W C L

i havea set of manley trubo tuff rods that i picked up for dirt cheap new in box, and was wondering the hp rating on them...

b16sedan

More than you're going to make.

earl

rods don't have horsepower ratings...they break because of rpms...horsepower ratings are just a figment of some marketing guy's imagination.

NJIN BUILDR

So true.They use to rate rods in #'s of tinsel failure.The test fixture held the rod thru the pin end and crank end.Then the rod was pulled apart at a set rate.The #'s it took to destroy the part was its rating.That must have been a fun job.
Glenn

b16sedan

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">rods don't have horsepower ratings...they break because of rpms...horsepower ratings are just a figment of some marketing guy's imagination.</TD></TR></TABLE>

What about torque? Diesels have some big beefy rods, but they're usually turning half or a third the RPM's a little honda turns.

W C L

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16coupe &raquo;</TD></TR><TR><TD CLASS="quote">More than you're going to make.</TD></TR></TABLE>

power is not an issue.....with my 76mm friend

earl

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16coupe &raquo;</TD></TR><TR><TD CLASS="quote">

What about torque? Diesels have some big beefy rods, but they're usually turning half or a third the RPM's a little honda turns.</TD></TR></TABLE> I am not a scientist but there is an equation something like
force=mass X Velocity Squared
force is what breaks the rod.
mass is the weight of the piston and rod
and velocity is a factor of engine rpms and rod/stroke ratio
since it is mass X velocity X velocity....rpm factors big into rod breakage
Since a diesel runs on detonation, I think the rods must be able to take the abuse for another reason.
I'm in over my head on this explanation but I hope there are some college physics majors who can expand on this

Boosted Chemist

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote"> I am not a scientist but there is an equation something like
force=mass X Velocity Squared
force is what breaks the rod.
mass is the weight of the piston and rod
and velocity is a factor of engine rpms and rod/stroke ratio
since it is mass X velocity X velocity....rpm factors big into rod breakage
Since a diesel runs on detonation, I think the rods must be able to take the abuse for another reason.
I'm in over my head on this explanation but I hope there are some college physics majors who can expand on this</TD></TR></TABLE>

i belive force = mass X acceleration, so the faster a motor is turning the faster it is accelrating, velocity squared would be gxm^2/s^2 and force is in the units of g x m / s^2

earl

yeah acceleration and I guess deceleration is a better way to put it than velocity. The higher the rpms, the quicker the rod has to accelerate and then decelerate in any given cycle.

Full-Race Geoff

exactly, its acceleration that breaks ****, not constant velocity.