The hot air gun trick does wonders on tight ABC engines... mind you they are not all so tight you need to heat them up, but MVVS's can be VERY tight when new.

A few weeks ago I ran in an engine (West Eurotec 50V1) that would just seize up if left idling for more than a few seconds. That one was extremely tight, and it sounded horrible when it seized. It didn't do any damage though, but like I said, it sounded horrible and scared me for a moment there...
It turned into a screamer after two tanks. Couldn't be better, although it is still very tight when cold. But this is the way they are supposed to be.

So if it is ABC and tight, get it up to temperature ASAP... even before you run it... going gentle on it will do more harm than good!