Go Back   FerrariChat.com > General Forums > Technical Q&A

Reply
 
LinkBack Thread Tools
  #1  
Old 09-16-2006, 01:41 AM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
Spark Plug Reading 101

http://www.dragstuff.com/techarticle...ead-plugs.html

by Meaux Racing Heads
This is only valid if you shut-off the engine after the finish line then tow the car back to the pits where you remove the plugs for reading !!
Or if you are on the dyno
VALID ONLY for full load acceleration or steady state dyno tests

Plugs are best viewed with a 10x power illuminated magnifying glass.


The "Ground Strap" [side electrode] = Heat Range
The "Plug's Base Ring" [circle at the end of threads] = Mixture
The "Porcelain" [white insulator] = signs of preignition/detonation

Heat Range
Heat Range = Ground Strap, the ground strap indicates the heat-range of the spark plug. If the "color" of the ground strap "changes" too close to the ground strap's end, (which is above the center electrode), then the heat-range is "too cold", meaning that the strap is loosing heat too quickly to the base ring, and is not able to burn off deposits until near its end. [plugs that are too cold will eventually foul the center electrode and white insulator, leading to misfires]

If the "color" of the ground strap changes near where it is welded/attached to the base ring (last thread ring), then it means that the plug heat-range is "too hot", because heat is not being transferred/cooled from the strap to the base ring quickly enough !!!! The strap might begin to act like a "glow-plug", eventually causing preignition and/or detonation later on.

Proper heat-range is when the "color" is at the halfway point on the ground strap, neither too cold or too hot.

(Color = meaning the evidence of heat/or lack of heat by the appearance dark vs lightened color of metal)
Attached Images
File Type: jpg Spark_Plug_Readings_Cold3.jpg (133.9 KB, 2063 views)
File Type: jpg Spark_Plug_Readings_Proper_HeatRange2.jpg (146.5 KB, 2051 views)
Reply With Quote
Non-Sponsor Ads
  #2  
Old 09-16-2006, 01:44 AM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
Mixture

The air/fuel mixture ratio shows up on the base ring (the last thread ring, it has the strap welded to it). You want a full turn of light soot color on the base ring!!! If you want to tune for max. power, then you want 3/4 to 7/8ths of a full turn of light soot color to show up on the base ring, but this is on ragged-edge of being too lean, but will make the most HP on most engines.

To be safe, leave it at a full turn of light soot color. If the base ring has a full turn of color, but there are "spots" of heavy buildup of "dry soot" on top of color, then mixture is too rich .
Attached Images
File Type: jpg Slightly_Rich2.jpg (20.9 KB, 2013 views)
Reply With Quote
  #3  
Old 09-16-2006, 01:46 AM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
If the base ring has a full turn of color with some spots of heavy dry soot, then mixture is too rich, REGARDLESS, if the porcelain is "BONE-WHITE"
Attached Images
File Type: jpg Spark_Plug_Rich2.jpg (15.3 KB, 2003 views)
Reply With Quote
  #4  
Old 09-16-2006, 01:50 AM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
Preignition/Detonation

Porcelain = the porcelain shows up preignition/detonation, it will not accurately reveal mixture/air/fuel ratios. To look for the first/beginning signs of detonation, search the white porcelain for tiny black specks or shiny specks of aluminum that have fused to the porcelain.

When detonation occurs, part of the air/fuel mixture explodes instead of burning, the explosion is heard as a "metallic knock", this audible knock is the result of a sound shock-wave, this shock wave travels back and forth across the clearance volume "disrupting" the cooler boundary layer gases that cover the entire clearance volume area. This disruption allows "more" heat to be transferred into parts, especially, domes/piston tops,...along with the very rapid rise in pressure like a hammer blow, pistons can get torched with melted sides and holes !!!

With the early signs of detonation, the shock-wave will also rattle rings causing the tiny amounts of oil that now gets by rings, to be fused to the white porcelain as tiny black specks, also fused as specks are soot that was clinging to clearance volume surfaces in the relatively "still-air" of the boundary layer. One step beyond the black specks, will be tiny specks/balls of aluminum coming off the pistons that will be fused to white porcelain,....the next step to be reached is occasional pieces of the porcelain being broken-off as detonation gets worse, ETC. Soon after that are holes, blown head gaskets, broken connecting rods, ETC.

