Board index

My Home Page

PilotOdyssey.com By hoser...


PilotOdyssey.com Chat Room

PilotOdyssey.com Photo Album

* Login   * Register * FAQ
http://www.pilotodyssey.com/PO/adm/images/imagemenu/smiley_cool.png PilotOdyssey.com Chat    http://www.pilotodyssey.com/PO/adm/images/imagemenu/find.png PilotOdyssey.com Google Search    http://www.pilotodyssey.com/PO/adm/images/imagemenu/emoticon_tongue.png FL400 Parts    http://www.pilotodyssey.com/PO/adm/images/imagemenu/emoticon_grin.png FL350 Parts    http://www.pilotodyssey.com/PO/adm/images/imagemenu/emoticon_evilgrin.png FL250 Parts    http://www.pilotodyssey.com/PO/adm/images/imagemenu/emoticon_unhappy.png Admin Email   
It is currently Thu Mar 28, 2024 9:20 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 15 posts ] 
Author Message
 Post subject: Spark Plugs
PostPosted: Wed Sep 29, 2004 5:59 pm 
Offline

Joined: Mon Dec 15, 2003 2:40 pm
Posts: 22512
Location: Chicago
Here are some old plugs I cut the metal off of to expose the porcelain

The plug on the left is way too fat you see black on the tip your jetting is
way off you need to lean out your air/fuel mixture the second plug is
also too fat but you notice the black only goes up about 1/2 way then
it is dark brown the 3rd plug is what I call normal but the smoke ring at
the bottom is still about 2 x wider than it should be the tip is almost tan,
if this was my plug I would lean it out some more, the far right plug was
not run long enough to really read but you can see the smoke ring at the
bottom starting to form (tip or red arrow) depending on the old plug I
would not panic and continue to run this plug with the current jetting to
see if it turned black or tan closer to the tip , when your jetting is right
that smoke ring at the bottom will be about 2x wider than you see in the
picture, the rest will be real light tan, this is safe, during race conditions
all white with the smoke ring at the bottom is ok, I have run this way
many times.

Search words...

spark plug
spark plug reading
reading spark plugs
read the plug

http://pilotodyssey.com/BillGivensjetting.htm


Attachments:
plugs.jpg
plugs.jpg [ 33.46 KiB | Viewed 12322 times ]
Top
 Profile E-mail  
 
 Post subject:
PostPosted: Wed Sep 29, 2004 6:07 pm 
Offline

Joined: Mon Dec 15, 2003 2:40 pm
Posts: 22512
Location: Chicago
Here is another view of the plug on the left, you can see that area the blue area
is pointing to has no color, looks new it is running so cold from a rich mixture
it wont change color, green arrow is pointing to the black unburned oil that sticks
to what is hot, the porcelain is hotter than the bottom of the threads.


Attachments:
plug2.jpg
plug2.jpg [ 11.16 KiB | Viewed 12318 times ]
Top
 Profile E-mail  
 
 Post subject:
PostPosted: Wed Sep 29, 2004 6:13 pm 
Offline

Joined: Mon Dec 15, 2003 2:40 pm
Posts: 22512
Location: Chicago
More info on reading the plugs


Attachments:
sparkplug.gif
sparkplug.gif [ 20.47 KiB | Viewed 12314 times ]
plugreading.gif
plugreading.gif [ 14.5 KiB | Viewed 11661 times ]
wordpic.gif
wordpic.gif [ 13.5 KiB | Viewed 10741 times ]
Top
 Profile E-mail  
 
 Post subject:
PostPosted: Thu Sep 30, 2004 1:11 am 
Offline

Joined: Sun Dec 28, 2003 10:38 pm
Posts: 228
Location: Knoxville, TN
Here is an article on the same topic.

How you can read spark plugs and select them - by Gordon Jennings
http://www.strappe.com/plugs.html


Top
 Profile E-mail  
 
 Post subject:
PostPosted: Thu Sep 30, 2004 9:30 am 
Offline

Joined: Fri Dec 19, 2003 9:37 pm
Posts: 824
Location: Howell, New Jersey
Great info Hoser - Thanks! It's also good idea to remind folks, as you did me last weekend, that before you dive in and begin jetting the crap out of your machine to check other possible causes of a fat or lean situation (i.e. dirty/clogged air filter, proper gas/fuel mix, etc.). It seems many (myself included) are way to quick to blame improper jetting for their performance problems when it is sometimes a much easier fix.


