Ignition Systems Chapter 9: Part 2

Ignition Coil: Composition

Ignition Coil: Composition

Spark Plugs Come in a variety of configurations Each type is manufactured for a desired outcome Very specific tolerances Contain many of the same parts across plug types

Spark Plugs: Parts

Plug Leads Exposed Clip Connector Advantages Less expensive to manufacture Easy to add a “Kill Switch” Disadvantages Exposed to dirt, oil, moisture, animals Easy to ground accidently Can lead to arching or flashover

Plug Leads Advantages Boot Type Connector Virtually eliminates arching Reduces flashover Protects terminal nut from debris Disadvantages Higher manufacturing cost Requires another type of “Kill Switch” Not as easy to remove

Spark Plug Reach Correct length must be selected To long = piston damage To short = poor combustion http://www.google.com/imgres?imgurl=http://www.sacskyranch.com/shortlongreach.jpg&imgrefurl=http://www.sacskyranch.com/faqsparkplug.htm&usg=__gdGRa_f1RsHNqDsnggEC2j740ek=&h=300&w=237&sz=7&hl=en&start=0&zoom=1&tbnid=Fd3UC2d2rroJGM:&tbnh=146&tbnw=100&prev=/images%3Fq%3Dspark%2Bplug%2Breach%26hl%3Den%26biw%3D1436%26bih%3D695%26gbv%3D2%26tbs%3Disch:1&itbs=1&iact=rc&dur=469&ei=YjsFTeSeOYGdnweMn_jnDQ&oei=YjsFTeSeOYGdnweMn_jnDQ&esq=1&page=1&ndsp=22&ved=1t:429,r:7,s:0&tx=47&ty=81

Spark Plugs: Parts

http://www.stealth316.com/2-sparkplugtech.htm

Spark Plug Reach Long Reach Cylinder Short Reach Cylinder http://www.google.com/imgres?imgurl=http://www.sacskyranch.com/shortlongreach.jpg&imgrefurl=http://www.sacskyranch.com/faqsparkplug.htm&usg=__gdGRa_f1RsHNqDsnggEC2j740ek=&h=300&w=237&sz=7&hl=en&start=0&zoom=1&tbnid=Fd3UC2d2rroJGM:&tbnh=146&tbnw=100&prev=/images%3Fq%3Dspark%2Bplug%2Breach%26hl%3Den%26biw%3D1436%26bih%3D695%26gbv%3D2%26tbs%3Disch:1&itbs=1&iact=rc&dur=469&ei=YjsFTeSeOYGdnweMn_jnDQ&oei=YjsFTeSeOYGdnweMn_jnDQ&esq=1&page=1&ndsp=22&ved=1t:429,r:7,s:0&tx=47&ty=81

Find your Kohler spark plug. Find your paper in file cabinet Find your Kohler spark plug. Find your paper in file cabinet. Grab a Champion Spark Plug Chart. (On the podium) Use chart to “decode” your plug.

Reading Plugs

Reading Plugs: Champion http://rc.runryder.com/helicopter/t92203p1/

Plugs and Manufacturers wapedia.mobi

Plug Heat Transfer Plugs must deal with heat All plugs have a heat range: from HOT to COLD Insulator nose size helps regulate plug temp Plug needs to match specific engine

Spark Plug Heat Transfer HOT COLD Insulator nose is longer Less likely to ‘foul’ from carbon deposits Using a plug that is to hot can result in engine failure Shorter insulator nose Transfer heat quickly Used in engines with HIGH COMBUSTION temps Note: the hottest part of the plug is the tip of the insulator!

