x24-7x

I just ordered a rebuild kit with 30 over pistons. Hoping to have my block in the machine shop in a week or so. Anyways, I was wondering what is the best way to break in the freshly rebuilt block? I know not to use fully synthetic oil..any opinions on the best oil to use? And for how long to use it before i switch over? Other than that is there any other things besides not running it hard at all that i should do? And for how long?

wrd1972

Baby it for the first 10 miles then hammer on it to get the rings broke in well. Dont beat the crap out of it, just lots of accell and decell.

x24-7x

that makes since, yet i have some people tell me to baby it for a really long time. and like dont get on it at all...i was told to do this so there is no adnormal wear inside the block and everything evens out right.. i just dont want to screw anything up..

96 Z-Ragtop

Heard nothing but good things about the following...

http://www.mototuneusa.com/break_in_secrets.htm

wrd1972

Babying it excessively will cause the rings and the crosshatch on the cylinder walls to not wear in right. This will lead to reduced performance down the road and lots of regrets. The only things that really wear again, are the rings and walls. Bearings dont really wear in. If something is going to go Kabbom, most likely it will do it right from the start without even having to get on it. Make sure you have good oil pressure and hammer down.

x24-7x

so run it light for the first 10 miles or so then do a lot of accellerating and deaccellerating? what would be the best oil to run through it and how often should i change it at first?

irocbsa

Run conventional oil for the first 200 miles, hammering on it whenever you can to seat the rings properly. Change the oil immediately after you first fire it up. Then 100 miles after that. I do it once more at 500 miles just to be safe, then I switch to Mobil 1.

jay_rich

Yup, my buddies car we ran the ****iest oil we could find with the least additives. Drove it slow for the first few KM, then went up and down the highway going through the revs. (alot easier on a 6speed tho)
Then later at night he drove it for about 4 hours on the highway going through the revs. Then switched to Synthetic. Drove the **** outta the car for the last year at 7200RPM shifts and it took it.

Jay

x24-7x

so how long do i need to do all of the accellerating and deaccelerating before i can drive it regularly?

95Blackhawk

You're gonna hear answers all over the board. I personally would go with 500 miles to make sure the rings are seated.

Further, the oil changes I use are: 20 minutes, 100 miles, 500 miles 1500 mile and then synthetic.

slomarao

+3 on seating the rings properly. Beat it hard, then let up, repeat process.

street demon2k3

This is from the guy who degreed my cam and installed my valvetrain, happened to be a hardcore racer for some time before he had an accident. "Do you really think we drive our race cars around town till the rings seat? We don't baby a race motor, we fire it up and then hope it stays together when it goes WOT!!!"

I drove my car for about 15min to make sure everything was o.k. then brought the RPMs up gradually going through each gear. After about 30 min of that I changed the oil and drove it hard till the next oil change. I sold the car before the motor had 500miles since it was parked for about 2yrs before it saw any track passes.