Just as a last post for me here, I would like to explain why quench is so sensitive.
Engines are quite a bit like human beings, and...robots, all combined as one disaster of an entity, metal, mineral, fluid, and a lot of other stuff with minds of their own, expected to act as one mind and body.
Quench is essential for piston deck cooling, and top ring sealing and cooling, when it is not correct, the engine suffers, pinging, detonation as a worse situation, cooling temp issues, the works.
But, the worst thing that occurs is heat expansion, not only in selected areas, but in all facets of operation, full engine. Take the actual physical sizing of the engine as it runs, and attains its heat. Ever changing, and final operating temps are a set deal, cast iron, 180, cast iron block/aluminum heads, 195, all aluminum, 200 deg/F. Not even running engine temps, like 160 on a full cast iron engine, will stop the physical "growth" of an engine, and clearances change as the temps change. Especially the crankshaft center to head deck length.
Lets look at this one, piston down in the bore .007, head gasket .027, total, .034. Too tight, mixture is pushed out of the quench areas, leaning them to detonation, or, less, pinging. Quench is designed to work with a heat expanded metal part assembly, change that final distance, or, area it should be operating in, problems endue. No engine stays at the cold set quench once it gets up to operating temperatures.
So, if the quench is off dead cold, it will be off when the engine is at full temps, no matter the engine temperature it is running at. Too cold, quench is also too small, too hot, quench is too large. At an incorrect operating temperature, amnd incorrect quench, that engine can be so far off, it isn't funny, and that no funny converts to the issues discussed in this topic. YES< other factors do come into play, and they all are as important as quench, but quench has caused more problems not easily solved than other issues.
Most of the changes I read about this engine are crutches to the hot engine quench not being correct. Thoise changes, such as 160 degree thermostat, really didn't help as much as thought.
Have a great day, everybody, I am going for my afternoon snack.