1 - Long time lurker I've learned a lot from this site. Thank you.

2 - I've read Lar's article on adjusting the valve train when hydraulic lifters are installed. It made sense and that's the procedure I used when assembling the engine. [Very mild rebuild, World Casting heads, stock style / ratio rockers, stock style push rods, Crane cam and lifters (Z-262 -2)]

During assembly I removed the inner spring of the valve springs in order to break the cam in and minimize the chance of wiping a lobe on initial startup. Engine ran fine.

I then went to install the inner spring for the valve springs. Using the technique of compressed air (25 lbs) to prevent the valve from dropping when removing the spring.

Engine set to TDC (verified by watch valve train and observing rotor position on distributor and TDC mark on harmonic balancer). Removed springs for #1 I & E, reinstalled with inner & outer springs. Made sure the pushrod was seated in lifter and rocker. Tightened slowly until no vertical play felt and a slight change in the ability to "twirl" the pushrod. No problem up to this point.

As soon as I would go another 1/8th turn or less I could tell the valve was off it's seat as I could hear air leaking from the carb. or exhaust depending on which valve was being adjusted. This is what confused me. I would of thought the lifter would of taken up this additional distance (preload) and the valve would remain seated.

As I needed to install all the inner valve springs anyway, I continued the process, turning the engine 90deg and going thru the firing order to replace the springs and adjust lash. Consistently, on all valves, once I felt no vertical movement in the pushrod and a slight change to twirling the pushrod, if I would go another 1/8th turn or less on the nut I would hear air as the valve started to open. Am I missing something?

Signed,
Confused in Tucker, GA

 

The biggest difference you are feeling is the difference in stiffness with the inner springs installed. They are not compressing the way they did when you first set your lash. Hydraulic lifters give you a lot of latitude and don't be afraid to get them all set with the new stiffness. Once done, rotate the assembly by hand a few revolutions and put it back on TDC and go back through the process of checking and tightening. Once gone through a few times and all your push rods are happy then you car run the engine. When changing springs I will always readjust the valves after the engine runs again. This can repressurize the lifters and it's possible a little more adjustment might be needed or at the very least rechecked.

 

Since the engine had already been run before, the lifters were completely pumped up.
When you heard the air, they just hadn't had time to bleed off a bit to adjust themselves yet.
There is a good chance that everything that you have done is just fine.

The other possibility is that your fingertips could use some fine tuning, and you bottomed out the lifters without realizing it.

 

Instead of 'spinning' the pushrods, back the adjustment nut off some, then tighten again [slowly] while shaking the rod up and down. There will be some 'slop' in the pushrod until it makes contact with the lifter. As soon as that 'slop' disappears, tighten another 1/2 turn and you're done.

The problem with the spin method is that inexperienced folks don't stop tightening until the pushrod starts to bind. The intention is that it will spin "freely" until the 'zero lash' point is reached. It will still spin after that point is reached...but not "freely".

The 'shake' method eliminates that confusion for most folks. [But, the 'die-hard' spinners will take issue, of course....]

 

Get them close when engine is cold. Finalize adjustment with engine idling and up to running temp. It's your call just how much to center the plunger in the lifter...from 1 complete turn past the clacking sound of a loose lifter to just making that sound stop, or anywhere in between.

Clips like these keep hot oil from spewing everywhere.



Or, cut the inner part out of an old stamped steel valve cover will do the same thing.

 

I suspect you're going well past zero lash before adding your preload.

Regardless of the method used, you must accurately locate zero lash. If you choose the spin method (as Lars lays out in his guide) then understand that zero lash is the first time you feel any hint of drag on the pushrod. Not when it gets harder to turn...but when you feel any indication that it's not freely spinning. If you're not sure, back off and tighten a few times until you get a feel for it.

Also note that the engine must be positioned correctly - it's not just about being at TDC...but on TDC on the compression stroke.

Another approach that works well is the companion cylinder method; only requires positioning the engine twice and works well for anything other than wild cams:

#1 at TDC compression:
Adjust Exhaust on 1, 3, 4, 8
Adjust Intake on 1, 2, 5, 7

#6 at TDC compression
Adjust Exhaust on 2, 5, 6, 7
Adjust Intake on 3, 4, 6, 8

 

Thank you to all who have responded. I was not able to look at the engine last night (work seems to get in the way, but I'm thankful to have a job) but will get to it this weekend.

As the engine is just mounted on the frame (body off) I've got plenty of room to work.

1 - Rotate the engine 2-4 times by hand (spark plugs are out) to verify no bind.

2 - Spin the engine using the starter 6-8 cycles. Do this 3 times (again, no spark plugs installed so she won't kill the starter), verify oil pressure is up during the spin. This should allow the valve train to settle and lifters a chance to adjust.

3 - Set to TDC (verify by watching valve train, and rotor position)

4 - See if there is any up/down movement in the pushrods for #1

4a - if there is movement, I had a flawed technique on the initial adjustment (socket binding the rocker arm when adjusting or something similar)

5 - Use fitting to put 25# air in #1

6 - Tighten nut on #1 Intake rocker arm until I hear air at carb.

6a - If I turn it 1/8th or less, then I had effectively bottomed out the lifter on the initial adjustment as Billla (post #6) indicated. Readjust all.

6b - If I can turn 1/2 to 1 turn before I hear air, then I was within an acceptable range on the initial adjustment and the lifters had not had a chance to bleed down as Driveshaft (post #3) indicated.

I have used the "back it off until it taps and then tighten to take the tap out + 1/2 turn" technique while the engine is at idle on a old 327 nearly 40 years ago. I was 18 and trying to use valve covers that were cut in half and still had oil everywhere. The clips would help with that. However, I should be able to get them adjusted without having to go that route.

Still open to suggestions / recommendations.

TIA

 

I'm not sure why you are applying air pressure to the cylinders?? You can determine correct TDC position by the movement of the valves. And, you certainly don't want to keep turning the adjustment down until you hear air; that would mean all the oil in the lifter was squeezed out and the lifter had [effectively] become a solid lifter. Remember, the hydraulic lifters can't "pump up" if there is no oil pressure in the engine.

With engine 'off', you are only working with the un-filled lifter, so only the 'first contact' point [Zero lash] is what you're looking for. Then, turn down another 1/2-3/4 turn and the hydraulic lifter will be properly adjusted.

 

My old stand by favorite is a quarter turn. Seems to work best for me.

 

Metro, you're making this way too hard I have no idea where the cylinder filling with air thing is coming from...? Certainly not from Lars' paper.

Reinstall all the plugs except #1 and #6.

Put your finger over the #1 plug hole and have someone "bump" the engine until you feel pressure - indicating that the cylinder is coming up on compression. Then align the timing marks for TDC.

#1 at TDC compression:
Adjust Exhaust on 1, 3, 4, 8
Adjust Intake on 1, 2, 5, 7

Put your finger over the #6 plug hole and have someone "bump" the engine until you feel pressure - indicating that the engine is coming up on compression. Then align the timing marks for TDC.

#6 at TDC compression
Adjust Exhaust on 2, 5, 6, 7
Adjust Intake on 3, 4, 6, 8

You're done

As an aside, there's no need to crank the engine over, remove all the plugs, etc. to "allow the valvetrain to settle". There's also no need to "pump up" the lifters; hydraulic lifters have a spring to hold up the cup, and if the cup isn't at the top of it's travel by the spring when unloaded...you have a bad lifter. There is absolutely no reason to adjust the valves with the engine running.