June is a the two year anniversary of this blog, and with that I am kicking off a series dedicated to the Cleveland 498 engine. The 498 engine has been shrouded in mystery over the years, and was one of the main driving forces of creating this page. I wanted to do a writeup on the engine, but had no place to put it! Just to put this right on top – if anybody has any stories, recollections, information, photos or documentation on these engines, PLEASE send me a message! I am trying to document these engines as best as I possibly can.

In the days after WWII, medium speed, 2-stroke diesel engines essentially hit a horsepower wall, around 1600HP or so.   A common way or obtaining a higher horsepower rating, was simply to add more engines!  Unfortunately, adding more engines, means more space is being taken up.  So, the solution is to try and get more horsepower out of what you already have. 

Enter turbocharging.  

Now, turbocharging was not a new concept by any means. Many diesel engines benefited by use of turbocharging, but these were almost all 4-stroke engines.  Cleveland Diesel had a single turbocharged 4-stroke engine design during WWII, the 258S (originally a Winton engine) which was a 2000HP direct reversing engine built for subchasers.  Even several WWII aircraft, including the B17 Bomber were turbocharged. Turbocharging a 2-stroke engine was an entirely new concept.  As it is, a 2-stroke requires some form of positive displacement blower for scavenging.  The issue with adding a lone exhaust-driven turbocharger, is in periods of startup, lower idle and acceleration, the engine gets starved for air, as it is not providing enough exhaust to spin the compressor.  Kind of a catch 22 situation.  More on this later. 

The basic operation of a turbocharger from a Garrett-AiResearch manual.

Throughout WWII, General Motors Diesel (Cleveland Diesel, Detroit Diesel & Electro-Motive) was the leading Diesel engine supplier to the war effort.  Cleveland Diesel would supply over 13,600 engines (from 7-1939 thru Dec 31, 1945), be sure to read our history about Cleveland Diesel here: Cleveland Diesel Engine Division – GM’s war hero turned ugly stepsister

Cleveland Diesel WWII Production:
16-278A: 1,930
12-278A: 771
8-278A: 243
6-278A: 554
Total 278A Production – 3,498 engines
16-278: 20
12-278: 352
8-278: 55
6-278: 72
Total 278 Production – 499 Engines
268/268A (all models) – 9,136 Engines
248 (all models) – 268 Engines
Miscellaneous – 239 Engines
Total – 13,640 Engines

The Cleveland 16-278A engine was one of the most widely used engines during the war and peaked at about 1800HP, which was about on par with the EMD 16-567C, which was introduced in 1953.  Alco was already there with their 12-251B, also making 1800HP, however this was a 4-stroke, with a turbocharger already.  Fairbanks-Morse cracked the magic 2000HP barrier in a medium speed engine with the 10-cylinder 38D OP engine by 1950, using only a Roots style blower.  

With General Motors (and Cleveland Diesel) still working closely with the Navy, an experimental test was devised by the Navy’s Engineering Experiment Laboratory in Annapolis, Maryland in 1947 to start testing turbochargers.  A proof of concept test was launched, using a Detroit Diesel 1-71 (yes, GM turbocharging has its roots in the diminutive, little 1-71 engine!).   With the proof of concept done, more testing was devised in the early 1950’s at the Engineering Lab using a bone stock 16-278A engine.   A test was devised in which a mock “turbocharger” (another Roots blower) was installed on the test floor, operated by an electric motor, to feed the engine in a simulated and controllable environment.  A goal was set to maintain a cylinder firing pressure in the area of 1300 PSI (compared to the stock 850-1050 PSI) and make 3,000HP. Numerous tests were conducted with various configurations of inner and after coolers, blower sizes, injectors, controlling exhaust timing and use of snorkels for Submarine use. A similar test was conducted using an 8-268A engine as well.   Unfortunately, I have yet to come across any photos of these tests. 

The winner – Using the stock configured 16-278A engine, with turbocharger feeding the Roots blower with an aftercooler made an impressive 2,990HP at its rated 750RPM.  With controlling the exhaust timing, the engine made 3,130HP.  Amazing numbers for a stock engine! Not to mention, a true testament to the engineering of this engine, and its ability to take such punishment.

Performance ratings for the test engine, from Turbo-charged engines for the Navy, by L. Wechsler and T.W. Shipp, Internal Combustion Engines Branch, Bureau of Ships

After the tests, three turbocharger manufacturers would begin working with the Navy to spec out an appropriate design, and how to supply the air to it, be it via individual ducts from each cylinder (common on 4-strokes), divided manifolds or a single manifold using a venturi system.   The results of the testing were concluded in a presentation at the SAE National Diesel Engine Meeting on October 27^th, 1954.  The report, High Supercharging, Development of a GM 16-278A 2-Stroke-Cycle Diesel Engine, was presented by Warren G. Payne and Wolfgang S. Lang of the US Naval Engineering Experiment Station. 

Unfortunately, not all the testing was complete at the time of this paper, so it is unknown just how well the testing progressed when the turbochargers were installed on the engine.  What is known, is that testing further proceeded at the Engineering lab on the 16-278A, The Lanova Corporation handled the 6-71 testing in New York, and De Laval Steam Turbine further tested the 8-268A at their own lab. 

The test 8-268A test engine at the De Laval test lab, used a model B-8 turbocharger. From a 1955 De Laval advertisement.

After the presentation, a discussion panel ensued, which is also part of the transcript of the report, in which comments were heard from other engine builders and engineers.  One such stands out:  Rudolph Birman of the De Laval Steam Turbine Co., who essentially picked apart the findings. Mr. Birman states several things, such as:

“Water cooling of the exhaust manifold cannot be tolerated in a turbocharged 2-stroke engine.”

