Guys if you have the money don't fool around on the valve train. Do what Bret says. I have an L98 motor with a modified TPI, Comp Cams XFI268 and the peak power is at 6050 rpm with power extending a lot higher.

People are amazed that the peak is a 6050rpm but I have all the heavy duty parts in the valve train. Comp Cams 1.6 Pro Mag rocker arms, Comp Cams 918 beehive valve springs and associated hardware, 7/16" rocker studs and last but not least Terry Manton 3/8" #4 pushrods.

 

I understand that bigger is better and the wiser decision would be 7/16...
I just think that the breaking of the stud has more to with the extra tension in the upward motion brought on by springs with a much higher pressure. And not necessarily the effects of the pushrod and valve stem not being parallel.
i could also see if a push rod was too long and causing the rocker arm to hit the stud...(which i'm sure is next to impossible for someone to actualy accomplish.)

I’m not trying to cause an argument but a little debate never hurts...

Also does anyone have a pic of a broken stud?

 

So, you want to debate that stronger is not better (for whatever the reason it might need to be stronger) ?

 

In the course of building the whole valvetrain whats another $35 for some 7/16" rocker studs??? Same with the chromoly pushrods. Yea they are $50 or so more expensive but in the long run the motor is going to last longer and be less prone to breakage.

 

um, i think i was more so debating what breaks them...

not that it really matters... i know 7/16" dia. is stronger than 3/8" dai., and thats going to be with any material...

 

as mentioned above i think the reason they broke was due to the bending rather than an axial load, given there are both loads on the stud the bending will weaken the stud and may cause it to break.

 

LMAO... Here we go again around the Bretgoround.
So Crane can claim a 12hp gain, pontificate that the gain was because of "pushrod deflection" even though that 12hp gain can be from a plethora of different variables... Interesting.
Where was this gain? All the way across the board or at a certain rpm? Funny how they chose not to go into detail.
Anyone who uses chromoly pushrods over hardened and adjusts their hyd. lifters from 1/2 turn to 1/16 of a turn so the plunger can "act" on the plunger retainer clip should gain at least 30rwhp!
The moral of the story is... For mild setups, sub par quality pushrods are bad. LPE hardened pushrods and guideplates are good. They have been tried and true.

 

And who makes these tried and true LPE hardened pushrods and guideplates?

 

No offense intended, but I don't think you fully understand the differences in tensile loading and the combination of tensile and bending loads on the stud.

Before you see a pic of a broken stud, where do you think it will break?

Of course you could also just take advice like "3/8" studs will be fine" without asking "why is that"?

 

if it were to break because of deflection i would say it would be the place where most leverage would be...

i would say that it breaks at the base of the 3/8" stud.(where in meets the hex)

if it were tension it could break anywhere below the polylock or locknut...

 

And what do you for a LIVING again? I guess the engine builders that I work on valvetrains for must be just RICH like Dave Chappelle and just blowing money for no good reason with me. OTOH you gotta be the cheapest SOB in the world to not spend $100 more for better parts that solve a plethora of problems.

Bret

 

Doesn't matter who makes them. Who makes Comp Cams pushrods? The point is they work for mild applications with guideplates.

Using "cheap" LPE stuff is my forte.
What exactly do you do for a living besides spend your days in the interweb avoiding questions?
I'll ask again... where was this power increase from Crane's claim?
... if only I had adjusted my rockers with .017 lash and used non cheap pushrods... just think of the possibilities...
I like you. You're silly.

 

I copied the quote verbatim, stop wasting MY time and just call them up and ask them. I haven't even had time to log on to here to answer more than one thread in about a week and argue with a moron like you about crap like this.

Bret

 

Ah c'mon Bret.. don't be that way.
The fact of the matter is you used that quote to confirm your claim not just once now, but at least twice yet now you are attempting to excuse yourself from it's claim in saying you simply "copied the quote verbatim..."? Do you just mindlessly copy/paste whatever claim is made regardless of whether you believe it or not to try to get the upper hand in a debate? I'd think you doing whatever it is you do for a living would have your own proof instead of having to rely on some random quote you copied to try and make your point. So basically you copy something that you can't confirm yourself. Hell you could've at least lied and said you had your own proof where a given pushrod gained XX amount of hp at (insert RPM here). It would've been a bit more believable. I don't get it. What is it again you do for a living?
From your last reply you've driven my point home beautifully with your simple "copy/paste" technique. Thank you.

 

Tell us again what you've learned through first hand experience? Oh yeah, I'm only interested in your results comparing the two over 6200 RPM because that's what applies to me (or anybody with a CC306, etc).

Thanks in advance.