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Old 03-24-2007, 06:55 PM   #1
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Default Intrested in engine tuning!

Hello!

I am wondering if someone have any link or info about engine tuning. With pictures and explanations. Not engine adjustments.. i mean when you change port timings, some modifications to crankshaft etc..

i am really intrested how to do this.. whats is possible to do and not to do.
i have an old Mega SX-21 Evo1 engine that i think can be improved like 1-2% :P
the crankshaft have engraved M.D.S?? what does it stands for?

i attach some pictures with crankshaft and sleeve.
i dont know what angles of the parts that can help
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Intrested in engine tuning!-1.jpg   Intrested in engine tuning!-2.jpg   Intrested in engine tuning!-3.jpg  

Last edited by Orfeous; 03-24-2007 at 08:20 PM.
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Old 04-12-2007, 10:26 PM   #2
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Very good question, I wonder the same!!
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Old 04-13-2007, 03:29 AM   #3
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read all info you can find here......

http://www.rctech.net/forum/showthread.php?t=30411
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Old 04-13-2007, 06:53 AM   #4
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Quote:
Originally Posted by M7H
read all info you can find here......

http://www.rctech.net/forum/showthread.php?t=30411
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Old 04-13-2007, 10:24 AM   #5
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it is real hard to do it yourself, the crankshafts have to be balanced, if not they don't run well after words
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Old 04-13-2007, 01:51 PM   #6
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Quote:
Originally Posted by rcrevolution
it is real hard to do it yourself, the crankshafts have to be balanced, if not they don't run well after words
Quote:
Originally Posted by the above thread
If you want to get fussy, and allow for the port being moved, balance on a "wheel" type balancer. This can even help on a stock type crank. (see some of the Russian engines, .15 size for examples). The amount of counterbalance needs to be in the 50~65% range of the weight of the piston,wrist-pin,(ring, if used) and 1/2 the weight of the rod. To test this, measure the weight of the reciprocating parts on a good gram scale, and make up bob-weights in this amount to add to the crankpin, before you put it on the balancer.The crankpin should "stop" at the 12 O'clock position. On a single cylinder engine: If you add weight to the counterbalance, or lighten the reciprocating weight. you DECREASE the PRIMARY shaking imbalance (vertical= Cyl. bore axis), and INCREASE the SECONDARY imbalance (crosswise= across the lugs).
For this reason, IT'S IMPOSSIBLE to balance a single Cylinder engine, without a secondary Balance shaft, as used in some auto engines. Adding weights (heavy slugs) to the counterbalance is done to change the resonant frequency at which you get a "Harmonic" or strong vibration level. You want this at a lower than full rpm number. Most of the ST X-40's used in Formula-1 Pylon and Fast Rat had cranks that needed this changed to resonate in the high-teens (RPM). Sometimes you could see the engine "shake" in this range, on the test stand. I never put a strobe light on one to see what one would look like while running. If the engine is balanced to "resonate" at full RPM, IT USUALLY COMES APART
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Old 04-13-2007, 03:21 PM   #7
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Here one of the "unusual" way to balance crank-may be will help to somebody. It is cut behind front bearing.
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Old 04-15-2007, 01:08 PM   #8
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Heres an engine tuner question. I have an Axial 28, what is the best pipe and clutch to run with it for use on a big dirt oval. Im using it in a 1/8 buggy single speed only?
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Old 04-15-2007, 06:02 PM   #9
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i understand that modding the engine isnt something to do if you dont know what you do but i am curious if something is doable on my sleeve and crankshaft? if you look at my pictures. My friend told me that they allready was modded. He also told me that i can use a dremel or just polish it to change timings. This is an old engine and it woluld be fun if there was something to do about it for test purposes
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Old 04-15-2007, 09:52 PM   #10
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what rpm should your clutch engage on a .28 as well?
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