Center Electrode = the very tiny sharply defined porcelain -"ditch" that encircles the center electrode, will also show up early signs of preignition/detonation and the wrong heat-range. Look for signs of the ditch beginning to be filled up with melted porcelain, you will need a 5x or 10x magnifying glass.
Attached Images
File Type: jpg saltandpepper.jpg (70.9 KB, 2005 views)
Reply With Quote
  #5  
Old 09-16-2006, 01:55 AM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
Ideal heat range/mixture/timing:
Attached Images
File Type: jpg ideal.jpg (35.4 KB, 2009 views)
Reply With Quote
  #6  
Old 09-16-2006, 02:04 AM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
Carbon Fouled

Soft, black, sooty, dry-looking deposits indicate a rich air fuel mixture, weak ignition or wrong heat range spark plug (too cold). These carbon-based deposits are conductive, much like oil fouling, and will allow the voltage coming out of the center electrode of the spark plug to track down the core nose rather than jumping the gap. This will result in an engine misfire and further aggravate the carbon fouled condition.

Check for correct plug heat range. On fuel injected engines, check for sticking injectors, malfunctioning cold start valves and/or circuits. Also check for correct fuel pressure specifications.

On computer controlled vehicles, the "limp home" computer mode will always result in a rich condition. Therefore, it is imperative that you check the operation and condition of the on-board computer system.

On all engines, severe vacuum leaks can decrease manifold vacuum, resulting in a rich condition. Weak and/or damaged secondary ignition systems will fail to spark across the gap lowering combustion chamber temperatures and promoting carbon deposits. This condition could also result from continuous low speed driving or poor cylinder compression.

http://www.nightrider.com/biketech/spkplghnbook.htm
Attached Images
File Type: gif carbon.gif (3.5 KB, 1980 views)
Reply With Quote
  #7  
Old 09-16-2006, 02:05 AM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
Fuel Additives

Red to purple deposits on one side of the core nose are an indication of a fuel additive. While many of these deposits are non-conductive and do not contribute to lack of performance, some fuel additives contain octane boosters that leave conductive deposits on the core nose. Care should be taken to select fuel additives which are compatible with ignition systems and do not contain conductive materials such as octane boosters.

Exerts Copyrightę 1998 Cooper Automotive (Champion Spark Plug)
Attached Images
File Type: gif fuel.gif (4.5 KB, 1984 views)
Reply With Quote
  #8  
Old 09-16-2006, 02:12 AM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
Part 2

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

Lets analyze this plug, sorry the numbered points aren't clear but it's 1-4 you can figure it out.

#1 Is a timing indicator, you'll see a definite color change on the ground strap, it doesn't show well here but you can still see it right about at the arrow. Too much timing and the color change will be very close to the threaded body of the plug, too little and it'll be closer to the tip. Ideally we want it right in the apex or center of the 90 bend on the ground strap. This plug shows too much timing for the combustion chamber efficiency or octane level.

#4 arrow shows another indicator of timing, you'll usually see a brown ring right at the tip of the porcelain area it should be a sharp and defined ring about .020 wide. Wider indicates not enough timing and any smaller , or only 1/2 way around or nonexistent as in this image is the second indication of too much timing in the motor.

#2 The tip of the ground strap is loaded with OIL deposits, fuel deposits are usually flat black in color and almost like a fine powdery deposit, this motor is leaking oil into the combustion chamber, bad valve guides, leaking valve covers allowing oil to seep through the plug threads, whatever it needs to be fixed.

#3 The threaded portion of the plug gives you the heat range, look at the threads you'll see that a few toward the tip are a dull burnt looking color the rest are black and shiny. You want about 2 threads showing the heat on the end of the plug and the rest of the threads to be shiny, this plug is impossible to read because of the oil mess. If you using a longer reach plug than this one 2.5 to 3 threads is optimum.
To increase the number of burnt threads increase the heat range of the plug, if you have 4-5-6 threads burnt you need to get a colder plug.

