spark plug info

[grumpyvette]

spark plug info..SO!...read thru the links theres a ton of good info,
but its spread over all the links, if you can get that skill mastered your well ahead of most guys who fail to take the time and effort to learn that skill
guys frequently ask me what plug gap to use, Provided your ignition functions correctly and your using the correct heat range plugs and a reasonably close fuel/air ratio and timing advance, Ive never seen any improvements in gaps tighter or wider than .045.
Ive never seen any advantage to gaps over .045 and Ive seen plug gaps as wide as .060 or under .035 cause misfires with some ignitions in a FEW applications so after years of testing and racing I generally set plug gaps at .045, if your having issues with misses at .045 its not the plug gap thats the cause,its some other problem with your ignition or fuel/air ratio or ignition timing advance,high resistance ignition wire, moisture,a bad coil,loose connections, firing order or arcing ignition etc..
BTW some of the older guys will remember that the SBC used to have 13/16" spark plugs and they were changed to the smaller 5/8" style in the early 1970s, and if your wondering why they changed it was because they found that smaller diam. plug threads allowed slightly larger coolant passages and allowed moving the plug location slightly closer to the exhaust valve and also allowed a slightly changed angle all of which allowed lower emissions, better control on combustion and less chance of stripped or cross threading plugs.
post very clear pictures of your spark plugs, label the cylinder # they came from, and measure the fuel pressure you can tell a good deal if you know those factors and how to read plugs.
most engine misses are related to either fuel/air ratio changes or ignition, so the first step is isolate the problem, or the cause, it could be the timing, advance curve, fuel pressure , a vacuum leak,or a defective ignition etc, you need to do a few tests

http://www.harborfreight.com/3x-magnify ... 94367.html

having a spark plug holder with numbered holes and a good inspection tool helps


http://www.summitracing.com/parts/PIT-229/
Ive found its a whole lot faster to use a quality IR temp gun, to locate a individual cylinder that's mis-firing as it tends to run significantly cooler than adjacent cylinders, or hotter if its a vacuum leak at times, as lean F/A mixes tend to run hotter
(Ive used this one for years)

http://www.professionalequipment.com/ex ... ermometer/
Wide temperature range from -58 to 1832°F (-50 to 1000°C)

many temp guns don,t read high enough or accurately enough
http://www.professionalequipment.com/ex ... ermometer/
that you can use on the engine to check ALL 8 exhaust temps, individually, this quickly locates plugged injectors or vacuum leaks ETC
Wide temperature range from -58 to 1832°F

when selecting an IR gun for automotive use, you really want to be able to read from 0 F deg-about 1400F deg. to cover most conditions you'll test for

READ THRU LINKS AND SUB LINKS
http://www.4secondsflat.com/Spark_plug_reading.html

viewtopic.php?f=70&t=3949&p=25481#p25481

learning to correctly read plugs is a KEY FACTOR in learning how to tune and diagnose engine conditions, ignition temperatures,fuel/air ratios and detect detonation

example
Here is a link to AC Delco for information on the codes.

On the R45TSX for example:

R=resistor spark plug
45=heat range
T=tapered plug
S=extended tip
X=wide gap

http://www.acdelco.com/parts/sparkplugs ... cation.jsp

some reference chart info

http://www.sparkplug-crossreference.com ... ence8.html

http://www.spark-plugs.co.uk/pages/tech ... htm#ISOJIS

http://www.pcmforless.com/index.php?opt ... &Itemid=56

http://www.mirage-performance.com/tech/sparkplugs.html

http://go.mrgasket.com/pdf/sparkplugs/U ... erence.pdf

http://www.autorepairinstructions.com/?cat=7

viewtopic.php?f=70&t=9

http://www.kennedysdynotune.com/Spark%20Plug%20Tech.htm

IF your trying to tune an engine or track down a problem,When you inspect plugs ,pull all 8 plugs , drill some (8) 1/2 holes in 2 parallel lines in a 12"" section of 2"X6" wood and label the holes, to indicate the cylinders
2-4-6-8
1-3-5-7
so you can stick the porcelain ends , of each plug ,the wires snap onto, into the holes so you can photograph and inspect the tips and electrodes in clear detail as they can tell you a great deal about the engines running conditions

viewtopic.php?f=50&t=892&hilit=+socket

I frequently get asked what brand of plugs I use or suggest,
Ive had good luck with
AC DELCO
NGK
BOSCH PLATINUM plugs
most gapped at .043-.045
these are companys making a decent plug, your engine might run better with something else but Ive had good results with these brands
all work well in most LT1 and L98 chevy SB engines
just stick to the single electrode ground designs as in most cases Ive found the multi ground plugs cost more and don,t provide ANY improvement, and before you go linking in tests showing plug brand XYZ makes 5- 7 extra hp you should realize any decent experienced dyno operator can rig the results that much, either way at will, and if company xyz pays you several hundred dollars to show their plugs provide a small margin of extra power you can bet your butt the dyno operator will find it!
and when the next company ABC stops by for a TEST, you can bet they also show a small advantage

reading plugs can tell you a great deal, but if you don,t read thru and understand the linked info youll be at a big disadvantage heres a very useful chart, depicting plug conditions to look for indicating combustion chamber temp and air/fuel ratio indicators

http://www.4secondsflat.com/plug_chart.html

http://www.4secondsflat.com/Spark_plug_reading.html

http://www.dragstuff.com/techarticles/r ... plugs.html

http://www.custom-car.us/ignition/spark ... range.aspx

http://ngksparkplugs.com/tech_support/s ... p?mode=nml

http://www.autorepairinstructions.com/?cat=7

viewtopic.php?f=70&t=5428

http://www.power-21.com/AutolitePower21 ... preads.pdf

http://kb-silvolite.com/article.php?action=read&A_id=63

http://www.autohausaz.com/html/spark-pl ... wires.html

http://en.wikipedia.org/wiki/Spark_plug

http://www.ngksparkplugs.com/techinfo/s ... lation.asp

http://www.verrill.com/moto/sellingguid ... rchart.htm

http://www.strappe.com/plugs.html

cross reference
http://www.angelfire.com/extreme4/skido ... ERENCE.htm

viewtopic.php?f=50&t=1853&p=4848#p4848
QUOTE
"Heat range

The operating temperature of a spark plug is the actual physical temperature at the tip of the spark plug within the running engine. This is determined by a number of factors, but primarily the actual temperature within the combustion chamber. There is no direct relationship between the actual operating temperature of the spark plug and spark voltage. However, the level of torque currently being produced by the engine will strongly influence spark plug operating temperature because the maximum temperature and pressure occurs when the engine is operating near peak torque output (torque and RPM directly determine the power output). The temperature of the insulator responds to the thermal conditions it is exposed to in the combustion chamber but not vice versa. If the tip of the spark plug is too hot it can cause pre-ignition leading to detonation/knocking and damage may occur. If it is too cold, electrically conductive deposits may form on the insulator causing a loss of spark energy or the actual shorting-out of the spark current.

