FrontEngineDragsters.Org Forum
Technical => Matt Shaff's Engine Shop => Topic started by: wideopen231 on October 23, 2021, 10:22:25 AM
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How much weight change before you rebalance crank. New rods .020 shorter but heavier on small end. Big end almost same .By almost I mean less than 10g. Small end on other hand is 240g old rods 275g on new rods. My thought is I can probably get most of it off pistons or at least half of it. One reason I will be putting another set in later anyway. Probably heavier than ones in motor since .125" bigger Would rather do that than grind on new set of $1500 MGP rods. Guessing difference is billet rod just denser material and heavier. If matters its billet crank also. Motor will probably rarely see 8000 rpm and if so will be brief flash . New pistons might be a while since nobody has anything to make parts out off just like cam guys have no cores to grind. Unfreaking believable. Thanks Joe Idiot.
Piston, rings, pin and rod weigh 1955 total 35 more than old combo. Pistons are not heavy but not lite. Thinking I can get maybe half that back there.Small end of rod shows biggest difference in two rods. Ig can get 15 or so grams off then only about 15 to 20 off old and thats right at 1% ,which I would think would be non issue, might be wrong. Nobody local I would trust to balance this crank and KB doesn't do cranks anymore from my understanding. Plus KB was bought out few years back and another group running it.
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if all the pistons and rods are the same weight it just the percentage that will change under 8000 it should live