how do you do it and how many thousandths are acceptable
I have my 026 set @ .015 to .017 the smaller the bore the tighter the squish band can be. But you will need to run premium gas in it. What is your comp. at now????????
the smaller the bore the tighter the squish band can be. But you will need to run premium gas in it.
Yes and no. Very high compression may require premium gas and may result in detonation, but it is possible to have tight squish and low compression, like my lame 066BB.bitzercreek1 said:When it starts getting tighter than that there is a greater risk for detonation.
I agree, for chainsaws.bitzercreek1 said:for the most part you want to stay over .020 in
Most all of my saws are between .016"-.020". You're not going to have any issues with fuel with just tightening up the squish. BTW, I use soft electrical solder to measure squish.
I've read that lower octane fuels can induce detotnation and knock more frequently with a tighter squish.
Could be. I was just saying that premium fuel is all you need. That's all I run in my ported and popup saws
I've read that lower octane fuels can induce detotnation and knock more frequently with a tighter squish.
I wonder if they are saying this assuming tighter squish is linked to higher compression?
In general given compression is the same tighter squish = higher squish velocity = reduced detonation potential. The exception to this is when squish is taken well less than 0.020 and the boundry layer gets stripped off the surface of the piston exposing the piston to direct flame which can seed pre-ignition remote from the sparkplug and set up a detonation potential from colliding flame fronts. Tell tail sign of this is a piston crown where the squish band area is covered in minature craters or looks like it has been etched with acid.
In a properly run chainsaw though I think detonation is a very rare event and not much need getting worked up about it.
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