Looking at the color of the porcelain I'd give this carb a passing grade at the mid range and not to bad on the idle circuits although that dam oil leak makes it tough to really get a good read. I'll get some better shots for lesson 2.
Attached Images
File Type: jpg plug1.jpg (54.0 KB, 1981 views)
Reply With Quote
Non-Sponsor Ads
  #9  
Old 09-16-2006, 02:13 AM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
2nd Plug Example

The plug is showing me by the deposits on the tip of the electrode and also the deposits right on the edge of the threaded body.
that it's slightly fat at idle.

The white porcelain is showing a lean condition at WOT, it's not too far advanced as the total timing mark or color change is right in the apex of the ground strap curve. The Idle timing is shown by the triangular hazing up on the flat of the ground strap and without even looking at the distributor specs I can tell you that the timing on this SB Mopar is about 18-20 initial and 34 total.

I would need a better picture of the threads to determine the heat range.

Changes:
I would try and lean it out just a touch at idle and up the jets by 2 points to fatten up the WOT circuit.

That slightly lighter color at the tip of the ground strap indicates too much gap, nothing serious but next time you change plugs I'd go to about a .036 gap from the current .040. Too much resistance caused by too wide of a plug gap can cause excessive heat on the tip which will shorten the life of the plug and really give you no benefits. I believe excessive plug gaps are not required on most Muscle and bracket cars, once you get into real big compression and major power you would open up the gap and replace plugs 2-3-4 times a year.
Attached Images
File Type: jpg Plug-2.jpg (26.5 KB, 1979 views)
Reply With Quote
  #10  
Old 09-16-2006, 02:15 AM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
Let's look at Image 1 (below).......
Note the change of color on the ground strap and it's position, this shows a timing issue. Unfortunately the reader who sent this image in didn't say what engine he was working on but by the condition of the plug I would guess a Small Block Chevy, 3 years old with 38* total timing and an Edelbrock Carb......I'm sure he will respond :-)

In the second image I used a green arrow to show the area where we want the timing mark to be on this engine and of course you can see that the motor has too much timing.

Image 3 shows only one thread heated on the plug and rest are oil soaked and wet this normally indicates that the plug is too cold, the oil indicates a valve cover leak and a New set of Cometic Aramid fiber gaskets would cure it.
Attached Images
File Type: jpg plug4a.jpg (11.7 KB, 1962 views)
File Type: jpg plug4b.jpg (12.8 KB, 1965 views)
File Type: jpg plug4c.jpg (25.5 KB, 1956 views)
Reply With Quote
  #11  
Old 09-16-2006, 02:17 AM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
The color on the plug indicates a decent idle A/F ratio and a good ignition system probably an MSD or some other type of aftermarket ignition. The hot spark is keeping the porcelain clean on the top area anyhow. Now if we look down into the bottom of the plug as seen in the above image where the porcelain reaches below the steel body we see black deposits indicating a rich condition at mid range to WOT. I would guess this engine is a little lazy in mid range and could get better mileage.

Changes:
Back off the total timing but keep whatever the initial is as it appears pretty good, I would shorten the total by 4* and do another check.
Fix the oil leak
Go up one heat range and after about 50 miles check to see if you have 2-3 threads heated up and discolored for correct heat range. Heating up the plug will help reduce the carbon build up and further tuning with the A/F ratios can be done

Before you can really tell what to do with the carb the ignition must be right as well as the correct heat range on the plug to get true readings.

...and check your Idler arm it appears to have some slack in it and your left rear tire needs 3# of air.
Attached Images
File Type: jpg plug4e.jpg (23.5 KB, 1953 views)
Reply With Quote
  #12  
Old 09-16-2006, 02:20 AM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
How To Read Spark Plugs

The Air/Fuel Map

Look at the porcelain and divide it into 3 areas, top, middle and bottom in about 1/3rds.

Top Area: This area is your idle circuit and for the racer real has very little meaning. However if your car is a street driven vehicle then we need to attempt to get this portion to a dark gray color by tuning the AFR, Idle Air Bleeds and the four corner Idle adjustments until we get a clean crisp idle and total combustion of the fuel at idle. Keep in mind that the idle circuits are totally isolated from the rest of the carburetor and can be tuned with very minimal affect on the WOT position A/F Ratio.

