Matt, with all due respect this simply is not true, LOP operations have been around a long time.
It is well know that Charles Lindberg used LOP to cross the Atlantic in 1927, and LOP operations helped win WWII not in theory, but in aerial combat....
To say the operating range of LOP is smaller is accurate, but certainly you are not going to "blow your engine up" if you set the engine up properly. It is not hard, in fact it is very simple. If you can run a clip board & a pencil you can run a standard Injector Nozzle Tuning flow test and record the results. Change the restrictors to get the cylinders to peak at about the same fuel flow rate and you now have an engine set up to run LOP all day long. The engine will run cooler, and longer.
Geico266- Thanks for the dialogue. Just so you know I (nor EI) preach LOP OR ROP, I follow the science of both.
In my opinion the keywords you wrote were: "if you set the engine up properly". I study this stuff daily and personally would have a very difficult time in determining mixture point, and literal proximity to peak EGT, w/ out a multi point EGT analyzer. I am sure Lindbergh had some of his own techniques, as I am sure Hughes and others did. Fundamentally experimental, unproven for the most part, and likely beyond the efficacy of the average modern pilot. The bottom line is the science, and it's very very clear.
Here is some of it: "
Haywood, J.B. Professor of Mechanical Engineering, Director, (1988).
Internal Combustion Engine Fundamentals,
MIT, Mcgraw-Hill inc."
The number one concern with LOP operation quite plainly is with detonation issues. This is due to the fact that detonation is probably the most destructive operating condition for any engine. Why is it a concern LOP? It's because of the proximity to "peak" in which you must operate (as you lean beyond peak). We know that an engine is MOST susceptible to detonation at peak EGT.
Light (incipient) to moderate (limiting) detonation can lead to heavy detonation.
What is detonation?
Once the fuel/air mixture (charge) is ignited in the combustion chamber the charge will burn at a uniform rate. The last portion of the charge to burn ("end gas") is where detonation will occur. When cylinder pressure is high (produced by power) and surface temps at the location of the gas is high, the end gas will auto-ignite and burn at a rapid rate (Ref. Heywood, 375). This causes the peak pressure in the cylinder to occur early and spike to a level which can be 10-50% higher than normal. Detonation can cause pressure in a O-470 engine to go from 11 tons to over 15 tons.
Unfortunately it is very easy to operate an aircraft engine in a manner that will produce detonation and engine damage. It is up to the pilot to operate the engine in a manner which will prevent detonation. Light to moderate detonation most likely will go unnoticed, it is a indication that heat energy is being transferred to susceptible parts of the combustion chamber. I know this is an experimental forum but FAR 33.47 very clearly states "each engine must be tested to establish that the engine can function without detonation throughout it's intended condition of operation." AC 33.47-1 outlines the detonation testes required by the FAA to T.C. (Type Certify) an engine to an aircraft.
Detonation can cause engine damage through to mechanisms:
1. Excessive Cylinder Head Pressure- Excessive pressure in a cylinder produced by detonation can cause cracks at the spark plug hole, injector port and exhaust valve port, broken rings, and broken ring lands. These kinds of serious problems are NOT uncommon.
2. Excessive Heat Transfer- When detonation occurs the end gases burn approx. 5-25 times faster than normal. This rapid burn produces a pressure wave (around 5,000 Hz) to bounces off the cylinder walls and can be heard as a knocking sound in an automobile but can not be heard in an aircraft engine. This high energy pressure wave increases the transfer of heat combustion (approx 4,000 deg. F) to the top of the piston and top of the exhaust valve. In extreme case where preignition is present, a hole can be melted through the top of the piston.
We all understand physical damage but heat damage to detonation may cause more problems than some pilots realize. Any sign of dimpling or erosion on the edge of a piston or exhaust valve is a serious matter which may require a change in leaning and/or operational methods.
Again, it is paramount to engine health that a pilot should ALWAYS operate an aircraft engine in a manner to AVOID detonation. This is the concern with LOP operation historically. It does not say that advocates of LOP are wrong on incorrect in there techniques but it is the concern.
Thanks for the chance to share this information!
Matt Sharp
A couple more fun detonation fact-odums:
1. Advancing your timing will increase peak cylinder pressure and chance of detonation.
2. Increasing RPM reduces burn time, wich slightly reduces chance of detonation. (Ref. Taylor2, Another MIT study)
3. Increased humidity has shown a tendency to reduce detonation.
4. Compression, you guessed it, higher the compression, higher the chances of detonation.
) and he was still flying at 170knts. 
