Record 185 Tons Of Redwood Logs Hauled In 1952 By Peterbilt With 300HP Supercharged Cummins Diesel – Worth A Half Million Dollars Today, The Wood, That Is

CC’s dman forwarded me this clipping from 1952. It shows a record load of old-growth redwood logs yielding 53,670 board feet of lumber being hauled to a mill in Fort Bragg, CA via a 26 mile private road. Pulling the (over)load is a Peterbilt Model 390 semi truck with a 300hp Cummins NHRS supercharged diesel engine, the most powerful truck diesel engine of its time. This was the only diesel capable of challenging the mighty Hall-Scott 400 gas engine, which was rated at 310hp and was also used widely in this type of extreme log hauling operations.

And just how much would that load be worth today? A cool half million dollars or more, based on a current price of some $10-12 per board foot for reclaimed or recycled old growth redwood.

Some details about this load. Those logs are some 40′ long and between 7 and 9 feet in diameter. Their weight is estimated at 375,690 lbs, or over 185 tons.  The combined truck and load tipped the scales at the mill at 421,610 lbs” (211 tons).  The load was 21′ tall and 19′ wide.

And how were these massive logs loaded on the truck? Someone left a comment elsewhere that explains it: “They dug a pit and drove the truck in the pit and rolled the logs on the bunks, the peaker or top log was rolled and assisted in the saddle with a heal boom loader. Lubberke Logging of Ukiah, CA was the logger involved.” 

Those 53,670 board-feet of lumber rather overshadows this load of 32,798 board feet that was being hauled here by a Hall-Scott Peterbilt at about the same time. These logs look to be old-growth Douglas fir as compared to the coastal redwoods.

As to the Cummins NHRS supercharged diesel, it had been well known for a long time that diesel engines respond well to forced induction. Turbochargers had been installed on large stationary and marine diesels going back to the 1920s, but the constantly varying speed demands of a road-going diesel truck were not yet suitable to the use of diesels, so Roots-type positive displacement superchargers were used. In 1954, both MAN and Volvo introduced the first production road-going turbocharged diesel trucks.

In the case of Cummins, they built their first supercharged diesel in 1937. And in 1950, when the new four-valve family of diesels appeared, Cummins took one (with a light weight magnesium block and aluminum head) with a supercharger to Indianapolis. The truck version was the NHRS (above); its ribbed supercharger case is clearly visible on the bottom right. There were several output variants; according to the article, the one hauling those redwoods had a 300hp version. That’s essentially the same output as the Hall-Scott 400 series six cylinder gas engines.

The supercharger was developed and built by Switzer-Cummins, but not the same Clessie Cummins who headed Cummins Engines; apparently it wasn’t even a relative.

Here’s another Pete 390 with a quite similar 275hp version of this supercharged Cummins. The exhaust sound of these is very distinctive (and loud!) because there’s no turbo to soften the exhaust pulses. The split exhaust headers only add to the music. This one is being revved up against a hydraulic retarder to put some load on it, but it’s probably still well below its maximum power and sound.

The Hall-Scott had a displacement advantage over the Cummins; 1091 cubic inches to 744. But the forced induction on the Cummins made up the difference. Non-supercharged Cummins diesels back then typically had 180-220hp.

The record-breaking truck at top was equipped with Brown-Lipe main and auxiliary transmissions, heavy duty Timken rear ends with “10-16 gear ratio”, 18 tires in size 1400 x 24,  Ross steering with Vickers power booster on a Schuler front axle, 20 x 8 Bendix-Westinghouse air brakes on the truck and trailer, with water cooling on the trailer brakes, and there was a “Hydro-tarder” hydraulic retarder for use on down grades, which also works to keep speed down on long down grades.

This truck was engineered to haul loads of at least 100 tons, up to 24,000 board feet at a maximum speed of 30 mph. So it appears it was just a wee bit overloaded with this Paul Bunyan load.


Related CC reading:
Vintage Truck: Peterbilt 354DT Hauling Load Of Giant Logs Powered by OHC Hemi-Head Hall-Scott Gas Engine – More Power Than A Wimpy Diesel

Vintage Truck: 1951 Kenworth With 600 HP 2181 Cubic Inch Hall-Scott V12 – The World’s Most Powerful Factory Road Truck Of Its Time

Automotive History: Hall-Scott – Legendary Builder Of High-Power Gas Engines For Trucks, Buses, Cars, Boats, Airplanes And More

Big Cummins Diesels Come To The Indianapolis 500