A spark plug is said to be "hot" if it is a better heat insulator, keeping more heat in the tip of the spark plug. A spark plug is said to be "cold" if it can conduct more heat out of the spark plug tip and lower the tip's temperature. Whether a spark plug is "hot" or "cold" is known as the heat range of the spark plug. The heat range of a spark plug is typically specified as a number, with some manufacturers using ascending numbers for hotter plugs and others doing the opposite, using ascending numbers for colder plugs.

The heat range of a spark plug (i.e. in scientific terms its thermal conductivity characteristics) is affected by the construction of the spark plug: the types of materials used, the length of insulator and the surface area of the plug exposed within the combustion chamber. For normal use, the selection of a spark plug heat range is a balance between keeping the tip hot enough at idle to prevent fouling and cold enough at maximum power to prevent pre-ignition leading to engine knocking. By examining "hotter" and "cooler" spark plugs of the same manufacturer side by side, the principle involved can be very clearly seen; the cooler plugs have more substantial ceramic insulators filling the gap between the center electrode and the shell, effectively carrying off the heat, while the hotter plugs have less ceramic material, so that the tip is more isolated from the body of the plug and retains heat better.

Heat from the combustion chamber escapes through the exhaust gases, the side walls of the cylinder and the spark plug itself. The heat range of a spark plug has only a minute effect on combustion chamber and overall engine temperature. A cold plug will not materially cool down an engine's running temperature. (Too hot of a plug may, however, indirectly lead to a runaway pre-ignition condition that can increase engine temperature.) Rather, the main effect of a "hot" or "cold" plug is to affect the temperature of the tip of the spark plug.

It was common before the modern era of computerized fuel injection to specify at least a couple of different heat ranges for plugs for an automobile engine; a hotter plug for cars which were mostly driven mildly around the city, and a colder plug for sustained high speed highway use. This practice has, however, largely become obsolete now that cars' fuel/air mixtures and cylinder temperatures are maintained within a narrow range, for purposes of limiting emissions. Racing engines, however, still benefit from picking a proper plug heat range. Very old racing engines will sometimes have two sets of plugs, one just for starting and another to be installed once the engine is warmed up, for actually driving the car."
learn how read the spark plugs their condition will tell you a good deal about cylinder burn conditions, get an IR temp gun,vacuum gauge and timing light they are a great tuning and diagnostic aid,as they can indicate problems like a clogged cat or faulty ignition, etc. don,t solely relie on a single indicator

http://www.strappe.com/plugs.html

http://performanceunlimited.com/illustrations/sparkplugs.html

http://www.dragstuff.com/techarticles/s ... rence.html

http://www.ngksparkplugs.com/techinfo/s ... country=US

the plugs are normally done (the electrodes cut back)with a dremel tool cutting disk




http://www.autorepairinstructions.com/?cat=7





heres a good indication of plugs running a bit rich at idle and real lean in the upper rpm range


keep in mind that different brands of plugs will have different lengths that can be critical with ignition wire to header clearances
http://www.centuryperformance.com/spark ... g-192.html

http://www.carcraft.com/techarticles/sp ... index.html

a few places to look for more info on plugs

http://www.centuryperformance.com/spark ... pg-26.html

http://www.dragstuff.com/techarticles/h ... plugs.html

http://www.youtube.com/watch?v=fiMM2S0aADM

http://opc.mr2oc.com/online_parts_catal ... _plugs.jpg

http://www.gofastzone.com/techtips/sparkplugs/sparkplugs.htm

http://www.ngksparkplugs.ca/documents/partnumberkey.pdf

http://www.autohausaz.com/html/spark-pl ... wires.html

http://www.acdelco.com/html/pi_plugs_ident.htm

http://www.autolite.com/framer.cgi?page=http://www.autolite.com/products/racing.htm

http://members.uia.net/pkelley2/sparkplugreading.html

http://www.circletrack.com/enginetech/c ... index.html

http://www.atlanticjetsports.com/_techtalk/00000005.htm

http://www.strappe.com/plugs.html

http://www.babcox.com/editorial/cm/cm59910.htm

http://www.4secondsflat.com/Spark_plug_reading.html

http://www.ngksparkplugs.com/techinfo/spark_plugs/partnumberkey.pdf

http://www.nightrider.com/biketech/spkplghnbook.htm

http://www.tsrsoftware.com/sparkplug.htm

viewtopic.php?f=70&t=1809&p=4671#p4671

http://www.gnttype.org/techarea/engine/plugs.html

http://www.dansmc.com/sparkplugs1.htm

http://www.ngksparkplugs.com/techinfo/spark_plugs/overviewp2.asp

http://www.pajjakid.com/ubipa/sparkplugs.htm

http://www.edelbrock.com/automotive/sparkplugs.html

http://www.bullittarchive.com/Maintenance/Sparkplugoverview/

http://www.powerarc.com/sparkplug.htm

http://www.carcraft.com/techarticles/64378/

http://www.wakularacing.com/TechnicalInfo.htm

viewtopic.php?f=55&t=109

http://www.geocities.com/MotorCity/Flats/3877/spark.html

viewtopic.php?f=44&t=773&p=1123#p1123


BTW IF YOU WANT TO AVOID ETHANOL LACED FUEL
http://pure-gas.org/

[grumpyvette]

heres an old post that will answer most questions if you read thru the links

in 35 years of engine building and racing I have not yet seen any increase in power or reliability or any other advantage to increasing the spark plug gap to more than the .043-.045 gap, and regularly gap my corvettes at .043-.045 regardless of the ignition system used, and I use VERTEX MAGNETOS and MSD, and HOLLEY ignitions extensively , and used to use the HEI and points ignitions in the past,, I have seen a reduction in power using under .040 or over .047 in some applications

asking for spark plug info..SO!...