Center Area: This is the area that will show the combustion chamber condition at part throttle or cruise with the power valve and secondary venturi's closed. Usually about 30-50 MPH depending on the gear and weight of the car.

Bottom Area: This is where the racer needs to concentrate all his efforts, using a 5x or 10x scope you need to look right down to the bottom of the porcelain where it meets the metal housing of the plug. This is the area that will leave the color that you need to study and tune to. The other 2/3rds of the porcelain will be burned clean by the high heat generated by WOT and high RPM, this is not the time to read for cruise or Idle characteristics.

We're looking for a colored ring right at the base of that porcelain which I refer to as a Fuel Ring. The color will vary depending on the type of fuel your burning, Unleaded Pump gas will leave very little color because of all the additives such as injector cleaners and methanol. Most of us run a 108 or 110 in our bracket cars and these fuels will leave a tan color while the C17 and higher octane fuels will leave an almost gray fuel ring. If you study the ring you will see that it starts to show color just below the base of the ground strap, this is caused by the shielding affect of the strap leaving that portion cooler thus showing the most color. The ring will develop from each side and form a full circle of correct color as you get closer and closer to the correct tune up. If you look down into the bottom of the porcelain and you detect a thin oily deposit you are seeing oil from the combustion chamber caused by either worn or improperly seated rings, you may also detect this with a new engine that hasn't fully seated the rings yet, just don't confuse this with the "Fuel Ring".

Plug Characteristics

Shiny or Glazed Porcelain: This occurs for two reasons, excessive idling or rich idle condition leaving heavy soot deposits. These deposits will burn and create excessive porcelain temps causing the glass to melt usually resulting in a down track popping through the exhaust..
You will usually see splotchy deposits on the plugs after the run, either green or yellow in color and of course the tell tale shiny glaze. The porcelain should have a chalky or dull finish.


Base of threads sooty: This is usually a indication of the plug not being tight enough allowing it allow air to pulled in to the chamber and fuel being pushed out, change the plug, tighten to spec. This area should have a nice dark to medium gray color without heavy deposits.

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.

Shiny little diamond like deposits: It's too late you've already started to blow the pistons out of it. Start over from scratch, fatten the carb, back-up the timing and cool down the plugs. Now start a proper tuning procedure and hopefully you caught it before too much damage was done.

No color mark on ground strap: If your showing good color on the porcelain but the ground strap fails to show an indicator then your plug is too cold, go up 1 heat range.

If the ground strap is showing a good color line but the porcelain is showing no color at the base then your plug is too hot, drop down a range.
I will use maybe 3 different ranges on one bank, make a pass and from those three different plugs determine which one is correct for the engine.

Variable heat readings: On a small block motor most have adjoining exhaust ports, these will always be your hottest cylinders and in some cases where there has been excessive port work and thinning of the metal between the ports it may be necessary to run a plug one step cooler in those cylinders, use a plug indexing washer to back the timing down in those cylinders slightly, or if you have an adjustable ignition system you may want to electronically back the timing down in the hot cylinders.
Reply With Quote
  #13  
Old 09-16-2006, 08:44 AM
thecarreaper's Avatar
F1 World Champ
Silver Subscribed
 
Join Date: Sep 2003
Location: southeast
Full Name: name
Posts: 13,864
thread of the month!

i learned a tremendous amount from this, and i *thought* i knew how to read plugs.

thank you for posting this!!!

everyone can benefit from this, anything with plugs in it can give you its best if you listen to what its saying to you!


great thread!
Reply With Quote
  #14  
Old 09-16-2006, 11:47 AM
smg2's Avatar
F1 Veteran
Sponsor
 
Join Date: Apr 2004
Location: Newport Beach
Full Name: SMG
Posts: 8,096
do mine! do mine!, oh man that's GREAT info! learn something new everyday.

