Engine Break-In
 

OPINIONS:

How many hours does it take to break in a new BBC engine?

LS JR.

An hour on the dyno. Avoid any idle time.

It depends.... if you have chrome rings.... the valves may be worn out before the rings "seat"... it all depends upon what kind of oil you are using... how hard the engine is run... etc etc... but a safe bet in a boat is about thirty plus hours... The big thing you have to worry about with a new engine is getting hot spots on the pistons and scuffing them.... usually within the first few hours of easy running the "high spots" have been shaved off and you can run it a little harder. Change the oil in about 5 to 10 hours the first time... 30 to 35 hrs after that... in cars heat usually destroys the oil first.... in boats it is usually contamination from moisture... if your oil gets up over 200 degrees you will turn the moisture into vapor and the oil will last longer... if your engine oil never gets up close to the boiling point of water it will begin to get contaminated with moisture and look like brown goop.

I prefer to change the oil and filter right after the initial warm-up and while the engine is still warm. Then 10-15 hours as Reed suggests.

I go so crazy scrubbing and cleaning the internals before assembly that I don't have to worry about any debris floating around during initial start-up... I've got the long bore brushes and take my engine stand outside and scrub the block and heads crazy with hot soap and water and then blow them out with compressed air... never had any problems.

My biggest deal is with the cam lube, assuming that a moly-lube is used on flat-tappet cam/lifters. It's not uncommon to have the filter plugged with the lube. That's becoming less frequent because a lot of people are switching to roller lifters. Yeah, I'm a big believer in assembling a clean/clean/clean engine too. Besides, you end up looking everything over very closely several times. It's amazing what you can find.

I've been told that the first hour on the trailer or dyno that you want to run cheap NON detergent oil (Valvoline 265 ??) for proper ring seat; Then a good Dino race oil for 20 hours or so; then move to you favorite synthetic.
I'm sure there are many methods and myths.
Dave;)

I am anal about it and run the motor for the first few hours without the thermostat.

Curious; Why?
I'm concerned about getting enough heat in at break in...:confused:

I take the thermostat out to make sure I get water to the heads right away on the first start up and I have always left it out for the first few hours just to be sure. Less heat, less friction, right?