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Re: Crankshaft profiling
[Re: polyspheric]
#3118172
02/01/23 06:06 PM
02/01/23 06:06 PM
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Joined: Oct 2006
Posts: 1,270
New York, USA
Chargerfan68
OP
pro stock
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OP
pro stock
Joined: Oct 2006
Posts: 1,270
New York, USA
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Getting the oil off the crank is a different question, even a sharp tail will do that.
The blunt CW leading edges create a lot of drag trying to plow through the hurricane of hot air, oil vapor, blah. Reducing the air density with a pump is a great idea: do both.
It's why modern boats have a "bulb" in front of the bow, but a rounded nose was used on the Nile 6,000 years ago. Thank you. That’s what I thought and it made sense in my mind. I am gonna call Crower..,,,then figure out best course of action to have it done. No sense, to me, in trying to accomplish a maximum effort build if I leave details untouched. This seems to be the modern, agreed upon shape at the leading edge:
Last edited by Chargerfan68; 02/01/23 06:11 PM.
1.50 60Ft. , 10.75@ 127MPH Hauling 3900 LBS.
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Re: Crankshaft profiling
[Re: dvw]
#3118281
02/02/23 11:37 AM
02/02/23 11:37 AM
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Joined: Jan 2003
Posts: 4,281
Shelby Twp. Mi
HardcoreB
master
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master
Joined: Jan 2003
Posts: 4,281
Shelby Twp. Mi
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The trouble with the deep skirted block is the oil comes off and hits the block skirt. Back when I was working with Koffels their 400 block comp motor had holes milled betweeneach main web from the crank C/L to the pan rail. There were large buckets on that side of the block going to the pan. As I remember the opposite side of the block was filled with epoxy and smoothed. I would pay more attention to scraper/tray/pan then worry about the crank shape.
Doug
X2 Also, if it makes you feel any worse LOL the crank i have is rounded on both edges of the throws like in your LAST picture of another crank. Other than the crank being an oddball that was on the shelf in their inventory I don't know why it is made differently. I can tell you its color is an indication that it WASN'T profiled AFTER it was heat treated. It has a 'baked' appearance.
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Re: Crankshaft profiling
[Re: Chargerfan68]
#3118282
02/02/23 11:38 AM
02/02/23 11:38 AM
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Joined: Jan 2003
Posts: 4,281
Shelby Twp. Mi
HardcoreB
master
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master
Joined: Jan 2003
Posts: 4,281
Shelby Twp. Mi
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Getting the oil off the crank is a different question, even a sharp tail will do that.
The blunt CW leading edges create a lot of drag trying to plow through the hurricane of hot air, oil vapor, blah. Reducing the air density with a pump is a great idea: do both.
It's why modern boats have a "bulb" in front of the bow, but a rounded nose was used on the Nile 6,000 years ago. Thank you. That’s what I thought and it made sense in my mind. I am gonna call Crower..,,,then figure out best course of action to have it done. No sense, to me, in trying to accomplish a maximum effort build if I leave details untouched. This seems to be the modern, agreed upon shape at the leading edge: Mine looks like this one!
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Re: Crankshaft profiling
[Re: Chargerfan68]
#3118323
02/02/23 01:03 PM
02/02/23 01:03 PM
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Joined: Jan 2005
Posts: 12,494
Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
Joined: Jan 2005
Posts: 12,494
Kalispell Mt.
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Getting the oil off the crank is a different question, even a sharp tail will do that.
The blunt CW leading edges create a lot of drag trying to plow through the hurricane of hot air, oil vapor, blah. Reducing the air density with a pump is a great idea: do both.
It's why modern boats have a "bulb" in front of the bow, but a rounded nose was used on the Nile 6,000 years ago. Thank you. That’s what I thought and it made sense in my mind. I am gonna call Crower..,,,then figure out best course of action to have it done. No sense, to me, in trying to accomplish a maximum effort build if I leave details untouched. This seems to be the modern, agreed upon shape at the leading edge: There can be a lot of power found in the detail stuff. I always figure if I can find 10 places to get just 5 HP that is 50 HP obviously assuming they are not all 10 doing the same thing. 5 HP from a top notch valve job VS run of the mill production shop VJ plus 5 HP from well thought out windage control is 10 HP but 5 HP from well thought out windage control and a vacuum pump that normaly gives you 5 HP would not nessacary be 10 more HP. DISCLAIMER!!! The numbers might not be those exact numbers but just trying to get the IDEA across.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Crankshaft profiling
[Re: Ray S]
#3118846
02/04/23 12:32 PM
02/04/23 12:32 PM
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Joined: Oct 2006
Posts: 1,270
New York, USA
Chargerfan68
OP
pro stock
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OP
pro stock
Joined: Oct 2006
Posts: 1,270
New York, USA
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Thinking on it, if a surface is always up against the web/cap it should not be round; it is not spinning in free air, rather should be shaped like an air dam on that side.
Pinching air & oil up against the web will hurt more than a flat edge. This point looks like it could be the reason why this Nascar crank is profiled this way. Good point!
Last edited by Chargerfan68; 02/04/23 12:33 PM.
1.50 60Ft. , 10.75@ 127MPH Hauling 3900 LBS.
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That is one of the main reasons to build and use a good crankshaft scraper 