here. i'll put up my pics, WARNING! it's not that pretty.
okay background,
1980 mondial 8, 12k on rebuilt motor. addition of supercharger in last 500miles. awaiting dyno time before more driving. the plugs look the same before and after the charger. i was thinking i might have to go to a colder plug with the charger in place. the plugs are a 5 heat range, which is colder than the 6 spec'd.

runing electromitve timing, 6* idle 24* at 3k and 0* adv/rtd for 8k; total 30* timing. fuel is 91, shell gas.

plugs are from cylinder #2 & #3, #2 pics are first 5 then the rest are #3.

on one plug the porcelain has a buildup that i chipped off with my fingernail. the plugs were pulled cold, so this may be all mute.
Attached Images
File Type: jpg 2a.jpg (69.6 KB, 1920 views)
File Type: jpg 2b.jpg (106.1 KB, 1913 views)
File Type: jpg 2c.jpg (77.2 KB, 1903 views)
File Type: jpg 2d.jpg (80.4 KB, 1894 views)
File Type: jpg 2e.jpg (59.6 KB, 1888 views)
File Type: jpg 3a.jpg (127.2 KB, 1894 views)
File Type: jpg 3b.jpg (64.5 KB, 1876 views)
File Type: jpg 3c.jpg (82.2 KB, 1869 views)
File Type: jpg 3d.jpg (76.3 KB, 1867 views)
Reply With Quote
  #15  
Old 09-16-2006, 01:43 PM
smg2's Avatar
F1 Veteran
Sponsor
 
Join Date: Apr 2004
Location: Newport Beach
Full Name: SMG
Posts: 8,096
okay, after some digging it looks as though going colder than the 5 isn't easy. porsche used a W3DPO plug on the 911 turbos of the same vintage. however the plugs are $$$$ at around $15 a pop. funny looking to, single pole electrode and the ground sits off the outer ring just enough. nowhere near as high as your multi grounds.

the plug was spec'd by bosch for the CIS turbo applications, i can only assume that this would be the way to move for the SC variant i've created.

any ideas?
Reply With Quote
  #16  
Old 09-16-2006, 05:57 PM
No Doubt's Avatar
Four Time F1 World Champ
Consultant
 
Join Date: May 2005
Location: Vegas+Alabama
Full Name: Mr. Sideways
Posts: 48,594
My Garage
Quote:
Originally Posted by smg2 View Post
okay, after some digging it looks as though going colder than the 5 isn't easy. porsche used a W3DPO plug on the 911 turbos of the same vintage. however the plugs are $$$$ at around $15 a pop. funny looking to, single pole electrode and the ground sits off the outer ring just enough. nowhere near as high as your multi grounds.

the plug was spec'd by bosch for the CIS turbo applications, i can only assume that this would be the way to move for the SC variant i've created.

any ideas?

ASH FOULED

An example of overheating is shown below. Note the dead white or gray insulator nose which appears "blistered." Electrode gap wear rate will be considerably in excess of that normally expected. This is often caused by overadvanced ignition timing, poor engine cooling system efficiency (scale, stoppages, low level), a very lean A/F mixture, a leaking intake manifold, or the use of a spark plug too hot for the application.

As shown below, a buildup of combustion deposits stems primarily from the burning of oil and/or fuel addatives during normal combustion.
These are normally nonconductive. However, when heavier deposits are allowed to accumulate over long mileage periods, they can "mask" the spark, resulting in a plug misfire condition.

Light brown deposits encrusted on the ground and/or center electrodes indicate ash deposits. This situation is caused by oil and/or fuel additives. When the deposits are found on only one side of the spark plug core nose, it is usually considered to be a problem with the cylinder head (valve stem seals or valve guides). When they are found on both sides of the spark plug, it is often considered to be a problem sealing at the piston rings. This condition can mask the spark and, in some cases, contribute to misfire. Check for worn valve guides and valve stem seals and/or piston rings. The spark plug shown below is the correct heat range and was a victim of the engine's condition, not the cause of it.
Attached Images
File Type: jpg ash.jpg (9.7 KB, 1834 views)
File Type: jpg 10-ashdeposits.jpg (3.2 KB, 1828 views)
Reply With Quote
Non-Sponsor Ads
  #17  
Old 09-16-2006, 07:13 PM
smg2's Avatar
F1 Veteran
Sponsor
 
