Back To The FutureThe Strange Life of Jeep's OHC 230
The trail of 4x4 history is littered with developments and ideas that were ahead of their times. One such creation was the Jeep 230ci OHC six. This engine came from the fertile mind of A.C. Sampietro, a transplanted Italian who came to Willys in 1952 and later became their Chief Engineer. "Sammy" Sampietro had extensive experience in designing high performance engines, having worked with the likes of the famous racer Donald Healey in Europe.
Sammy was a proponent of "power through breathing," and breathing well was one thing that the Willys L and F-head engines did not demonstrate. In the late '50s, he got his chance to design an engine that featured power through breathing. Kaiser/Jeep had embarked on a project to build an all-new Jeep by 1963, and this project needed an engine. The project would yield the legendary Wagoneer and Sampietro's OHC six was its power plant.
SOHC inline six
133 @ 4000 (2-bbl, 7.5 CR)
140 @ 4000 (1-bbl, 8.5 CR)
155 @ 4000 (2-bbl, 8.5 CR)
199 @ 2200 (2-bbl, 7.5 CR)
210 @ 1750 (1-bbl, 8.5 CR)
230 @ 2000 (2-bbl, 8.5 CR)
8.5:1 (7.50:1 optional and military)
2-bbl Holley 2300 (most models)
1-bbl Holley 1920 (military & some civvy)
Though Jeep considered outsourced engines, they settled on a project to design the all new OHC six in-house. Design work on the new Jeep engine began in February of 1960 and the first prototype engines were run exactly one year later. They passed their 100 hour, full load, full-speed testing and went into production in April of 1962, just in time for the new Wagoneer. These engines were also fitted into the old design Jeep Station Wagons and pickups.
Dubbed the "Tornado," the new SOHC (Single Overhead Cam) 230 cubic inch engine shared the basic lower end design of the Kaiser L-head 226ci. The L-head had a good reputation in Jeeps having been installed in them for many years. However, a lot of extra effort went into refining its crankshaft for the 230 application. It was one of the first times Tufft riding (a surface hardening process) was used by a major engine production line to strengthen internal engine components.
The crossflow head had Siamesed intake ports with individual runners for the exhaust and a decent flowing exhaust manifold. The single overhead cam had only six lobes, each operating both the intake and exhaust followers on one cylinder. It breathed through either a one or two barrel carb and both high and low compression versions were produced. The engine's rated output exceeded all the similar displacement sixes in trucks at the time and Willys was widely touted for being way ahead of the technology curve. But the hoopla soon died.
From the beginning the Tornado had problems that eventually tarnished its reputation beyond repair. These were real problems, but diligent research shows that they have been magnified by time. The early engines suffered from oil leaks and oil consumption problems, all of which were cured in engines built after early '63.
The mechanical problems commonly mentioned (cam & bearing failures) were almost always the result of low oil levels from the leaks and oil burning. The fixes came too late. After several updates, the civvy 230 became a reliable engine. However, because of its tarnished reputation and the fact that it was relatively expensive to produce, it lead a short life. Kaiser Jeep dropped it in the early part of '65 for the less expensive outsourced AMC 232ci six. But this wasn't the end of the Tornado.
At the same time it was orphaned by Jeep, it was adopted by IKA (Industrias Kaiser Argentina), a subsidiary of Kaiser in Argentina. It debuted in the '66 IKA Torino, basically a Rambler American. This became an extremely popular sporty car in South America and the engine soon got some useful massaging in the form of individual intake runners, allowing it to produce 155hp and giving it the new name of "Tornado Interceptor." A hi-po version, with three side-draft 45 DCOE two-barrel Webers made 176 hp. The even hotter 380W variation made 220 hp. Speaking of racing, a 4-liter version of the engine was used in the Cooper T-81 Formula 1 car.
In 1973, by then called the "Tornado Jet," the engine got its first major redesign, with the lower end being upgraded to seven main bearings from four and the head recieving more massaging. In this guise, the Tornado made up to 215 hp was used in the Torino until at least 1981.
The Tornado also had a life in the U.S. military, though this was after Jeep dropped it from the civvy market. A 130 hp version was used in the '66-69 M-715 1.25-ton military Gladiator trucks. Legend has it that these engines were built in Argentina but that story cannot be confirmed.
An interesting side note: At the same time Sammy Sampietro was developing the OHC six, he designed an OHC four. With 154 cubic inches, it was simply a Tornado with two less cylinders. Rated at 102hp and 152 lbs-ft., it was perfect for a Jeep CJ. Why this engine never made it into Jeeps we will never know, but a small number were produced.
The Tornado was a giant step forward for Jeep followed by several steps back. It does hold the record of being one of the earliest American built OHC productions engines, just behind the Crosley and the Duesenburg.