beehive springs/steel retainers OR dual springs/titanium retainers

Taper, in every instance makes the pushrod weaker when compared to a straight wall equal to the largest O.D. of the tapered pushrod. Adding material to the center of the 3/8" pushrod is adding considerable weight, without adding as much to the pushrod's ability to resist buckling. It is not a matter of opinion but a calculation based on Euler's equation for column buckling strength. When calculating the buckling strength of a steel column(pushrod), the outside diameter is more important in most cases than how thick the wall is. If there is a taper, then you are reducing how rigid the pushrods is and making it weaker. The three determining factors are length, Outside diameter, and wall thickness. The alloy of steel used is not a major factor.

7/16" pushrods are heavier, they also transmit more of the cam lift to the valve than the tapered or the 3/8". Nascar and other motorsports that spin over 9,000 rpm for extended periods don't use the lighter 3/8"(.375") or the heavier7/16" (.4375") but 1/2"(.500") and 9/16" (.5625"). By your argument they should be going for the light weight thinner pushrods. Greg, as a "Cam Manufacturer", I would expect you to know that there is more to be gained from more lift, created by a more rigid valvetrain, than a few grams savings with reduced lift. I would also expect you to know that a 12 valve pushrod has a; 3/8"(.375") cup , a 5/16"(.3125")ball, and that 3/8"(.375") is different than 10mm (.3937"). After visiting Bullet 3 weeks ago, I would also expect you to know that the Chinese cams with narrow lobes you use for your reground Cummins cams will not last as long as wider lobed cams with superior alloy. Is your bore spacing on your new block allowed the same variance that your pushrods are? May I ask how much you are getting for the Chinese cores?

I can see that you didn't take my advice. Good luck on the forums.
 
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Thanks for chiming in Zach..... I'm no engineer, but seems to me from a logical perspective, if you try to "sqish" a pipe in a vice lets say, it will bulge out in the middle...... Now, bulge the middle out on purpose, and you've just magnified the problem because now, you don't even have to deflect the walls to start the bulging... They're already bulged. I don't know.... I've never seen bridge pilons that are shaped like that and I bet there's a reason.

Now, for side deflection (bending) I'm going to venture a guess that the tapered rod would be stronger than a straight one...... But, since our valve trains put very little side deflection on the pushrod vs the crushing force, my original argument still stands.

But, here's my thoughts.... Aren't we fighting ourselves on this? Basically, the power curve of a diesel begins to fall off pretty quick after 5k.... From what I've read and studied, the combustion of diesel fuel is only just so fast, and to get the fuel injected to fully combust at 5500rpm+ would require injecting the fuel very close to the bottom of the compression stroke..... I remember seeing someone do the math on this somewhere.. Can't find it now though....

Just my $.02
 
With 20 + years of cam and valve train design, it’s amazing what people don’t really understand about the dynamics of what goes on under the valve cover.

First to clear it up , the cups are 10 mm on my push rods because the balls on both the 12 valve and 24 valve/ CR are 10 mm. If someone is using a 3/8’s cup you’re not having correct engagement.

As to taper push rods the 7/16 tapered push rod and 3/8s on each end, making it infinitely stronger than a 3/8s straight wall push rod.
The reason we use tapered wall, as do all of the professionals in any race category is strength of a larger push rods with the clearance of a smaller push rod and weight reduction. The bigger center also reduced harmonics which is especial pertinent in lower rpm engine platforms.
Here is a CR rocker and the measurement is 10 mm ( .396 )



IMAG1043.jpg
 
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How does a picture of a 24v rocker settle the debate of the 12v ball/cup size?
 
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COMP461 said:
both are the same , both are 10 mm not 3/8's
Click to expand...

Well, sorry greg, I'm going to side with Zach over you on this one. Zach's out there making 12V's haul while you're busy telling everyone that the p-pumped 12v is "backwards" compared to your fancy electronic CR motors..... But, to prove my point, here are photos that I just took. I had to get off my lazy bum and go dig out parts from my storage bin to take these photos, so I hope everyone shows proper appreciation by groveling at my feet and admiring my DIESEL RACE PERFORMANCE PROGRAM! LOL

And for the metricly deficient, 3/8" is equal to .375" And, I've shown pictures with both inch and metric readings, and 1 picture to prove I zeroed the caliper. LOL
 

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I've seen so many people bash or disagree with Hamilton but I've yet to see anyone prove him wrong. Good thing I've got Hamilton pushrods. I think ill order a cam this week. Keep up the good work!!
 
20000 push tubes Greg, come on that is 1666 engines you are so full of chit and really make yourself look as smart as you are. If you know half of what you think you know you would have at least on of your "programs" running competitive. Today you have proved just how "smart " you are. Everyone knows a 12v has a 3/8 cup.
 
Hamilton 12v (.3125" radius) with your 12v (.3937" radius) Greg your pushrods will not seat on the bottom of the lifter but the outside lip unless you have 24v lifters
DSC01331.jpg


Hamilton pushrods with a stock pushrod

DSC01239.jpg


Greg, since you get your pushrods from trend and they mostly do gas rods with hydraulic lifters, these pushrods have a oil hole which allows them to partially fill with oil adding more mass in the pushrod and having less surface area for the pushrod to pivot on.

DSC01213.jpg


Greg, this is your 12v pushrod (10mm) with some Hamilton, stock, and Source 24v pushrods(10mm)

DSC01251.jpg
 
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:shake:Well i must say, I believe im going to be ordering a set of Hamilton pushrods and a cam very soon just over this thread :Cheer:
 
When did the 24v go to 10mm balls on the pushrods? I have a set of pushrods out of a 2000 24v that has 8mm ball ends.
 
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