Northwest Arkansas Times from Fayetteville, Arkansas on October 24, 1974 · Page 27
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Northwest Arkansas Times from Fayetteville, Arkansas · Page 27

Fayetteville, Arkansas
Issue Date:
Thursday, October 24, 1974
Page 27
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Northwest Arhnnsi; TIMES, Thursday, October M, 1874--5 10,080-Mile Spark Plug Change Favored On Chance Of Failure Battery May Not Solve Woes A spark plug may look good to the casual observer after 15.000. 20.000 or even 30.000 miles. So why change plugs- after 10,000 miles of use in your family car? There's a good reason ac- cn'-ding to experts. The 10.000 nnle change recommendation is nol actually based on the fact that spark plugs are "worn out" in the strictest sense alter 10.000 miles of service Tliis figure -- selected after extensive spark plug life tests -- merely represents a safely factor beyond which plugs may misfire under the sudden demands ot peak acceleration or extremely heavy load. It also represents the point at which gas economy begins to drop. In addition, the car is harder to slarl, power is lost in passing. A spark plug is considered worn out when it reaches the point where it is likely to mis- f i i e -- regardless ut its appearance. And, contrary to popular o p i n i o n , misfiring doesn't necessarily mean the plug didn't create a spark. It means simply that the plirg failed to ignite the gasoline properly -whether a spark was produced or not 1 5,000 VOLTS A new spark plug with the correct gap setting needs about 5.000 volis to fire. However, as the plug remains in service, constant beat and chemical attack plus electrical erosion cause the gap to become wider, thus increasing the amount of voltage to fire the plug, Spark plug gap growth occurs. ;U a rate of about .001 inch for each 1,000 miles of driving. Consequently, a set of plugs that has been in service for 10.000 miles generally will have gaps that are about .001 inch wider than the original settings and higher voltage is needed to make them spark. And, this is only for normal driving. Operating the engine at very high speed can decrease the amount of coil voltage available to fire .the spark plugs by 30 to 40 per cent! Ac- celeralinrg to pass on a highway may practically double the voltage burden on the spark plug. M O R E VOLTAGE That's why misfiring is first n o t i'c e d while accelerating because it's here that the plugs actually can require more voltage to produce a spark than the ignition system is capable of producing -- especially if the plugs are badly worn. Gas Mileage Helped By Emmission Control If you were thinking about r e m'o v i n g emission control equipment in your new car to boost gasoline economy, you may be doing more than polluting the air. According to a study by the Environmental Protection Agency, chances arc you'll be getting even poorer gas mileage. The EPA in its survey tok 10 cars to private garages and service stations, instructing mechanics to "do what's necessary to improve gasoline mileage." . Changes made by the repair shops resulted in an average loss of 3.5 per cent in fuel economy and a drastic increase in hydrocarbon, carhon monoxide and oxides of nilrogen emissions. Cost of the work done by the garages ranged from $12.50 to $37.50, In addition to disconnecting emission control equipment, garages generally enriched the carbiieretor idle setting and advanced timing with individual losses in fuel economy o[ up to 15.5 per cent. Remember, as plugs remain in service, more voltage is needed to make them spark. As the ignition system ages, its ability to produce high voltage lersens. If the point is reached where the spark plugs require more voltage to spark than the system can produce, the spark plugs misfire. Changing spark plugs at 10,000 mile intervals prevents this from- happening. Servicing or replacing the car battery may not be the answer to a car's winter starting woes. That's what a high percentage of motorists learned when they experienced starting failure and sought to correct it solely through attention to the battery. According to a hard-starting survey conducted last winter, repeated failure w a s experienced by 38.D per cent of car owners who had their batteries charged after initial "can't starts." Of those motorists installing a new battery after not star- ling, 25.0 per cent had at least one other failure. When car owners treated starling woes with engine ttine- up, they had belter success in forestalling future problems, tha survey showed. Rale of repeat can't starts was 14.6 per cent after a tune-up. Installation of new spark plugs alone was a better answer to starting trouble than battery service since 18.7 per cent had acldi- Uonal problems with new plugs. The survey also revealed hard starting continues to be the leading problem confronting motorists. In the U.S., 29 per cent of owners reported at least one failure last winter. In Canada, 30 per cent had trouble. Cold weather was not solely to blame for starting trouble. Warm weather regions in the U.S. were only slightly below the national average in reported "can't starts." In Pacific Coast stales, 27 per cent of car owners surveyed had at least one failure while the South Atlantic states had a 28 per cent "can't start" rate. These areas also had the iow- est incidence of tune-up purchases in the U.S. WAL-MART DISCOUNT CITY WAL-MART WE StU 'FOR LESS Southgatc Shopping Center Prices Good Thurs. Thru Sat. Al WAL-MART Discount City S A T I S F A C T I O N · ^ G U A R A N T E E D . Size 7OOxl3 £78x14 F78xl4 078x14 H78xl4 560.15 076x15 H78xl5 Reg. Price 19.O2 23.73 24.56 25.42 29.2O 18.19 26.34 29.15 Special Price 12.97 18.97 19.97 2O.97 22.97 12.97 2O.97 22.97 Plu* FET 1.95 2.24 2.41 2.55 2.77 1.78 2.63 2.62 Belled 2 Plies Polyester 2 Fiberglass Belts 4 Ply Tread fl"78"x!3 Silent Traction Crtot Gilp for Steady, Positive Troxllon «Yfld«, Deep (16/32") Tread biles hard. ·Husky shoulder logj pull In deep snow. · Traction "I" ribs flgM wet of snov/y loads, ·Interlinked pattern lot smooth ilde on dry coads. Reg. 20.69 Rt Wai-filar* THETimETOSRVEISNOW! W A L - M A R T WAL-MART DISCOUNT CITY WAL-MART

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