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426 Hemi V8 Development Stories

Willem Weertman and the 426 Street Hemi engineWillem Weertman (engine design leader) wrote about the 426 Hemi:

We had been using the wedge-head big block V-8 engine and we weren’t doing very well with it [in racing], we were being outgunned by the very experienced and well-equipped Ford and Chevrolet teams.

Our senior management thought it would be nice for us to win races.  They asked the question “What would it take for use to win a race?”

After a lot of consideration, the engineering response was that we should go back and try to see if we can run our Hemi engine again because we did so well with the first generation Hemis that had come out in 1951 and had been raced in NASCAR and had a tremendous amount of victories. 

The inquiry came to us in engine design, “could we put a Hemi head on top of a raised B (RB) engine?”  That’s when the story started and ended up with our indeed being able to do that and we had engines ready for the 1964 NASCAR race in Daytona Beach and we did extremely well and continued doing well during that season.

When the order came we assigned our best designer to it, with Bob Rareya and me looking over his shoulder.  By making changes to the block we were able to do that job with a brand new set of cylinder heads having machined Hemi chambers that just happened to have the same included valve angle as the 1951 Chrysler Hemi and it worked.  It was quite a program for us; it was a very rushed program and we were extremely happy when it was successful on race day and we blew the competitors off the track. [For more, see our interview with Willem Weertman]

Candymatic

Pete Hagenbuch (engine development engineer) wrote:

I was running valve dynamics (pump-up speed) on one of the 300 letter series engines with the long cross ram intake manifolds. This entailed me being in the performance cell close to the engine but not in line with the prop shaft. The dyno operator was at his console which sort of protected him from flying parts; but not me! As I remember we were going up from 6000 to 6400 rpm when suddenly the room filled with dense white smoke! My operator hit the big red button on his way out with me stepping on his heels.

426 Hemi engine dyno test

When things quieted down a bit we went back in and found a leak had developed between exhaust manifol and cylinder head surface. The exhaust gas was blowing right onto the cork cylinder head cover gasket. When it burned through we had hot gases inside the head cover! Scary!

This one was before my time but it was certainly possible. [I heard that] When the original "Double Rocker" was expanded to 392 cid, a weakness was discovered in the main bearing bulkheads, which would crack leaving the crankshaft to fail eventually. And, at least on lab endurance engines, this lead to unbelievable mayhem. The block would sort of disintegrate spewing out all sorts of parts from pistons and rods to valves and pushrods. Not to mention pieces of the crankshaft. All in all quite spectacular.

You know that basic engine continued to be a favorite with the dragster guys but perhaps you're aware that they all used a "steel girdle" between block and oil pan to hold things together.

street Hemi

Another favorite story I can't prove: John, a good friend of mine who was in the Bearing Group at the time was in an endurance cell listening for some sort of noise in the engine. Our endurance lab at that time (1960s) consisted of six cells, each with two engine running 24/7 (a term that didn't even exist then). Anyway, John's boss was right behind him, between engines, when the exhaust system on one of them just plain broke and fell off. The engine was running 4000 at wide open throttle at the time. Legend has it that John was first out of the room and that his boss had a footprint on his chest due to John's hasty exit. [For more, see our interview with Pete Hagenbuch]

No story of the Hemi would be complete without Tom Hoover, often called the “father of the Hemi.” Born around 90 minutes west of Harrisburg, Pennsylvania, Mr. Hoover’s first car was a 1952 DeSoto with a Hemi. He joined Chrysler in 1955 and started work on the Bendix fuel injection system (Electrojector), an early version of today’s electronic fuel injection systems, and was later part of the development of the successful Slant Six Hyper-Pak project. He said:

Tom Hoover and other Ramchargers speaking at Carlisle 2009 (about 40 minutes)

When we got the green light to go ahead and adapt the Hemi head to the big B engine, we realized that one day it would be something revered, that it would be something that everyone would look back on as something very special indeed. ...

