Rebuilt engine: blue clouds / oil burn--AFTER warm up

[RigsPGT]

Why you are replacing oil 2 times in 2 days and in 50-100 miles?????
One oil change after 800 miles after rebuilt is recommended,not necessary!
You're "braking in" engines in wrong way.

Most of the shavings will be in the very first few miles and it is nice to drain it instead of crossing fingers that the filter will take care of them. Extra $60 doesn't compare to a 2K engine I think, so if that's not necessary, don't do it. I will still follow this route as I try to minimize possible problems. As for braking them wrong, I've broken in 4 engines (KLDE/ KLZE from 93-97 Ford Probe GTs) while 2 were with boost (no, KL engines don't come with turbos) and the first one which didn't get the oil change right away, didn't peak at 203psi (max) but instead topped at 195psi. The 3 others were happy campers in that aspect. All engines used good filters (bosch), actually over sized ones from Corvettes (same specs with bigger body).

Anyway, I've read all sorts of stories and guides from engine builders, enthusiasts like me and racers and one thing in common on all is the varying on the rpms and vacuum braking (allowing the engine to slow down the car). The rest could fall into whatever you feel comfortable with

[docLocke]

The thread was about abnormal oil burning after rebuild. We'd be happy to discuss breaking in--how often change what kind of oil at what rpms--if we had a normally operating engine.
A suggestion from another source was valve guides--not seals, which were replaced. Any thoughts on those, given the warm-up state when burning occurs? Hate to take the whole thing down to the last bolt again until we have some idea what to look for.

[misha]

@rigsPGT
I'm telling you what experts do,not shade or hobby mechanics.
There is no need to change the oil up to first 1000km after rebuilt.Even then it's not a MUST it's recommendation.That's directly from guys who rebuilt engines for 30+years....professional mechanics.
About braking in period.....factory also recommends braking it in slowly.Not because you will damage the engine right away....it's because it will last longer.
There are engines which fails in 100-150k km....but there are also the engines which goes after 300-400k km without actual engine problems.I'm talking about the same engines.

Regular oil changes contributes a lot on engine durability but the most important thing is how the engine was "broken in" when it was new or after rebuilt.

Same engines in same car can consume up to 1l of oil per 1000km and some of them can consume 0.1l/1000km with engine completelly ok.It all depends of how it was driven during "braking in" period and driving style.