Oil Coolers

[Jafo28]

I have an oil cooler on my 07 Ultra Classic and it does make a difference when running in hot weather. I also run a cooler spark plug. Don't know how much that helps but I know my engine does not ping anymore.

[bosozoku]

Originally Posted by Jafo28

I have an oil cooler on my 07 Ultra Classic and it does make a difference when running in hot weather. I also run a cooler spark plug. Don't know how much that helps but I know my engine does not ping anymore.

The heat range of a sparkplug doesn't have anything to do with the engine temp. If you have a detonation problem, look for something else to blame, as going to a colder plug on a streetbike will, at most, only mask the true cause.

Put the stock heat range plug back in.

[Gojira]

On a side note, I saw a pair of shrouds fitted to a Harley, attached to the frame to shield the rider's legs from the heat. Doesn't help the engine, but I thought I'd mention.

[akfxdl]

Originally Posted by bosozoku

You guys are overthinking this process...

Without fuel in there, there's no additional heat from combustion, so temporarily there's a lower heat load in that cylinder.

As to the heat of compression, that goes away as soon as the piston starts to descend from TDC...the compressed gas within the cylinder cools once again, when it's allowed to expand. It'll pick up heat from the head and cylinders as it cools, then that heat and the air depart out the exhaust valve.

Heat of compression alone doesn't make any heat whatsoever...it just temporarily raises the temperature of the gas while it's being compressed. It's analagous to concentration, in that when the gas is compressed, the heat in that gas is squeezed into a smaller volume, so the apparent temperature goes up. Aside from friction, no heat is produced in that cylinder without combustion, and the comparatively cool air going through the cylinder takes heat with it out the exhaust.

Adiabatic fluids do that...

If you understand how a diesel engine lights up its' fuel charge, this is pretty obvious.


Cutting off the fuel is a crutch for overheating: in this situation, an oil cooler is the right answer.

+1 I figured I was over thinking it, I knew that it helped cool things down, just couldn't explain the science behind it. Thanks for the explanation Steve.
Got to agree with you, the oil cooler is the way to go.

[Flyin Hawaiian]

I have those shrouds that deflect heat coming from the rear cylinder. It helps a lot. I used to own a Fat Boy. BIG difference!! It blends in with the bike, but only problem is that on my list of "to do" items (after the oil cooler) is I want to install a rider back rest. The lever that adjusts the back rest mounts right where the deflector is located. (mounts to the frame) I'm wondering how that's gonna work out.? But then again, I could be wrong.

[akfxdl]

Originally Posted by Flyin Hawaiian

I have those shrouds that deflect heat coming from the rear cylinder. It helps a lot. I used to own a Fat Boy. BIG difference!! It blends in with the bike, but only problem is that on my list of "to do" items (after the oil cooler) is I want to install a rider back rest. The lever that adjusts the back rest mounts right where the deflector is located. (mounts to the frame) I'm wondering how that's gonna work out.? But then again, I could be wrong.

I've also got the heat deflectors, the seem to help. It sounds like you want to install the fancy Harley Adjustable Back Rest.
I put a Mustang back rest on mine. Between the Mustang back rest and a Airhawk seat cushion I can do 600+ mile days no problem. Mustang back rest was around $125 if I remember right that included mounting hardware. If you get the Jagg Oil Cooler you can save some money by not getting the adapter with the thermostat if you don't mind some longer warmups on colder 40 + degree days.

[Flyin Hawaiian]

I'm vertically challenged. A fixed back rest might not be the ticket. I'll look both of them up though. Thanks for the info!!

[Darth Lefty]

How smart are these oil coolers you guys intend to install? Do they have thermostats, or fans? Any danger to the lubrication when running on a 45F day?

[Law Dawg (ret)]

Originally Posted by akfxdl

I've also got the heat deflectors, the seem to help.

So all that global warming (aka climate change) making things hot on your Harley in the Alaska ice box?

The F800GS gots air, liquid, and oil cooling. Came that way from the mother ship...

[akfxdl]

Originally Posted by Law Dawg

So all that global warming (aka climate change) making things hot on your Harley in the Alaska ice box?

The F800GS gots air, liquid, and oil cooling. Came that way from the mother ship...

Nope, "Climate Change" has made for one of the better summers in 10 or 20 years. I have had to buy a sprinkler to water the lawn. However we got the word from the weather people the other day that "Fall and Winter weather patterns appear to be setting in." Translation rain winds and highs of 50 degrees. That means I will be having to put my left hand between the cylinders to keep it warm, and the heated vest will get used.