Top
 Profile  
 
 Post subject:
PostPosted: Thu Sep 30, 2004 4:25 pm 
Offline

Joined: Sun Dec 28, 2003 10:38 pm
Posts: 228
Location: Knoxville, TN
one thing on pilots i have seen before that may make them feel like they are very rich is a bad spark plug boot. that one took a while to figure out, but a new boot cleared everything up!


Top
 Profile E-mail  
 
 Post subject:
PostPosted: Fri Oct 01, 2004 2:33 pm 
Offline

Joined: Mon Dec 15, 2003 2:40 pm
Posts: 22512
Location: Chicago
Here is a new plug run for about 1 mile at high speeds, see the smoke ring but
nothing on the tip, pink arrow shows where the coating on the reach is burning
back . Jetting is a little on the rich side.


Attachments:
plug3.jpg
plug3.jpg [ 34.81 KiB | Viewed 12239 times ]
Top
 Profile E-mail  
 
 Post subject:
PostPosted: Sat Apr 01, 2006 7:53 pm 
Offline

Joined: Mon Dec 15, 2003 2:40 pm
Posts: 22512
Location: Chicago
Another pic.


Attachments:
mixture-ring.jpg
mixture-ring.jpg [ 31.09 KiB | Viewed 12105 times ]
Top
 Profile E-mail  
 
 Post subject: Plug reading
PostPosted: Sun Apr 02, 2006 9:34 am 
Offline

Joined: Mon Mar 01, 2004 6:58 pm
Posts: 357
Location: Wichita, Ks.
This is invaluable information. I know for certain I have all of my cars jetted rich as I've toasted many engines from jetting to close to the limit.

My plug chops show very dark brown insulators.

My question is how much harm is there from this practice?


Top
 Profile  
 
 Post subject: Re: Plug reading
PostPosted: Sun Apr 02, 2006 9:59 am 
Offline

Joined: Mon Dec 15, 2003 2:40 pm
Posts: 22512
Location: Chicago
Toyman wrote:
This is invaluable information. I know for certain I have all of my cars jetted rich as I've toasted many engines from jetting to close to the limit.

My plug chops show very dark brown insulators.

My question is how much harm is there from this practice?


Harm from what?


Top
 Profile E-mail  
 
 Post subject: Plugs
PostPosted: Sun Apr 02, 2006 8:52 pm 
Offline

Joined: Mon Mar 01, 2004 6:58 pm
Posts: 357
Location: Wichita, Ks.
Hoser; From running carb. jetting rich. Any harm in this other than a lower performance level from the Engine?


Top
 Profile  
 
 Post subject: Re: Plugs
PostPosted: Sun Apr 02, 2006 9:55 pm 
Offline

Joined: Mon Dec 15, 2003 2:40 pm
Posts: 22512
Location: Chicago
Toyman wrote:
Hoser; From running carb. jetting rich. Any harm in this other than a lower performance level from the Engine?


Nope not at all, you need to take plug chops to establish your jetting plug colors from general riding can vary alot, extended warm up times with the choke on can fool you into thinking your jetting is ok when it is not, once you get your engines jetting dialed with some seat time experience you will get to know your Engine by the sound and feel, the tone if the exhaust will be crisp the throttle response will be quick and sharp also, then on a warm day you will feel it getting mushy and flat, on a cold morning or late night ride you will feel it "run better than its ever ran" that's when you want to watch out...

http://pilotodyssey.com/jetting1.htm


Top
 Profile E-mail  
 
 Post subject: Rich Jetting
PostPosted: Mon Apr 03, 2006 9:52 pm 
Offline

Joined: Mon Mar 01, 2004 6:58 pm
Posts: 357
Location: Wichita, Ks.
Oh yeh, I've had that sensation several times.

I have a distroyed piston collection.

They always run their best right before they melt down.

