Khizer,
You should also read the thread on general tapered-bore break-in, as linked below.
It is true many tapered-bore engines will sustain no real damage, perhaps even none at all, from a four-stroking, rich break-in, as Brian wrote in the thread referred to, in post #5.
But why take any chances that anything does go wrong, as 2slow2matter wrote in post #2?
A tapered-bore engine is best broken-in as described in [link=http://www.rcuniverse.com/forum/Tapered%2DBore_Engine_Break%2Din_%2D_Upgraded/m_1850473/tm.htm]this RCU thread[/link].
Doing it as described there, at normal running temperature, low load and with the extra insurance of 25% oil, with added Castor, there is absolutely nothing else that can go wrong, as a result of this procedure.
And also, this type of break-in will be completed faster, with much less fuel waste.
If a new engine was assembled un-professionally, with incorrect clearances and badly manufactured parts and something is bound to fail, it will and a 'wet' break-in will not set it right anyway. So, why bother.
Just do a running temperature break-in procedure.
Original: downunder
As in when the oil can't be squeezed out fast enough by the pinch it develops enough internal pressure to compress the piston and expand the liner to maintain a clearance.
Brian,
This is not right. I personally heard a couple of tight engines, where the piston was squeaking at TDC, while they were running rich and cold. It was audible over the exhaust note.
This is what metal-to-metal contact sounds like. This happens only if the oil film was squeezed out!