Dman sent me another vintage shot of an early Peterbilt, and this one is a monster, in more ways than one. It’s an extra-heavy duty model 354DT, part of a fleet bought in 1948 by Feather River Pine Mills, located in Northern California. They were obviously harvesting giant old-growth pine trees, and needed powerful trucks to haul them out of the remote logging sites to the mills.
And they chose to have them be powered by Hall-Scott gas engines, the legendary OHC hemi-head torque monsters that generated significantly more torque and horsepower than the naturally-aspirated diesel engines of the day.
The 400 series was the post-war successor to the Invader and other legendary truck, bus, marine, airplane and rail-car engines built by the pioneering high-power firm of Hall-Scott, located in Berkeley, CA. The big inline six had a 5.75″ bore and a massive 7″ stroke, for a displacement of 1091 cubic inches (17.9 L). Hall-Scott engines produced their massive power thanks to a hemi head with an overhead cam, allowing excellent breathing. This was at a time when most truck (and car) gas engines were flatheads.
Here’s a dynamometer chart of a H-S 400. Peak output was 950 lb.ft. @1300 rpm, and 295 hp @2000 rpm. The big Cummins diesels back then made between 160 and 200 hp. It wasn’t until diesels were turbocharged that they could equal the power outputs of a H-S gas engine.
Update: the first chart is for a gas engine version using 73 octane gas. Here’s the one in for the butane fueled version (as used in these log-haulers) that makes 965 lb.ft of torque and 310 hp, thanks to a higher 7.1:1 compression ratio to take advantage of the higher octane of butane (LPG).
In the post-war era, there was a rapidly growing demand for larger trucks, higher speeds and more power. The greater efficiency of the diesel was very compelling, and diesels quickly gained market share.
But there were holdouts. Some operators, typically in the West, where mountains slowed down diesel trucks significantly, were willing to accept higher fuel costs for the higher average speeds that Hall-Scott engines delivered.
There were even a few operators that installed Hall-Scott’s giant V12 engines, capable of making 500-900 hp.
One reason some operators in the West kept running H-S engines into the ’70s was that they could be specified to run on butane, which was a byproduct of oil refining, and often available quite cheap back then within the proximity of a refinery.
And that’s what the Feather River Mills Peterbilts were burning (I found some additional info and images on this fleet of trucks at a post on them at hemmings.com). Because of all the power they made, and being intrinsically less efficient than a diesel, one downside of H-S engines was their ferocious output of heat, making the cabin floor a burn danger.
But the bellowing, thundering sound of the Hall-Scott at full chat was described as “awesome” by one of the drivers, even if he did have to stop and soak his leather boots in the river to keep from burning his feet as he pushed his trucks wide open up the steep grades. It gives new meaning to the expression “hot-footing”.
I have been promising a full write-up on Hall-Scott, which has a fascinating history going back to the very early days of the automobile. And I will do so this winter.
Check out CC’s huge collection of articles in our Big Trucks and Vans Archive
Related reading: CC Tech: Why Gas Engines Intrinsically Make More Power Than Diesel Engines
What logs, what a truck.
Sweet Pete, and sweet engine. I love them. The date on that dyno sheet was my mothers 19th birthday. This made my morning. Thanks
I know nothing of these—or truck powerplants in general–but the overused word “awesome” comes to mind–wow.
Same with the pictures of the big, *tall* loads.
R&DMan, you got me looking closer at the dyno sheet date. My parents = almost the exact same vintage, just days’ difference . Thanks!
Wow, that load is scary. Very top heavy. Hate to think about how many roll overs occurred.
When I lived IN NE Maine I saw two logging trucks rolled over in 2 years. Scary sight indeed. I don’t know the details but they guys I know who did logging up there said the trucks were often spec’d with as big an engine as possible, for the hills but also because on some of the private roads in central Maine (like the 100 mile long golden road) there are no weight limits so they often hooked two full size trailers in tandem to save time and money.
Back then I often drove the locally infamous airline route (now much more level and straight) and trucks were rarely slowed down by the hills (they were often Macks and Western Stars with some Pete and Kenworths)
These were run only on private roads, and the roads were built without a crown, to reduce the chance of that happening. And they ran at low speeds.
East coast logging rigs
And one more this one claims it was the heaviest logging truck in the US at the time.
Mack F series COE brutally tough trucks very heavy duty
Mr. Niedermeyer, off subject, my wife’s maiden name is also niedermeyer from wyoming, relation?
Hi Lonny. Hope you’re doing ok. Dogs and us miss you.
If wrong Paul, take care.
Terry
I cannot imagine how scary it would be to be in that pickup in the first picture…next to that load tied down with those 3 chains. They look like threads next to those logs.
Not chains, but 5/8″ steel cable.
Tension and drama communicated in just one frame. That’s efficiency.
Big loads and no bolsters on those loggers its all chained, but the figures on the dyno sheet are impressive to say the least not by todays standards but back in the day that is massive torque and horse power. The fuel consumption must have been phenominal.
