- Honda Car Owner's Manual

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68
ENGINEWEIGHTREDUCTIONTECHNOLOGIES
Allenginepartshavebeenmadeaslightaspossible.Majorweight-reducingfeaturesare:
• Sleevelesscylinderswithminimaldimensionbetweenbores
• TheintakemanifoldusedontheInsight's1.0-literengineismadeoutofplasticresininstead
ofaluminumalloy.Theentiremanifoldweighsonly2.2pounds,roughlyhalftheweightofa
comparablealuminummanifold.Theindividualpiecesthatmakeupthemanifold,suchasthe
intakerunners,plenumchamberandthrottle-bodymounting,arepermanentlyconnectedwith
avibration-weldingtechnique.Thecylinderheadcoverisalsomadeofplastic.
• Additional weight-saving engine components made with plastic resin include a 0.39-pound
water-pumppulley,a0.2-poundair-intaketubeanda0.88-poundvalvecover.
• Singlerockerarmshaftsharedbyintakeandexhaustvalves
• Rockerarmsmadeofaluminum
• Optimallylightpistons.
• BorrowingthetechnologyfromHonda'shigh-performanceS2000sportscar,theIMAengine
usesspecial compact, high-strength, forged-steel, carburized connectingrods. Carburization
toughens the rod's surface so that it resists crack formation. Carburizing allowed Honda
engineersto reduce the cross section of the connecting rods, therebyreducingtheir weight
(alwaysapenaltyinareciprocatingengine)by25percent,whileincreasingtheirstrengthby
morethan50percent.
• TheInsightIMAenginefeaturesamagnesium-alloyoilpan.Likeacast-aluminumpan,the
Insight'smagnesiumpanaddsstiffnesstotheengineblock,helpsmuffleenginenoiseandalso
helps to cool engine oil, but it is 35 percent lighter than aluminum. The magnesium alloy
specified for the Insight engine's oil pan is a new type that exhibits less thermal-induced
expansionandcontraction(creep)athightemperatures,sotheoilpanremainsoiltight.Honda
engineersdesignedadditionalweight-savingmeasuresintotheInsight'smagnesiumoilpanby
incorporating the engine oil-filter bracket, AC-compressor bracket and an engine-block
stiffenerintothecasting.
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Magnesium-alloyoilpan
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