Originally Posted by mbtech
When I worked at Garrett we had many engineers that came from auto manufacturers, most told me the break in most used (in a vehicle) is:
warm up at 1500-2000 RPM
after oil temperature reached operating temp (about 10 mins after water) shut down
check all fittings connections make sure everything is stout.
after engine cools down about an hour start engine wait for oil temp to reach operating temperature again.
Drive vehicle slowly make sure you have all gears and oil pressure is 100%, and temperatures are good.
Now the break in
Maintain 20-25mph in second gear. Slowly open up throttle to 50% until 55mph is achived(or about 5000rpm)
then let off throttle. (still in second gear)
Let engine braking slow vehicle back down to 20 mph. Repeat 4 times.
Now open up to 75% and 5000 rpm and once again engine brake down to 20mph.(4 times)
Now open throttle to 100% and up until 6000rpm.engine brake once again down to 20 perform this about 6 times.
(some transmission with very short gearing may perform this cycle in third gear)
I have been told after this cycle engine is almost broken in. (depends on ring material) I have run this cycle many times. Works good but I never had any intramentation installed to verify effectivness.
Seem a really good procedure