would the increased bob weight of h-beam rods and forged pistons decrease the hp handling capability of my stock crank or will my crank handle hp the same and my engine just benefit from the upgraded rods and pistons. i don't think the pistons are much heavier than stock but i am guessing the rods are at least 100g more than stock. i know i should have bought stronger crank but i have what i have now.

 

You need to get your engine balanced.

The counter weights on the crankshaft must balance out the pitons, rods, rings, etc. to reduce harmonics, increase power and prolong bearing life.

 

engine is balanced. i just know that h-beams have quite a bit more meat than stock i beams and although it is balanced, the crank is turning more rotating weight. i figure it's working harder and might possible handle less power put to it than with lighter stock rods....maybe this is just what i get for thinking....?

oh and is there any direct relation between rotating weight and harmonics? would two identical short blocks, one with heavy rotating assembly, and one with a light one, both balanced out nicely, have similar harmonics?

 

I wouldn't worry too much. Unless you've added massive amounts of power,
the crankshaft wont be at risk.

If anything, you've strengthened the rod's tensile load handling and that
will save the engine from throwing a rod.

The added weight might show up as inertial loss under acceleration, but I
doubt it's worth losing sleep over.

 

thanks for the help, that was just kinda buggin me. what you see in my sig is what i got. after tune and break in, i may throw a 100-150 wet shot at it just to go ahead and break the stock 10 bolt, but that's about as far as my hp goals are gonna go.

 

If I were you I would yank that motor out and install a 302. Those rods weigh to much!

 

The aftermarket rods are only a small amount heavier usually and the pistons are lighter 90 per cent of the time so the bobweight usually is somewhat lighter not heavier anyway.

 

If your new rods are indeed 100 gm heavier, and the pistons aren't a lot lighter than stock, in other words if the reciprocating weight is significantly heavier, inertia (g) loads on the crank will increase at every rpm. That will load the crank more.

With stock heads you probably aren't revving it very high, so the inertia loads shouldn't be something the crank can't handle. If you were increasing your revs to 68-7000 range with better heads, etc. it might be more of a problem.

What was the bobweight used during balancing?

 

Too much worry about silly things....

If you're going to lose sleep over something, it should be over how in the world you're ever going to outrun me next season.

 

for some reason sneaky, after hearing whos repairing your hot rod, i'm no longer concerned or "losing sleep" over that one.....

 

Doesn't matter who repairs it.... I'll still be the one driving/tuning it.

I saw that they have Nyquil on sale at the Wal-Mart in McKinney. You should probably go stock up while it's cheap.

 

You fools are retarded. Chad Ewell pwns both yall!

 

Hmmm..... How bout this.

Here's a list of things that have OWNED "Pistonslap" over the last few months:

1. The hood on his own car, "made a nice mess when it blew open going down the highway".

2. The carb. that is currently on his car right now, "brand new and will not run right for crap".

3. His cousin, "who geekishly owns him on BF2 every night."

4. DLC and his vert Ls1, "this one hasn't happend yet, but pretty sure it will".

 

lol. Nobody cares.