Been looking for info.

[Mykneesbehurtin]

So I have been researching for an answer to a question I have about the cooling fans available from several companies.I know that those who have them swear by them,but my question is when you see the head temp readings I am wondering if these readings are taken only from the fan side of the head.

I am curious as to what the temp readings are from the push rod side of the head and what kind if any lowering of oil temps there are with the fans and not an oil cooler.

 

[DK Custom Products]

So I have been researching for an answer to a question I have about the cooling fans available from several companies.I know that those who have them swear by them,but my question is when you see the head temp readings I am wondering if these readings are taken only from the fan side of the head.

I am curious as to what the temp readings are from the push rod side of the head and what kind if any lowering of oil temps there are with the fans and not an oil cooler.

Hey Steve,

This is a subject that I have been a bit obsessed about for years. I have spent thousands of hours researching and testing various strategies of cooling down the Twin Cam. I have logged temperature data over many years and tens of thousands of miles.

You can see a report I wrote up a while back at this LINK.

Here is one of many threads where there is a bunch of info on the subject-

http://www.triketalk.com/forum/thre...id-of-the-excessive-heat-on-my-2011-Tri-Glide

In case you don't want to go to either of the above links...short answer of your questions below-

I used to be far more concerned about oil temps, but then I realized that oil temps are a Result, not a Cause.

The Cylinder Head temperature and the piston temperature are the primary sources of the oil temperature.

While it is important to cool the oil with an oil cooler, cooler oil will not have a very big effect on cooling down the metal temperatures of the engine.

However, cooling down the metal on the engine will have a Very Big effect on not heating up the oil as much.

The Twin Cams (and it looks like the M8's are not much different) run far too hot for their own good.

There is no one thing that can be done to get the Twin Cam engine down to a temperature that is healthy....so in looking for strategies for cooling, I recommend not looking for a "silver bullet", I have not found one, and don't believe one exists. (including any of the fans)

So, what do the fans do.

I used to check both sides of the engine at the top And the bottom of the jugs for temperature readings. With and without fans.

What I found was that with the Wards Fans (and I assume the Love Jugs) that if it lowered the temps on the left side by X degrees, the right side followed suit. So, after a while I realized I only needed to measure on one side, knowing that I would get a similar reduction in temps on the other side.

Oil temperatures are a bit more tricky. Oil will heat up much more slowly than metal, and it will cool down much more slowly than metal (while the engine is running). Because of this, the causal factors of fans, and other strategies for cooling are not immediately apparent in oil temps.

However, they are completely predictable. It just is a matter of taking a plethora of variables into account, and giving time for the oil to catch up with the metal...both directions...heating up & cooling down.

What we discovered is that if there is a proper balance of cooling the metal and cooling the oil, the following will occur:

After 30-60 minutes (depending on ambient temperatures) that temperature of the front Cylinder Head and the temperature of the oil will mirror themselves. If your CHT is 220, the oil will be 220.

If riding variables change and the CHT climbs to 230, then within 5-10 minutes you will see the oil temp climb to 230.

When we see a bike where this is not happening....ie. CHT at 250 but oil does not go above 230, or vice versa....then we know that something is out of balance.

When the engine is out of balance, cooling wise, there will be a drop in performance, drop in MPG, and drop in engine longevity.

Dadgum, I thought I was going to give you a short answer. I'm sorry. It is really not a simple subject. Even with this long-winded response, I have left a bunch of stuff out that is banging around in my head from all our research.

Hope the above helps.

Kevin

 

[Mykneesbehurtin]

In a nut shell yes you gave me the answers i was looking for. I am looking at the Jagg oil cooler was hoping that someone would come out with a fan assisted oil cooler for the wet heads but noting so far.

So i will be gutting the head pipe,installing a free flowing air cleaner and doing a download.Also looking at your oil filter relocation kit.Thank you for your help.

 

[Casper]

What's your take on the new HD fan that mounts behind the rear jug? Supposed to pull the heat down towards the ground. Sounds good.

 

[DK Custom Products]

In a nut shell yes you gave me the answers i was looking for. I am looking at the Jagg oil cooler was hoping that someone would come out with a fan assisted oil cooler for the wet heads but noting so far.

So i will be gutting the head pipe,installing a free flowing air cleaner and doing a download.Also looking at your oil filter relocation kit.Thank you for your help.

Yeah, there just is not much room on the wetheads. To my knowledge, we are the only ones making an oil cooler that works with the wetheads.

You could put a fan assisted oil cooler under one of the rear fenders....we looked at this, but thought it would be overkill.

What's your take on the new HD fan that mounts behind the rear jug? Supposed to pull the heat down towards the ground. Sounds good.

We have not tested this, but have spoken to a few folks running them. They said the same thing we were thinking when we saw them. They do not work so well.

We are still going to test it, because, more than a few times we have seen something work that was counter-intuitive.

(if you want to cool down, do you put a fan facing away from you, to pull air across you? Or do you point it towards you to blow air onto you?)

Kevin

 

[frostbite51]

Those fans that blow across the heads - does that put more heat on the driver?

 

[Mykneesbehurtin]

Those fans that blow across the heads - does that put more heat on the driver?

From what I'm reading it does put a little more heat on your right leg but nothing unbearable,but if you ride in shorts it could be fairly hot.

 

[Capt.Bob]

Won't go down this road too often

I stopped by the local Harley dealer on an 80 mile blat with my street-legal race car this afternoon. I have been testing out my new OBD II Bluetooth scanner that sends real-time ECU data to my Android phone. I have some specific concerns about engine temperature management and some other parameters on the race car and am looking at the real-time data to get a sense of what is happening.

A fellow and his wife came out of the dealership squawking about not being able to buy a mismatched rain suit when I said hello. At that point, I should have wished them well and walked back to my car to carry on with my own activities. But noooooo, I mentioned to the fellow that his 2017 M8-engined wet-head Ultra would likely benefit from some cooling fans and mentioned the issues related to the "limp mode" when our new Harleys find themselves cooking like cakes on a griddle. You would have thought that I had fecal matter coming out of my mouth. How dare I say that his beloved new, over-priced iron, could possibly be running hot???

As I shared my experiences and some of the things we have shared on this website, he seemed to get progressively agitated with yet another thing in his life that was not going well along with his not too pleasant wife that was bitching up a storm about not getting her way in the store. Sensing that things were going downhill with his scowling look, I wished them a safe journey and retreated back to my own world with the ignorant bastard not fully comprehending why I had shown him a picture of my M8-engined TGU with cooling fans.

Seems to me that there are a lot of folks that would prefer to place their heads in the sand or possibly up their rectums rather than face the issues that many of us have been progressively becoming more aware of. I find many HD riders to be fun but many of them seem to lament the "good old days" and seemingly forget how relatively unreliable and leaky our "good ole' Harleys" were. Ignorance is bliss and I have decided that I will continue to read, understand and potentially ameliorate some of the shortcomings of my machines but am going to be a bit more leery of sharing my thoughts with dumbass know-it-alls. Just wish the dumbass know-it-alls had a sign on their forehead that blinked out a warning to steer clear.