check this out. It's from GM about engine install and break-in procedures

http://www.gmgoodwrench.com/resource...Procedures.pdf

 

Also, make sure to read this:

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

Might change how you feel about properly breaking engines in.

 

That looks like it was for motorcycle engines though...

 

Read it a little more carefully, it is for all engines.

 

For this application (roller cam) the way to break in a motor is to start it, set base timing, make sure there are no leaks and good oil pressure etc. Then if it is a stock rebuild, go drive it on a nice mountain raod with different load conditions, low rpm hill climb, high rpm corner turns, the rings need to be seated as stated above. Now for a modified motor you need to be on a dyno with AFR readout to break it in. If you have the air/fuel ratio too far off to begin with you will have serious ring sealing issues, too much fuel will wash down the cylinders and never let the rings seat, oil consumption will become an issue. For example, for every motor we build, the customer or we install it, then it is put through a single heat soak cycle where timing is set, manifolds re-torqued etc, then it is loaded on the dyno and beat for 5-6 passes while the timing and air/fuel maps are calibrated correctly. As some said above I am a firm believer in the "drive it like you stole it" mentality.

 

Read the breakin procedure on linked site. The other linked site above, addresses the OEM 'mentality' using common sense approach for his statements/reasoning. GM or anyother OEM could care less, whether or not anyone has a fast ride. As long as there are no tangible complaints, warranty concerns, or law suits, (all three represent $$$) they have been successful. This AFAIC, represents 99% of the basis of their decision making.