 “All starting, idling and high exhaust back pressure problems are eliminated, however, if the positive displacement blower is retained and the turbocharger arranged to operate in series therewith.”

“There is a similar disagreement between the findings of the authors and those of De Laval with regard to the location of the intercooler in a turbocharger-positive-displacement-blower in series arrangement.”

I do not know if De Laval were working behind the scenes with GM/Cleveland Diesel already (given the time frame, they must have been), however, Mr. Birman’s commentary would essentially be the entire basis for what would become the 498 engines in just a few short years. 

The concept drawing of the Cleveland 498 first appeared in the August 1955 issue of Diesel Times, along with some basic specifications and features.

Another set of comments worth noting, was from A.K. Antonsen and E.L. Dahlund of Fairbanks, Morse & Co. FM was working in-house on their own turbocharger design, starting in 1945 on a basic 10-cylinder 38D 8 1/8^th OP engine used in submarines, as well as a smaller 3-cylinder 5¼” OP engine.  Full production of a turbocharged OP engine was not offered commercially until sometime in the late 1950’s (Anybody have a specific year?). The Turbo OP would be a very popular stationary power engine, and would peak at over 4,400HP for the 12-cylinder engine.

FM’s Turbocharged OP engine is still produced today, producing astronomical amounts of horsepower mainly for standby power generation. Note that like the Clevelands, it retains the Roots blower. FM Brochure

As mentioned above, one of the shortcomings of the turbocharger on a 2-stroke is the lack of enough scavenging air.  The issue was addressed by simply retaining the Roots blower, but it was found a smaller one would work (we will get to this more in Part II).   With the testing on the 268A engine, in place of the blower a small hydraulic motor was tested mounted to the turbocharger.  In periods of low RPM, the hydraulic motor would turn the compressor, essentially making artificial air pressure with the turbo.   The pump for the hydraulic motor was driven by the engine.  

An early Detroit Diesel 6-71T engine used for an industrial application.

With Cleveland Diesel now working on a whole new turbocharged engine – GM sister division Electro-Motive was doing the same.  EMD started their own program in January of 1955 to turbocharge their current 567C engine, unlike Cleveland, they did not start by redesigning the entire engine from the ground up. Like the Navy tests, EMD used an electrically-driven Roots blower in a mock test using a 12-567C engine for development purposes, but EMD would design their own turbocharger for the 567C engine.  Instead of using the combination Roots blower and turbo in series, EMD designed their own all new turbocharger, which would be mechanically-driven from the camshaft through a geartrain during starting, low speed, low power and accelerations, providing scavenging air. The turbocharger is connected to the geartrain through an overrunning clutch.  At certain power levels (approximately Throttle Position 6 on a locomotive), there is enough energy in the exhaust so that the turbo runs faster than the geartrain, the overrunning clutch disengages, providing “free” turbo-supercharging.  This would go on to become a very successful design and used throughout the 710 line (with several refinements of course).   EMD’s first production turbocharged locomotive, the 2400HP SD24, was introduced in 1958. We may do an article specific to EMD turbocharger history down the road, but for now we will stick to the CDED 498. 

The prototype turbocharged EMD 16-567C engine from “Performance of a Turbocharged 567C engine” by A.N. Addie/EMD. Production turbochargers would be used only on 16 cylinder engines, and were given the “D” model. Turbochargers would not be used on 12-cylinder engines until the 645 line.

Union Pacific Railroad was doing their own separate development with adding turbochargers to the 567C used in GP9 locomotives starting in 1955.  Working with Garrett-AiResearch – (later makers of the turbocharger used on the 6-71), a manifold was devised, and four small turbochargers were added feeding into the stock Roots blowers through an intercooler.  UP would also test engines with turbochargers made by Elliot, but using only two slightly larger ones then the Garrett installation.  These tests were successful, and several engines were converted.  UP would send GP9’s to EMD in 1959, which were upgraded with new EMD turbochargers for further testing. Ultimately these test engines were converted to EMD turbochargers, or had them removed.  I urge everyone to read Don Strack’s Utah Rails page on the Omaha GP20’s for much further information on this test program. Please be sure to visit the links below.

Omaha GP20’s, Union Pacific’s GP9 turbocharging program
Omaha GP20’s Diesel Era V7 #6, 11/12 1996

The quad Garrett turbochargers installed on the 567C. Note the complex plumbing for the exhaust and charge air going to the blowers. Union Pacific Photo, Don Strack Collection.

The Elliot installation was a little more simplistic, with a single exhaust manifold feeding a pair of slightly larger turbochargers, with each one feeding one of the blowers. Union Pacific Photo, Don Strack Collection.

The Cleveland 498 made its public debut at the General Motors Powerama Festival.  Powerama was held August 31^st-September 25^th of 1955 in Chicago, Illinois.  The event, “A Worlds Fair of Power”, would be a giant showcase of products from General Motors, including Cleveland Diesel, Electro-Motive, Detroit Diesel, Euclid, Allison, GMC Truck & Coach, Fabricast and Frigidaire.  On display were numerous engines, pieces of heavy equipment, locomotives, and even the Great Lakes Towing tugboat Laurence C. Turner, and the Fleet Submarine Tautug SS-199.

The first Cleveland 498 displayed at Powerama. I have my doubts that this was a full production engine, as it just does not look “right”, especially the exhaust jumpers and manifold. I think this was more of a mock up model for display. Note the differences just in the cutaway model on the left. The first production engine used commercially was still several months out. Unknown photographer, VDD collection.

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Stay tuned for Part II, where we will discuss the 498’s design features and specifications.

This will be a four part series, the links of which will appear for each post as they are added.
Part II – Engine design features & specs
Part III – Uses and installations
Part IV – The last one, Tug Idaho

Note: A complete set of bibliography and notes will appear in Part 4