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short rod crank question


sangheraent

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I know short rod cranks are less reliable because they put more friction on the cylinder and pistons. Now if I go to short rod crank and raise my mixture from 40:1 to 32:1 or maybe 30:1 wouldnt that help increase reliability and lower friction?

 

My banshee has good top end and was rebuilt recently and I dont want to buy new pistons and all that because im poor (well not really) on my budget i cant afford to buy all new pistons and stuff so Im going with the short rod crank but I want to get as much reliability as I can.

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i forgot to say Im thinking of porting and 4mill crank but im on the fence about going 4mill stroker with short rod. everything is fine on my engine now but people say short rod gives more friction so i thought if I increased oil ratio it would reduce friction

Edited by sangheraent
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i forgot to say Im thinking of porting and 4mill crank but im on the fence about going 4mill stroker with short rod. everything is fine on my engine now but people say short rod gives more friction so i thought if I increased oil ratio it would reduce friction

I am not sure about increased friction with the stock stroke length. It is more the angle that the force is applied with. When running a long rod crank the angle of force is closer to 180 degrees as opposed to the stock rod length which would be an angle closer to 90 degrees then the long rod. Obviously we are not talking about a huge angular difference, but this should give you an idea of the concept.

 

SP

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I use to run a short rod 4mil stroker crank and it would rev up faster than my long rod but i broke alot of piston skirts, adding more oil to your fuel will not fix this problem of being unreliable.With the longer stroke it changes the working angle of the rod it is about geometery not about friction.If you have an agressive port job with big ports this helps amplify the problem because it lets the piston rock back and for more in the bore were the long rod will put less sideways force on the piston. I have a box of broken pistons to prove this.

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