Thanks Paul for expanding on my snapshot. As a Berkeley native who lived there from infancy until after college, and despite being a gearhead from an early age, I wasn’t aware of Hall-Scott until years later. I guess unless you’re from Detroit or the Midlands in England, industrial history is neglected by local educators.
One of these pictures shows the board feet of a load, over 30,000. I saw another picture of a Pete logging rig that was carrying well over 40k board feet. The gross scale weight was supposedly over 400,000 pounds. Pine logs weigh about 4-5 tons per 1000 board feet so with the weight of the truck and trailer that’s not impossible. The caption for that photo said that the load was hauled entirely on private logging roads from forest to mill.
Anyone living in Southern California from the 50’s to the late 70’s would be no stranger to the sound of a Hall-Scott. Hall-Scott engines were widely used in fire apparatus, most notably that manufactured by Crown Coach of Los Angeles. Both Los Angeles City and County had vast numbers of Crown apparatus, as did most of the smaller cities in the area. In addition to Crown, a lot of Seagrave apparatus in Southern California was also Hall-Scott powered. The Hall-Scott did indeed have a unique (and loud) sound, and there was nothing like experiencing a Crown Firecoach basting by you running Code 3 at speed.
Torque and horsepower mathematically have to cross at 5252 rpm. H = T x rpm/5252
So the dyno graph puzzles me that they cross at 1400 rpm. Not trying to come off as a wise guy. Honestly curious if something changed in measurement standards since then.
Thanks!
PS Great photos. Please do follow up with another article on these engines.
The scale for horsepower is on the left side of the graph, and the scale for torque is on the right side. Different units and ranges.
Thanks! I missed that.
They had monster torque!
EJ Hall and Jessie Vincent co-designed the Liberty engine. After the war, Packard tried to claim the Liberty as entirely Vincent’s work. But, if you look at the Liberty, it looks pretty much like two pre-war Hall Scott 6s on a common crankcase. Hall commented that he had personally built more aircraft engines than Jessie Vincent had even seen. Before the war, Hall-Scott was the second largest aircraft engine maker in the US, trailing only Curtis. The aircraft engine technology carried directly over to their marine and truck engines.
H-S never developed a successful diesel, so their market dried up in the 50s. They were eventually bought out by Hercules Engine in Canton Ohio.
As near as I can tell, the building with the sawtooth roof is what remains of the Hall-Scott factory on Heinz Ave in Berkley. iirc, the office building was around the corner, on Seventh, but it was torn down long ago.
If any of you folks get bored over the winter, this is an interesting read.
Great post. Have always been a fan of HS. Only direct experience I have with their engines is on large Crown touring buses. The exhaust exited out the side and when revved, the ground nearby vibrated…
Looking forward to the upcoming post!
That monster on the dyno did it with one carb. I do know that LA County Fire repowered some of their earlier equipment with Hall – Scott 855 cubic inch monsters with 2 giant Zenith updraft carbs. We had a ’29 LaFrance triple combination pumper set up like that. County also had a pair of shorty special Crown Coaches made and they had pancake style 500 inchers hanging midships. Hall -Scott turboed that thousand incher motor later in life, my dad was with LA County fire and got to drive a truck like that. He said that it was impressive. About the only more powerful fire apparatus was the Napier Deltic powered pumper in NYC.
That is one scary looking load. Doubt OH&S would condone such now, even if they are on private roads.
Old 17 was gaseous fueled.
Dual sparkplugs visible in the 400 cutaway.
I’ve seen dual sparkplug engines, but always in fire apparatus and each plug was served by its own ignition system, completely independent of the other. Redundant systems for more assured reliability.
However, with the 400 cutaway redundancy doesn’t appear to be the purpose of dual plugs. HS was probably early to recognize the value of dual “flame fronts” in a combustion chamber?
I pointed out that this whole fleet was butane fueled.
The typical spark plug position in a hemi is in the very center. That really wasn’t going to work with the cam and valve train right there. And one one the far side alone wasn’t going to do the trick, presumably. hence two.
And with such a long stroke, the combustion chamber could be big enough for two positioned like that. In a small, high compression car engine, that wouldn’t really work.
Maybe I wasn’t so clear on my pondering?
Namely, was dual ignition initially about reliability gained with two seperate redundant ignition systems? Or was it about performance gains of coordinated dual ignition? Seems it could have been both.
In firetrucks, for example, dual ignition is about reliability. I’ve played with dual ignition, switching from battery to magneto ignition on the fly. In my limited seat-of-pants evaluation, battery ignition performance was much better, however, mag ignition still kept the truck rolling. There would be no performance gains to be had by using both ignitions simultaneously.
My belief is that the initial justification for designing with dual sparkplugs was to achieve the redundancy of two completely separate ignition systems. Notice the dyno sheet mentions that the test engine was equipped with distributor but not a mag? That seems to confirm that some engines had both.
Now, with war production over, and log trucks not on critical fire duty, was it then decided to exploit the “extra” sparkplug for performance gains?
