how many miles should you put on a fresh rebuild before you hit it

[geneo4116]

what do you think complete rebuild how should you break in easy or like you just stold it

[hemiken]

I would just drive normally as every day use, then change out the oil after about 500 miles.  Just slowly get on it harder and harder.  Listen for noises as you go.

[GoodysGotaCuda]

With a fresh machined bore and such. About the cam break-in is plenty. Tolerances of machine work are a lot tighter than they used to be. Never hurts to baby it, but many people break them in like they're going to drive them after the cam sets in.

I don't say that you'll get more power, but this is an interesting read
http://www.mototuneusa.com/break_in_secrets.htm

"On the Street:
Warm the engine up completely:
Because of the wind resistance, you don't need to use higher gears like you would on a dyno machine. The main thing is to load the engine by opening the throttle hard in 2nd, 3rd and 4th gear.

The best method is to alternate between short bursts of hard acceleration and deceleration. You don't have to go over 65 mph / 104 kph to properly load the rings.

The biggest problem with breaking your engine in on the street (besides police) is if on the freeway (too little throttle = not enough pressure on the rings) or if you get stuck in slow city traffic. For the first 200 miles or so, get out into the country where you can vary the speed more
and run it through the gears !

Be Safe On The Street !
Watch your speed ! When you're not used to the handling of a new vehicle, you should accelerate only on the straightaways, then slow down extra early for the turns. Remember that both hard acceleration and hard engine braking (deceleration) are equally important during the break in process. "

[Chryco Psycho]

I have always been easy on it for the first 500 miles , flooring it regularly but keeping the RPM down under 4000 or so , then change the oil & drive it

[Jacksboys]

I would just drive normally as every day use, then change out the oil after about 500 miles.  Just slowly get on it harder and harder.  Listen for noises as you go.

   That is what I would do   

[nivvy]

I dont even have 500 miles on mine yet...... I havent pounded it at all......... 

[Aussie Challenger]

  The cam is the first item you have to be carefull with, then the bearings, both mains and big ends, the rings bed in fairly easily, but the bearings take at least 500miles. I give a new motor higher loadings for short bursts, between 1500 & 3000 rpm.  be carefull.   

[jwalk]

with my last stroker kit after new machining and new rods pistons bearings I was told and I quote,"Break in the cam 25 min at Ithink 2500 after that drive it like you hate it. If its gonna break it might as well be while your tools are still out."  this was from a competitive perf shop that competes in engine builders national competitions. 

[FJ5_440]

I put about 500 "normal" miles on it then I change the oil, retorque the important stuff and start the upgrade path by seeing what breaks first.

[FirebirdStud]

with my last stroker kit after new machining and new rods pistons bearings I was told and I quote,"Break in the cam 25 min at Ithink 2500 after that drive it like you hate it. If its gonna break it might as well be while your tools are still out."  this was from a competitive perf shop that competes in engine builders national competitions. 

EXACTLY! When I built my 385 for the Bird, I started the car, let it warm up at idle, burping the throttle every 10 seconds, then took it out on the road. I varied the throttle as I was driving, occasionally revving it up to 3000. After 25 miles I pulled back into the shop, drained the oil, and filled her back up. Drove it for another 50 miles, varying the throttle from 2000 to 4000, and then changed the oil again. After that, I drove it like a stole it, and its been kickin ass on the street ever since. I work with two guys who race NHRA, and all they do is let it warm up, drain the oil, and then break it in at the strip, WOT baby!
If its gonna break, its best you find out sooner then later. Your already in build mode, so you can fix it now. Drive it like you stole it.

[Changin Gears]

The cam and rings are the only things requiring break in/seating.  Everyone knows the cam break-in procedure.  Rings always seem to be seated by 50 miles.  My ring seating method has been, in high gear, wide open a couple seconds, let off a few seconds. Repeat 10 -20 times.  The theory being wide open burns off the oil and seats the rings while letting off lets oil back on the cylinder walls to cool everything off.  Bearings require no break-in.

This of course only applies to a street car, with a race car its either a dyno or a few laps around the pits.

[matt63]

I think it depends on the rings.  I was told that with plasma moly rings they are broken in within 20 minutes.  Cast iron or chrome rings may take much longer. 

[Swedefish]

Here`s a link about "how to break inyour engine" I found a couple of years ago.
http://www.mototuneusa.com/break_in_secrets.htm

This is typically how I didn`t do it  .
I had my engine running at idle way to long before I put any load at it.

[CUDA8U]

 

so lets hear a version of a break-in gone wrong to see what not to do!!!!!

[Chryco Psycho]

I have had 3 cam failures in the 20 min break in period .
Bad oil , bad cam , two definatly thr lifter didn't rotate