My Kohler K321 14HP rebuild thread

[Eugen]

Oil pan on. Hm.. Two 1/4 in npt elbows that I have and both are broken.

Off to the hw store to find some. When, I don't know yet. A week of work in the big smoke awaits me.

[DavidBarkey]

Oil pan on. Hm.. Two 1/4 in npt elbows that I have and both are broken.



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Off to the hw store to find some. When, I don't know yet. A week of work in the big smoke awaits me.

If you can get to PA and get a hydraulic fitting 90, they are stronger and less likly to brake .
Dave

[Eugen]

Passing through Barrie next week so I'll try to stop by Princess auto.

[Eugen]

The flywheel is cast iron. When it goes back in the key should be in this position, according to the manual.

The manual also says 50-60 lb ft torque for the nut and hold the flywheel in place with a strap wrench. You better not stick anything between the flywheel fins. But what if you don't have that strap wrench? You can improvise one from a hammer handle and a piece of strong strap. Like so

Got to about 57 lb ft of torque with this.

[Eugen]

I know I departed from the original paint color, making the engine silver. But I like it better than black. Wish I didn't install the oil pan before giving it a coat of paint. Oh well...

[Gordy]

In my studies of solar heat collectors, I ran across a number of references that black paint is not only better at collecting heat than other colors, but is better at shedding/radiating heat as well. So there is a reason they were black, not just the Henry Ford thing "You can have it in any color you want as long as you want it in black"


Gordy

[Eugen]

In my studies of solar heat collectors, I ran across a number of references that black paint is not only better at collecting heat than other colors, but is better at shedding/radiating heat as well. So there is a reason they were black, not just the Henry Ford thing "You can have it in any color you want as long as you want it in black"


Gordy

hahahaha! well well... but it'll overheat in what I think it is a beautiful silver clean color!

now you made me read this 1956 master's thesis by Richard F. Justus: "Heat transfer coefficient of paint films"

@Gordy It must be the real reason why the green painted kohlers in JD tractors fail more often. Same with the yellow-orange of the cast iron 16HP B&S.

Laughing matter aside, you made a good point, I'm inclined to take the silver paint off and go back to black.

[Eugen]

Looky looky, conclusions from that thesis:

Now, this block and cooling fins had no paint. It was mostly bare metal and rust. According to the info above, that is the worst case scenario. An aluminum based paint increases the heat transfer by about 4%. While a white paint based on titanium dioxide increases it up to 15%. The black paint is almost as good as the white paint.

This motivates me to take off the silver paint and go back to black. As I don't think I can find white engine paint.

thank you @Gordy !!!

[MattA]

Eugen - When it comes to electronics heatsinks, a black anodized aluminum heatsink radiates heat 14x -20x heat more than a raw unfinished aluminum heatsink. You can look up the emissivity of the materials. Raw aluminum is 0.04-0.06 and black anodized aluminum is 0.83 to 0.86 (the scale goes 0 to 1 AFAIK). This is only for the radiated portion of the heat transfer. You also have convection and conduction heat transfer. The radiated heat transfer makes up a decent amount of the heat transfer in a passively cooled system (no fan) but in an active cooling system (fan), the amount of cooling that radiation makes up is much less.

Not really tractor related but its a similar concept.

[Eugen]

Thanks @MattA, I think I won't bother to strip the silver paint, I put a very thin single coat. I'm thinking a single coat of black high temp paint should be just fine.