Friday, January 24, 2020

1942 WLA Flathead heads by @alleywaykustoms, who made them lighter, and likely created air turbulence which ought to cool the engine better. Why didn't the factory do this? It wouldn't seem difficult or a time consuming procedure.

7 comments:

  1. I want to se the math on the adding surface area claim. By drilling a hole you have removed surface area twice each hole. Does the area of the edge of the inside of the hole make up for that? Have to know the thickness of the cooling fin and drill diameter to calculate. Also, not sure that added turbulence is a good idea. That would tend to separate air flow from the surface of said cooling fin. A smooth air flow over the fin is better for removing heat.

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    1. Well daggone it, I sure never thought about that. The bigger the hole the more surface area removed. Damn. Unless the material were ridiculously thick, with a small hole.
      Damn, that is an astute observation sir!
      Dimpling the surface, like a golf ball, would increase the surface area, regardles of the thickness of the material.
      But a think material like these cooling fins, will not get a surface area boost from a perpendicular hole.
      Now, a nice small hole, at a sharp angle, that should make more surface area.

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    2. I admire your observation! Also, the turbulence would need to be significant, as a tornado doesn't separate air flow from the surface of things, it's quite thoroughly tumultuous. So, if the turbulence created were great enough, there would be a benefit.
      Wouldn't the the heat convection increase with the holes?

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  2. Actually, as an engineer, you want turbulent flow for best heat transfer. Laminar flow develops an insulating layer of air against the surface to be cooled.

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    1. Then you agree with me... and the laminar vs turbulent was what I was getting at, and completely agreeing with you. Seems to be a matter of only a couple minutes to drill through the fins, not a difficult or time consuming procedure. I think the factories should have done this.

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    2. Whatever the cooling effect is, it really does look good. Think of the time to do the layout before you could even begin to drill.

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  3. Why didn't the factory do this? Cost.

    Don in Oregon

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