if I use a engine building grease on the lobes that have surface rust and pre-oil the valve train and pistons for a few days, will that damage the engine?

the diesel looks better than the gas engine from what I observed, these won't have a chance to run for another 4 months so I am a little worried

would hate to have to buy new engines since these were both top notch plants less than 6 mos ago

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1992 850i 6 speed
1991 M3 S54B32 swap
2007 328iT/6 RWD sport wagon
1987 325E 330iZHP engine swap
2004 Vespa 200GT
1976 W115 240D getting a much bigger engine. 5.5L
1997 R129 SL600 5AT