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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
how does the pushrod length look for you? The slight purple paint at top and bottom is sharpie, the middle is the wear pattern of the roller tip. Little Bit shorter or OK?
Ideally you check with a modified lifter that won't compress or weak test springs. You can find weak springs at a hardware store, the comp ones are too small dia for most valve seals.
Pattern looks too wide to me. Can't tell which length error is causing it.
As said, you have to test it with one of 2 things: either a solidified lifter IDENTICAL to the ones you're going to be using, NOT a "solid" one, since an actual "solid" may or may not be the same height as whatever hyd ones you're using; or, some VERY light springs, so that the lifter plunger doesn't get depressed.
OK so I bought this checking tool to verify whether the pushrod length is right. Studs are 3/8-24". I have the summit HT214 lifters. They need .050 - .100" of preload, I tend to give it a little more preload. So I think .080", could you Help me determine how much of turns this will need? More than a full turn, right? Cause this should be something in the 0.50" I read, please correct me if I'm wrong! How do you calculate preload in hand turns?
Oh and just a question to the end: The tfs-30310006 heads im driving are good up to .540" valve lift. How close could I go to that number? Like .536" for example or better not more than .520" where I am now to leave some safety?
Thanks and greetings,
Chris
Last edited by Chris_Formula; 05-12-2023 at 07:37 AM.
3/8-24 rocker studs are 24 threads per inch. That means 1 full turn = 0.0417"
I have no idea where you got the 0.050 - 0.100" or preload from. The majority of lifters only need less than 0.050" of preload.
Typically after zero lash, you tighten the rocker nut an additional 1/2 to 3/4 of a turn then leave it alone. I wouldn't turn it more than 1 full turn after zero lash. The lifter will bleed down and the pushrod will feel loose again but this is normal.
As for lift, there are a lot of factors to examine. Since you said the heads are already set up for 0.540" lift, we won't look at head setup. The only other factor is piston to valve clearance. The intake valve chases the piston on the intake stroke and the piston chases the exhaust valve on the exhaust stroke. Depending on valve timing, piston design and valve lift, there's always a possibility that the piston can make contact with a valve. Rule of thumb is you need a minimum of 0.080" clearance on the intake side and 0.100" on the exhaust side.
I asked Summit Tech help again. They said the HT214, which im currently driving, has a plunger travel of .200" and needs a preload of .050 -.100". So .100" puts the plunger in the middle. Im aiming .075" so at least 1 1/2 turns past zero lash or am I missing Something? Because of that, I have to recheck my pushrod length. I calculated a half turn past zero the first time. But they are a little bit noisy with that half turn. I increased that to 1 full turn and it's getting quieter. But not gone complete. I think Im on the right way but to make things more reliable, could you confirm that right in theory with the preload?
04-15-2023, 02:51 PM