a few places to look for more info on plugs


http://www.carcraft.com/techarticles/sp ... index.html

http://www.carcraft.com/howto/116_0703_ ... index.html

http://www.acdelco.com/html/pi_plugs_ident.htm

viewtopic.php?f=50&t=892

http://members.uia.net/pkelley2/sparkplugreading.html

http://www.atlanticjetsports.com/_techtalk/00000005.htm

http://www.strappe.com/plugs.html

http://www.babcox.com/editorial/cm/cm59910.htm

http://www.ngksparkplugs.com/techinfo/spark_plugs/partnumberkey.pdf

http://www.nightrider.com/biketech/spkplghnbook.htm

http://www.tsrsoftware.com/sparkplug.htm

http://www.gnttype.org/techarea/engine/plugs.html

http://www.dansmc.com/sparkplugs1.htm

http://www.ngksparkplugs.com/techinfo/spark_plugs/overviewp2.asp

http://www.centuryperformance.com/spark.asp

http://www.centuryperformance.com/spark ... pg-26.html


http://www.edelbrock.com/automotive/sparkplugs.html


http://www.powerarc.com/sparkplug.htm

http://www.carcraft.com/techarticles/64378/

http://dodgeram.org/tech/gas/spark_plugs/s_plug_faq.htm

http://www.centuryperformance.com/spark.asp

http://www.powerarc.com/sparkplug.htm

http://www.edelbrock.com/automotive/sparkplugs.html

http://www.answers.com/topic/spark-plug

lots more info here in the sub links, of this thread, keep in mind reading plugs tells you a great deal about the conditions, of temperature and fuel/air ratio, and heat ranges the combustion chamber sees, info that with experience can be used to tune and diagnose an engines condition and burn characteristics

viewtopic.php?f=44&t=773

BTW
A/F RATIO CHARACTERISTICS
5 RICH BURN LIMIT: Combustion is weak/erratic.
6-9 EXTREMELY RICH: Black smoke and low power.
10-11 VERY RICH: Some supercharged engines run in this range at full power as a means of controlling detonation.
12-13 RICH: Best power A/F: Un-supercharged WOT.
14-15 CHEMICALLY IDEAL: At 14.6 the A/F is at the theoretical ideal ratio with no excess fuel or oxygen after combustion. Good A/F for part
throttle cruise and light to moderate acceleration.
16-17 LEAN: Best economy A/F ratio. Borderline for part throttle Drive ability) (worse than borderline if EGR is used).
18-19 VERY LEAN: Usual lean limit (Drive ability).
20-25 LEAN BURN LIMIT: Varies with engine
and system.

cross over chart


btw if your at the track on test & tune and screw up the tune getting the plugs fuel soaked you don,t have to pitch nearly new fuel soaked plugs in the trash, they can be cleaned, thats why having a few tools and a spare set of plugs at the track along with things like carb jets,power valves and a spare set of ignition wires won,t hurt
TUNING LINK
viewtopic.php?f=55&t=109

if they are not in bad shape a 5 minute soak in brake parts cleaner solvent or a good spray down,then use a propane torch to dry the tips threads and porcelain, insulator and ground electrode and threads, off.
doing so usually has them operating ok if they just got oil or fuel soaked, don,t forget the ANTI-SEIZE paste on the plug threads, and to verify the gap, before you re-install them







now I freely admit before I start this thread that the methods used for testing were less than exact or something Id suggest you do, and yes much of the improvement noted might be related to the newer plugs and checking over a good deal of the ignition system, but at the same time I was impressed with how the work obviously made a difference, and we didn,t change much but the plugs and distributor cap.

BOB, stopped back over with his 1966 chevelle and asked for a bit of help with a tune-up ,
(HERES A PREVIOUS related THREAD)
viewtopic.php?f=87&t=8801&p=35305#p35305

he brought over a new distributor cap, plugs and asked me for help installing and side gaping plugs as he had read some place it was worth a few extra hp, now I pointed out that it was not likely to be something worth the time and effort required and it was hardly something that was likely to provide a long term benefit on a street driven car but if he wanted to try it we could do so, but I pointed out that it might result in a set of spark plugs that would not last nearly as long as the standard plugs might in a similar application.
we would need a dremel tool with a cut off disc,side gapping plugs generally works best on 12:1-14.1 compression engines that are well tuned with about 12.7:1 fuel air ratios where you can actually see the small benefit in ignition improvement at peak rpms I doubt its measurable on your average 9:1-10:1 street engine that rarely sees over 5000rpm, and runs closer to a 14.7:1 fuel air ratio.

a plug gap measuring tool

and he would need to understand what we were doing and why!
we used the cut off disc to cut the ground strap on the plugs so the tip of the round strap ended with about only 1/4 of the edge of the central electrode under it and gaped the plug ground at a .040 gap, we replaced the distributor cap, and checked the ignition firing order and timing and timing advance, this was set at 10 BTDC at 900RPM which was as low as the idle speed would work on that engine.
we verified total timing came in at 38 degrees at 3400rpm, while thats most likely not ideal, we felt it was close and the older plugs we removed looked to be running reasonably well and have a decent heat range and showed a decent fuel/air ratio


the plugs used were the 5/8" hex long reach champion plugs I don,t remember the number, but I think they were RN14YC but the end result was that after they were installed the engine seemed noticeably more responsive or "CRISPER"and when he drove off, he was able to leave two long black parallel tire burn marks and significant tire smoke and he called a few minutes later to thank me for the help!

btw the old plugs were
R43XLS

· R = Resistor
· 4 = 14 mm Thread
· 3 = Heat Range (range 1-5 start with a 3)
· T = Taper Seat (No T for your gasketed plug)
· XL = Extra Long Reach, 3/4" fully threaded
· S = Extended Tip


plugs like the E3 with multiple ground electrodes shroud the spark significantly more than standard plugs

[grumpyvette]

related info that might help when tuning an engine

obviously you need to have a consistent base line advance curve to work with,
on most Chevy v8 engines that run cams designed for street/strip use Ive generally found a advance that goes from about 8 degrees at idle speed (800-900rpm in most cases) and smoothly advances the ignition to about 36 degrees or about 28 degrees advance from where it started at to reach 36 degrees at about 3200rpm , is generally a good place to start, or about 82 rpm increase per degree of ignition advance , up to about 3200rpm, where increase turbulence and squish tends to speed the burn process, you can then play with the engine and determine what changes MIGHT be require





viewtopic.php?f=4&t=1337&p=2921&hilit=+infrared#p2921

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[grumpyvette]

http://www.aa1car.com/library/2002/ic120214.htm

http://www.se-r.net/engine/specialty_spark_plugs.html

http://www.autobarn.net/bosplat4spar.html

http://www.howstuffworks.com/ignition-system2.htm

[grumpyvette]

read the links below, if you want to take the time to index the spark plugs in your heads you'll need to carefully mark where the electrode ground is on the plugs insulator where you can easily see it with a permanent marker and use spacer washers to insure that the open area of the plug faces the area between the valves but slightly favoring the exhaust valve location, WITH THE GROUND ELECTRODE INDEXED UPWARD TOWARD THE COMBUSTION CHAMBER ROOF , because in some high compression applications, its fairly common for the pop-up piston dome to contact the ground electrode and bend it, closing the gap if the plugs ground electrode is placed in the lower 270 degrees on the plug when its installed , especially ,if you failed to correctly check clearances, between the piston and combustion chamber
in this example the plugs GROUND electrode is ALMOST EXACTLY OPPOSITE, OF THE IDEAL INDEXED location

example , similar too...

