Need a sanity check on my math:

Since there are "stocked" pistons made for a 4" stroke Crank using a 6.125" Connecting Rod.

Shouldn't I be able to run those pistons with a stock stroke crank(3.622") and a 6.314" connecting rod or there abouts?

 

right on the money, assuming a measured DH of 9.245". you'd be looking at what a 71% rod/stroke ratio.

 

cool, thanks for the math check

 

You could run a 4.8 rod (6.285) and deck the block .030 and have the same thing for a lot less money.

 

To tell where the piston will wind up in relation to the deck, I always use deck height-1/2 stroke-rod length-comp height. + number= out of the hole, - number= in the hole, 0=zero deck.

So with the two compression heights being the same:
9.245"-2.00"-6.125"-X=9.245"-1.811"-6.314"-X

You are correct sir, but where are you going to get a rod with that exact length? Custom? Titanium perhaps?

 

That is why I suggested the 4.8 rod.
A custom set of pistons and stock rods would be a lot cheaper than pistons and custom rods of course as well.

 

Those would put him about 0.029" in the hole, assuming the off the shelf stroker pistons are at zero deck with the 4" stroke/6.125"rod combo. It'll drop his compression ratio quite a bit too.

 

The 4.8 uses a longer rod? interesting.

 

that would leave him with a CH of only .93". that would make for a lightweight piston that's for sure. wouldn't you run into some piston rock unless tolerances were dead nuts on???

 

See post #4.

"wouldn't you run into some piston rock unless tolerances were dead nuts on???"

The length of the skirt controls that.