Runwell vs Zeda crank

[willis617]

With a lathe, after your achieve acceptable alignment, you could skim the od and faces of the weights for a better balanced, smother running motor.

 

[Street Ryderz]

With a lathe, after your achieve acceptable alignment, you could skim the od and faces of the weights for a better balanced, smother running motor.

I use both methods and the lathe is handy for checking if it's trued,but you wouldn't skim the od or the faces, once it's trued the weights should be identical in dia and both lateraly and verticaly square.You also dont want to turn the faces as that will increase case volume lowering c.c.r. a bit and every bit helps,more important is that mass needs to be removed to improve balence and from a certain area so again all the mass left in place helps rather than hurts it.If you reduce too much of the mass the engine strugles to accelerate properly as it fights to over come the compression.

 

[Spare_Parts]

The local guy uses a lathe. If I had a good set of v blocks and a set of dial indicators with bases, I'm sure I could handle it. Costs less to have someone else do it.

 

[willis617]

Same diameter is no problem, and square, is achievable, and I'm talking .005-.010" skim cut, maybe less, wouldn't the benefits outway slight increase to case volume?

 

[Street Ryderz]

Same diameter is no problem, and square, is achievable, and I'm talking .005-.010" skim cut, maybe less, wouldn't the benefits outway slight increase to case volume?

So if the dia are the same and it's square what benefits would there be to skim cutting it? That won't improve balence it just reduces mass even though it's not much and yes it's only slight increase in case volume but there are other area's in witch we increase it and it all adds up quick so as I said every bit left in place helps.Trueing the crank eliminates alot of the unwanted vibes,further balencing it helps to shift the dynamic balence (sweet spot) up in the rpm range,so if your building an engine to make it's peak output higher in the rpm range you want that dynamic balence where the engine spends most of it's time.

 

[Lukesky36]

My question is what are the pros and cons of a longer rod and the pros and cons of a shorter rod on these motors other then port clearances

 

[willis617]

I use both methods and the lathe is handy for checking if it's trued,but you wouldn't skim the od or the faces, once it's trued the weights should be identical in dia and both lateraly and verticaly square.You also dont want to turn the faces as that will increase case volume lowering c.c.r. a bit and every bit helps,more important is that mass needs to be removed to improve balence and from a certain area so again all the mass left in place helps rather than hurts it.If you reduce too much of the mass the engine strugles to accelerate properly as it fights to over come the compression.

Street,
After reading your response a 2nd time i get what your saying about proper alignment bringing everything else to place, thanks

 

[FNTPuck]

Zeda now includes balanced cranks in all the triple40 motors which is nice. Big difference from the stock junk I was used to.

FWIW they also do welded, balanced, and trued cranks done to min of .002" but they are expensive as hell @ $70...

 

[gary55]

Zeda now includes balanced cranks in all the triple40 motors which is nice. Big difference from the stock junk I was used to.

FWIW they also do welded, balanced, and trued cranks done to min of .002" but they are expensive as hell @ $70...

The stock triple 40's are balanced similar to nearly all the modern engines on the market. The welded crank engines have improved balance and trued cheeks.

 

[Street Ryderz]

My question is what are the pros and cons of a longer rod and the pros and cons of a shorter rod on these motors other then port clearances

Even though it's only 2mm difference between the strokes that 2mm equates to quite a few degrees in rod angularity and that allows higher power density to be attained due to the extra dwell at the top and bottom.And a long rod takes advantage of this aswell and having both a long rod and longer stroke is better again to take full advantage of this.