Gear pattern
Gear pattern
I'm setting up new gears, what do you think of the pattern?
Re: Gear pattern
When ever we try to help anyone set up gears we always need the BACKLASH setting ( .008 or .010 something like that) ??
and the pinion depth. (.025 or .030 or .036 )??
The type of rear end your setting up ex.( 8.2 chevy 8.5 corp 12 bolt chevy Ford 9" )
Type of parts will help too : gear brand, posi brand etc.
Thank you.
Jim
JD Race
and the pinion depth. (.025 or .030 or .036 )??
The type of rear end your setting up ex.( 8.2 chevy 8.5 corp 12 bolt chevy Ford 9" )
Type of parts will help too : gear brand, posi brand etc.
Thank you.
Jim
JD Race
J D Race
Re: Gear pattern
Pattern looks pretty good so far...BUT we must have the backlash reading to be sure.
Normally the 8.5 will use a .038 - .035 pinion shim - AGAIN this is from years and years of setting up rears.
What ever the gear wants to get a good pattern that is where you go with the pinion shim depth.
Also try a bit more oil on the teeth and spin it.... should help the pattern really pop.
FEEL: the feel of a ring and pinion mesh should be smooth and noise free from any binding and metal cutting noise. BOTH directions
Normally the 8.5 will use a .038 - .035 pinion shim - AGAIN this is from years and years of setting up rears.
What ever the gear wants to get a good pattern that is where you go with the pinion shim depth.
Also try a bit more oil on the teeth and spin it.... should help the pattern really pop.
FEEL: the feel of a ring and pinion mesh should be smooth and noise free from any binding and metal cutting noise. BOTH directions
J D Race
Re: Gear pattern
Sorry I didn't provide enough info. It is a GM 10 bolt 8.5" with bolt in axles from a '76 Pontiac GP.
Pinion depth is .039" and backlash is .006"
Thanks.
Pinion depth is .039" and backlash is .006"
Thanks.
Re: Gear pattern
I meant to say pinion shim is .039
Re: Gear pattern
I changed pinion shim from .039 to .035, backlash is .006/.007. I don't see much difference in pattern.
Re: Gear pattern
open up the backlash for now to get a better pattern and then squirt a little bit of gear on the teeth and spin that rear around 5-6 time forward and backwards. Show more pics. Jim
J D Race
Re: Gear pattern
It's a USA Standard Gear 3.08 ratio. I'll make some adjustments today and try to post more pictures. I'm replacing the stock open differential with
an Eaton Truetrac. Yesterday I changed the pinion shim to .030 just to see what changed with the pattern, it looked too high on the tooth which is what I expected. I did notice that the gears were much more quiet than when I used .035 shim. I shimmed it to .032 and it was still quiet and the pattern moved down a little.
an Eaton Truetrac. Yesterday I changed the pinion shim to .030 just to see what changed with the pattern, it looked too high on the tooth which is what I expected. I did notice that the gears were much more quiet than when I used .035 shim. I shimmed it to .032 and it was still quiet and the pattern moved down a little.
Re: Gear pattern
I have more trouble trying to add pictures than I do working on the car. Here are some more pics with different backlash, I don't see much difference.
.034 pinion shim, .009 backlash
.034 pinion shim, .009 backlash
Re: Gear pattern
Here are pictures with .034 pinion shim and .014 backlash. I thought just a few thousands would make a big difference in pattern?
Re: Gear pattern
oH bOY ...BEING A CHEAP GEAR this might be a difficult deal ...lol. Buy low cost get low cost.
Well that pattern is very skippy to get an idea on.
the pinion shim is in the neighborhood of where most 8.5 gears set-up.
Backlash is too wide. .010 is where we want to be for a pattern
do you have the bearing caps on the carrier?
keep with the .035 and try it out.
Being USA standard gear...they stick any gear set they get cheap from any manufacture that may be slightly off but still will run.
So you might get a whine you may not.
Get that backlash in the .008 and .010 range make sure the carrier shims get tapped in and the carrier can not be pulled up by hand. IT MUST be pryed out or it is NOT tight enough.
Go back to your first set-up as that from the pictures you gave seems to be the best your going to get on these gears.
JIm
JD Race
Well that pattern is very skippy to get an idea on.
the pinion shim is in the neighborhood of where most 8.5 gears set-up.
Backlash is too wide. .010 is where we want to be for a pattern
do you have the bearing caps on the carrier?
keep with the .035 and try it out.
Being USA standard gear...they stick any gear set they get cheap from any manufacture that may be slightly off but still will run.
So you might get a whine you may not.
Get that backlash in the .008 and .010 range make sure the carrier shims get tapped in and the carrier can not be pulled up by hand. IT MUST be pryed out or it is NOT tight enough.
Go back to your first set-up as that from the pictures you gave seems to be the best your going to get on these gears.
JIm
JD Race
J D Race
Re: Gear pattern
So I was setting up for .008 backlash and noticed an issue, probably cheap gears as you said...I thought I set it at .008 but after measuring in a few places I had inconsistent readings. I went back and measured backlash at every tooth and it varied from .003 to .009, seems like too much to me. I'll try to check a runout measurement too. This is for a street cruiser type car, not racing. Yes the bearings caps are on and torqued to 60 ft lbs, carrier shims are tight. I verified the pinion bearing races are all the way in. I may need to order new gears from you if you have them. I'll try to call later.
Re: Gear pattern
If you have any debris from when the ring was installed to the carrier...It would cause this. some time when the gear gets pulled or pressed on to the carrier the carrier body may get scraped from some material and then this gets lodged between the ring machined surface and the carrier machined surface and will cause the run out.
ANOTHER reason we like to spin the gear 360 degrees about 4-5 time around each way...It helps to see run out on the gear too.
From what I see it is not so much run out just the pattern is not laying a good consistent swipe of the face of the gear either side.
Put more oil on the gear face to help move that compound to see where the pattern really is.
Being that the gear set is no lapped as much as a higher quality gear you will have to really spin those gears a lot to get the pattern to come in...ALMOST like your lapping the gears...
Try that before giving up totally in the gear set.
ANOTHER reason we like to spin the gear 360 degrees about 4-5 time around each way...It helps to see run out on the gear too.
From what I see it is not so much run out just the pattern is not laying a good consistent swipe of the face of the gear either side.
Put more oil on the gear face to help move that compound to see where the pattern really is.
Being that the gear set is no lapped as much as a higher quality gear you will have to really spin those gears a lot to get the pattern to come in...ALMOST like your lapping the gears...
Try that before giving up totally in the gear set.
J D Race