if your using high compression pistons like these youll soon see the reason for indexing plug ground electrodes



OBVIOUSLY A PLUG SOCKET DESIGNED TO HELP INDEX PLUGS IS HELPFUL AT TIMES
http://www.jegs.com/i/JEGS-Performance- ... 0/10002/-1
,this can in some cases smooth the idle slightly and add a few hp, in other applications its basically wasted effort, but in some cases the engine clearances make it mandatory, a good deal depends on the compression, intake runner and combustion chamber design, and it should be obvious that if your not running up close to the limits on your ignition advance curve and octane limits on your fuel you probably won,t notice the slight improvements in ignition,only careful testing in your engine will tell you if its worth the effort in your combination.....now I have guys that tell me its always wasted effort, and if you use the 2-4 electrode ground strap plugs is not going to change, well thats true, if you have several ground straps on the plugs you shroud the spark enough that youve effectively reduced its efficiency too ignite a clean flame front, so yeah if you use those its wasted effort[/color]


http://www.jegs.com/i/Moroso/710/71910/10002/-1




http://en.wikipedia.org/wiki/Spark_plug

http://corp.advanceautoparts.com/englis ... 1001sp.asp

http://www.boatsetup.com/PlgIndex.pdf

http://www.bullittarchive.com/5005.htm

http://www.hubgarage.com/mygarage/summi ... logs/10030

http://dodgeram.org/tech/gas/spark_plug ... dexing.htm

http://www.aa1car.com/library/sprkplg2.htm

BTW don,t forget to use ANTI SEIZE on the plug threads







common but not very accurate

slightly more accurate



http://www.sears.com/shc/s/p_10153_12605_00994133000P

good accuracy at a low price

thread chaser


inspection tool

http://www.verrill.com/moto/sellingguid ... rchart.htm

http://www.4secondsflat.com/plug_chart.html

http://www.ngksparkplugs.com/tech_suppo ... aqread.asp

http://www.harborfreight.com/3x-magnify ... 94367.html
dirt cheap plug inspection tool

[grumpyvette]

do yourself a favor and build a spark plug holder you simply take a scrap section of 2"x 6" lumber about 14" long and drill two parallel lines of 4 holes in each line and label them.
IF your trying to tune an engine or track down a problem,When you inspect plugs ,pull all 8 plugs , drill some (8) 1/2 holes in 2 parallel lines in a 12"" section of 2"X 6" soft pine wood and label the holes,clearly with large numbers, to indicate the cylinders
2-4-6-8
1-3-5-7
so you can stick the porcelain ends , of each plug ,the wires snap onto, into the holes so you can photograph and inspect the tips and electrodes in clear detail as they can tell you a great deal about the engines running conditions, glue a couple strong magnets to the lower side and then glue a thin sheet of old inner tube rubber to the base so the block will stick to a fender or radiator shroud and not fall, slide or mar paint, its a very good tool to have

vaguely similar to this, but this ones holding the plugs wrong end up, you want to have the porcelain, side the plug wire snaps to inserted in the holes so you can read the electrodes grounds and temp. indications in the combustion chambers




heres a cheap professional version but you can make a really nice one for a couple dollars that will last your lifetime


its amazing what you can learn about engine combustion chamber conditions, air/fuel distribution and temps, from reading spark plugs



heres some pictures from the other spark plug thread that might prove useful





http://www.4secondsflat.com/

Black or brown specs: This is an indication of detonation usually caused by too hot of a plug, drop one or two heat ranges and it should go away. The plug gets so hot that it will start to detonate the fuel before the ignition fires, this cause a double flame front and reduces the efficiency of the combustion process as these two flame fronts battle each other in the combustion chamber. The black spots are the result of the fuel deposits being burned onto the porcelain by the double flame front. Once you cool down the plug and remove the secondary ignition source you can re-set your timing to produce the correct combustion chamber temp for optimum power.

I've heard 100's of so called tuners and engine builders tell people that this is normal and nothing to worry about......WRONG. Do not underestimate the damage that this condition can do to your engine, drop the plug heat range.

BTW swapping to a colder plug and increasing the fuel octane DID prevent this. below is a colder plug after the changes from the same engine


viewtopic.php?f=70&t=202

viewtopic.php?f=57&t=4701&p=12741&hilit=detonation#p12741

viewtopic.php?f=50&t=208&p=244&hilit=detonation#p244

viewtopic.php?f=44&t=331&p=405&hilit=detonation#p405


it would hurt nothing to print this picture and glue it between the plug rows

it certainly won,t hurt to have access to a fuel/air gauge

Edelbrock 6593 Air/Fuel Ratio Gauge

http://www.summitracing.com/parts/EDL-6593/


fast air fuel gauge

http://www.summitracing.com/parts/FST-170402/?rtype=10

rsr air fuel gauge

http://www.rbracing-rsr.com/rsrgauge.htm


http://www.competitiondata.com/air_fuel ... _vs_nb.htm


If you do a little research you will find lots of “Air/Fuel Meters” on the market priced in the $100 to $ 400 range. These are “narrow band” products based on production car Oxygen or Lambda sensors. You will also find products priced at $ 1000 to $ 4000 per channel and even higher. These are wide band products.

What’s the Difference?

Wide Band

* Shows Actual Air/Fuel ratio.
* Precise display of ratio on the rich side of “stoichiometric”, which is where all performance engines run. Usually displays Air /Fuel ratio to the second decimal place.
* Useful for maximizing power from race and other performance engines.
* Fully temperature compensated.
* Higher cost.




Narrow Band

* Shows indication of rich vs lean.
* Usually has very “coarse” display of ratio on the rich side of “stoichiometric. Some units only have 2 LEDs for the entire rich range!
* Really only useful for making sure your engine is not running on the lean side.
* Usually not temperature compensated, so the same air/fuel condition in the motor will result in an indication on the meter that will vary depending on sensor temperature.
* Low cost.



Bottom Line:

If you are a builder or tuner of performance engines who needs to maximize performance of the engines you work with, then you need to be measuring Air/Fuel ratio with a wide band meter.