This is why I jet alittle rich but worried maybe there may be some harm from carbon buildup etc.

I run it pretty hard at times so I'd be surprised if there was much.


Top
 Profile  
 
 Post subject:
PostPosted: Wed Jun 24, 2009 7:25 am 
Offline

Joined: Mon Dec 15, 2003 2:40 pm
Posts: 22512
Location: Chicago
More info


SPARK PLUGS
People who are relatively inexperienced in the art of tuning racing two-stroke engines seem always to
all into the trap of trying to use a spark plug that is too "cold", and / or one having the wrong nose
configuration, which they then compensate with a too-lean mixture. This kind of error probably stems from a
basic misunderstanding of spark plug heat-range, and the reason for having more than one type of plug. The
reason?

As it happens, the temperature of the burning mixture in the combustion chamber is high enough to melt the
Engine, and it fails to do so only because heat is carried away from the combustion chamber's walls fast
enough to prevent them from reaching flame temperature. The spark plug reaches much higher temperatures
than the cylinder head itself, because heat moving away from the plug's nose must cross the joint formed, by
the threads on the plug and in the plug hole. And, of course, the exposed plug electrodes are separated from
the cylinder head's cooling fins by -a very long heat-path, and in the case of the center electrode, by the plug's
insulator. Consequently, the electrodes get extremely hot, and that is very much a mixed blessing: Fairly high
temperatures are required to keep the plug's electrodes and insulator tip burned clean, to prevent the
formation of sooty deposits that can short-circuit the spark. But if the electrodes are allowed to become too
hot, they will constitute an independent and uncontrolled ignition source. That is to say, the electrodes may
become hot enough to ignite the air/fuel mixture in advance of the spark. When that occurs, combustion
chamber temperatures climb even higher which causes auto-ignition still earlier and that yields yet higher
temperatures in an ascending spiral that quickly leads to outright Engine failure.

So, the correct spark plug for a given Engine is one that stays hot enough to burn its electrodes and
insulator tip clean, but does not reach temperatures high enough to cause auto-ignition (more commonly
termed, "pre-ignition"). Unfortunately, all spark plugs transfer heat from their electrodes to the cylinder head
into which they are threaded at a rate fixed by their construction, while Engine operating temperatures vary
enormously. "Correct" selection of a spark plug is therefore a matter of choosing one having a heat-transfer
rate compatible with the application at hand. The process of selection is less exacting today than in the early
days of the internal combustion Engine, principally because the mica and porcelain used as insulators have
been replaced by aluminum oxide ceramics that are stronger and much better conductors of heat. Other
improvements in spark plug construction have further widened plug heat-range, hut not to such extent that
any plug will perform satisfactorily in any Engine. Touring plugs have extended tips, which burn clean but
have exposed ground electrodes and center electrodes, and these respond to prolonged full-throttle operation
by becoming incandescent; racing plugs have short, shielded electrodes and will tolerate higher combustion
chamber temperatures but foul very quickly under starting and idling conditions.

The most common spark plug configuration is the one in which the ground electrode extends over the
end of the center electrode. A much better type, in any two-stroke Engine application, has the ground
electrode reaching in slightly lower to approach the center electrode from its side. The improvement, here, is
that the ground electrode is somewhat shorter, and being shorter offers a more direct heat path to the plug
body - which means that it is less likely to become white-hot. A refinement of this design has a short bit of
platinum wire inserted in the tip of the ground electrode. This wire's diameter is quite small, and it is used in
conjunction with a center electrode also reduced in diameter at its tip, an apparently minor difference unless
you consider that much less voltage is required to form a spark between two points than between two flat
surfaces. An ordinary iron ground electrode cannot be made pointed, because its tip would instantly overheat
and melt, but platinum -with a melting point of 1774 C, as compared with 1535 C for iron - is less likely to
melt, has a thermal conductivity 18 times greater than iron, and will not oxidize. As a result, the platinum
electrode survives its hostile environment very well even when used in small diameters, and I would not
hesitate to recommend the platinum-tip plug for most racing applications. At any given heat-range, the
platinum plug will provide longer life and less tendency to foul than any conventional type plug. Pure racing
plugs, which have deeply recessed insulators and center electrodes, with an extremely short ground electrode
bridging straight across from a hole through the side of the plug body, should be used only as a last-resort in
two-stroke engines. Racing plugs of the type described are very, very prone to wet fouling, oil fouling and
every other kind of fouling possible. They are a necessary evil in hyper-horsepower road-racing engines, but
should never be used where extended-nose plugs will serve. Not unless there is some kind of major
breakthrough in either spark plug or ignition system design, which always is a possibility. I would recommend
that all who are serious about keeping ahead of the pack keep abreast of developments in these areas. All the
spark plug manufacturers are working constantly to give us improved foul resistance and reduced spark-
voltage requirements, and they are very accommodating to anyone who takes the trouble to write and ask for
literature.


