crank case pressure HIGH!!!

[Billla]

Originally Posted by Sport/Truck

Then you won’t agree with this…….. http://www.mototuneusa.com/break_in_secrets.htm
s/t

Hmmm: "Although the examples shown here are motorcycle engines"...

Otherwise, it's just a big collection of crap IMHO - I don't see any "secrets". This guys credentials are...what? Some of the comments are OK - but they're well-known and nothing magical.

The best break-in for a GEN I, after cam break in is complete if required is to follow the guidance in the shop manual - cycles of acceleration at about 60% throttle and then letting off to "compression brake" the engine. With current ring technology and a machine shop that knows how to make the right surface for them the engine can be considered fully broken in after about 300 miles. I've pulled enough broken rings out of engines that were beat on in the first 20 miles to disagree with the "just do it" approach.

Note that racing engines are different; they're typically running forged pistons with relatively loose clearances - maybe even .005+ - vs. the hypereutectics with .001.

This is a little rambling, but the bottom line is that street engines aren't race engines and require a different technique.