Do forged internals stop spun rod bearings?

[MalcolmV8]

I'd never really thought about this one before but a buddy of mine is having me rebuild his 02 GT 2 valve motor because he spun a rod or main bearing. We're not 100% sure yet as the motor hasn't be torn down yet. Anyhow he asked me to use all forged internals so he doesn't spin another rod bearing... I actually had to stop and think for a sec and to be honest I don't know the answer. Does that really stop you from spinning a rod bearing? Then it got me to thinking what exactly is the cause of spinning a rod bearing?

[Dave]

I hate these quiz type questions. Really don't think the forged has much to do with it, more of how the clearances are set-up. Speaking of forged bottoms, what viscocity of oil do you run in yours? I was told to run 5W-50, not sure if that with the wider clearances or the heat from the blower.
Dave

[MalcolmV8]

Wow 5w-50 seems crazy. Although I think that's what my buddies '11 GT500 takes too. My car is just 10w-30. Factory spec for my car was 5w-20 but that was for emissions. Really the motor needs 10w-30. When I rebuilt my engine the machine shop said to use 10w-30 and not 5w-20 especially now that I have slightly more clearance than factory spec to accommodate the extra power/heat etc.
If I drove it in the winter I'd probably put 5w-30 in it for winter temps.

[plowboy34]

forged materials will not stop spun bearings. Spinning a bearing is caused by friction between the crank and bearing being high enough to force those little bearing locks out and wala, bearing is spun. Somehow someway it lost lubrication to that journal and stuff happens. It could have been a thousand things that caused it to lose lubrication, a itty bitty spec of dirt can do it.

[MalcolmV8]

Makes sense. Along the lines of what I was thinking. Thanks.