"Reading" spark plugs, and the process of selecting correct heat-range, falls much more into the realm
of art than science, and it is an art in which one becomes really proficient only after long and sometimes
painful experience. But there are a few rules that may be used for guidance by those who have yet to acquire
experience - or by the many whose experience has left their ignorance largely undiluted: First, you should
know that it is all but impossible to read anything in the appearance of a spark plug unless the Engine has been
cut clean after having been brought up to operating temperature and given a long burst of wide-open throttle.
Very experienced tuners will see the signs they're looking for under the layer of soot, oil and fuel that
'accumulates so quickly at idle, but even they vastly prefer to work with clean-cut plugs. Second. get the right
heat-range before you try to rend mixture strength, and my recommendation is that you always use the hottest
plug the Engine will tolerate. You'll know a plug is too hot when you observe signs of blistering around the
insulator nose (which will also be scorched white) and on the electrodes. A too-lean mixture will also give
you a whitish insulator, but will not usually produce the burned, pitted appearance of the electrodes that is
characteristic of a too-hot spark plug. Also look for signs of melting along the sharp edges at the ground
electrode's end – any sharp corner will get hotter than other areas along the electrode, and trouble will first be
revealed there. A plug that is too cold simply looks, and is, wet. Plugs of the correct heat-range get hot
enough to burn away oil, and soot, and will have only dry, brown to tan deposits on their insulators after a
hard run. As noted before, the correct mixture strength will be wry slightly leaner than that which is just lean
enough to keep the Engine from four-stroking. How much leaner? Not very much, and until you have gained
considerable experience with a particular Engine you should not reduce strength below the jetting that
provides clean running. To get a bit closer to the optimum, I watch the faint, almost invisible ring of soot that
forms around the electrode on the insulator's nose, and the light dusting of soot over the exposed end of the
plug body. There is a point at which I see "just enough" soot, and if there is more or less than that - I interpret
the signs to mean a mixture that is too rich or too lean, respectively. And I couldn't begin to tell you how

much soot is "just enough”; that would be like trying to explain a taste, or sound, or smell. With experience,
you learn to recognize what it is you're looking for, and there is no substitute for that experience. You will
also learn - if you know where to look - that the faint light spot on the electrodes at the sides of the spark gap
are an important clue to ignition system performance. When you have a spot of about the same diameter as
the ground electrode's end showing on the center electrode, or vice versa, then you may be sure the magneto
is doing its job. When that spot begins to fade, or become ragged around the edges and shrinking in diameter,
the ignition system isn't performing as it should. Finally, with experience you'll learn to give your very close
attention to all aspects of the mundane task of selecting jets and plugs, and spark timing, because in these
things you ultimately succeed or fail as a tuner; all the rest is mere mathematics, surgery and wrench-twirling.


2 Stroke Tuners Handbook by Gordon Jennings


Attachments:
sparkplugs.pdf [451.01 KiB]
Downloaded 502 times
Top
 Profile E-mail  
 
 Post subject: Re: Spark Plugs
PostPosted: Sun Mar 11, 2012 11:00 am 
Offline

Joined: Mon Dec 15, 2003 2:40 pm
Posts: 22512
Location: Chicago
More on plug reading by adnoh in another thread viewtopic.php?f=1&t=5587&start=25


Top
 Profile E-mail  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 15 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Registered users: Bing [Bot], Google [Bot], wyeeoddy


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group