Oil engines were on the diesel family tree but not technically diesels. There were two varieties, low compression (70 to 150 psi approximately 5:1 to 8:1 CR) or medium compression (between 150 and 250 psi - up to 13:1 CR, or so). In studying the old texts, the medium-compression oil engines were often called “semi-diesels” and in later years, oil engines were often lumped together under that term. Like the diesel, fuel was ignited by heat of compression but with the oil engine, the fuel had to be heated and vaporized first... sometimes known back in the day as “cracking.”
Typically that fuel heating was done by a hot spot in the combustion chamber. These hot spots came in many forms, from bulbs to tubes (so-called hot bulb and hot tube engines) and other types. On a cold, or even cool, start, external heat was applied to the hot spot, heating the combustion chamber so that when fuel was injected, it instantly vaporized so it could be ignited at the lower compression ratios.
When the engine was under load, the hot spot was designed to retain enough heat so that combustion could be maintained. The hotter it was, the better it ran... and vice versa. Typically, a kerosene torch was use to heat the hot spot and how long you had to do that depended upon the ambient temp, the condition of the engine and the lightness of the fuel (heavy oil took more heat).
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INSIDE ADAM FOLTZ' 5.90 INDEX SECOND-GEN AFTERMATH
At only 4,100 pounds, Adam Foltz knows he doesn’t need crazy horsepower to be competitive in the 5.90 Index class, which is probably why he has fueling on the P-pump pulled all the way back and has focused more on dialing in the chassis lately. “With a small nitrous tweak we went from 6.50 to 5.80,” he told us. “But once we know it’s going to go straight every time, we’ll be shooting for low 1.2’s on the 60-foot (on the trans brake).”
A 1947 US MOTORS DIESEL GENERATOR ON A HISTORIC SHIP
WEEKEND ON THE EDGE 2020
2020 was the year of cancelled events. Nothing was what it was supposed to be with the ‘Rona running rampant everywhere.
COOL DOWN AND STOP IT
“THE MOUNTAIN DECIDES
The ninety-eighth running of The Broadmoor Pikes Peak International Hill Climb (PPIHC), also known as “The Race to the Clouds,” is an invitational automobile hill climb to the summit of Pikes Peak – America’s Mountain in Manitou, Colorado.
COMPLETE OIL CHANGES
REMOVING THE LAST TRAPPED QUART FROM THE DURAMAX, WITH PPE’S UPGRADED OIL PAN
FORD UNDERRATING THEIR 2020 SUPER DUTY?
MAKING A STATEMENT...
DERRICK BARNEY’S 1,400HP, 68RFE-SHIFTED ’11 MEGA CAB
TIM TUTTLE’S 1,500 HP CUMMINS RAM LIMITED PRO STOCK PULLER
BARN FIND GOLD!
1949 CLETRAC ADH