Author Topic: things plug  (Read 373 times)

0 Members and 0 Guests are viewing this topic.

Offline 1manband

  • Nitro Hotsaw
  • *******
  • Posts: 759
  • Karma: 52
things plug
« on: July 25, 2015, 07:07:24 am »
cut up a plug,

dodge.  about 20,000 miles on the plug.  computer controlled, fuel injected, etc.

hope it gets clearer as to why, as the thread moves its way along.
hiatus

Share on Facebook Share on Twitter


Offline 1manband

  • Nitro Hotsaw
  • *******
  • Posts: 759
  • Karma: 52
Re: things plug
« Reply #1 on: July 25, 2015, 07:35:48 am »
at the lower left of this pic, it shows a broken insulator.  this was my first attempt at cutting to find where the ceramic meets the metal.  was a little high, and broke the plug.

this will most likely take a couple of tries to find the correct cut off point.

pencil is pointing to the 'fuel ring'

in each photo, the position of the cut off ground electrode and threaded portion is oriented as if it were attached to the plug.

the bright silvery metallic color below the pencil point, is actually ceramic.  this is very hard material, and will not be cut.  the bright metal was worn and got deposited on the ceramic, came from the HSS cut-off tooling.

hiatus

Offline 1manband

  • Nitro Hotsaw
  • *******
  • Posts: 759
  • Karma: 52
Re: things plug
« Reply #2 on: July 25, 2015, 07:38:01 am »
some things that can be seen:

-at the ceramic tip, a flow pattern is there.  one of the things that influences where these deposits form is the curved ground electrode.  on the curved side, more deposits.  on the open side, less.

-fuel ring at bottom of plug insulator:  is wider on the ground electrode curved side.  thinner at open side.

some things that i could unfortunately not show clearly in the photos were:

-deposits/color of the top of the metal ring.
-deposits/color on the ground electrode.

there was not an opportunity to show those because the plug was coated with white ash deposits on the exposed metal, this ash is covering what i wanted to show underneath.

-------------------
next hope to compare to 2 stroke plug with some time on it, a few 'plug chop' method plugs in rich, lean and good tune conditions.....etc.

i don't own a electronic controlled carb saw.  if anyone has one, and has access to a lathe or cut-off tool it would be interesting to see your photos.

hiatus

Offline 1manband

  • Nitro Hotsaw
  • *******
  • Posts: 759
  • Karma: 52
Re: things plug
« Reply #3 on: July 25, 2015, 09:25:06 am »
things fuel ring:

-widest portion of fuel ring = 0.116 inches
-narrowest portion of fuel ring = 0.067 inches

so what to do... with this info.....

need the average.  average = 0.0915 inches.  this is about the width of the ring at the other two sides of the plug on either side of the plug.

going to call this number the 'reference plug'.

assuming that the computer controlled injectors are doing their thing correctly, the factory picked the correct heat range for the spark plug, etc.

going to use this width as a target for the 2 stroke plug.


hiatus

Offline 1manband

  • Nitro Hotsaw
  • *******
  • Posts: 759
  • Karma: 52
Re: things plug
« Reply #4 on: July 25, 2015, 12:10:21 pm »
up next is a plug from my saw motor.

plug has about 15 tanks through it.

last 2.5 tanks through it:  stumping a 40 inch plus diameter white pine.  air temp high 80's to low 90's.  motor was very hot under heavy load.

fuel ring:

(at least) minimum = 0.095 inch
(at least) maximum = 0.110 inch
approx. 0.1025 inch average

will describe what i see, when time permits.  in short, rich and/or wrong plug heat range for load.

plug and ground orientations shown similarly as in the previous dodge photos.

 
hiatus

Offline 1manband

  • Nitro Hotsaw
  • *******
  • Posts: 759
  • Karma: 52
Re: things plug
« Reply #5 on: July 25, 2015, 02:56:52 pm »

things are clouded up here, threatening rain....after i woke up from a nap......postponing a brake job.

imo.......

top photo: 
looking at the bottom of the threaded metal portion exposed to combustion.  portion of one side looks clean.  the remainder has black deposits.  shows uneven heat distribution.  if this was wet with fuel after a hot shutdown, rich.  clean area possibly rich washed.  should be colored and color should be uniform around its entirety. 

top photo, 2nd down, 3rd down:
looking at curved ground electrode.  in top photo is is bare of any deposits....getting too hot.  should show deposits about half way on flat section exposed to combustion.  the pencil is pointing to the first signs of deposits on the side of ground.  notice it's down in the curved portion.  electrode is getting too hot in these views as well.

the rest of the photos show a very wide fuel ring.  it will be wider than the dodge plugs.  showed the dodge plug width to establish an example of proper ring and minimum width.

the saw plug was black on on one side of the insulator due in part to ground electrode shrouding coupled with the minuscule distance between the insulator and threaded metal portion of the plug.

the plug in question, is an ngk bpm8y.  going to look for a colder #9 plug replacements and try some different tunings at this point.

don't think the saw will ever see higher loads and heat than it seen in those last 2.5 tanks.  i want to make sure to tune for the most heat soaked and heavy load conditions.

more to come after i get some more plugs.

hope it helps
-joe



hiatus

Offline aclarke

  • Nitro Hotsaw
  • *******
  • Posts: 1676
  • Karma: 172
Re: things plug
« Reply #6 on: July 25, 2015, 06:16:15 pm »
I'll cut a 562 plug now.   Thks for sharing all the pics and info

Offline aclarke

  • Nitro Hotsaw
  • *******
  • Posts: 1676
  • Karma: 172
Re: things plug
« Reply #7 on: July 25, 2015, 06:39:01 pm »
Ngk cmr6h.  562xp. Three tanks on plug

[img http:///img]

Offline aclarke

  • Nitro Hotsaw
  • *******
  • Posts: 1676
  • Karma: 172
Re: things plug
« Reply #8 on: July 25, 2015, 06:48:16 pm »
Ground electrode


[img http:///img]

Offline aclarke

  • Nitro Hotsaw
  • *******
  • Posts: 1676
  • Karma: 172
Re: things plug
« Reply #9 on: July 25, 2015, 06:57:35 pm »
Better...

[img http:///img]

 

Related Topics

  Subject / Started by Replies Last post
2 Replies
390 Views
Last post October 09, 2011, 07:23:58 pm
by Cut4fun .
56 Replies
1626 Views
Last post March 10, 2015, 12:02:35 pm
by dutchsawdoctor
6 Replies
226 Views
Last post March 20, 2013, 05:45:45 am
by dutchsawdoctor
2 Replies
226 Views
Last post August 18, 2014, 09:02:55 pm
by 1manband
4 Replies
1195 Views
Last post June 04, 2014, 11:54:13 pm
by 3000 FPS
9 Replies
87 Views
Last post August 08, 2015, 12:01:40 pm
by 1manband
5 Replies
161 Views
Last post July 20, 2016, 07:33:47 pm
by 1manband
1 Replies
312 Views
Last post January 06, 2017, 02:48:19 pm
by Cut4fun .
1 Replies
165 Views
Last post June 06, 2017, 08:50:57 am
by Cut4fun .
9 Replies
358 Views
Last post June 18, 2017, 08:25:10 pm
by Al Smith