In 1964, the proudest moment to me was the first time the car went 130.06 at the Nationals to set the record. So ’64 was a good year, then things started to get funny. ... Then the wheelbase change, we went through fuel injection and to nitromethane fuel.

Tom Hoover

Part of the Hemi’s success was a strong shakedown. Mike Buckel remembered, “In what proved to a great piece of foresight, Tom Hoover rented the Fontana Drag Strip for shake-down testing of the Hemi cars. All four A/FX cars were there along with the Super Stock cars from the same teams. Then came the big disappointment: the Hemis were the same or slower than the wedges.” The problems were worked out and the Hemi went on to dominate racing for years.

Marc Rozman, engine tester, added:

The cell next to me, cell 7B, ran the NASCAR Hemi testing... Mike Buckel, was one of the actual engineers in the dyno area. We got talking one day and he said, yeah, that was his favorite test cell, 7B, running the engine with NASCAR simulation on the Hemi in that cell. They actually had it set up where they’d actually run the RPM on that cycle, with the little punch cards and what have you, and a tape, and you record the NASCAR tracks, and the actual RPM and load and what-have-you. They load a program, like a tape, as you run the engine, and that was pretty high tech for back then.

... Cell 13 was in the middle of that building, and that’s where he ran a lot of the Hemi stuff, because it was a 10,000 RPM dyno. Cells 12, 13, 6A, and 7B were all higher RPM dynos; it cost a little more. Because they were higher RPM dynos, they were used for the Hemi. Back in the early 1960s, Bill Weertman and Al Adams came up with the idea of testing engines by matching the demands made on the engine during an actual race.

test cell

Ed Poplawski wrote:

ed poplawski and marc rozmanMost of the performance engineers were real motorheads so they were easy to work with and were really interested in their jobs. One of the fun guys to work with was Al Nichols. He was the camshaft guru and he had a language all his own that you had to learn so you could communicate with him. He was into everything from carbs to cams and those newfangled things called computers.

[The Ball-Stud Hemi] was pretty straightforward program. As far as I remember they only built the 444 cid motor with a Thermoquad. I think they built about a dozen engines but I'm not really sure. Had a few issues with pulling out the studs for the rockers but that was fixed pretty quick. I remember there was at least one car with the engine in it, a 1970 Plymouth GTX. The engine made a little over 400 horsepower with the Thermoquad. There were no plans for a dual quad engine as they were going to try to make it pass emissions.

Neil Newman, as interviewed by John Gunnell in Auto Trader (reprinted with permission), remembered one of the major tire companies using a Chrysler-engineed racing car running alcohol fuel to test tires. “Firestone was also building an Indy Car with some form of Hemi engine. An Offy engine would only last 500 miles before it needed to be rebuilt, but the Hemi would last for many more test cycles.” (See the A311 Hemi created for the Indy 500.)

Roger Meiners wrote:

That would be the Firestone Indy car, the Kurtis 500 (500C?) that ran a 331 cubic inch Chrysler FirePower hemispherical engine running fuel injection (Hilborn). The car was put together and maintained by Ray Nichels and driven by Sam Hanks and Pat O’Connor. When the Chrysler Indy project died, Firestone kept going with a later installation for tire testing only. That car also ran laps at Monza before the Race of Two Worlds just to test tires (but set a lap record at 170 mph, with OConnor driving). Hanks set a world closed-course record at Chelsea at 182.55 mph in June 1953. Yes, the Hemi could run all day at speeds faster than an Offy could achieve.

426 Hemi Creating the HemiHemi CentralNASCAR HemisRamcharger Mike Buckel’s stories

Willem Weertman • Pete Hagenbuch • Tom Hoover

Modern Hemis 5.7 Hemi • SRT 6.1 and 6.46.4 Truck Hemi • Supercharged “Hellcat”
Classic Hemis 426 HemiOld Hemi History • 392 Crate HemiDevelopmentPlane Hemi

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