flyrotary@lancaironline.net Mailing List Archive

Al,
I don't have all the information you're requesting, but I can take measurements today (if the wife will let me out of the house).

I would describe my system as series-parallel. The series portion relates to the oil flow circuit. The oil leaves the engine and enters the oil/air exchanger where it drops 10-15*. From there, the pre-cooled oil enters the oil/water exchanger, dropping another 15-20*. Finally, it exits the oil/water exchanger and returns into the engine at the oil filter adapter. Hence a series circuit. Note: If I could improve the efficiency of the oil/air exchanger I might not need the second exchanger, but for now, this is working.

The water portion is a little more elaborate. You can think of this as a parallel circuit. To do this, I drilled and tapped a hole (1/2" NPT) in the water pump housing after the pump, but before where the water turns 90* to enter the front side housing. (Clearance from the two alternators was a significant factor in where I located this hole.) This circuit supplies the oil/water exchanger. The exit of the exchanger tees into the line leading from the discharge on the water pump housing (leading to the radiator inlet). So, the water that has been heated by the oil doesn't go through the engine, but rather through the radiator to be cooled before returning to the wp inlet. I believe doing it like this increases the efficiency of my water radiator. You can see that with the addition of this circuit, there are now two parallel paths for the water. This is very similar to the circuit feeding the cabin heater except it taps the water at its coolest point rather than at its hottest.

I'll try to take some pictures and measurements today or tomorrow and post them for the group.

Mark S.

On Sat, Mar 15, 2008 at 9:40 AM, Al Gietzen <ALVentures@cox.net> wrote:

Kelly,
After reading Al's post, I need to make a clarification on my previous oil temp information. The 245* temps were after the cooler, at the oil filter pad, so who knows what they were coming out of the engine.

Mark; It's likely that the temps in the pan weren't a lot higher, because the reason the temps after the cooler were so high is that the cooler was ineffective – meaning that the temp drop across the cooler was only 10-15 degrees.

Over the last year I've instrumented my oil & water cooling systems so many different ways that I sometimes get confused as to what I'm reading on the EFIS & EM-2. Presently, I'm taking oil temp readings after the first oil/air cooler, then after the oil/water exchanger (as the oil enters the engine). I do this to monitor how well each of the oil coolers are working. Sorry for the confusion.

Tell me more about your oil/coolant exchanger setup. In series or parallel on each side? Coolant side on return leg after radiator? Typical temps before and after each cooler? Dimensions of the cooler?

Thanks,

Al