If you simply want an indication that you are rich or lean to make sure you are not going to burn the motor up, you can get by with a narrow band meter



Narrow Band vs. Wide Band Air Fuel Ratio Meter

An air fuel ratio meter is a type of gauge that is used in cars, boats or any vehicle that has an internal combustion engine. Its job is to detect how much voltage is emitted by the engine’s oxygen sensor, and in so doing, it can gauge the engine’s air-fuel ratio. Air fuel ratio meters are important because they help to ensure that your vehicle is using fuel efficiently, helps your catalytic converter to work optimally and thus cuts down on toxic emissions, and maximizes the engine’s performance in general. Nowadays, there are 2 types of air fuel ratio meters on the market: narrow-band readers, and wide-band readers. Keep reading to find out how the two are different, and their pros and cons.
Narrow Band vs. Wide Band Air Fuel Ratio Meter: Physical Qualities

The narrow band meter has long been the standard in cars, although now it’s becoming a bit antiquated. They are present in your car in a round-shaped housing. Like the other gauges in your car, the mounting usually measures in either 2 1/16 inch diameter or 2 5/8 inch diameter, with 10 to 20 LEDs. Some are available with a needle-style gauge interface. The reliability of the narrow band meter can be negatively affected by increasing gas temperatures, so they have to be used with care.

www. Siemens. com/ Air_Flowmeters


Wide band meters are newer and more accurate. They can either stand alone or be mounted in round housings also. Unlike the narrow band meters, these have a numeric display, and can display much more sensitive and accurate information. They have a linear output of 0 to 5 V and can function no matter what the temperature of your car’s engine.
Narrow Band vs. Wide Band Air Fuel Ratio Meters: Which One Should I Use?

If you have an older car that you just need to check on from time to time, especially if you suspect that something might be wrong with the oxygen sensor, then a plain old narrow band reader will probably do just fine. These models are cheaper, and as long as you’re not worried about getting a very sensitive reading, then the narrow band should do just fine.

On the other hand, if it’s your treasured sports car that we’re talking about, or if you need to perform some really sensitive, highly refined maintenance, then you should really spring for the wide band meter. The wide band meter gives you more accurate information, gives you more precise numbers, is reliable no matter the temperature and is easier to read. If you feel that there’s a lot at stake for the health of your car, then, it’s worth the extra investment in a wide band air fuel ratio meter.
viewtopic.php?f=55&t=109

viewtopic.php?f=50&t=2891&p=9279&hilit=ratio+meter#p9279

viewtopic.php?f=50&t=1853&p=4848&hilit=ratio+meter#p4848


viewtopic.php?f=70&t=3438&p=10844&hilit=vacuum+gauge#p10844

viewtopic.php?f=70&t=4683

http://www.classictruckshop.com/clubs/e ... ac/uum.htm

READ THRU THE LINKS ABOVE




Read more: http://www.doityourself.com/stry/narrow ... z104zOE8IJ


Read more: http://www.doityourself.com/stry/narrow ... z104z4RvcZ

read these links below

http://autospeed.com/cms/title_InCar-Ai ... ticle.html

http://autospeed.com.au/cms/article.html?&A=2191

[grumpyvette]

Spark Plug Info

Stock replacement plugs for the C5 Corvette are as follows
There were 3 different AC/Delco plug designs on c5. And each one had a different electrode protrusion. 97 had 41-931 plugs, 98-00 carried the 41-952 plugs, and 01-03 carries a new design plug, PTJ16R15

If anyone Else would like to add to this thread for the LS7,
LS2,LS3, ZR1 including your combo and the plugs you are running, Post em up !

Also if you care to list OEM Direct replacements for all the various model years of corvette from 1953-2010
Don't forget to include plug gap And OEM # !

Bon

Aftermarket plugs




**Note: Heat ranges are determined by NGK standards. Not all plug manufacturers follow the same guidelines.

***Note: List is intended for reference only. Please consult with head mfg. and ignition mfg. for proper gap.

****Note: NGK IX and Denso plugs are Iridium.

LT1
Thread – 14mm
Reach - .708”
Socket – 5/8 hex
Seat - Taper
Stock Heat Range: 5
Gap: .050
Plug: NGK TR55 (stock number 3951); NGK TR55IX (stock number 7164); Autolite 764; Champion RS14YC6 (stock number 13); Denso IT-16 (stock number 5325)

Nitrous (one step colder)
Heat range: 6
Gap: .035 - .038
Plug: NGK TR6 (stock number 4177); NGK TR6IX (stock number 3689); Autolite 103; Denso IT-20 (stock number 5326)

Nitrous (two steps colder)
Heat Range: 7
Gap: Consult
Plug: NGK BR7EF (stock number 3346); NGK TR7IX (stock number 3690); Autolite AR94; Denso IT22 (stock number 5327)


LT1 w/ AFR heads
Thread – 14mm
Reach – 3/4”
Socket – 5/8 hex
Seat – Gasket
Stock – MFG Recommendations
Heat Range: 9
Gap: Consult ignition mfg.
Plug: NGK 5672A-9 (stock number 7405); Autolite AR3910; Champion C59YC (stock number 792); Denso IQ27 (stock number 5315); Denso IQ01-27 (stock number 5708)(diagonal platinum ground); Denso IQ02-27 (stock number 5711)(horizontal platinum ground)

Nitrous (one step colder)
Heat Range: 10
Gap: Consult ignition mfg.
Plug: NGK 5672A-10 (stock number 7942); Autolite AR50; Denso IQ31 (stock number 5323)

Nitrous (two steps colder)
Heat Range: 11
Gap: Consult ignition mfg.
Plug: Denso IQ34 (stock number 5324)


LT1 w/ Trick Flow & Edelbrock Heads
Thread – 14mm
Reach – 3/4”
Socket – 5/8 hex
Seat – Gasket

Stock – MFG Recommendations: approx under 9:1 compression
Heat Range: 4
Gap: Consult ignition mfg.
Plug: NGK FR4 (stock number 5155); NGK BKR5EIX (stock number 6341); Autolite 3926; Champion RC12YC (stock number 71); Denso IK16 (stock number 5303)

MFG Recommendations: approx 10.5:1 compression
Heat Range: 5
Gap: Consult ignition mfg.
Plug: NGK FR5 (stock number 7373); Autolite AR3924 (Racing Plug); Autolite 3924; Champion RC9YC (stock number 2075); Denso K20PR-U (stock number 3145); Denso IK20 (stock number 5304)

MFG Recommendations: approx 11:1 compression
Heat Range: 8
Gap: Consult ignition mfg.
Plug: NGK R5672A-8 (stock number 7173); Autolite AR3911; Champion C63YC (stock number 796); Denso IQ24 (stock number 5314)