Spark Plug Heat Transfer HOT COLD

How do they measure plug temps? Thermocouple Plug

Gapping Plugs Gap refers to space between electrode tip Specific to engine type in conjunction with correct plug selection Must be installed to manufacturers specifications

Gapping Plugs: measure then bend 1. Verify dimension with specs 2. Check gap 3. Use notched end to bend to desired clearance

Most common gap .030”

Electrode Designs Most common

Electrode Designs http://www.google.com/imgres?imgurl=http://www.fordanglia105eownersclub.co.uk/images/tech/tech-plug04.jpg&imgrefurl=http://www.fordanglia105eownersclub.co.uk/tech-sparkplug.htm&usg=__bQVJtH85ufutwGCe0JpR0H9fjXE=&h=181&w=282&sz=7&hl=en&start=22&zoom=1&tbnid=Phu_K8FDT9kOqM:&tbnh=105&tbnw=164&prev=/images%3Fq%3Dspark%2Bplug%2Belectrode%26hl%3Den%26sa%3DG%26gbv%3D2%26biw%3D1419%26bih%3D695%26tbs%3Disch:10%2C367&itbs=1&iact=hc&vpx=136&vpy=456&dur=2640&hovh=144&hovw=225&tx=106&ty=82&ei=pending&oei=AE4FTbK2EdP9nAfL-OTeBQ&esq=2&page=2&ndsp=32&ved=1t:429,r:8,s:22&biw=1419&bih=695

Electrode Designs http://www.google.com/imgres?imgurl=http://archive.carcaresupplement.com/images/ss2005/bosch3b_electrodes.jpg&imgrefurl=http://archive.carcaresupplement.com/supplement/ss2005/bosch3.html&usg=__St44cB5UWKTH7gTSg_GrEnlLOIs=&h=1168&w=900&sz=253&hl=en&start=52&zoom=1&tbnid=Nu3t71iVzI1OGM:&tbnh=126&tbnw=97&prev=/images%3Fq%3Dbosch%2Bspark%2Bplugs%26hl%3Den%26gbv%3D2%26biw%3D1419%26bih%3D695%26tbs%3Disch:10%2C1241&itbs=1&iact=hc&vpx=543&vpy=344&dur=781&hovh=256&hovw=197&tx=82&ty=171&ei=LU4FTaC5BIWonQeavaXlDQ&oei=FU4FTanbCcXGnAeer5noDQ&esq=3&page=3&ndsp=32&ved=1t:429,r:27,s:52&biw=1419&bih=695 http://www.google.com/imgres?imgurl=http://www.aaautospares.com/images/ngk_bosch_sparkplugs_POPUP.jpg&imgrefurl=http://www.aaautospares.com/maintenance.html&usg=__0LxurFi9WoKuojslHnrUg1u-MMQ=&h=240&w=311&sz=40&hl=en&start=84&zoom=1&tbnid=5T1bASntKiy8_M:&tbnh=120&tbnw=156&prev=/images%3Fq%3Dbosch%2Bspark%2Bplugs%26hl%3Den%26gbv%3D2%26biw%3D1419%26bih%3D695%26tbs%3Disch:10%2C1604&itbs=1&iact=hc&vpx=692&vpy=395&dur=4781&hovh=192&hovw=248&tx=148&ty=113&ei=lE4FTbPHCeHonQevjJHlDQ&oei=FU4FTanbCcXGnAeer5noDQ&esq=9&page=4&ndsp=32&ved=1t:429,r:12,s:84&biw=1419&bih=695

Problems with Spark Plugs Flashover Bridging Fouling Detonation Worn electrode Melted

Flashover http://www.moparmusclemagazine.com/techarticles/mopp_0612_reading_spark_plugs/photo_03.html

Bridging Accumulation of deposits on the electrode Can be caused by: Oil inside the combustion chamber Plug is the wrong temp range Can also be caused by fuel additives

Carbon Fouling Carbon deposits can build up on the electrode This eventually causes a conductive path from electrode to the ‘reach’ (threading) Plug continues to ‘fire’ but spark does not occur Causes: rich fuel mixture and or cold plug

Detonation VERY BAD!! Can cause severe engine damage! Looks like bits of pepper on the electrode Fuel is not completely detonating Causes: Improper octane fuel Incorrect timing Wrong plug temp

Worn Electrode Note the rounded electrode Plug needs to be replaced Simply worn out Replace with correct plug to manufacture specifications

Melted Electrode Oops Potential causes: Wrong Plug Timing to early Faulty distributor Wrong Plug Not commonly found on single cylinder engines Check engine manufacture specifications and replace immediately

Review: Parts