The internet has provided a platform for anyone that has an opinion to speak out so to say.
Been around motorcycles since I was 15 years old. Been working on motors a couple of years more. The most common killer of any engine is heat.
As an air cooled engine the Harley has to rely on air movement over the case and fins for "Max" cooling. Even when your sitting still the fins are still radiating heat. Ask the people with "fried thighs."
With the change of the motor to include a piston spray Harley reduced the piston heat by about 50º. But this did add a temperature rise in the oil. Add the change to fuel injection and the epa requirements and we have more heat.
I'm old school in that I believe you need to know what your engine is doing. I added oil temp and oil pressure gauges on my 2006 Low Rider and on my current ride a 2007 Heritage. I can tell you that my TC88 and TC96 requires a 25 to 30 minute ride in 75º outside temp to bring the oil up to an operating temp of 220º.
In ambient temps of 100º the oil in the TC88 of the FXDLI and the TC96 of the FLSTC would borderline on 260º rising to 280º+ if required to idle in traffic for extended periods. This is not good even with me running synthetic in both rides.
I added a billet style oil cooler by
wimmer with a
Jagg oil takeoff adapter (thermostat controlled) to my Low Rider to get control of the temps in the extreme heat. I mounted the oil cooler horizontally just below the regulator. I had an overal reduction of approximately 20º at idle to 25º at normal rpm. Yes even at idle a oil cooler radiates heat. I have not put one on my Heritage yet but it is sitting in the toolbox ready to go.
The oil pressure of the TC88 and TC96 ran 30 to 35psi at 3000 rpm and would drop to 5 to 9 psi at idle. With the addition of the cooler I saw no noticeable pressure drop on the Low Rider or the Heritage. I have not performed a flow test but I would not expect the cooler to reduce the flow much at all.
Jagg specs for their 10 row cooler is shown below. Taken from their site.
I can tell you from personal experience his fear of pressure drops and gushing oil leaks (I do know how to tighten a fitting) is without merit.
Oil coolers do the job they were intended for. By using a temp controlled takeoff you will not risk the chance of lowering the oil temp below operating standards.
Tips for the Oil Cooler installation:
Use a temperature controlled bypass. Oil will not go through the cooler until it bypasses. The Jagg 4700 starts at 185º and is fully open by 195º. You will not run your oil "too cool".
Use fittings designed for flow not show. The wimmer cooler came with 3/8" hose fittings that had a huge id. You can see the size of the hole on their page. (link above)
Use good hose and clamps. And for heaven sake just tighten the dang things.