MFG Recommendations: approx 12:1 compression
Heat Range: 9
Gap: Consult ignition mfg.
Plug: NGK R5672A-9 (stock number 7405); Autolite AR3910; Champion C61YC (stock number 785); Denso IQ27 (stock number 5315)

MFG Recommendations: approx 13:1 compression
Heat Range: 9 - 10
Gap: Consult ignition mfg.
Plug: NGK R5671A-9 (stock number 5238); Autolite AR3933; Champion C59CX (stock number 296); Denso IK27 (stock number 5312)

MFG Recommendations: approx 14:1 compression
Heat Range: 10
Gap: Consult ignition mfg.
Plug: NGK R5671A-10 (stock number 5820); Autolite AR3932; Champion C57CX (stock number 295); Denso IK-31 (stock number 5321)

**NOTE: Use chart for static compression and adjust heat range for nitrous use accordingly.



LS1/LS6 Stock and AFR HEADS
Thread – 14mm
Reach - .708”
Socket – 5/8 hex
Seat - Taper
Stock Heat Range: 5
Gap: .060
Plug: NGK TR55 (stock number 3951); NGK TR55IX (stock number 7164); Autolite 764; Denso IT-16 (stock number 5325)

Nitrous (one step colder)
Heat Range: 6
Gap: .035 - .038
Plug: NGK TR6 (stock number 4177); NGK TR6IX (stock number 3689); Autolite 103; Denso IT-20 (stock number 5326)

Nitrous (two steps colder)
Heat Range: 7
Gap: Consult
Plug: NGK BR7EF (stock number 3346); NGK TR7IX (stock number 3690); Autolite AR94; Denso IT22 (stock number 5327)

Nitrous (two and a half steps colder)
Heat Range: 8
Gap: Consult
Plug: NGK R5724-8 (stock number 7317); NGK TR8IX (part number 3691); Denso IT-24 (stock number 5328)

Nitrous (three steps colder)
Heat Range: 9
Gap: Consult
Plug: NGK R5724-9 (stock number 7891); Autolite AR93; Denso IT-27

Nitrous (four steps colder)
Heat Range: 10
Gap: Consult
Plug: NGK R5724-10 (stock number 7993); Autolite AR92


LS1 w/ Edelbrock and Dart Heads
Thread – 14mm
Reach – 3/4”
Socket – 5/8 hex
Seat – Gasket

Stock – MFG Recommendations: approx under 9:1 compression
Heat Range: 4
Gap: Consult ignition mfg.
Plug: NGK FR4 (stock number 5155); NGK BKR5EIX (stock number 6341); Autolite 3926; Champion RC12YC (stock number 71); Denso IK16 (stock number 5303)

MFG Recommendations: approx 10.5:1 compression
Heat Range: 5
Gap: Consult ignition mfg.
Plug: NGK FR5 (stock number 7373); Autolite AR3924 (Racing Plug); Autolite 3924; Champion RC9YC (stock number 2075); Denso K20PR-U (stock number 3145); Denso IK20 (stock number 5304)

MFG Recommendations: approx 11:1 compression
Heat Range: 8
Gap: Consult ignition mfg.
Plug: NGK R5672A-8 (stock number 7173); Autolite AR3911; Champion C63YC (stock number 796); Denso IQ24 (stock number 5314)

MFG Recommendations: approx 12:1 compression
Heat Range: 9
Gap: Consult ignition mfg.
Plug: NGK R5672A-9 (stock number 7405); Autolite AR3910; Champion C61YC (stock number 785); Denso IQ27 (stock number 5315)

MFG Recommendations: approx 13:1 compression
Heat Range: 9 - 10
Gap: Consult ignition mfg.
Plug: NGK R5671A-9 (stock number 5238); Autolite AR3933; Champion C59CX (stock number 296); Denso IK27 (stock number 5312)

MFG Recommendations: approx 14:1 compression
Heat Range: 10
Gap: Consult ignition mfg.
Plug: NGK R5671A-10 (stock number 5820); Autolite AR3932; Champion C57CX (stock number 295); Denso IK-31 (stock number 5321)

**NOTE: Use chart for static compression and adjust heat range for nitrous use accordingly.

for canfield Race rite 180 and 220
Spark Plug Starting Points:
CHAMPION RN12YC or AUTOLITE 3924
for Pump Gas (RR 180 & RR 200)
NGK R5671A-8 for Racing Gas (RR 200)

[grumpyvette]

Indycars POSTED THIS INFO


I did a short search of this forum, but didn't find anything on Torquing Spark Plugs in an aluminum head. When I found
this info I thought it might be helpful for others. Hope I'm not duplicating info that is already on the website.

http://www.ngksparkplugs.com/techinfo/s ... lation.asp

A. Installing spark plugs

Torque is one of the most critical aspects of spark plug installation. Torque directly affects the spark plugs' ability to transfer heat out of the combustion chamber. A spark plug that is under-torqued will not be fully seated on the cylinder head, hence heat transfer will be slowed. This will tend to elevate combustion chamber temperatures to unsafe levels, and pre-ignition and detonation will usually follow. Serious engine damage is not far behind.

An over-torqued spark plug can suffer from severe stress to the Metal Shell which in turn can distort the spark plug's inner gas seals or even cause a hairline fracture to the spark plug's insulator...in either case, heat transfer can again be slowed and the above mentioned conditions can occur.

The spark plug holes must always be cleaned prior to installation, otherwise you may be torquing against dirt or debris and the spark plug may actually end up under-torqued, even though your torque wrench says otherwise. Of course, you should only install spark plugs in a cool engine, because metal expands when its hot and installation may prove difficult. Proper torque specs for both aluminum and cast iron cylinder heads are listed below.

SparkPlugTorqueValues.JPG

B. Installing spark plugs - Lawn & Garden Equipment

1. Confirm that the thread reach of the spark plug is the right one for your engine.

2. Remove the dirt at the gasket seal of the cylinder head.

3. Tighten the spark plug finger tight until the gasket reaches the cylinder head, then tighten about 1/2-2/3 turn more with a spark plug wrench. (Taper seat: About 1/16 turn more).

C. Gapping

Since the gap size has a direct affect on the spark plug's tip temperature and on the voltage necessary to ionize (light) the air/fuel mixture, careful attention is required. While it is a popular misconception that plugs are pre-gapped from the factory, the fact remains that the gap must be adjusted for the vehicle that the spark plug is intended for. Those with modified engines must remember that a modified engine with higher compression or forced induction will typically require a smaller gap settings (to ensure ignitability in these denser air/fuel mixtures). As a rule, the more power you are making, the smaller the gap you will need.

