Author Topic: Quality control  (Read 561 times)

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Offline Cut4fun .

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Re: Quality control
« Reply #10 on: December 25, 2013, 12:49:58 pm »
Yes the case, it was a closed port jug. I dont know how I could file this?

Redneck Idea:  If no lathe etc.  Take thick plexiglass or something else similar and make hole where cylinder O goes in. Then attach different emery cloth sheets around hole to take down base by hand.   Make sure sanding base area is level and flat.
Make sure to measure all 4 corners and keep all even all the way around once you are removing base to where you want it.
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Offline alsled

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Re: Quality control
« Reply #11 on: December 25, 2013, 12:52:25 pm »
^^^^^^^^^ :)

Offline alsled

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Re: Quality control
« Reply #12 on: December 25, 2013, 12:57:26 pm »
3/4 scrap piece of cabinet grade plywood would probably work also, can also staple emery to wood.

Offline Al Smith

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Re: Quality control
« Reply #13 on: December 25, 2013, 06:56:28 pm »
It's not my saw nor am I being picky about the methods but it's normal practice to carve the cylinder base down instead of filing on the case .The fact that it's a closed port transfer port designed engine  has nothing to do with it ,so are most Stihls and Husqvarnas .

Offline alsled

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Re: Quality control
« Reply #14 on: December 25, 2013, 08:04:02 pm »
Al,

Its all good, I never thought of doing the hole in the plexi, nor do I have access to a lathe, so i didn't think I could file the jug down with the protruding portion of the jug.

Offline alsled

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Re: Quality control
« Reply #15 on: December 25, 2013, 08:05:20 pm »
To tell you the truth, I thought of cutting the rod and welding it back together, just a little longer.

Offline Magnus

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Re: Quality control
« Reply #16 on: December 26, 2013, 05:48:35 am »
Never understood why there is so much talk about squish measurement...
If you change hight on cylinder the gain you get is from port timing, rather than higher compression.
I'd rather have bigger volume so I can get in more fuel.
To me it is better to get more fuel above piston that can create power.
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Offline alsled

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Re: Quality control
« Reply #17 on: December 26, 2013, 08:38:38 am »
Magnus,

Don't knock it till ya try it, it works!!!! :)

Offline KilliansRedLeo

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Re: Quality control
« Reply #18 on: December 26, 2013, 09:02:29 am »
WOW Alan, that is some pretty radical thinking! Cutting and welding the rod, would not have worked out too well. I have seen it done by a few people 'just to see' before having a custom rod made. The welded rods did not last very long and when they came apart they trashed everything in their path!

Well good luck with it but just in case something goes wrong, why don't you try the filed cases with another cylinder, that way you won't ruin that pretty OEM closed port cylinder! Then if all proves out you can swap for the CP jug.
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

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Offline alsled

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Re: Quality control
« Reply #19 on: December 26, 2013, 09:05:59 am »
And when you lower the jug or put a taller piston on you are not changing the volume between the top of the ports antop of head.  To lessen the volume in this area, you would have to bring the head down, which is very hard to do as the jug and head is all one piece.

 Compressing fuel air mixture to just a point before detonation will yield the most power.

Kinda the same as when you have a tired saw with low compression due to worn rings, re ring it and leave everything stock and it runs better again, reason, compression.

I was concerned a while back about some of these high compression ratios on a saw with 93 octane fuel, i think the inefficientcy of a chainsaw muffler design vs a real tuned pipe on lets say a dirt bike or snowmobile is the reason.  I have built 800cc snowmobile engines that made 185 hp and over 100 ftlbs of torque.  125 cc dirtbikes were putting out over 30 hp.  Chainsaw engines with the muffler can't come close.

Getting back to compression, the 185 hp engine could only have 120lbs of compression, due to when running the pipe design sucked more fuel and air in, we don't have the luxury of tuned pipes on a work saw, so squish the hell out of it!!!

 

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