Stromberg Shootout, Pt #2

Builders,

Dan and Tracy Sheradin arrived at 9pm Friday, after a long drive from NC. They were here to have some fun, and put a great effort into the Stromberg Shootout. Below are a few pictures of a long Saturday of testing which ran from 7:30am until midnight, with only a few short breaks.

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Tracy does a ‘Vanna White’ style presentation of our test carb line up. We ran them all today. That is a lot of carb, airbox, fuel line and throttle linkage changes on a hot motor in a single day.  We also paused to do compression tests and adjustments on my 3,000cc Corvair to insure we were running controlled tests.

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Above the engine running in front of my house with the first carb. The timing light is giving the RPM. Large round gauge is manifold pressure.

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Above, we ran two different kinds of plugs in the engine and tested fine valve adjustments to precision tune the engine. In the photo we are using a dynamic compression tester to measure trapping pressure in the cylinder, and comparing this with adjusting intake rockers.  It wasn’t the focus of the testing but it fit in with the series of tests.

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Above, this is what is inside a Stromberg. Hangar ‘experts’ claim these are “just a one barrel carb” but in reality they are a very well made, fully adjustable, robust carb. We disassembled three of the carbs to make internal adjustments.

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Above, Dan works on setting the float height, which is one of several mixture adjustments. the higher the fuel level in the bowl, it runs richer, This combined with main jets and air bleeds sets the air fuel mixture. A unique feature of the design is being able to set the float height on the table with the top of the carb off.

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After a full fay of testing, we looked at the results and chose to follow this recommendation from Bob Kachergius, “the Stromberg specialist.” We reset Terry Hand’s carb to this, and it will be the first one we run on Sunday. (Sunday update, I suspect we copied a number wrong, as this didn’t want to run well from 1,000-2,200 rpm. More later)

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Above, Dan got a kick out of looking at my decades old carb books, dating from my days at Embry Riddle. In looking through the book he saw that a scored 100% on the exam on MA-SPA  series carbs, but later found that I only scored 70 on a snap quiz on Strombergs…..he thought it explained a lot of why the day was taking a long time.

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Above, the engine running cleanly today

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More, after further tests..Wewjr