spark plug question...

[jcs003]

are you guys running your plugs with or without the crush ring?

i ask this because i was talking to a friend of my fathers who raced in the 70s early 80s and he said he would remove the crush ring to lower the plug in the combustion chamber.

it didnt sound like a very good idea, so i thought to ask around.

you know some of them old timers can become confused about the old days after a few beers.lol

[hartwill]

your piston may hit the plug if it sits too low in the head, aside from that the crush ring acts as a gasket so you will probably loose compression and power without it. hope this helps.

[rooster300ex]

It also keeps it from vibrating out. They have the crush washers for a reason

[jcs003]

thanks for the clearity. there is so much misinformation in this world its necessary to get a majority concurence.

[atvmxr]

Originally posted by jcs003
there is so much misinformation in this world its necessary to get a majority concurence.

I suppose you never heard the phrase "never underestimate the power of stupid people in large groups" ?

its definately a challenge to find out answers for anything, there is just as much, if not more, misinformation on the internet. some times there are things that work that the majority of people will say wont work... i figure its best to just try it yourself.

so in this case, how do you even get the crush sleeve off of the plug in first place? do you have a spare head to try in out on so you can see how much it lowers the plug and how the plug will seal on the head?

[wilkin250r]

They make extended-nose spark plugs.

I'm not ever going to knock testing and the pursuit of knowledge, but particular issue seems silly. If the technology already exists, I'd have to think the design engineers have looked at it. If it was really beneficial, they would have designed it in.

[HondaATC500X]

hypothetically, the closer the plug is to the piston, the more heat and chance for detonation you have. sounds like a bad idea to me.

[wilkin250r]

Originally posted by HondaATC500X
hypothetically, the closer the plug is to the piston, the more heat and chance for detonation you have. sounds like a bad idea to me.

And there are a TON of issues to consider when making a change like this.

You are correct. In theory, if you start the combustion process closer to your piston, closer to the center of the combustion chamber, you'll get a better burn, more uniform. But since you are starting closer to your piston, you'll transfer more heat to the piston, more likely for detonation. The head will generally be much cooler than the piston because of the liquid cooling.

If the spark plug is protruding into the combustion chamber more, you'll have a longer path for heat to travel to get rid of it, so you're spark plug will run hotter, and increase the risk of a hot spot.

Your head design will also play a significant role in all these aspects, whether you have a combustion chamber that is wide and flat with a narrow squish band, or if the chamber is taller with a wider squish band.

And, my personal opinion, if you don't know about all these factors, and how they affect your combustion process and how the spark plug nose is influenced by them, then you shouldn't be changing things until you understand them.

[jcs003]

Originally posted by wilkin250r
And there are a TON of issues to consider when making a change like this.

You are correct. In theory, if you start the combustion process closer to your piston, closer to the center of the combustion chamber, you'll get a better burn, more uniform. But since you are starting closer to your piston, you'll transfer more heat to the piston, more likely for detonation. The head will generally be much cooler than the piston because of the liquid cooling.

If the spark plug is protruding into the combustion chamber more, you'll have a longer path for heat to travel to get rid of it, so you're spark plug will run hotter, and increase the risk of a hot spot.

Your head design will also play a significant role in all these aspects, whether you have a combustion chamber that is wide and flat with a narrow squish band, or if the chamber is taller with a wider squish band.

And, my personal opinion, if you don't know about all these factors, and how they affect your combustion process and how the spark plug nose is influenced by them, then you shouldn't be changing things until you understand them.

i understand the whole process through an engineering standpint. but as i was trained we always include safety factors.

i was more interested in the practicle benefit of this. i have learned that the lil tweaks can make a world of difference in a 2-cycle. im glad there are others to pass on their wisdom when i may have been led astray.

[fearlessfred]

[QUOTE]Originally posted by atvmxr
[B]I suppose you never heard the phrase "never underestimate the power of stupid people in large groups" love this quote.
your comment on little tweaks making a differance is true, but this is one i wouldnt do. try blue printing your intake track.i have always had good luck with that. years ago harry klemm wrote a four part artical on what is wrong with an atvs intake track, but he left it up to the reader to figure what changes to make. one of the biggest clues he gave was the fact that a carb draws almost all of its air from the outer edges of the airhorn and that you could place asilver dollar vary close to the center of the carbs airhorn and not effect flow and that a volicity stack would be the ultimate setup

[wilkin250r]

Originally posted by fearlessfred
years ago harry klemm wrote a four part artical on what is wrong with an atvs intake track,

What is the matter with you, man?!? Don't just TELL us about the article, go out and find it and post it here!!!

[fearlessfred]

Originally posted by wilkin250r
What is the matter with you, man?!? Don't just TELL us about the article, go out and find it and post it here!!!
i have no idea were to find those magazine articles. i thru away all my mags a year ago ( 20 years worth ) mabe some other old person might remember were to find it.