Good work

I just changed my 355 chevy pushrods by . .200 because these rockers are a weird geometry by Texas Racing Engines circa 1990 (still in the box) I didnt measure much of a difference at .025 difference. Smokey Yunick used to cheat and use too long a pushrod, putting the rocker tip towards the outside of the valve stem. He used to gain another .070 lift on the cam that way to cheat the rules. Yes it puts more stress on the valvetrain and wears the valve guide more, but his dyno results showed more power with too long a pushrod.

@HeadFlowInc

6 жыл бұрын

Don Rutter Changing from the 7.400” to the 7.375” on the non-adjustable LS setup changed my lifter preload from .080” to roughly .0554”-.0615”. I could have left the .080” preload but decided to make the preload closer to the other 15 rockers. Smokey Was an innovator and was great at experimenting! 👍

You could take the one valve to machine shop and have it tip ground. 030?

@HeadFlowInc

6 жыл бұрын

Richard Storms There’s not enough hardened material on the tip to remove .030”. The tip on a valve stem has a hardened “Cap” to handle the abuse from the rocker arm. Thanks for the feedback, this shows people are trying to create solutions! 👍

.080" preload is bad? I'm about to button my rockers down and my comp tool says I'm at .084" On my LSA (LS3), I've heard .060"-.100" is acceptable. Thanks for the vid.

@HeadFlowInc

4 жыл бұрын

FasNuf ZL1 you’re right, lifter preload varies greatly depending on camshaft company and lifter manufacturers. GM .050-.060 Katech.070” BTR .090-.100” I have mine set at .070” now and they’re not as quiet as I would like. But I also have the Straub Ind.. solid trunnions in the OEM rockers which might make some noise. There’s two theories on controlling the lifters at RPM 1. More lifter preload reduces the amount of oil under the plunger, less likely to float. 2. Less preload allows the engine to rev quicker? 🤔🤔🤔

@fasnuf

4 жыл бұрын

HeadFlowInc so I called BTR today and yes that said for my stick lifters .080-.085 was just fine. They had others running .100. Good to hear

@johnnyfive3872

3 жыл бұрын

@@HeadFlowInc I’ve heard the opposite that the solid trunnions actually reduce noise. 🤷‍♂️

What size cam are you using. If it already has 600+lift ya. I’d think anything over 7.4 would be dangerous.

@HeadFlowInc

4 жыл бұрын

theozman38 Oh no, the cam is way below .600” lift! Elgin 1838p/Trick Flow .560/.560 @.050” 216/220 adv 285/292 LSA 114 The BEST method is buying the $25.00 adjustable pushrod and measuring for zero lash then adding in the preload to find the total length. JD

@theozman38

4 жыл бұрын

HeadFlowInc. Ya I’m kinda getting around to understand preload. Preload is set by the cam specs. If it calls 0.50 preload then if your length is like 7.250 a 7.4 would be close to it. A half turn or 3/4 turn would be getting there.

@theozman38

4 жыл бұрын

HeadFlowInc I’m thinking of putting 1.8 adjustable on 7.4 pushrods. I’ve looked it up on Wikipedia. Stock is 7.385 with 1.7 pushers on a 465 lift cam. I’ll be close to or over 500 lift. I think.

@HeadFlowInc

4 жыл бұрын

All you do is find the length needed to establish zero lash, which means the rocker bolt is tight but there’s zero up/down play and the pushrod still spins freely. Then add what ever preload you want to run. In your example 7.250” + .050” = 7.300” long. As you stated the preload difference is based on lifter type and cam manufacturers recommendation. Good luck have fun! JD

@HeadFlowInc

4 жыл бұрын

Yeah, if you had a .465” lift with 1.70 rockers, divide .465”/1.70= .2735” “lobe lift”. Multiply lobe lift by the new rocker ratio: .2735 x 1.80= .4923” lift. JD

How much to port a set of heads

@HeadFlowInc

3 жыл бұрын

Send your project goal to My email: jeffdubray@gmail.com

hey, so i upgraded my lifter to comp cam 850 & i have a 600lift tsp stage 4. i have 7.400 rods, with stock lifters when i did the cam, came with the kit. after i ended up putting on the new lifters valve train was noisy and i also realize that one of the rod was squirting out a lot of oil. i did the preload and got 7.325. lifter says that when torquing it should be between 3/4-3/8 when tighten, that’s what i got when i torque it with the pushrod length tool. i also got zero lash and side to side movement. do the 7.325 seem close enough to you?

@HeadFlowInc

3 жыл бұрын

How much lifter preload are you using? When you’re using the pushrod length tool you’ll need to find zero lash with the lifter on the heel of the cam then add the amount of lifter preload to that length to find the total. If the engine is noisy it’s most likely the PR’s are to short. JD

@lsxramirez3782

3 жыл бұрын

@@HeadFlowInc .50. we did what 187 custom showed on his video by doing the math. So it should be bigger then? it was my first time so it was a little confusing with the numbers

@lsxramirez3782

3 жыл бұрын

@@HeadFlowInc have to return the ones i ordered then. See if i can get help doing it right, so they would have to be bigger than 7.400 80