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Old 10-21-2009, 06:33 PM   #1
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Questions?? Piston c-clip position???

What's the better c-clip position to place when we change connecting rod??

I have recieve my Jammin 28 as in #1 pics, but want to know you, how you install it, because i think that the position of the clip is important.

pic #1


pic #2


pic #3
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Old 10-21-2009, 06:51 PM   #2
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It doesn't matter as long as it is in the grove securely.
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Old 10-21-2009, 07:02 PM   #3
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It DOES matter.
when that engine is going 40,000 rpm, that little clip is: moving in one direction, stopping almost instantly, then reversing direction 80,000 times per minute. That's a lot of inertia. It's own mass can cause the clip ends to "close towards each other" more freely if the gap is at the 3 or 9 o'clock position. I ALWAYS assemble with the gap at the bottom or top. ( 6 or 9 o'clock)
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Old 10-21-2009, 07:17 PM   #4
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Originally Posted by motomatt View Post
It DOES matter.
when that engine is going 40,000 rpm, that little clip is: moving in one direction, stopping almost instantly, then reversing direction 80,000 times per minute. That's a lot of inertia. It's own mass can cause the clip ends to "close towards each other" more freely if the gap is at the 3 or 9 o'clock position. I ALWAYS assemble with the gap at the bottom or top. ( 6 or 9 o'clock)
You're not serious are you?

The tension of the clip will out hold the inertia of it's own weight.
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Old 10-21-2009, 07:35 PM   #5
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You're not serious are you?
Very.
The stroke of a .21 engine is approx. 17mm. This means the piston would travel 17mm 40,000 times per minute/666 times per second/ for a final value of.........11,333 mm traveled per second. "Uncle Albert's" theory of relativity states that E= MC squared. Energy equals mass times the square of the velocity. Inversely, as speed doubles the energy of the mass (insert the word circlip) squares.
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Old 10-21-2009, 08:00 PM   #6
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Uncle Albert's theory is not what's at play here. The equation you cited indicates how much energy would result from the complete conversion of the mass of the clip into energy, not its inertia nor even its momentum (which is what is really the force involved). The momentum (momentum=mass x velocity), the decceleration, and the spring constant of the clip would be used to determine if the clip would deform enough to dislodge from the groove.
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Old 10-21-2009, 08:09 PM   #7
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It doesn't matter as long as it is in the grove securely.
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Old 10-21-2009, 08:12 PM   #8
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Ok moving away from theory and to actual practice.
I slap the clips in and run the motor till the rod breaks in half

Seriously though, it does not matter where the clip is pointing.

Next thing we'll be debating is if having your motor tilted will increase wear on the low side of the engine
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Old 10-21-2009, 08:17 PM   #9
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Next thing we'll be debating is if having your motor tilted will increase wear on the low side of the engine
You mean it doesn't!!! Now I find out after all that time I spent shimming my engine exactly perpendicular to the chassis
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Old 10-21-2009, 08:19 PM   #10
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Those hyper 9's must go through engines like crazy.
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Old 10-21-2009, 08:34 PM   #11
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I can tell you on a two stroke, chaisaw, weed eater,back pack blower, snowmobile , jetski, dirtbike, boat motor, four stroke engines that turn upwards of 10k rpm it is absolutely critical.Now in nitro if it doesn't matter.... i will make sure the opening of the clip is at ether 12 o clock or 6 o clock. If you put the opening at 3 or 9 it can deform.physics change at the speed of light/nitro. FACT
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Old 10-21-2009, 08:38 PM   #12
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In practice, it doesn't seem to matter since most motors are not going to last long enough to matter.

However, if you want it perfect, the little tab should be straight up and down (vertical). Top or bottom doesn't matter.

The reason: if the tab is horizontal it will bend up and down slightly with every stroke. This constant flexing could cause the metal to fatigue and the tab to break off, doing serious engine damage. I have actually seen this happen on motorcycle motors with LOTS of time on them but like I said, ours don't seem to last long enough to fatigue them.
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Old 10-22-2009, 08:53 AM   #13
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Quote:
Originally Posted by rstnboy View Post
Uncle Albert's theory is not what's at play here. The equation you cited indicates how much energy would result from the complete conversion of the mass of the clip into energy, not its inertia nor even its momentum (which is what is really the force involved). The momentum (momentum=mass x velocity), the decceleration, and the spring constant of the clip would be used to determine if the clip would deform enough to dislodge from the groove.
Thank you for explaining that.

Otherwise we would have to have to tried to figure out E=MC2 vs. kgm/s2
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Old 10-22-2009, 09:07 AM   #14
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Default hey dakamat...question...

sorta unrealted question.....i've got two jammin .28's. had to break both down for rebuilds. found the CON ROD on one of them with the bushing OILING HOLE facing the front of the engine(typical) and the other one with the OILING HOLE facing the rear(??...not exactly typical). ran this finding by the NITROHOUSE guys(picco knowledge base). they told me that the .28's have the con rod oiling hole facing the rear of the engine where it can pick up more lube(somehow)...??? sounded kinda wacky to me.....so.......which way the the OILING HOLE facing on your .28...??
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Old 10-22-2009, 09:44 AM   #15
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I REALLY dont think it matters - but out of the piston and rods i have seen they are all like PIC 2/3
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