I'm using TA Hybrid adjustable push rods due to my 455 is using 430 rocker arms, the reason of using adjustable push rods is that I don't know why but I've ever had a lot of issues with valve adjustment I've tried to adjust my valves setting the push rod to 9.378" which I think is the stock push rod length but after testing I can notice some valves are hanging open and engine is misfiring. Also tried to adjust them going cylinder by cylinder, put it at TDC, finger tight the push rod to set it at zero lash and then open it one full turn to set the lifter preload but even this way some valves are still hanging open, the only thing that seems to work on the valves that are hanging open is not equally set the lifter preload one full turn, some of them just half turn, others 1/4 of turn but the thing about this way is that sometimes while driving the valves goes loose and then the annoying ticking sound starts Valve springs are new, lifters are new and I'm using TA performance hybrid adjustable pushrods TA_1428B I'm not sure if I'm doing something wrong or something is wrong with the engine or what but this is stopping me from using the car
Was it at TDC on the compression stroke? I adjust 1/2 turn preload or a hair more. After doing #1 I turn the crank 90 deg. then #8, turn another 90 deg. and do #4 etc,chasing the firing order, some purists don't do it this way but it works for me.
yes I double checked the TDC, I'm thinking about removing the intake just to be more than 100% sure that both lifters are on the base circle
I have done it the way Gary does it. Mark the balancer in 90* increments. That is basically every 5 1/4". Start with the #1 cylinder at TDC firing. Take the cap off and verify that the rotor is pointed at #1 if you are unsure. It helps to spin the pushrod between your thumb and forefinger as you adjust. When you hit 0 lash, you will feel a slight drag. Turn it an additional 1/2 turn, no more. Then follow the firing order each time turning the crank 90*. 1-8-4-3-6-5-7-2. It will take 2 complete revolutions of the crank to do all 8 cylinders.
It is easier with the intake off to turn the pushrods, but not necessary. Both valves will be closed at TDC firing. The hardest part is accurately "feeling" zero lash.
I roll it over and adjust the valve when it's partner is at max lift. I mark each rocker with a dab to keep track of it. Two revolutions and it's done. Same procedure otherwise.
I think I'm going to try the 90 degree mark method with the intake off just to be sure I'm not leaving anything on the table But... let's say that doesn't help and the engine still runs like crap. What should be next? what could cause the lifter load go crazy?
Depending on cam size and overlap adjust cam get tricky. This is how do it with #1 cylinder Intake Valve at full valve lift .... Adjust #6 Intake Valve with #8 cylinder Intake Valve at full valve lift .... Adjust #5 Intake Valve with #4 cylinder Intake Valve at full valve lift .... Adjust #7 Intake Valve with #3 cylinder Intake Valve at full valve lift .... Adjust #2 Intake Valve with #6 cylinder Intake Valve at full valve lift .... Adjust #1 Intake Valve with #5 cylinder Intake Valve at full valve lift .... Adjust #8 Intake Valve with #7 cylinder Intake Valve at full valve lift .... Adjust #4 Intake Valve with #2 cylinder Intake Valve at full valve lift .... Adjust #3 Intake Valve Then do the exhaust in the same order. with #1 cylinder Exhaust Valve at full valve lift .... Adjust #6 Exhaust Valve with #8 cylinder Exhaust Valve at full valve lift .... Adjust #5 Exhaust Valve with #4 cylinder Exhaust Valve at full valve lift .... Adjust #7 Exhaust Valve with #3 cylinder Exhaust Valve at full valve lift .... Adjust #2 Exhaust Valve with #6 cylinder Exhaust Valve at full valve lift .... Adjust #1 Exhaust Valve with #5 cylinder Exhaust Valve at full valve lift .... Adjust #8 Exhaust Valve with #7 cylinder Exhaust Valve at full valve lift .... Adjust #4 Exhaust Valve with #2 cylinder Exhaust Valve at full valve lift .... Adjust #3 Exhaust Valve
1. The big problem with using fingers to SPIN the pushrod when looking for "zero lash" is that the pushrod ends are polished, so it will spin LONG after you're tighter than "zero" if you have enough grip on the pushrod with your fingers. It's entirely possible to collapse the lifter plunger by "spinning the pushrod" looking for zero lash. Then the valves stay open because the preload is WAY TOO TIGHT. This is exactly what you're describing. Stop trying to spin the pushrod. Push up 'n' down on the pushrod end of the rocker arm. When there's no free-play...you're at zero lash. The lifter plunger is spring-loaded--so be sure you know the difference between "free play" and compressing the lifter plunger spring. 2. SOME VALVE TRAINS JUST MAKE NOISE. If you're set on getting rid of every last bit of valve train noise, you'd better have terrific oil pressure, a mild cam with gentle ramps, NO WEAR between rocker arm and rocker shaft, appropriate leak-down rate on the lifters, proper clearance between lifter and lifter bore, NO WEAR on lifter bottom or lobe, etc. 3. There's at least three ways to measure pushrod length of a hollow pushrod. At least two ways to measure a solid pushrod. If you're setting yours to 9.378, are you measuring the same way GM did? 4. I've seen hydraulic lifters with more than a quarter-inch of plunger travel. If you are ANYWHERE in the operating range between bottomed-out, and topped-out of your lifter plunger, you should have no valves hanging open and no lifter noise. SOMETHING ELSE is wrong.
