Author Topic: Plug Chop  (Read 3061 times)

aas5f6

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Plug Chop
« on: February 11, 2009, 12:14:54 PM »
How do you perform a plug chop and what information does it tell you?

hoodlum

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Re: Plug Chop
« Reply #1 on: February 12, 2009, 06:22:07 AM »
Quote from: "aas5f6"
How do you perform a plug chop and what information does it tell you?

A plug chop tells you how lean/rich your engine is running...
To do a chop,let you engine get up to temp and ride it around for a bit.....This clears all the excess fuel from the crankcase....
Get in a large area such as an open field or long stretch of road....Hammer it wide open and don't let off...Let it run for 10-15 sec after it has reached speed,then without letting off the gas,hit the kill switch and let it roll to a stop....Pull the plug and look at the ceramic part of the plug down below the electrode.....
If it's black,you're rich...If it's whitish,you're lean....You are looking for a nice brown color,sorta like a ups truck....
Hope this helps...
Hoodlum

Adnoh

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Plug Chop
« Reply #2 on: February 12, 2009, 04:53:33 PM »
Heres how I do it. I can do full post if anybodys interested on how the hacker does it.

aas5f6

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That would be great!
« Reply #3 on: February 12, 2009, 06:10:31 PM »
I read this site right here: http://www.dfn.com/benkaren/plugchop.html and I just need a picture to be able to compare what its supposed to be to what it is. Does it have to be under a load when  you perform the chop? Or can I just jack up the rear of the odyssey and floor it?

Ozpilot

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Plug Chop
« Reply #4 on: February 12, 2009, 10:48:22 PM »
Under load will give a proper reading - there is really no use knowing what is happening with no load.  The idea is to see what is actually happening at a certain point in the rev range under certain load conditions.  Therefore, you ride at the point in the rev range you want to check then you preserve the condition of the plug by "chopping".

It may be good to slip into neutral (or engage the clutch if it's not CVT) when you hit the kill button.  If you don't do that the plug could fuel up from unburnt fuel and/or the engine could suffer from lack of oil (assuming its a 2 stroke).  (I'm sure Hoodlum assumed this part so didn't set it out)

Adnoh

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Plug Chop
« Reply #5 on: February 13, 2009, 02:12:35 PM »
Heres a pics for comparison. If you cut all the way around and remove its easier to read. It also allows you to heat range as well. I my case I use N4c or 7.

Adnoh

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Plug Chop
« Reply #6 on: February 13, 2009, 02:20:12 PM »
FYI. These plugs are from the wife new motor in her pilot. It has been ported and had head work done.

Weed

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Plug Chop
« Reply #7 on: February 13, 2009, 02:24:07 PM »
As my Mexican amegos at work would say.....EXCELLENTE!!!

Great work Adnoh!!!!

Adnoh

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Plug Chop
« Reply #8 on: February 13, 2009, 03:15:37 PM »
Thanks weed. I take it the new job going well. Bummer the pilot jug discontinued.

hoodlum

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Jug
« Reply #9 on: February 13, 2009, 04:12:35 PM »
Quote from: "adnoh"
Thanks weed. I take it the new job going well. Bummer the pilot jug discontinued.


What?!?! jug discontinued?!?!

aas5f6

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Spark Plug Chops
« Reply #10 on: February 13, 2009, 08:44:44 PM »
I am going to perform my chops next weekend and I will post the pictures here. I think Im rich still because without cutting the spark plug threads, i could see that the white insulator was a dark brown, and the plug was brand new. This was chopped without a load on it though.

Adnoh

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Plug Chop
« Reply #11 on: February 14, 2009, 10:50:00 AM »
Do not pre judge untill you measure smoke ring. This next info is for discussion only.

Sometimes a dark porclean is to cold of plug. Example. This is fact bassed on plug choped done at dune. There was an odyssey that we done chops on that was bored,water cooled head and the addition of a cooling fan. The owner jetted it to the understanding that go fat untill stumbles and then drop one. This is the normial procedure. Now with that in mind we did some chops. The results showes a little fat but had  a lot of black soot on the porclen( his ngk 8 plug).  Upon his rebuild he stated thee was a lot of carbor build up on the exhasut port. Why is there build up if the jetting is right. Two reasons possable. #1 too cold of plug #2 trans oil in the cylinder. So we tested first with a  new 8 plug which resulted in a ok smoke ring with build up. Then we tested a 7 which resulted in very close to ok but lean with the build up gone. A simple neddle adjustment would bring the main into line. The reason I believe it had the build up was due to over cooling caused by the fan on the water cooled head wicking to much heat from the cylinder lowering cylinder temp and not burnig the plug clean.  This machine did not have any thermo switch to control expansion rate taking heat fromthe collent. One could unplug fan to check but time did not permit. The throttle responce did improve due the total combustion of the mixture allowing a broder prower stroke which could be felt by the seat of the pants.

Please do not go hotter on heat range without checking.  On the plug chop if it was to hot it would have shown signs of spotting on the porclean which is why you cut it up and measure smoke ring as well as examine the porclean. On key thing to rember is always gap the plugs the same prior to runs. In this example it required a gap of .045 to get proper gap spark.

Rember when in dout use mfg recomedations and it better to foul one than burn up a top end. If you use the .080 and tan porclean besure to run the mix the same and all filters are clean and you use same octane levles. Better to play it safe and be a little fat than lean. However if you alter the set up in any way you must do plug chop to get it right and achieve max preformance.

Can't wait to see you pics and read your post. Be sure to take notes. what octane ,what mix, filter clean, cranking compression, altatiude, ect. it willhelp later if theres a problem. Oh ya have fun while doing it.