rearend break-in ? ?

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If that's what you wanna do then do it. The heck if I am gonna argue with you anymore.
 
I don't believe I did anything. I might have let the wheels spin while on jackstands but there was no real break in.
 
Technically no heavy loads for the first few hundred miles while the gears bed in if your expecting a long service life.
 
doogievlg said:
I don't believe I did anything. I might have let the wheels spin while on jackstands but there was no real break in.
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X2. I was told to let them spin for about 15-20 minutes. Mancini's told me this when I purchased a rebuilt center section back in '95.
 
Your running a spool, if your happy with the setup
and think you got it right, go rip and roar.
You'll know soon enough.
 
on jack stands ran it through the gears...forward and reverse...drove it on the trailer...

unload from trailer...drove to staging lanes....made pass...nothing broke...so they are broke in.....
 
RustyRatRod said:
If that's what you wanna do then do it. The heck if I am gonna argue with you anymore.
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Not to worry triple R I'll do the arguing, and you keep making sense !? Notice I've been posting on the racing forum because a 90% of the time race car. I'm not sure how the racers break in there 410 spool ? Do they fill up with race fuel and gently drive 500 miles ? It's all I can do to drive my car gently til it's warmed up !!
Let's take my drive to the scrap yard scales the other day. I top off with race fuel ($5.20 per gallon) in ten gallon tank. I drove maybe 40 miles round trip (no speedo) (when I care haw fast the car is I look at my time slip). So I'm back home and I empty a five gallon can to re top off.
There has to be a better way than doing that 6 times before the next race !?
 
longarm said:
Your running a spool, if your happy with the setup
and think you got it right, go rip and roar.
You'll know soon enough.
Click to expand...

To get it right - i bought a used 489 case . Called dr.diff (cass) ordered new everything. took it down to the most reputable differential only shop in town and payed nearly 200. Thats the best idea I had ? ?
 
mopowers said:
Here's an idea... How bout you call the manufacturer of the gears and ask them what they recommend???
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I seen your build on the other threads (and I love it!!!). Check back in with me at the end of the summer and tell me how easy it would be to drive it gently for 500 miles? Manufacturers are always trying to cover there butts.
did you remove the inner springs during break in ? ?
 
j par said:
I seen your build on the other threads (and I love it!!!). Check back in with me at the end of the summer and tell me how easy it would be to drive it gently for 500 miles? Manufacturers are always trying to cover there butts.
did you remove the inner springs during break in ? ?
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Thanks. 500 miles is what they said?? Wtf! Did you ask Cass? When I built my 3.91 8 3/4 (with parts from Cass as well), I just put the rearend up on stands and ran it at a fast idle in 3rd gear for about 15 mins to circulate the gear oil and heat up the gears a little. Then I let them cool off before driving them around under a light to moderate load for a little bit. They seem fine with no noises. They're just gears; what's the worst that could happen? As long as they're set up correctly, I don't see any issues.

To answer your question, I don't have inner valve springs. Brian at IMM set up my RHS heads with beehive springs that have plenty of spring pressure for my small hydraulic camshaft. I've got a mile of valve-piston clearance too (>.200"). Everything seems fine after break-in. Gonna change the oil tonight and cruise it around this weekend.
 
Heat-cycling them a few times under a light load is a good idea to get everything stabilized and wore-in together, but there is also the black oxide coating that wears off which isn't particularly good for the bearings. Use conventional gear lube & thoroughly drain the rear to eliminate the coating and any break-in metal wear. It can only help in the long term.

I'm not saying you have to or that you'll break something if you don't. I've done it plenty of times with minimal break-in by making several trips down the return road and then racing. Just saying that it would be better for it, if you have the time and a couple of extra quarts of fluid to do it with.
 
I've been doing these since the 90s, including some time at a 4wd shop where we did 3-4 a week:
On any street vehicle, with street material gears: 15 minutes with no load (on stands) at 30-50mph. Then let cool completely (overnight). Then test drive, light throttle, no hard accel for 5-10 miles, then let it cool. If it's been quiet, it's good to go. If it's not quiet on the jackstands you have a chance to addres the setup. If it is noisey on the test drive the setup wasn't right and it probably never will be quiet. Pattern is only one peice of the total picture.
On a race car - only the first step is fine & I do what Loco says - run it on stands with dino oil, let it cool completely, then replace the fluid with synthetic, and go.
 
j par said:
Not to worry triple R I'll do the arguing, and you keep making sense !? Notice I've been posting on the racing forum because a 90% of the time race car. I'm not sure how the racers break in there 410 spool ? Do they fill up with race fuel and gently drive 500 miles ? It's all I can do to drive my car gently til it's warmed up !!
Let's take my drive to the scrap yard scales the other day. I top off with race fuel ($5.20 per gallon) in ten gallon tank. I drove maybe 40 miles round trip (no speedo) (when I care haw fast the car is I look at my time slip). So I'm back home and I empty a five gallon can to re top off.
There has to be a better way than doing that 6 times before the next race !?
Click to expand...

Why do you run race fuel on the street..whats your comp.??
 
mopowers said:
Here's an idea... How bout you call the manufacturer of the gears and ask them what they recommend???
Click to expand...

Because that makes too much sense. He'd rather ask here and then argue with the answers. lol
 
mopowers said:
Thanks. 500 miles is what they said?? Wtf! Did you ask Cass? When I built my 3.91 8 3/4 (with parts from Cass as well), I just put the rearend up on stands and ran it at a fast idle in 3rd gear for about 15 mins to circulate the gear oil and heat up the gears a little. Then I let them cool off before driving them around under a light to moderate load for a little bit. They seem fine with no noises. They're just gears; what's the worst that could happen? As long as they're set up correctly, I don't see any issues.

To answer your question, I don't have inner valve springs. Brian at IMM set up my RHS heads with beehive springs that have plenty of spring pressure for my small hydraulic camshaft. I've got a mile of valve-piston clearance too (>.200"). Everything seems fine after break-in. Gonna change the oil tonight and cruise it around this weekend.
Click to expand...

be careful the first couple times you hit the loud pedal hard! Make sure you're in a bit of open space when that power comes on you're going to need it or want it. Have fun!
 
RustyRatRod said:
Because that makes too much sense. He'd rather ask here and then argue with the answers. lol
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When people have ideas or suggestions challenged it seems to make them uncomfortable ? They use insults to cover up insecurities likely do to a small drive line ? LOL
 
I think I'll go with the vast majority and cycle it under as light a load "as i can manage".

I do have more one question - (i don't think I can ask the manufacturer this one triple R )
Has anybody else ever welded a bung in the bottom of the housing to make oil changes easier and more thorough ?
 
j par said:
When people have ideas or suggestions challenged it seems to make them uncomfortable ? They use insults to cover up insecurities likely do to a small drive line ? LOL
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I never suggested anything. But I have something in mind.
 
j par said:
I(i don't think I can ask the manufacturer this one triple R )
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I wasn't the one who suggested the manufacturer. Like I said, I didn't suggest anything.
 
I drilled a hole and installed a 3/8 pipe plug for a drain. easy and cheap.
 
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