ever heard of butchering a crank?

[pitbull419]

i found this site that butchers cranks
knife edges it shaves it
they say it lightens it by 7 pounds
but doesnt affect the strength of it
has anybody ever heard of this or used one?
let me know
thanks
josh

 

[TotalEclipse112]

A butchered crank is a machined and lightend crank. Stregnth is not affected becuse the only thing that is machined is the counter weights of the crank. Machineing the counterweights, lightens the crank, thus reducing the rotating mass of the motor. By knife edeging the machined counter weights there is less drag and disturbance as the cranks turns through the oil in the pan, reducing effort to turn the crank. However on the down side because the crank is machines and knife edeged, it loses some of its ability to sling oil upwards onto the pistons. Hope that helps.

 

[Defiant]

By knife edeging the machined counter weights there is less drag and disturbance as the cranks turns through the oil in the pan, reducing effort to turn the crank.

Crankshafts rotate above the oil, not splashing through it. It does cut down on wind resistance in the case.

However on the down side because the crank is machines and knife edeged, it loses some of its ability to sling oil upwards onto the pistons. Hope that helps.

Pistons and cylinder walls are usually lubricated by jet holes in the rod, and on turbo DSMs there are oil jets from the block which also fire oil up onto the bottoms of the piston crowns for cooling purposes.
Slingers went away from automotive engines about the time the Model A Ford faded away, although dippers and/or slingers are still common on lawn mower and similar engines.
Knife-edging has no deleterious effect on cylinder wall or piston oiling. The attendant weight reduction goes toward reducing rotating weight in the way a lightened flywheel does.

 

[TotalEclipse112]

The crank does turn through the oil in the pan, if you don't belive me take a DSM pan, fill it with the required amount of oil for your model year, and see how high it goes. Thats why there is a baffel in the top of the pan to channel it downwards, towards the bottom and ultimatly the oil pick up. The crank case also exists in somewhat, not a total state of vacum, the postitve crankcase vent uses the venturi effect of the intake pipe the vent the crankase of hydrocarbons from piston blowby.

 

[Defiant]

The crank does turn through the oil in the pan, if you don't belive me take a DSM pan, fill it with the required amount of oil for your model year, and see how high it goes.

And subtract from that the amount in the filter and lube system while the engine's running. No motor runs with its crank slopping around in a pond.