A spark plug's voltage requirement is directly proportionate to the gap size. The larger the gap, the more voltage is needed to bridge the gap. Most experienced tuners know that opening gaps up to present a larger spark to the air/fuel mixture maximizes burn efficiency. It is for this reason that most racers add high power ignition systems. The added power allows them to open the gap yet still provide a strong spark.

With this mind, many think the larger the gap the better. In fact, some aftermarket ignition systems boast that their systems can tolerate gaps that are extreme. Be wary of such claims. In most cases, the largest gap you can run may still be smaller than you think.

D. Indexing

This is for racers only !!
Indexing refers to a process whereby auxiliary washers of varying thickness are placed under the spark plug's shoulder so that when the spark plug is tightened, the gap will point in the desired direction.

However, without running an engine on a dyno, it is impossible to gauge which type of indexing works best in your engine. While most engines like the spark plug's gap open to the intake valve, there are still other combinations that make more power with the gap pointed toward the exhaust valve.

In any case, engines with indexed spark plugs will typically make only a few more horsepower, typically less than 1% of total engine output. For a 500hp engine, you'd be lucky to get 5hp. While there are exceptions, the bottom line is that without a dyno, gauging success will be difficult.

E. Heat Range selection

Let's make this really simple: when you need your engine to run a little cooler, run a colder plug. When you need your engine to run a little hotter, run a hotter spark plug. However, NGK strongly cautions people that going to a hotter spark plug can sometimes mask a serious symptom of another problem that can lead to engine damage. Be very careful with heat ranges. Seek professional guidance if you are unsure.

With modified engines (those engines that have increased their compression) more heat is a by-product of the added power that normally comes with increased compression. In short, select one heat range colder for every 75-100 hp you add, or when you significantly raise compression. Also remember to retard the timing a little and to increase fuel enrichment and octane. These tips are critical when adding forced induction (turbos, superchargers or nitrous kits), and failure to address ALL of these areas will virtually guarantee engine damage.

An engine that has poor oil control can sometimes mask the symptom temporarily by running a slightly hotter spark plug. While this is a "Band-Aid" approach, it is one of the only examples of when and why one would select a hotter spark plug.

F. Using "racing" spark plugs

Be cautious! In reality, most "racing" spark plugs are just colder heat ranges of the street versions of the spark plug. They don't provide any more voltage to the spark plug tip! Their internal construction is no different (in NGK's case, as all of our spark plugs must conform to the same level of quality controls) than most standard spark plugs.

There are some exceptions, though. Extremely high compression cars or those running exotic fuels will have different spark plug requirements and hence NGK makes spark plugs that are well-suited for these requirements. They are classified as "specialized spark plugs for racing applications". Some are built with precious metal alloy tips for greater durability and the ability to fire in denser or leaner air/fuel mixtures. However, installing the same spark plugs Kenny Bernstein uses in his 300+ mph Top Fuel car (running Nitromethane at a 2:1 air/fuel ratio and over 20:1 dynamic compression) in your basically stock Honda Civic (running 15:1 a/f ratios with roughly 9.5:1 compression) will do nothing for you! In fact, since Kenny's plugs are fully 4 heat ranges colder, they'd foul out in your Honda in just a few minutes.

NGK as a company tries to stay clear of saying that a racing spark plug (or ANY spark plug) will give you large gains in horsepower. While certain spark plugs are better suited to certain applications (and we're happy to counsel you in the right direction) we try to tell people that are looking to "screw in" some cheap horsepower that, in most cases, spark plugs are
not the answer.

To be blunt, when experienced tuners build race motors, they select their spark plugs for different reasons: to remove heat more efficiently, provide sufficient spark to completely light all the air/fuel mixture, to survive the added stresses placed upon a high performance engine's spark plugs, and to achieve optimum piston-to-plug clearance.

Some of these "specialized racing plugs" are made with precious metal alloy center/ground electrodes or fine wire tips or retracted-nose insulators. Again, these features do not necessarily mean that the spark plug will allow the engine to make more power, but these features are what allow the spark plug to survive in these tortuous conditions. Most racers know screwing in a new set of spark plugs will not magically "unlock" hidden horsepower.

G. Using high power ignition systems

Many of the more popular aftermarket ignition systems are of the capacitive discharge type. They store voltage, or accumulate it, until a point at which a trigger signal allows release of this more powerful spark. Companies like Mallory, MSD, Crane and Accel, to name a few, offer such systems.

They affect spark plugs in that they allow the gaps to be opened up to take advantage of the increased capacity. The theory is that the larger and the more intense the spark you are able to present to the air/fuel mixture, the more likely you will be to burn more fuel, and hence the more power you will make.

We encourage the use of such systems, but only on modified or older non-computer controlled vehicles.

In reality, computer controlled vehicles do such a good job of lighting off the air/fuel mixture (as evidenced by the ultra-low emissions), added ignition capacity would do little to burn more fuel since the stock configuration is doing such a good job. Older non-computer controlled vehicles or those that have been modified with higher compression or boosted (nitrous, turbo, supercharged) engines can certainly take advantage of a more powerful ignition system.

[grumpyvette]

http://www.dragstuff.com/techarticles/r ... plugs.html

http://www.dragstuff.com/techarticles/p ... tures.html

http://www.dragstuff.com/techarticles/h ... plugs.html

[DorianL]

I am going to try an recap this a bit because it is somewhat inconsistent in my mind:

Spark plugs need to be examined immediately shut down at the RPM and load to be analyzed. In other words, you can read plugs for WOT as well as for idle and cruise - but difficult to do both together.

The Ground Strap
This one is a bit ambiguous to me but possibly it's not as inconsistent as I think. The ground strap reads timing (and?) or heat range. There basically a colored line across the strap where the metal has been annealed due to the very high temps it is subjected to. If the mark is tending toward the tip - the metal has seen little excessive heat: timing is too conservative for top performance and efficiency (and/or the plug is too cold?) If the mark is tending toward the ground, the metal has seen significantly high heat: too much timing (and/or the plus is too hot???)

The mark should be at the elbow or thereabouts and producing max power. That seems easy enough to tweak. However it becomes more complicated if you can adjust the heat range there.

From my perspective - I tend to conclude that I can read the timing there - and will not tune the heat range that way. From what I read BTW, heat range really only plays a significant role at the very edge of performance. Most plugs, as recommended, will be in right range.

Finally - there can be more than one mark on the strap: cruise and WOT.


The Porcelain
From what I understand this divides in to three. Deep inside is where you read WOT. The tip is where idle/cruise is read. The mid area: power valve on but not WOT. Once again - you shut down immediately after the range you are to examine. The porcelain progressively loses its color from tip to base - that is why you examine deep down the effects of WOT on the porcelain. It get quickly colored over from tip on through mid to base.

