Seems its a question asked alot and made out to be far more complex then it really is. I have been commenting on differnt peoples spark plug pics but really, you need to look at the piston tops as well to get a full view of whats taking place inside your engine. You can easily look at the pistons tops with the use of a bendable little led light. You can get these at most any hardware store and they are small and fit right into your pocket. Just remove the sp.plug and then you can see down inside by inserting the end of the light thru the sparkplug hole in the head.
You can see the whole view of the piston top depending on where the piston is in relation to the stroke, you simply grasp the clutch and rotate is forward or backward to see a certain area, youll have to move your head around to see it but youll pick this up quickly, its easy.
I have written on a few pics of pistons with the heads removed only so you can see better what to look for.
They say a picture is worth a 1000 words, so heres your 1000 words. Click on the pictures to make bigger and read my chicken scratch/paint writing
.
1.) Rich: piston will be silver,wet/shiny looking and have carbon build up in the center only. The piston top will show no signs of little pit marks or problems with detotnation. The edges will be clean looking and undamaged. The pic I have of a rich piston is rich,.. but not so bad the sled would perform too badly, it is likely about 1-2 main jets too big, or the needle is just a bit too rich thru out the range, but it has alot of safety in it for temp drops. Sometimes with todays bad fuel your better off to be richer, its much cheaper then pistons.
2.) Lean: Lean piston will be dry on top, dull colored and will show signs of pit marks if detonation is starting to rear its ugly head. In this pic you can see the piston has no wash marks at the rear, they are dry and no silver coloring(piston washed clean), also youll note the little pick marks all around the front edges, they look like sand grains, this is detonation starting, too much heat/lean mixture. Very little carbon build up forming because the piston is too hot to form it.
3.) ideal mixture: ((First off let say this was a brand new engine not run very long, just dyno time, so its lacking the carbon on top and the tan coloring is just beginning to form but it shows a few key areas well, so thats why I used this pic)).
You will see the wash marks at the rear, see the silver piston color showing, like little curves,silver/wet looking. The center is beginning to form carbon on it, it will eventually cover most of the piston top, it will range from dark brownish/black to a lighter tan coloring, depends on your oil used.
You can also see slight wash marks on the sides( there is solder marks used from checking the squish as noted on pic), but the other slight wash marks will show up in this area, they will no where be as noticeable as the rear are.
You need this piston top to match the spark plug to know what you have going on inside the engine. these 2 items coupled together and youll have a perfectly running engine producing very good power and have a bit of safety in it for the late night temp drops. better to always be richer by a jet size then leaner.
You can see the whole view of the piston top depending on where the piston is in relation to the stroke, you simply grasp the clutch and rotate is forward or backward to see a certain area, youll have to move your head around to see it but youll pick this up quickly, its easy.
I have written on a few pics of pistons with the heads removed only so you can see better what to look for.
They say a picture is worth a 1000 words, so heres your 1000 words. Click on the pictures to make bigger and read my chicken scratch/paint writing
.1.) Rich: piston will be silver,wet/shiny looking and have carbon build up in the center only. The piston top will show no signs of little pit marks or problems with detotnation. The edges will be clean looking and undamaged. The pic I have of a rich piston is rich,.. but not so bad the sled would perform too badly, it is likely about 1-2 main jets too big, or the needle is just a bit too rich thru out the range, but it has alot of safety in it for temp drops. Sometimes with todays bad fuel your better off to be richer, its much cheaper then pistons.
2.) Lean: Lean piston will be dry on top, dull colored and will show signs of pit marks if detonation is starting to rear its ugly head. In this pic you can see the piston has no wash marks at the rear, they are dry and no silver coloring(piston washed clean), also youll note the little pick marks all around the front edges, they look like sand grains, this is detonation starting, too much heat/lean mixture. Very little carbon build up forming because the piston is too hot to form it.
3.) ideal mixture: ((First off let say this was a brand new engine not run very long, just dyno time, so its lacking the carbon on top and the tan coloring is just beginning to form but it shows a few key areas well, so thats why I used this pic)).
You will see the wash marks at the rear, see the silver piston color showing, like little curves,silver/wet looking. The center is beginning to form carbon on it, it will eventually cover most of the piston top, it will range from dark brownish/black to a lighter tan coloring, depends on your oil used.