I understand what you’re saying. My point is that I’m pretty sure that in a hemi head like this, a single plug on one side would probably not suffice for adequate ignition of the mixture quickly enough. So in this case, it was probably essential to have two plugs regardless of whether there were two redundant ignition systems or not.
But I say “probably”. I’ll look in my H-S book and see if I can confirm that.
And yes, there were a number of two-plug non-hemi head engines too. And not all because of using redundant ignition systems. I think assuring quick ignition of the mixture in these large and low-compression combustion chambers was not always so easy.
For another monster engine, check out
Skip to minute 44 for the actual startup. This is a Roiline (Le Roi) 884 cubic inch V-8 from an Onan genset running on natural gas.
This has left me feeling very small.
I love the torque output there. It barely changes until after about 1,500 rom, almost as flat as an electric.
I wonder what the pricey-looking OHC was all about? It’s giant engine with big breathing needs, sure, but ultimate revs are surely going to be limited by that two-story-high stroke and reciprocating weight (and practical application in use, come to that). So what advantage would there be over simple pushrods for only 2,00rpm?
A second question, does anyone know what the fuel graphic means? In car terms, it’s impossible to imagine this motor getting more than 1 mpg in use.
Fuel chart is reference to the amount of fuel ( by weight, which can be converted to gallons, or whatever) that would be consumed under different load conditions.
Presume for example that the equipment uses 10 brake horsepower to maintain an idle, that consumes X pounds of fuel in an hour. When pumping water at 100 horsepower, that consumes XX pounds of fuel per hour.
To further clarify, that is lb per hour, per HP, at a given rpm.
I wonder what the pricey-looking OHC was all about?
Overhead cams aren’t only about high revs.From the earliest days of the IC, there have been OHC heads, and typically they were of course quite slow-revving.
The better question is: if you were designing a big engine for optimum reliability and durability, why wouldn’t you use an overhead cam? It’s a much more elegant solution. Why have a slew of unnecessary sticks flogging around?
The Hall-Scott engines all have their origins in extremely advanced airplane (and high performance car) engines, from the ’00s. Hall was a brilliant designer, and left a lasting legacy of high-output engines of all kinds of sizes and applications. And a hemi head with OHC was an intrinsic part of his design brief.
The famous WW1 Liberty V12 airplane engine is part of his legacy.
These H-S engines were built to a standard, not a price. H-S was famous for having the highest standards and the best precision and the most advanced tools, including a number of them made by themselves. These engines were known to run up to a million miles before needing a major overhaul.
There’s two things that ultimately killed them: they never built a proper competitive diesel, and the mass truck manufacturers came out with much cheaper high-power gas engines, designed for lower manufacturing costs, and essentially scaled up passenger car engines.
It’s been fully proved a long time ago that a properly designed pushrod engine can rev very high indeed. But if you’re designing to the highest engineering standards, an OHC is of course the way to go. Even in giant ship and truck engines.
Murphy engines too. I’m not sure what their backstory is, but what a level of precision and refinement (OHC and show car display class aluminum work) for some lump waiting on standby in the dark basement for years, prepared for and anticipating “his day” that never comes. LoL
HS 1091C.I. got about 4mpg respectively on butane. My 2018 Cummins x15 (915c.i. dohc 24v turbo diesel) gets only 5 i haul 103k poind loads. So its not as bad as everyone thinks. Big tech for the times for sure nearing 300hp and almost 1000ft.lbs of tq. Is amazing for the time and can e further refines from there. At the time there was performance manifolds available for both intake and exhaust, some adding 1 or 2 more carbs making it easy to up performance. Even by todays standards it still gets good mileage for what it is.
Did they ever drop a log I wonder?
Murphy engines too. I’m not sure what their backstory is, but what a level of precision and refinement (OHC and show car display class aluminum work) for some lump waiting on standby in the dark basement for years, prepared for and anticipating “his day” that never comes. LoL
Classic, conventional Peterbilts. I can’t see enough of them, regardless size and engine.
I still see alot of Pete’s working hard at 30+ years old. It has become a bit of a thing for some local operators (most hauling bulk things like sand gravel rock etc) buy old ones and have them completely rebuilt.
I wish had some pictures there is one company here that has several lowered ones that haul rock/gravel bulk trailers, really fancy paint jobs for that kind of work, they have 2-3 of them I see from time to time on I84 in CT.
Had a tank retriever in South Korea late sixties Daily News 10 wheel drive rear tandem for chain driven Pacific Railways built the truck had a whole Scott 6 cylinder dual ignition distributor each side do not know if it was overhead cam or not but it was a monster and it was very very powerful who’s actually obsolete at the time I was over there but we were still using it cold about a 65 foot trailer
Was a toll collector on the Golden Gate Bridge 1959. Can recall Hall Scott power going thru the Toll Plaza carrying lumber. The engine was on its side behind the front axle ahead of the drive group. Flames coming out of the exhaust stack. Must have been 4-6 feet.