I have had great success spinning the pushrod while slowly moving the adjustment. This admittedly is more difficult with adjustable pushrods, but it is doable. The slight resistance I mention is very subtle, but it is there, and I am confident that I am not compressing the lifter plunger. It is much easier to feel with the roller rocker adjustment. I do it several times for each valve just to be sure and to be confident. I have adjusted the valves on both my 462 and 470 and never had any problem with excessive noise or valves that weren’t sealing. Vacuum has always been excellent as well. My current Johnson roller lifters are marketed as short travel, so they require less preload, no more than 1/2 a turn. My 470 has never been as quiet and makes a full 15” of vacuum in Park, and 12” in gear. It works for me.
A way of adjusting the valve train. You need that once you go away from factory stock, or even a rebuild where they resurface block/heads.
Given a "stock" Buick non-adjustable, shaft rocker arm system, pushrod length changes nothing except lifter preload. This is NOT true with the "Chevy" style of individually-adjustable rocker arms via turning the nut on the rocker stud (as used on the Edelbrock "Buick" heads.) The "Chevy" system requires proper-length pushrods because it affects rocker arm geometry at the valve tip, while also providing lifter preload. SOME guys want the lifter plunger near or at the top of it's travel, so it can't "pump up" and hold the valve open. SOME guys want the lifter plunger near the bottom of it's travel, so it can't "collapse" under high valve spring loads. SOME guys want "X" amount of plunger preload because they've always done it that way, and "it's worked for them". SOME guys want exactly "Y" amount of plunger preload because that's what Buick or Ford or Chevy or Mother Mopar says in the Service Manual. With the Buick system on a stock-to-moderate street-driven engine, "I" say that if the lifter plunger has "some" preload, but not "too much", it's fine. You want enough preload so that you have reasonable service life before the accumulated wear in cam lobe, lifter bottom, rocker pivot, and every other contact point in the valve train doesn't exceed the lifter plunger travel for the expected service life of the engine. OTOH you want to be far enough away from bottomed-out so that wear on the valve face and valve seat doesn't collapse the plunger and hold the valve open for a reasonable engine service life. There's a lot of room in the lifter plunger travel between those two points. Control plunger collapse by not buying leaky lifters and excessively-stiff valve springs, control "pump up" by having adequate valve springs. There's more important things to worry about than the exact amount of lifter plunger preload.
How do you know if the valves are hanging open? Describe the mis-firing... is it popping thru the carb? Is it popping thru the exhaust? Stock cam should be a rock steady idle, if valves are hanging open, you essentially would have dead cylinders, AND popping thru the carb or exhaust, plus the engine will rock like a sombitch. A misfire is ignition related, bad wire, cap, rotor, coil. A mis fire is USUALLY intermittent, not consistent like a valve hanging open.
It is popping on the exhaust, also the exhaust starts burning eyes and just as @LARRY70GS said the vacuum gauge needle isn't stable, once the engine is started it goes steady to 20" vacuum and then starts dropping and bouncing to 18 - 19" and even 17"
