Author Topic: Grooving the cylinder  (Read 336 times)

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Offline joe_indi

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Grooving the cylinder
« on: March 10, 2015, 06:17:52 am »
We have been thrashing this subject of grooving on cylinder heads on an automobile forum. Yesterday a member posted these links. I had a MS460 come in today for a piston replacement. It seemed a golden opportunity to try a bit of grooving. So, after getting the necessary assent from the customer to use his saw as I guinea pig, I got down to it and faced my first hurdle, how to groove the cylinder head!
The customer started getting some anxious moments seeing my attempts and was on the verge of withdrawing his assent  when I got the bright idea of grooving the piston top instead.
5 minutes later I was tightening down the cylinder.
Started the saw up and waited for it to warm up and gave the new piston to run a bit.
I checked for any changes.
Since I had no test instruments I had to go by my senses.
When throttling the sound at the air intake is more pronounced.
A hint of a deeper note at the exhaust.
Feels as if mid range has increased.
I had to move the H  screw out a bit beyond 1 turn to get a four stroking at full rev.
The L screw also needed to be turned out a bit more to get a smoother idle.
I was able to take a couple of snaps of the piston before and after the grooving.
Unfortunately the customer was not in a mood  to take a video of the running saw with my Blackberry.
I am on a slow connection right now. I will upload the images later. (I have uploaded  the images
I will try to get a video later.


http://www.somender-singh.com/

https://www.youtube.com/watch?v=5YbcOhiwmkE

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Offline Cut4fun

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Re: Grooving the cylinder
« Reply #1 on: March 10, 2015, 01:44:57 pm »
Seems like it would impede flame travel across the piston? Then again maybe I am thinking into it to much.
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Online srcarr52

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Re: Grooving the cylinder
« Reply #2 on: March 10, 2015, 03:11:20 pm »
This is only beneficial for low RPM (low velocity) and will hurt performance as you get to higher RPM where turbulence already exists due to the high velocity (E.G higher Reynolds number).

Offline aclarke

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Re: Grooving the cylinder
« Reply #3 on: March 10, 2015, 04:26:05 pm »
  With a Hemi type head seen on many chainsaws the "swirling motion" (turbulence) is created when the fuel/mix enters the chamber in a vertical swirling motion if I'm not mistaken.

Not sure how the piston grooves  would help that?

The Indian guy , Somender  Singh has been cutting grooves on key portions of heads to improve burning of stagnant areas in combustion chambers for years with apparent dyno proven results. I tried this on a few saws and didn't feel any difference.  Lol


   



Offline joe_indi

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Re: Grooving the cylinder
« Reply #4 on: March 11, 2015, 05:45:01 am »
  With a Hemi type head seen on many chainsaws the "swirling motion" (turbulence) is created when the fuel/mix enters the chamber in a vertical swirling motion if I'm not mistaken.

Not sure how the piston grooves  would help that?

The Indian guy , Somender  Singh has been cutting grooves on key portions of heads to improve burning of stagnant areas in combustion chambers for years with apparent dyno proven results. I tried this on a few saws and didn't feel any difference.  Lol



As I had mentioned in my post, the grooves are to be cut on the head, not on the piston. Since I had no tools handy to cut grooves on the head  through the restricted space of the cylinder I tried these grooves instead on the piston.
But I dont know if the grooves on the piston give results similar to grooves on the head.
Joe

Offline aclarke

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Re: Grooving the cylinder
« Reply #5 on: March 11, 2015, 05:39:51 pm »
Some detailed dyno reports of Singh grooves on a 3 cylinder Suzuki (geo metro) engine.   Looks like improvements under some conditions, and stock is better under others.



www.herningg.com/singh

Offline 1manband

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Re: Grooving the cylinder
« Reply #6 on: March 14, 2015, 06:21:55 am »
the piston crown is also the floor of the combustion chamber.

not a fan of sharp edges on the piston though, hot spots.  (old school).  maybe if it was ceramic coated?

there was a company that manufactured race pistons years ago with raised pattern 'grooves/ribs' that is no longer around(?)

will look around for a photo. edit: http://www.autoserviceworld.com/issues/image.aspx?src=/daily_images/117003-49057.jpg&size=170

^what scarr wrote.

please show some photos after it was run.

cool experiment joe!


-(another) joe



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Online srcarr52

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Re: Grooving the cylinder
« Reply #7 on: March 14, 2015, 11:29:51 am »
the piston crown is also the floor of the combustion chamber.

not a fan of sharp edges on the piston though, hot spots.  (old school).  maybe if it was ceramic coated?

there was a company that manufactured race pistons years ago with raised pattern 'grooves/ribs' that is no longer around(?)

will look around for a photo. edit: http://www.autoserviceworld.com/issues/image.aspx?src=/daily_images/117003-49057.jpg&size=170

^what scarr wrote.

please show some photos after it was run.

cool experiment joe!


-(another) joe


Those cut outs in that piston are valve reliefs. 

Offline Cut4fun .

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Offline 1manband

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Re: Grooving the cylinder
« Reply #9 on: March 14, 2015, 02:16:23 pm »
the piston crown is also the floor of the combustion chamber.

not a fan of sharp edges on the piston though, hot spots.  (old school).  maybe if it was ceramic coated?

there was a company that manufactured race pistons years ago with raised pattern 'grooves/ribs' that is no longer around(?)

will look around for a photo. edit: http://www.autoserviceworld.com/issues/image.aspx?src=/daily_images/117003-49057.jpg&size=170

^what scarr wrote.

please show some photos after it was run.

cool experiment joe!


-(another) joe


Those cut outs in that piston are valve reliefs.

little ones.  have never seen or heard of them made for 2 strokes.  would guess that they would not be effective.

have to see if i saved some pics off the web of "yin/yang" pistons (don't know what they were called) on my old laptop, a few different designs of smokey's idea (?) by some other folks.

the pic above looks like it's only 1/2 swirl?

edit:
could not find the photo.  think the drawing of smokes piston in a patent looks a bit different from the photo of them i saw.  (the ramps lead to flat spot on the photo.  drawings do not seem to show this).  brain cells dying off.  https://encrypted.google.com/patents/US4467752

ironic thing is that smokey seems to have been quoted that it didn't quite work after he built a flow bench.  don't know if this is true.

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