So once again - you can examine the idle/cruise here by looking at the tip of the porcelain. Sooty/tan/white-ashed. Rich/good/lean. So that is a change of primary jets

!!!!! But you can also read the heat range here... THAT is confusing again. My feeling here is if jetting down a bit doesn't clean up plug soot - try a hotter plug. And of course vice versa.

For WOT you would shut down immediately and look for a grayish tan line that rings around the base. Incomplete ring needs more jet. Too fat rings: less jet.

Speckles on porcelain indicate detonation.

Glazing: too hot!


Base-ring
Here it is unclear - some say this is jetting idle/cruise. Others say this is idle and has nothing to do with jetting.

From my little experience. Leaning out the idle has cleaned my base ring. The soot is dryer and doesn't go all the way around... and that is what one should shoot for. Tailpipes still smell rich but there is no wispiness

I have ALSO read that the three first threads are an indication of heat range: 3 = good. more = too cold. Less = too hot. Possibly not inconsistent.



Hmmmmmmmmmmmmmm

[grumpyvette]

over all your correct in your basic assumptions, there are factors that can and do tweak the observed results and the fact that your running a supercharger is one, because a rapid increase in combustion pressure tends to make the plugs and fuel air ratio a bit harder to diagnose simply because your exhaust temps tend to go up with the increased volume of fuel air mix being burnt, as the rpms increase, while the combustion chamber temps don,t climb AS rapidly , and the fact that any supercharged engines tends to push a bit of unburnt fuel/air mix out the exhaust during the cam overlap


this is a very informative picture, you will not normally see plugs in this clean condition after being run awhile of course, but
ID expect to see the total timing mark just a bit closer to the threads
ID expect to see the the porcelain a light tan or beige
ID expect to see the threaded body a bit lighter ,dry and a darker tan or beige not what looks oily black

read thru these again

http://www.4secondsflat.com/Spark_plug_reading.html

http://www.dragstuff.com/techarticles/h ... plugs.html

[grumpyvette]

http://www.summitracing.com/parts/SUM-900313/




Im always amazed at the guys that not only don,t have decent spark plug tools but don,t even know what they look like or are used for for that mater.
I went to the local napa stores to buy a decent spark plug gaping tool and could not find one, when I described the tool he stated he had never seen or heard of anything similar, he had those little throw away dollar tools only


and when I asked him what the ohms resistance was per foot in the spark plug wire, in the set of spark plug wires he had for sale, I got the very strong impression he had no clue what I was asking, Id bet at least $20 hes never bothered to measure ignition wire resistance on a car with an ohms meter, in his life!
and while Im sure he had heard of gaping plugs Id bet he installs them right out of the package without checking a darn thing


http://www.harborfreight.com/5-in-1-dig ... 98674.html

http://www.ehow.com/how_7592234_test-ig ... wires.html

http://www.aa1car.com/library/spark_plug_wires.htm

[grumpyvette]

heres a few links and bits of spark plug related info that might prove useful

http://www.carcraft.com/howto/116_0703_ ... ewall.html

http://www.carcraft.com/techarticles/sp ... index.html

http://www.nightrider.com/biketech/spkplghnbook.htm

http://www.custom-car.us/ignition/spark ... range.aspx

http://www.summitracing.com/expertadvic ... eat-Range/

http://www.corvettefever.com/techarticl ... ewall.html

http://www.circletrack.com/enginetech/c ... index.html

http://www.circletrack.com/enginetech/c ... index.html

http://www.circletrack.com/enginetech/c ... index.html

http://www.stockcarracing.com/techartic ... index.html

[grumpyvette]

now I freely admit before I start this thread that the methods used for testing were less than exact or something Id suggest you do, and yes much of the improvement noted might be related to the newer plugs and checking over a good deal of the ignition system, but at the same time I was impressed with how the work obviously made a difference, and we didn,t change much but the plugs and distributor cap.

BOB, stopped back over with his 1966 chevelle and asked for a bit of help with a tune-up ,
(HERES A PREVIOUS related THREAD)
viewtopic.php?f=87&t=8801&p=35305#p35305

he brought over a new distributor cap, plugs and asked me for help installing and side gaping plugs as he had read some place it was worth a few extra hp, now I pointed out that it was not likely to be something worth the time and effort required and it was hardly something that was likely to provide a long term benefit on a street driven car but if he wanted to try it we could do so, but I pointed out that it might result in a set of spark plugs that would not last nearly as long as the standard plugs might in a similar application.
we would need a dremel tool with a cut off disc,side gapping plugs generally works best on 12:1-14.1 compression engines that are well tuned with about 12.7:1 fuel air ratios where you can actually see the small benefit in ignition improvement at peak rpms I doubt its measurable on your average 9:1-10:1 street engine that rarely sees over 5000rpm, and runs closer to a 14.7:1 fuel air ratio.

a plug gap measuring tool

and he would need to understand what we were doing and why!
we used the cut off disc to cut the ground strap on the plugs so the tip of the round strap ended with about only 1/4 of the edge of the central electrode under it and gaped the plug ground at a .040 gap, we replaced the distributor cap, and checked the ignition firing order and timing and timing advance, this was set at 10 BTDC at 900RPM which was as low as the idle speed would work on that engine.
we verified total timing came in at 38 degrees at 3400rpm, while thats most likely not ideal, we felt it was close and the older plugs we removed looked to be running reasonably well and have a decent heat range and showed a decent fuel/air ratio


the plugs used were the 5/8" hex long reach champion plugs I don,t remember the number, but I think they were RN14YC but the end result was that after they were installed the engine seemed noticeably more responsive or "CRISPER"and when he drove off, he was able to leave two long black parallel tire burn marks and significant tire smoke and he called a few minutes later to thank me for the help!

btw the old plugs were
R43XLS

· R = Resistor
· 4 = 14 mm Thread
· 3 = Heat Range (range 1-5 start with a 3)
· T = Taper Seat (No T for your gasketed plug)
· XL = Extra Long Reach, 3/4" fully threaded
· S = Extended Tip


plugs like the E3 with multiple ground electrodes shroud the spark significantly more than standard plugs

[87vette81big]

Has Bob noticed a driving improvement with the Side Gapped spark plugs Grumpy ?

The trick works pretty good in high RPM engines with over 12.0 :1 static compression ratios, cam of 250-280 degree duration @ .050" lift, 108- 98 Intake centerline, Vertex Magneto.
High octane race fuel.. Timing locked out.
Even better results on Methanol alcohol .

On street only good indication is throttle response improvements.