Run-Rite SLEDGEHAMMER

Rough idling, reduced gas mileage, misfires, knock and P0420 trouble codes are all signs the fuel system, intake manifold, valves and/or combustion chambers are coated in carbon, soot and varnish deposits. RockAuto now carries SLEDGEHAMMER, a professional strength, detergent based, low VOC compliant product formulated by catalytic converter manufacturer Davico and Run-Rite, maker of specialty cleaners, lubricants and equipment for automotive service centers. SLEDGEHAMMER is designed to safely remove heavy concentrations of carbon, soot and varnish in the engine and fuel system.

After use of SLEDGEHAMMER, you can expect:

1. Smoother idle and acceleration.
2. Restored fuel economy.
   
3. Longer life from Oxygen Sensors and Catalytic Converters.
   
4. Reduced tailpipe emissions.
5. Reduced gasoline octane requirements.
   

Happy Holidays

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Repair Mistakes & Blunders

Tell us about your most infamous auto repair blunder or unconventional fix. Use your woe to help others avoid similar mistakes or share off-the-wall solutions that worked (at least for a while!). Please email your story to flamur@rockauto.com. Include your mailing address and if you would like a RockAuto T-Shirt (please let us know your shirt size) or Hat if we publish your story. See the T-Shirts and Hats under Tools & Universal Parts in the catalog. The story will be credited using only your first name and your vague geographic location (state, province, country, continent, etc.) so you can remain semi-anonymous!

Automotive Trivia

What is the ideal gasoline air-fuel ratio:

A. 26.3 parts air to 1 part fuel
B. 7 parts air to 2 parts fuel
C. 14.7 parts air to 1 part fuel

Winter Fuel Economy

A reader from Ontario recently reported his truck uses significantly more gasoline in cold weather. He asked if winter fuel economy suffers because fuel injected engines do not have heat risers like old carbureted engines do. Great question!

A heat riser uses the hot exhaust manifold to preheat air entering the carburetor. Typically there is a steel box attached to the exhaust manifold and a pipe ("pre-heater hose" under "Fuel/Air" in the RockAuto catalog) running from the box to the air cleaner inlet.

pre-heater hose between exhaust manifold and air cleaner inlet

A carburetor delivers the same amount of gasoline whether the incoming air is hot and thin or cold and dense. Heat risers help maintain the correct fuel/air ratio by ensuring the incoming air is within a set temperature range.

Most fuel injection systems do not need pre-warmed incoming air. Air charge temperature, manifold pressure (MAP), mass air flow and other sensors (found under "Fuel/Air" and "Emission") tell the engine computer how dense the incoming air is. The flow of air and fuel injector on/off cycles (pulse width) are adjusted continuously to maintain the optimum fuel/air mixture. Fuel injectors operate at high pressure so the gasoline can be properly vaporized even at colder temperatures.

What has a big impact on a fuel injected engine's winter fuel economy is how quickly it warms up to operating temperature and moves from "open loop" to "closed loop" operation. Engines are usually in open loop mode when they are started cold or during unique events such as wide open throttle. Open loop means the fuel/air system runs using parameters already stored in the computer.

Closed loop mode means the computer (found under "Electrical") is now getting feedback from the oxygen sensor(s). If an O2 sensor indicates the fuel/air mixture is too rich or too lean then the computer immediately adjusts the fuel injector pulse width. The fuel injector pulse width might be twice as long in open loop mode compared to the average pulse width in closed loop mode. Open loop mode often uses more gasoline than is necessary and fuel economy suffers.

A heat riser would help an engine warm up a little faster, but the benefit would probably not be worth the trouble of fabricating a do-it-yourself heat riser system. Here are a few of the parts already on modern engines that should be questioned if an engine is slow to warm up and enter fuel efficient closed loop mode: Is an old thermostat (found under "Cooling System") allowing cold engine coolant to circulate through the radiator? Is a failing coolant temperature sensor slow to tell the computer the engine is warm? Has an oxygen sensor become sluggish or is its internal heater broken?

On super cold days in my wife's hometown in northern Minnesota, some drivers block off their grilles with cardboard (found enclosing most RockAuto parts orders!) in an attempt to create a "heat riser" effect using the entire engine compartment.

Tom's Follow-Up Note: Several readers pointed out that "heat riser" is not the correct name for the intake air pre-heat system the Ontario reader asked about and which is described above. A "heat riser" is the plumbing that routes engine exhaust from an exhaust manifold to the intake manifold when the engine is cold. Warm exhaust gas heats up the base of the carburetor which helps the gasoline vaporize. A temperature controlled heat riser valve in the exhaust manifold typically stops the flow of exhaust once the exhaust/engine are sufficiently hot.

Exhaust gas heat risers were common on carbureted and early throttle body fuel injected engines. Modern high pressure fuel injectors do not need heat risers to vaporize the gasoline. Like pre-heating the intake air, an exhaust gas heat riser system would help warm up an engine a little faster, but that probably would not be worth the costs. The valve in the exhaust manifold is often prone to rattling. I remember being surprised decades ago when exhaust gas started shooting out of a rust hole in my Chrysler V8's intake manifold.

This is my family's 1966 Buick Sportwagon. My father purchased this car in 1976 from my aunt who had purchased it new in 1966. I am the oldest of seven, and this was the family wagon from 1976 until 1986, when I turned 16 and began driving it to high school. Although ownership always remained with my father, this was my primary transportation throughout high school (I delivered pizza in it most nights those four years) and into college. After my first two years of college I replaced it with a daily driver of my own in 1990, and my dad retired it out back of the family home under a large cherry tree where it sat until 2011. My father had wanted to restore it himself, but the size of this project was apparently too daunting for him. So he delivered it to my home and told me to do what I wanted with it. Scrap it, restore it, whatever.

My wife, kids, and I restored the car in 2015 in anticipation of the 2015 annual Peach Days Car Show in Brigham City, Utah. It was our goal to have it completed by then, and we met that goal. We completed the entire project ourselves! It is painted Tangerine Twist Orange. My wife custom tailored the entire interior, from the black tuck and roll alligator skin leather and vinyl seats, to the light gray headliner. All interior and engine colors are original, only the exterior color was changed. This car was optioned with custom chrome trim (Sport Wagon Custom). It has the original Super Turbine 300 transmission, ice cold R-12 AC that didn’t even need re-charging after decades of sitting, and 340 cubic inch Wildcat 375 engine. (Editor note: Buick's "Wildcat 375" decal on the air cleaner indicates the engine has a 375 ft. lb. torque rating.)

RockAuto provided many of the parts for the restoration including ignition, belts, hoses, filters, brakes and much more!

Anthony in Utah

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