Posted By: juicedcuda
Pushrod question? - 08/30/09 12:30 AM
Do you think manton or smith bros can make a 5/16 pushrod that would be equally as strong as a 3/8? I am running a pretty stout solid roller.
Pushrod question?
Posted By: MR_P_BODY
Re: Pushrod question? - 08/30/09 12:39 AM
Quote:
Do you think manton or smith bros can make a 5/16 pushrod that would be equally as strong as a 3/8? I am running a pretty stout solid roller.
I'm pretty sure they can but the wall thickness would
make them pretty heavy.... its alot easier to pick
up the strength in the diameter
Posted By: juicedcuda
Re: Pushrod question? - 08/30/09 12:46 AM
Yeah but I have already clearanced the heads as much as I am comfortable with and I am still afraid that a 3/8 would lay on the head and not sit in the rocker cup all the way.
Posted By: MR_P_BODY
Re: Pushrod question? - 08/30/09 12:56 AM
Quote:
Yeah but I have already clearanced the heads as much as I am comfortable with and I am still afraid that a 3/8 would lay on the head and not sit in the rocker cup all the way.
If you dont have any 3/8 push rods that are the right
length to test with.... get a piece of 3/8" threaded
rod and cut it to length and hit the ends on a grinder
so they sit in the cup and lifter and check it... its
a cheap way to check... just use a light test spring
Posted By: thecarfarmer
Re: Pushrod question? - 08/30/09 01:17 AM
If you do find you need to run 5/16 pushrods, Smith Brothers makes 'em.
I'm running 8.35" X .115 wall in a solid roller application (540# pressure over the nose of the cam) in a B engine.
They've been first-class guys to deal with.
I'm running offset rockers (too good a price to pass up) on Stealth heads, hence the small pushrod.
BTW, I'd run 3/8" if there were room...
-Bill
I'm running 8.35" X .115 wall in a solid roller application (540# pressure over the nose of the cam) in a B engine.
They've been first-class guys to deal with.
I'm running offset rockers (too good a price to pass up) on Stealth heads, hence the small pushrod.
BTW, I'd run 3/8" if there were room...
-Bill
Posted By: polyspheric
Re: Pushrod question? - 08/30/09 03:41 PM
In practical terms, it's impossible.
Almost all of the column stiffness of a pushrod is a function of its diameter (not wall thickness), and even a solid 5/16" bar is weaker than a 3/8" OD pushrod with only 1/32" wall. Compared to a common 3/8" .083" wall, it's 53% as stiff.
Almost all of the column stiffness of a pushrod is a function of its diameter (not wall thickness), and even a solid 5/16" bar is weaker than a 3/8" OD pushrod with only 1/32" wall. Compared to a common 3/8" .083" wall, it's 53% as stiff.
Posted By: Anonymous
Re: Pushrod question? - 08/30/09 04:03 PM
Quote:
Do you think manton or smith bros can make a 5/16 pushrod that would be equally as strong as a 3/8? I am running a pretty stout solid roller.
how "stout" are the springs for that roller and what is the approximate length?
Posted By: juicedcuda
Re: Pushrod question? - 08/30/09 04:57 PM
Quote:Quote:
Do you think manton or smith bros can make a 5/16 pushrod that would be equally as strong as a 3/8? I am running a pretty stout solid roller.
how "stout" are the springs for that roller and what is the approximate length?
The approximate length is 9 5/8" long. The springs are Comp, here are the specs:
Dual Valve Springs I.D. of Outer Dia.: 1.125"
# I.D. of Inner Dia.: .719"
# Seat load: 228lbs @2.050''
# Open load: 636lbs @1.300''
# Coil bind: 1.192''
# Rate: 544lbs/in
# With damper.
Posted By: thecarfarmer
Re: Pushrod question? - 08/30/09 05:45 PM
Well, your open pressure is about a hundred pounds over the pushrods are about an inch longsr. Don't know if what I'm getting away with will work for your setup or not.
But, the guys who make the parts can tell you: pushrods.net or (800) 367-1533
If anybody'd know, I'd bet they would.
-Bill
But, the guys who make the parts can tell you: pushrods.net or (800) 367-1533
If anybody'd know, I'd bet they would.
-Bill
Posted By: sshemi
Re: Pushrod question? - 08/30/09 08:29 PM
Quote:
In practical terms, it's impossible.
Almost all of the column stiffness of a pushrod is a function of its diameter (not wall thickness), and even a solid 5/16" bar is weaker than a 3/8" OD pushrod with only 1/32" wall. Compared to a common 3/8" .083" wall, it's 53% as stiff.
And a 5/16 solid is weaker than a 5/16 tube.
Posted By: polyspheric
Re: Pushrod question? - 08/30/09 10:31 PM
And a 5/16 solid is weaker than a 5/16 tube.
Widely repeated, but wrong.
Removing metal does not increase stiffness, it increases stiffness per pound, or stiffness per square inch of load.
Widely repeated, but wrong.
Removing metal does not increase stiffness, it increases stiffness per pound, or stiffness per square inch of load.
Posted By: Anonymous
Re: Pushrod question? - 08/31/09 03:08 AM
Quote:Quote:Quote:
Do you think manton or smith bros can make a 5/16 pushrod that would be equally as strong as a 3/8? I am running a pretty stout solid roller.
how "stout" are the springs for that roller and what is the approximate length?
The approximate length is 9 5/8" long. The springs are Comp, here are the specs:
Dual Valve Springs I.D. of Outer Dia.: 1.125"
# I.D. of Inner Dia.: .719"
# Seat load: 228lbs @2.050''
# Open load: 636lbs @1.300''
# Coil bind: 1.192''
# Rate: 544lbs/in
# With damper.
you should be able to get 5/16 pushrods that will handle that with no problem.
