Die unbestrittene Technik-Koryphäe auf dem Harley-Sektor ist der Autor Donny Petersen. Er schreibt regelmässig die Technikkolumne in American Iron. Genau wie ich probiert er gerne selber alles aus, bevor er es schreibt.
In der Ausgabe 312 des American Iron (22.7.14) schreibt er in einem Artikel über Ölkühler:
"A Harley Engine is vulnerable to the ravages of heat since the motor depends on cooling air to control destructive excess heat. Why do people argue about whether an oil cooler is necessary
on Big twins and Sportsters? I just don´t get it. There´s no reason whatsoever not to run an
oil cooler on a stock engine or even two oil cooler on a performance engine. I´m not not
talking about those litle chrome ones either, although they are better than nothing. I want
those big, ugly-to-some, black coolers with 10 rows of turbulation enhancers mixing up the
hot oil in the tubing to obtain maximum haet exchange.
Back in 1999, I heard a H-D engineer, who wishes to remain anonymous for obvious reason, say
that he thought The Motor Company didn´t recommend oil coolers for the new Twin Cams because
the powers-that-be felt that the H-D rider would interpret their inclusion as an indicator
that there was something wrong with the new engine.
...
Bob Wood of Wood Performance who has a great knack for simplifying the complicated, told me that I needed two 10-row Jagg coolers on my Twin Cam or a high-performance Evolution. That´s 20 rows of Jagg oil Cooling to sufficiently lower the temperature in the heads to revent spontaneous combustion (aka preignition, spark knock, detonation). Bob says that head temperature needs to be reduced to 210-220 F (105°C), particularly in higher compression engines. Harley Davidson allows for 230F (110°C) with stock compression. I followed Bob´s advice, and I have to say that it works and works well."