I personally have never heard of an engine failure caused by how hot these things run, just keep in mind that the hotter the oil gets the faster it breaks down. That's why many of us are running synthetic.

 

I understand all touring bikes have coolers now. A Dyna Switchback on the showroom of my local dealer has the 103 but no cooler, so I guess they're limited to the touring class and CVO's.

 

I also haven't heard of an direct oil-related failure caused by heat, but it is true what you say about oil breakdown, as it oxidizes exponentially as temperatures increase over about 180°. Keep peak OT's in line and the oil's integrity (viscosity) will remain closer to new specs, and this can't help but improve lubrication.

Synthetic breaks-down slower and can handle more heat, but the problem doesn't go away by using it. A cooler will do a better job of controlling peak oil temps than no cooler at all, and the bigger the temperature swings the more engine tolerances change over the course of normal operation, which doesn't help long-term durability.

 

Now that is a good post.
Oil type with temps and 65K on the clock.
And I got shook when mine was stock and hit 255.

 

Based on independent tests I've seen your Amsoil's viscosity starts breaking down at about the same temperature as other high-quality synthetics. Please show evidence for your claim that it doesn't oxidize until 400°. Thanks in advance. Amsoil is a good oil but it isn't a panacea and there are many other good synthetic products on the market.

Coolers work when stationary by convection--not as well as when airflow is present, but there is some cooling effect that occurs. Plus, the temperature starts out lower than it would be otherwise giving you more time to get moving again before the oil gets to a critical temperature.

 

If you are running a high lift cam you are also using heavy pressure valve springs. The valve springs are cooled by oil flow alone. If you can keep the temperatures lower on the valve springs they will last longer. There will not be a temperature related failure that you can see. The spring rate will soften, especially at full lift and valve float will set in at high rpm's. That is when your engine will fail and you'll have no idea that it was oil temperature related. Stock engine? No problem. Modify it, cool it. There are a couple of forced air coolers out now, UltraCool and Jagg. If I invested as much money IN my engine as it takes to light these mothers up; I would put that kind of investment ON my engine.

 

I ran a few hours in 85-90 heat last week. Got home and had the old oil temp oil gauge from my flstf, stuck it on the engine fins and let it rest there a few minutes until it quit at 240 degrees.
I am running castrol 20-50 v twin, and will go to mobil1 20-50 synthetic this week.
I got 1500 miles on the bike and will have 1K service done, and I change he oil at 1K.
I think an oil cool as the RKC comes with with the 103 is a nice feature.

These buggers run hot, and hope dyno tune will take some of that heat down.

Cheers,

Mark

 

The point is the oil never reaches a critical temperature even using the HD fossil oil. Any good synthetic oil is good to 400*. I'm not saying an oil cooler is a bad thing I'm very doubtful as to how necessary it is. I do respect your opinion however. I'm going to send off a sample of my oil for analysis next oil change. (5,000 mi) I will try to post the results on the forum.

 

A critical temperature to me is any time the oil oxidizes more than it needs to, and I don't see any particular temperature as a magic number to avoid. Higher temps mean faster oxidation, and that affects the oil's integrity, most notably viscosity. How much the oil can tolerate as a worse-case scenario is something that would vary from brand to brand, possibly sample to sample, but I personally wouldn't want my oil going higher than 230° even for a short time. It doesn't in my case and 300° is simply out of the question--but that's just my criteria. Ask an oil engineer and they will wince if you discuss oil temps of 300° or higher, and they will warn not to sustain those temps for long. In a discussion with one synthetic maker a few years ago I was told that my turbo car's oil-temp thermostat should be lowered from its stock 225° setting, and 180° was recommended as an ideal temp for oil. I didn't do it because the oil never exceeds 220° in that car, usually staying below that point, and that's tolerable when change intervals are 5k miles, IMO.

That would be good to look at, so please do. I think there's even a sticky thread for oil-analysis reports in the oil section of this forum, too. What range do you normally run in these hot summer days?

My position on oil coolers is mostly that they keep oil at a more consistent temperature with smaller swings upward, which IMO is not only better for the engine components but minimizes oxidation of the oil.

 

My oil temps run 225-260* depending on air temp. At 75 mph it is usually 238-250* when air temps are 98*-103*. That is 2 up and loaded. In the winter it will barely reach 220*. My concern here in Fl is getting the oil hot enough to cook off water condensation and other impurities. Oil that is too cool will create acids that are harmful to all metal parts of an engine. I quit wrenching yrs ago but back then engine parts would be heavily pitted from acids. Haven't had the need to take any late model engines apart and at this point have no idea what one might find. It will probably be another month or two before my bike will need an oil change but will pm you the results. I use 20w50 Amsoil. what is your favorite?