Adjusting hydraulic lifters

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by: Alittle1, Augusto, Cobalt327, Crosley
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Generic hydraulic lifter
Schubeck hydraulic lifter made to be zero-lashed


[edit] Overview

The following is information and instructions on how to successfully adjust the preload on adjustable hydraulic lifter valve trains. For non adjustable valve trains, refer to Fast and Easy Way to Check Hydraulic Lifter Preload when using Non-Adjustable Rocker Arms from Crane.

[edit] A word on the correct length pushrod

To obtain the correct valve train geometry, the correct length pushrod needs to be determined and installed before setting the lifter preload. Below are some things to check that could have changed the correct pushrod length:

  1. Camshaft base circle diameter
  2. Pushrod length due to wear or replacement
  3. Milling heads/block
  4. Different thickness head gaskets
  5. Valve seat height changes from seat replacement or from valve seat grinding/cutting done during valve jobs
  6. Grinding the tip of the valve stem when doing a valve job or different length valves
  7. Lifter pushrod seat height due to different manufacturer
  8. Change in rocker arm type, design, or ratio

[edit] How much preload should I use?

Lifter cutaway preload.jpg

The basic idea is to set the lifter plunger to the center of its travel. That gives the most leeway for temperature expansion/contraction. The amount of turns needed to set the plunger in the middle of its travel will vary from engine to engine because of differences in the thread pitch, rocker ratio, and lifter design.

The old Chevy factory manuals said to use anywhere from 1 to 1-1/2 or more turns after zero lash, but this has largely been replaced by using 1/2 to 1 turn total. For instance, Comp Cams recommends 1/2 turn for regular SBC lifters.

The recommendation given to use 1/2 to 1 turn past zero lash is based on what has been shown to work well on many engines when using stock or most performance hydraulic lifters. However, the amount of preload may be different, depending on the type and brand of hydraulic lifters being used as well as the reasons mentioned above. For example, there are Rhodes lifters that are set using a feeler gauge- something that's traditionally reserved for solid lifters. Always refer to the manufacturer's instructions first before proceeding. If the manufacturer's instructions differ from those given here, follow the manufacturer's recommendations.

[edit] Should I "pump up" my lifters with oil before installing them?

Generally speaking, no. The lifters can be dipped into a container of oil but unless the manufacturer's instructions tell you otherwise, there's no need to pump the lifters up before installing them.

There are some exceptions to this. For instance Rhodes lifters DO recommend their "original" lifters be pumped up prior to installing and adjusting them to 3/4 of a turn, or so the lifter cup is about 1/16" below the retainer. The Rhodes "V-Max" lifters are adjusted so the plunger is from 0.010" to 0.030" from being fully compressed- quite different than 'normal' hydraulic lifters are adjusted.

[edit] Can I replace a damaged lifter with a new lifter?

Warning Note: See Repairing or replacing lifters
Arrow points to check ball retainer on the end of the plunger
Three styles of lifter cup retainers. The internal C-clip type is stronger and should be used especially with solid lifters or when "zero lashing" lifters.

When a lifter is noisy, often all that has happened is the check ball retainer assembly isn't fully seated into the recess on the bottom of the plunger, or a speck of dirt has lodged between the check ball and seat. This can be fixed, but requires the intake to come off to get to the lifter. Usually you can clean up the sludge inside the lifter using carb cleaner and it will perform fine again, but first check the surface of the lifter that faces the cam, if it's flat or concave just trash it, it must be sligthly convex.

Shown left, is a disassembled GM hydraulic roller lifter. Most current flat tappet lifters have the same internal construction as this roller lifter, although there are different styles. But as long as the styles are the same, the piston from one can usually be fitted into another body. The arrow shows the location of the cup, spring and check ball assembly mentioned above.
Details are at the page linked to above.

[edit] Chevy OEM hydraulic roller cam and lifters

Warning Warning:
According to Crane's Director of Valvetrain Research and Development, Mark Campbell, valve lifts of more than 0.530 inch at the valve with a 1.5:1 rocker can allow the lifter to fall deep enough into the lifter bore (because of the lobe's small base circle) that the steel retainer can lose its grip on the lifter body. This allows the lifter to spin in the bore and destroy the camshaft.

Crane sells a long travel lifter, p/n 10535-16a that will work for reduced base circle/high lift cams.

[edit] Before beginning you will need to know:

Chev sb bb v8 firing order.jpg

[edit] The firing order and the direction the distributor rotates

[edit] The order of the valves as they are located in the cylinder head

  • The small block Chevy V8 is E - I - I - E - E - I - I - E

Other engines can be found at the BoxWrench site.

[edit] Adjusting hydraulic lifters for proper preload

The following adjustment procedure is based on instructions originally from Crane Cams. It is recognized by many as being the "go-to" method of valve adjustment. This method also works on any OHV engine using hydraulic lifters that has an adjustable valve train.

Some possible differences between various engines are the:

  • Firing order
  • Order of the valves in the cylinder head
  • Number of turns to set the preload (this determines the distance of the lifter plunger below the retainer)

[edit] EO/IC Method (Exhaust Opening/Intake Closing)

  • In order to adjust the preload, the lifter must be properly located on the base circle or "Heel" of the lobe.

At this position the valve is closed and there is no lift taking place. You will need to watch the movement of the valves to determine when the lifter is properly positioned for adjusting.

1. Remove the valve covers, and pick a cylinder that you are going to set the preload on.

2. Hand rotate the engine in its normal direction of rotation and watch the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop and adjust that cylinder's intake rocker arm. (Why? Because when the exhaust valve is just beginning to open, the intake lifter will be on the base circle of the lobe- the correct position for adjusting the intake.)

3. Back off the intake rocker arm adjuster and remove any tension from the pushrod. Wait a minute or two for that hydraulic lifter' push rod seat to return to the "up" position. The spring inside the lifter will move the pushrod seat up against the retaining lock if you give it time to do so. (If you are installing brand new lifters they will be in the "up" position when they come in the box.)

4. Now spin the intake pushrod with your fingers while tightening down the rocker arm. When you feel a slight resistance to the turning of the pushrod, you are at zero lash.

NOTE: If you are uncertain that you are feeling when all the lash has been removed (the "zero lash" point), jiggling the push rod up and down can give a better sense of when all the clearance has been removed.

5.Turn the adjusting nut down one half to one full turn from the zero lash point. Lock the adjuster into position if using polyloks. The intake is now adjusted properly.

NOTE: If using stock-type lock nuts, be sure to use new lock nuts; old lock nuts can back off and the preload will be lost. Do not use stock type lock nuts on aftermarket studs or the threads will be damaged. Follow the manufacturer's instructions.

6. Continue to hand turn the engine, watching that same intake. It will go to full open and then begin to close.When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. (Again, when we see the intake almost closed, we are sure that exhaust lifter is on the base circle of the lobe.) Loosen the exhaust rocker arm and follow the same procedure described before in steps 3 and 4 to adjust this rocker arm.

6. Both valves on this cylinder are now adjusted, and you can move on to your next cylinder and follow the same procedure again.

Something that you also might find useful, is go to How To Make A Timing Tape. This temporary timing tape will allow you to check and set the total timing even if you don't have a timing light that reads advance or a degreed damper. You can also use it to permanently mark the damper for full advance, etc. as you see fit.

If there's any doubt as to whether or not the timing mark on the damper and the timing tab is accurate, refer to Determining top dead center.

[edit] Adjusting lifters using a video presentation

Sometimes a video presentation helps to fill in the voids in describing a written direction of a project. Valve lash adjustment video

[edit] Resources

Crankshaft Coalition Wiki articles
Crane info
Personal tools