| engine piston and rings - This is the major source of controversy. The motoman technique comes from his experience working on air cooled snowmobiles and motorcycles and flies in the face of what automotive engineers and the factory manual all suggest. This article from motortrend also thinks that it's wrong. motortrend I am bringing this up because I was reading on another car forum where a "trusted member" posted this: "When the engine is cold rev the engine to at least 2,500 rpms " (this is about 55-60% rpm to redline, I thought this was kind of high for a diesel engine, this is what caught my attention)
..".The reason for this is to keep the turbo on boost...and to apply firm pressure to the rings for optimal sealing against blow-by gasses. The rings need the boost to seal since its a turbo charged engine, babying the engine is detrimental and will lead to issues with compression if done so for very long" This doesn't make sense to me...a diesel engine has over 400psi compression, how much is boosting 8 psi going to help the rings seal? A gasoline engine has 160-180 psi compression and they seal fine. Is there something about diesel vs gasoline construction that would prevent the rings from sealing properly? I am also guessing that a cold turbo would probably experience more bearing wear if you stay in boost immediately after engine start. Or is there no bearing play when the turbo is cold? Valve head - what kinds of break in does a valve head need? I am guessing that other than the valve guides, little to none. engine crankshaft and main bearings- these are precision machined parts that require no break in and start wearing down from hour 1.
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