dlabooda

iTrader: (2)

I'm wrapping up a major rebuild of my Chevelle that involved a new rear end and some engine upgrades. I am trying to set up a dyno tune to get the engine running right but the rear gears have not had time to break in yet. Do I need to get some miles on the gears before I can get on the dyno or should I just go for it?

Thanks,
David

Carl at CRP

iTrader: (9)

If You want to give Your gears a chance of long life and quiet operation You should do a full break in.

Carl

Won-Ton

Why take a short cut on a major build with the chance of having to do it over again....Absolutely put some miles on them.

I think they usually suggest 500 miles. With my rigs I can't drive 500 miles so I run it on jack stands gradually increasing speed. Then drive it around my yard as much as I can and finally change the fluid.

Awesome car by the way, Chevelles are one of my favorites

dlabooda

iTrader: (2)

Thanks for the input. Do y'all have a recommended break-in method? There are a thousand different opinions online.

Carl at CRP

iTrader: (9)

Here is a copy and paste from Strange Engineering on gearset break in.


Break-in procedure for street gears: No harsh acceleration! Drive the vehicle 50 miles then allow a 1/2 hour for the differential
to cool down. Repeat this sequence for a total of 250 miles. At 500 miles remove the differential cover, fully clean the
inside, seal the cover and reinstall.

Hope this helps,
Carl

dlabooda

iTrader: (2)

So after 250 miles would you say it's ready for they dyno so should I wait until the 500 mile mark?

Carl at CRP

iTrader: (9)

I would not dyno it until after the 500 miles.
Carl

Won-Ton

What Carl said and don't skip the cooling part....X2 on going 500 miles.

01ssreda4

iTrader: (96)

Just did a set with no break in. Dead silent for 5 miles. Took the track and after the first pass they are noisy as hell. Whoops

blackandgold

iTrader: (2)

I think the legitimate concern here is that if you can't dyno the car can you safely drive it with the base tune? I'd rather be stuck swapping out gears in a year than blowing up the motor. If you can drive it without that risk before a tune then absolutely go through break-in, might be a good chance to break in the motor before an aggressive tune as well.

LLLosingit

iTrader: (4)

He could also put it on the dyno for a break in tune, Just a safe tune to put some miles on it before bringing it back for a performance tune.

onebadbowtie86

iTrader: (13)

I did 2 sets of gears last summer (two different cars, ones my own) and didnt do the 250 or 500 mile break in.

After finishing the install, I drove easy for 20 miles, then parked the car and let the rear end cool off. I did this 3 times, or 3 heat cycles. Still havnt changed the oil in either of the cars and they are silent, no whine. The gears were motives. Not saying this is the correct method, but if you could put a few heat/cool down cycles on the gears before the dyno it wouldnt hurt.

01ssreda4

iTrader: (96)

^^^Thats fine and dandy until you shock them.

onebadbowtie86

iTrader: (13)

I havnt had my car to the track yet, but its been abused on the street with no issues. By shocking it, do you mean launching it at the track? or any WOT driving?

01ssreda4

iTrader: (96)

WOT for one but a good dead hook or even a case of wheel hop rocks their world.

blackandgold

iTrader: (2)

Agreed, the 4.10s in my 10 bolt were fine on the street. One casual trip to friday night flashlight drags and it was all over.

onebadbowtie86

iTrader: (13)

fortunately I have 700 miles or so on the street on my gears now, so they should be good to go to the track.

Why do you need to worry so much about a long break in period if you re build the rear end with new gears, but not when the cars brand new from the factory?

FirstYrLS1Z

iTrader: (4)

When the car was brand new from the factory,it came with a warranty. Purchased aftermarket gearsets(irregardless of what brand)don't come with a warranty.

01ssreda4

iTrader: (96)

Well for one thing stock type gears are made to stay quiet. Their tooth cut and material selection helps this. An aftermarket set generally is more geared towards strength and in turn tend to be noisier by design. Also, 99.9% of people aint beating on no brand new car, definitely aint gonna have drag radials on it within 500 miles etc.

dlabooda

iTrader: (2)

Thanks for the advice, y'all. I guess I'll plan on doing the slow 50 mile heat cycles for the first 250 miles then do some heat cycles on the highway until the 500 mile mark. How does that sound?