Join Date: Apr 2004
Location: Newport Beach
Full Name: SMG
Posts: 8,096
so is the ash fouling a result of the craptacular gas we have here in CA? shell now adds a percentage of E and the others are still pumping in MTBE although the're not supposed to anymore.

if the plug range is still to hot, then what? the 5 is the coldest i've found short of the expensive w3dpo's.

i guess i'll see when it goes on the dyno and i can tune the curve from there. the fuel management is the CIS no lambda. i'll be going back to the stock silver plugs but the colder 5's to see what happens there. my old bmw's didn't like the platinums so i had to go back to the silvers also.
Reply With Quote
  #18  
Old 09-16-2006, 08:06 PM
thecarreaper's Avatar
F1 World Champ
Silver Subscribed
 
Join Date: Sep 2003
Location: southeast
Full Name: name
Posts: 13,864
Quote:
Originally Posted by smg2 View Post
do mine! do mine!, oh man that's GREAT info! learn something new everyday.

here. i'll put up my pics, WARNING! it's not that pretty.
okay background,
1980 mondial 8, 12k on rebuilt motor. addition of supercharger in last 500miles. awaiting dyno time before more driving. the plugs look the same before and after the charger. i was thinking i might have to go to a colder plug with the charger in place. the plugs are a 5 heat range, which is colder than the 6 spec'd.

runing electromitve timing, 6* idle 24* at 3k and 0* adv/rtd for 8k; total 30* timing. fuel is 91, shell gas.

plugs are from cylinder #2 & #3, #2 pics are first 5 then the rest are #3.

on one plug the porcelain has a buildup that i chipped off with my fingernail. the plugs were pulled cold, so this may be all mute.



not sure what plugs you are using, but NGK5 plugs are "HOT" not cold. i have found the BP6 series to be excellent in the carb 308's. if you want to go colder from a 5, then you need a 6. from the looks of your overheating, i would say a 6 would help?

best
Reply With Quote
  #19  
Old 09-16-2006, 09:07 PM
smg2's Avatar
F1 Veteran
Sponsor
 
Join Date: Apr 2004
Location: Newport Beach
Full Name: SMG
Posts: 8,096
i'm running bosch plugs, the chart on the bosch site lists cold from 06~13. see here http://www.boschautoparts.com/NR/rdo...ationcodes.jpg

i also just checked the compression, cold engine (dead cold, not run in a week)
here be the numbers;
#1 : 190
#2 : 190
#3 : 185
#4 : 195
#5 : 190
#6 : 195
#7 : 195
#8 : 185
Reply With Quote
  #20  
Old 09-16-2006, 11:13 PM
Formula Junior
Not Subscribed
 
Join Date: Feb 2005
Location: West Coast
Full Name: Steve Hill
Posts: 899
Informative information on the spark plugs.

FYI, this is not how NGK determined the proper plugs for several of my Ferraris. They sent me several series of plugs, told me put 300 miles on each set with my usual driving habits, and ship them back for analysis. They cut the plug open vertically and looked for the flame front pattern on the plug. For the 288 GTO, it was a 9EV (became the EVX); 512TR, 8EV(X); Daytonas BP6ES and BP7ES. The 6ES plugs worked in a Spyder, and the 7ES plugs in a Coupe. The Spyder was a USA car. The Coupe a Euro car. I also drive the Coupe harder than the Spyder. Also, it should be noted, this was on CA crap gas, with MTBE. The amount of energy in the gas can make a big difference in plug gaps.

Oh, and remember, with NGK, the heat range is cooler as the number goes up.

Steve
Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


LinkBacks (?)
LinkBack to this Thread: http://www.ferrarichat.com/forum/technical-q/121401-spark-plug-reading-101-a.html
Posted By For Type Date
Ferrari 348 This thread Refback 01-19-2013 07:10 PM


All times are GMT -5. The time now is 03:43 PM.


FerrariChat.com has no association with Ferrari S.p.A.
vB Ad Management by =RedTyger=

ShowCase vBulletin Plugins by Drive Thru Online, Inc.