5/16 or 11/32 pushrods
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5/16 or 11/32 pushrods ok guys so I've got the yells terra 1.85 ultralites along with the btr platinum kit as recommended by him for my stock ls3. But now I'm going to measure for pushrods and I originally wanted to go with 3/8 but Brian had concerns about the control of those pushrods since they are so heavy and the fact that with larger rockers they wouldn't clear the ls3 heads. He's thinking the 5/16 is plenty strong for this application and I'm not questioning that but still am wondering.
I asked Brian about going with an 11/32 setup but I haven't heard back yet.i know push rod weight isn't important nearly as much as over the valve weight but still is it enough for to where it could overload the valve train with that setup?
I asked Brian about going with an 11/32 setup but I haven't heard back yet.i know push rod weight isn't important nearly as much as over the valve weight but still is it enough for to where it could overload the valve train with that setup?
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Ya in running the stock ls3 cam. Brian said his 5/16 would be fine and I believe him I was just wanting some extra insurance but I'm not sure just how much the added weight of the pushrod contributes to the valvetrain I know it's not much but still
Mass on the pushrod side of fulcrum is second to stability. You want the largest OD pushrod you can get in the engine. Wall thickness doesn't count. Pushrod is a column, you want diameter.
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There was a write up on here some time ago that compared stability of different sized prods. The 3/8 tapered came out on top with respect to stability and weigh overall. I'm running Trend taper 3/8 rods in my AI 243 heads. No grinding needed. They are pricey though.
Very good read!
Red, I would think your spring pressures would determine the rods you need along with the ramp rates on your cam. If your using Brian's springs and he is saying 5/16, you should be ok.
FWIW, Tony recommended 11/32 for mine, and his builds don't seem to have valve control issues.
You are on the short travel side of the lifter, so distance, velocity, acceleration will all be about 55% vs over the valve. Mass will be far less important.
FWIW, Tony recommended 11/32 for mine, and his builds don't seem to have valve control issues.
You are on the short travel side of the lifter, so distance, velocity, acceleration will all be about 55% vs over the valve. Mass will be far less important.
Board member contacted me the other day. Been through everyones lifters. Thought he had a lifter issue. Had cracked pushrod seats in the engine. Thats is from valvetrain instability. 5/16" pushrods. Then come to find out he had shaft rocker with 180 radius pushrods. Engine was prone to "spit" pushrods out going down the road. No wonder....Flex plus the cup hitting the pushrod.
Hell in NASCAR they run 1/2" diameter stuff to 10,000 rpm!!!
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Guys lol I understand the complete importance of diameter... I want the biggest pushrod I can go to my only concern is that the added weight will effect control and will outweigh the benefits. I know it's not as important as mass over the valve but it still has to place an added load on the valvetrain from the weight no?
As Tony Mamo I believe once said, you want mass (or lackthereof) over the cylinder eg. valves, springs, retainers etc. and you want strength and stability on the other side eg. lifters, pushrods etc.
I've never heard of anyone going less on the pushrod side to save weight but I've heard many times about going less on the valve and spring side to save weight. Everyone I know says to run the biggest stiffest pushrod possible as whatever miniscule weight savings you might get with a narrower rod will be overshadowed by it's inherent weaknesses over a beefier one.
I've never heard of anyone going less on the pushrod side to save weight but I've heard many times about going less on the valve and spring side to save weight. Everyone I know says to run the biggest stiffest pushrod possible as whatever miniscule weight savings you might get with a narrower rod will be overshadowed by it's inherent weaknesses over a beefier one.
Were talking about a bolt-on LS3 here. If BTR said 5/16 is the right push rod for the application, then I would be comfortable running it.
The 11/32 won't hurt anything.
Even though he's running a stock cam, he is running 1.8:1 Yella Terras and BTR Platinums. So there's a lot more spring pressure than factory and weight over the valve. Will the 11/32 make it more stable? Probably not. He won't be spinning the motor high enough to see any issues with the hydraulic setup. However, there's no real downside to it other than cost.
Even though he's running a stock cam, he is running 1.8:1 Yella Terras and BTR Platinums. So there's a lot more spring pressure than factory and weight over the valve. Will the 11/32 make it more stable? Probably not. He won't be spinning the motor high enough to see any issues with the hydraulic setup. However, there's no real downside to it other than cost.
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I'm probably going to order the mantons as long as they won't screw with the valve control from the added weight. Vette nuts I was reading your write up on the YT shimming did you just go get some checker springs from Home Depot? What size were they if you can remember