the picture, I don't think the lap them as much as US gear or Richmond do so on the first set up they don't look great. What does the coast side look like I only saw one picture of it?

I set up at least 4-5 a month for a local speed shop and none of the Motive gears they send me are a perfict paturn. The US or Richmond on the other hand set up great, set the pinion depth at their spec put in .008-.012 backlash and run it. The pinion depth on a Motive is a starting point for me as the paturn looks pretty bad when you set it with their #.

Goldduster360 08-04-2008 09:10 AM

Coast Side
 
There are a couple of good picks of the coast side under the title "Removed only .004" a couple postings up on this thread. The first pick shows both the drive and coast patterns. I thought the coast actually looked closer to "optimum" than the drive did. At this setting both the drive and coast looked as good as I could get them.

Thanx for your inputs Mike H., I was wondering why no matter what I did, good or bad none of my patterns looked like anybody's pictures or illustrations. The directions and pattern suggestions that came with the gears were not very helpful for a newbie on his first gear set up either. I also did the math and tried setting up the gears at the suggested pinion depth, results were poor. With lots of internet surfing I was able to deduce that no gear set up is going to be picture perfect and only trial and error based on several pattern readings is going to get it right.

I also suppose the lower priced sets are not going to have the factory type of lap job that would yield a more perfect first set up pattern. I can also assume that I should be pretty gentle with this set during it's first couple hundred miles as they will finish lapping themselves during break in.

I can't stress how important it is to anyone contemplating one of these jobs for the first time that they really don't know what they are in for until they get into it. That being said, anybody who can turn a wrench and read a dial indicator can probably set one of these up. It will require being very patient, looking at several examples on the internet of acceptable/unacceptable patterns to guide them in what corrections to make along the way and posting on this site for support when needed. Contacting the gear manufacturer with a picture of your pattern set up can be very helpful too, which is what I ended up doing.

Mike H 08-04-2008 04:32 PM

Quote:

Originally Posted by Goldduster360
There are a couple of good picks of the coast side under the title "Removed only .004" a couple postings up on this thread. The first pick shows both the drive and coast patterns. I thought the coast actually looked closer to "optimum" than the drive did. At this setting both the drive and coast looked as good as I could get them.

Thanx for your inputs Mike H., I was wondering why no matter what I did, good or bad none of my patterns looked like anybody's pictures or illustrations. The directions and pattern suggestions that came with the gears were not very helpful for a newbie on his first gear set up either. I also did the math and tried setting up the gears at the suggested pinion depth, results were poor. With lots of internet surfing I was able to deduce that no gear set up is going to be picture perfect and only trial and error based on several pattern readings is going to get it right.

I also suppose the lower priced sets are not going to have the factory type of lap job that would yield a more perfect first set up pattern. I can also assume that I should be pretty gentle with this set during it's first couple hundred miles as they will finish lapping themselves during break in.

I can't stress how important it is to anyone contemplating one of these jobs for the first time that they really don't know what they are in for until they get into it. That being said, anybody who can turn a wrench and read a dial indicator can probably set one of these up. It will require being very patient, looking at several examples on the internet of acceptable/unacceptable patterns to guide them in what corrections to make along the way and posting on this site for support when needed. Contacting the gear manufacturer with a picture of your pattern set up can be very helpful too, which is what I ended up doing.



The other thing you learn after you have done 50+ installs is what it takes to make a change in the look of the pattern I set them up with the pinion depth on the new pinion but before I take out the original I check the PD that way I can figure the shim I need to start with.( I have the T&D pinion depth tool and it was worth the $ I paid for it the first time I used it. The $99.00 ones are junk don't waste your money) Also if the pattern looks bad from the get go I make a big jump .012-.018 or so in the pinion shim (you would not putt the entire hole when golfing). The first pictures looked to me like you had to much shim (or on a 8-9" ford not enough) Tooth up on edge and toward the root of the ring gear. I bet it made noise when you were turning it to check the mesh of the teeth. I would run what you have but take it easy on it for 40-50 miles, drive it 2-3 miles then let it cool off a few times before getting out on the freeway. If you want to break it in then pull the cover again and run another test pattern it will look better.


Feal good in the fact that you did not have to take it to someone else to do it. Mike

Goldduster360 08-05-2008 07:33 AM

Quote:

Originally Posted by Mike H
The other thing you learn after you have done 50+ installs is what it takes to make a change in the look of the pattern I set them up with the pinion depth on the new pinion but before I take out the original I check the PD that way I can figure the shim I need to start with.( I have the T&D pinion depth tool and it was worth the $ I paid for it the first time I used it. The $99.00 ones are junk don't waste your money) Also if the pattern looks bad from the get go I make a big jump .012-.018 or so in the pinion shim (you would not putt the entire hole when golfing). The first pictures looked to me like you had to much shim (or on a 8-9" ford not enough) Tooth up on edge and toward the root of the ring gear. I bet it made noise when you were turning it to check the mesh of the teeth. I would run what you have but take it easy on it for 40-50 miles, drive it 2-3 miles then let it cool off a few times before getting out on the freeway. If you want to break it in then pull the cover again and run another test pattern it will look better.


Feal good in the fact that you did not have to take it to someone else to do it. Mike

Thank you again Mike, your insights have been greatly appreciated both by me and certainly by anyone else surfing this thread looking for answers.

And yes, the gears were noisy when turning them over by hand when the depth setting was too deep, I thought it was just my imagination, it almost sounded like a wood pecker pecking away in the distance when they were turned, thanx again, that is a good piece of information. I have set up quite a few straight cut gears on my radio controlled models by sound and feel, too notchy, you know it's meshed tight, high pitched whine usually a little loose.

Also, my stock gearset was at -0, could still read it on the pinion face but yet there was an .072" thick shim under the pinion bearing inner race. Based on my original math I had added like .038" of shims based on the suggested pinion depth on the new set(was not aware of inner race shim yet either). Was not even close. Also, not sure why that spacer was under the bearing cup, but it had to come out as I was still about .004" too deep with it in because with no shims on the pinion stem it was still too deep. I am sure there was a reason for it to be there originally but as a newbie to this it is just another piece of the puzzle I had to put together on my own. I did not see anything on my instruction sheet about checking for shims behind bearing races. Imagine the frustration of taking all the shims from behind the set up bearing on the pinion and finding out that it was still sitting too deep(after about 5 attempts at set up). Out of frustration I hammered out the old race with a brass drift to install the new race and found this .072" thick shim.

One more question Mike while I have your attention:

I understand about setting the pinion bearing drag at 22-25 inch pounds for new bearings but what should you do for pre-load on the carrier bearings? Mine being a chrysler 8-1/4" it has threaded adjusters. Do you just snug them up to make sure there is no play before attaching the little anti-loosen brackets? I have been using an elbow screw driver and a rubber mallet to gently snug them up. It sounds crude but it's free and it works.


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