Intrested in engine tuning!
03-24-2007 | 05:55 PM
#1
Thread Starter
Tech Regular
Joined: Mar 2006
Posts: 293
From: Umeå, Sweden
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
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
Last edited by Orfeous; 03-24-2007 at 07:20 PM.
04-13-2007 | 02:29 AM
#3
Tech Elite
Joined: Dec 2004
Posts: 2,198
From: The Netherlands
04-13-2007 | 05:53 AM
#4
Originally Posted by M7H
04-13-2007 | 12:51 PM
#6
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
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
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
04-15-2007 | 05:02 PM
#9
Thread Starter
Tech Regular
Joined: Mar 2006
Posts: 293
From: Umeå, Sweden
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
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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