You can also see slight wash marks on the sides( there is solder marks used from checking the squish as noted on pic), but the other slight wash marks will show up in this area, they will no where be as noticeable as the rear are.
You need this piston top to match the spark plug to know what you have going on inside the engine. these 2 items coupled together and youll have a perfectly running engine producing very good power and have a bit of safety in it for the late night temp drops. better to always be richer by a jet size then leaner.
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FJViper
New member
Another excellent article Mr. Viper as always. Much appreciated.
not sure why but i got the plug in perfect color now but never end up to get some wash .....must be the way cylinder are ported ?????????
SWEDE
New member
Thanks Mr. Viper, good reading as usual!
YAMMIEGOD3:16
Active member
Nice Don. 3:16 (yammie Tony)
modsrx said:
porting can change the way it looks,slightly somewhat. If your bored run it good and hard and shut it off. Tow back to garage and take off a head and post a pic, also pic of the plug. be happy to look at it for you. Alot of times its the octane masking the readings, so if your dabbling in race fuel it makes this harder to read.
if your piston is closer to the rich one shown your better off likely a size or 2 too rich but good for long,long pulls.
This needs to be put in the Tech FAQ section or Turks Tech corner and Pinned.
Nice write up!!!
Mac
Member
For any of you tuners who want to see the top of the piston without removing the head. You can purchase a light with a flexible shaft and see the piston top through the spark plug hole. Don't make the mistake of purchasing a light that is not bright enough. I made this mistake with the blue light pictured below. The light must be super bright. The Steelman was my second purchase and is the only other light i have used and is plenty bright. I have found the light difficult to use or see out on the lake or trail. Who knows maybe its me and you young guys may have better vision. When used in my enclosed trailer or garage with all lights off I can see everything perfect. Nice info MrViper.
09nytro
New member
Very nice write up
Mac said:For any of you tuners who want to see the top of the piston without removing the head. You can purchase a light with a flexible shaft and see the piston top through the spark plug hole. Don't make the mistake of purchasing a light that is not bright enough. I made this mistake with the blue light pictured below. The light must be super bright. The Steelman was my second purchase and is the only other light i have used and is plenty bright. I have found the light difficult to use or see out on the lake or trail. Who knows maybe its me and you young guys may have better vision. When used in my enclosed trailer or garage with all lights off I can see everything perfect. Nice info MrViper.
the little lights I use are brighter then even the "bend a lights", and you cant break the bulb like a bend a light
(dont ask how I know..lol) The little lights I have just got from the plastic container at the register at the hardware store, has 2 buttons on it, 1 is a red laser pointer and the other is for the flexible tip, about 4-5 inchs long and has a LED bulb on end with a little housing to protect it, very,very bright. Uses 2 of the LR44 batterys in it, oh ya.. has a magnet on the end to store it on your toolbox top....lol
heres one on evil bay-cheap too!
http://www.ebay.com/itm/book-light-...4127242?pt=US_Flashlights&hash=item35b83aca0a
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need to keep this one at the top
to the top
to the top
Great Stuff!
YAMMIEGOD3:16
Active member
GREAT TOOL RIGHT THERE. 3:16 (yammie tony)
mrviper700 said:the little lights I use are brighter then even the "bend a lights", and you cant break the bulb like a bend a light
The little lights I have just got from the plastic container at the register at the hardware store, has 2 buttons on it, 1 is a red laser pointer and the other is for the flexible tip, about 4-5 inchs long and has a LED bulb on end with a little housing to protect it, very,very bright. Uses 2 of the LR44 batterys in it, oh ya.. has a magnet on the end to store it on your toolbox top....lol
heres one on evil bay-cheap too!
http://www.ebay.com/itm/book-light-...4127242?pt=US_Flashlights&hash=item35b83aca0a
I picked up one of these lights. Works great! Came with 3 extra batteries. Fits right down the plug holes and easy to move around. I should have bought two. No more pulling pipes to try to get a decent look at an entire piston top. Love this little bugger.
bokat said:
makes life easy doesnt it? Good job!!
sockeyerun
Test Dummy
Ditto, I just bought two myself.
musselman
Active member
Question: say you were running lean and the pistons were pretty dry looking and you richened the jetting quite a bit, how long would it take to get a good wash reading? (ie. wash the caked on carbon off on the intake)