Flat spots on a crank?

[63t-cab]

Had a fella tell me a crankshaft can get "FLAT SPOTS" from a engine sitting for long times without being rotated.what in the world is he thinking??? these are round parts with clearance for oil,"FLAT SPOTS" WOW!!!

Joseph R. Zeiger

[31Streetrod]

Don't know about flat spots, but the crank will rest on the 5 main bearing caps when not running. Over a period of 5 to 10 years a minute flay spot could occur.

Lost in the 50's

[rockne10]

[PackardV8]

Not going to happen. Think of the pounding a crank takes from combustion at max RPM. Then think of the relatively weak force of gravity versus high RPM pounding. Think how hard a forged steel crank is. The guy doesn't have a clue.

thnx, jack vines

PackardV8

[irish]

Packard V8 is right, the forged steel crank isn't going develop flat spots, especially when it's resting on the relatively soft bearings.

Joe

[Jeff_H]

I wonder if this thinking is from applications with roller or ball bearings where the contact from the shaft to bearings is more concentrated compared to a crank?

This reminds me of a tour of a standby generator facility I had as a student. This was one of those facilities the utility co has to provide peak demand. There was a tank farm of fuel and 2 turbine powered generators. They were each powered by what the guide likened to a pair jet engines with the thrust nozzles pointed at the generator turbine blades. The advantage was the facility could be up and running within a few minutes unlike a coal plant or the like.

For this discussion, the thing that sticks with me is the generator and turbine shafts were slowly rotated with a small motor when not in use. We got to walk through the turbine area and the shaft was turning slowly like 1 rpm or less. The guide explained this was to prevent the shaft from warping/sagging under its own weight and the bearings from getting damaged.

Haven't I heard someplace to not store loose cranks laying on their sides but to hang them or stand up vertical for similar reasons?

Jeff in ND

'53 Champion Hardtop

[bams50]

quote:Originally posted by rockne10

A crank that sits for an extended period of time would receive no lubrication. I suppose, eventual humidity could induce some corrosion at the lifter contact.

Typo, Brad? I don't think lifters contact the crank (unless you get BIIIIG trouble)

Robert (Bob) Andrews- on the IoMT (Island of Misfit Toys)
Parish, central NY 13131

GOD BLESS AMERICA