Hydraulic Lifters

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Submissions by Jacks.

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The Earlier Type Rocker Gear. Note each Rocker Arm has its own support Stud and Nut. Image by Josh Lammi. Click to Enlargen

Hydraulic Lifters:

The lifter forms an integral part with the rotation of the cam shaft, as the lobes on the cam shaft rotate, this action forces the lifter to be pushed up, as the push rod which is located on the push rod seat of the lifter body, forms a linkage to the Rocker Arm, the arm then pivots on the rocker post, the Rocker Arm is secured in place by an adjustable nut.
As each Hydraulic Lifter is opened by its Cam lobe, it is rotated.
The same Hydraulic Lifters are used on Adjustable and Non-Adjustable Valve Gear. Image by Talk Wrench. Click to Enlargen
The Rocker Arm, pivoting on the post, now pushes down on the Valve Stem, this then forces the opening of the valve seat
The valve spring which is being compressed at the same time, will maintain its compressed pressure until the cam lobes move further around, then the valve spring pressure that is pushing on the valve cap will now come into play and force the valve to close again completing the valve cycle
Hydraulic Lifters and Pushrods in a 179 Engine. Photo by Jacks click to enlargen.

So in short we have the cam lobe pushing the valve one way and the valve spring pushing the other way, in between all this is the workings of the hydraulic tappet, along with the movement of Rocker Arm pivoting on the tappet post
The rocker arm controls the "valve lash", so shall talk on this a further down the page.
The Hydraulic Lifter helps to soften or cushion the opening and closing of this valve action.

Workings of the Lifter:

Photo by Jacks click to enlargen.

As the lifter is being lifted by the cam lobe, there is an ingenious little device situated inside the lifter body itself, which seldom needs attention, the main function of the lifter is that it serves as an automatic adjuster which maintains zero lash in the valve operation linkage throughout the full RPM working range. 

Lifter Working Parts:

Photo by Jacks click to enlarge

The hydraulic valve lifter consists of a few parts that I have numbered in the picture opposite.

1:Push rod seat retainer, 2:Push rod seat, 3: Plunger, 4: Check ball, 5: Check ball spring, 6: Ball retainer, 7: Plunger spring, 8:Lifter body.

How it Works:

The design being hydraulic, relies on oil pressure, so whenever "lash" is present then the plunger spring will expand, thus pushing the plunger until solid contact is made with the Push Rod and the linkage assemble, this then creates a difference in oil pressure on either side of the Ball Check Valve
The low pressure being below the plunger and the higher pressure being above the plunger, the high pressure will will then force oil to flow to the chamber below until the oil pressure become equalised  

Ball Check Valve:

Photo by Jacks click to enlarge

When the lifter is raised by the cam lobes action, the increased oil pressure below the plunger forces the Ball Check Valve against its seat and the oil then becomes a solid connecting link, there is also a certain amount of oil there that will leak between the lifter body and the plunger while the engine valve is open and oil pressure is thus applied to the lifter, the small amount of leak down here is ok as this will help to remove the possibilities of any negative valve lash clearance conditions.
Now if you have removed one of the lifters and there is carbon dirt etc, then it likely that the other lifter will be in the same situation so it best to clean them as well, Note: don't mix them up

Hydraulic Lifter Operation:

Animation by T Jan 19th 2007:


Leak Down:

You will notice that when the engine has been standing for a while, upon starting of your engine, the tappets are are quite noisy, this is due to the fact that the oil pressure in the lifters has dropped off, it's called “Leak-Down", the good news is that it disappears as the oil pressure builds up and the lifters are now working 100%
However, some times a noise will appear, so we have to locate the source as there are quite a few hydraulic valve lifters there to choose from, there are a couple of ways to check:

Finding Noisy Tappet:

Get a length of garden hose, about 4 ft will suffice, place one end at the bottom of the inlet and exhaust valve, with the other end in your ear, this should help to localized the noise
the other method is to place your finger on the top of the valve spring retainer, you might feel a distinct shock went the valve returns and hits the seat

Bleeding Hydraulic Lifters:

Before installing new Lifters into an Engine they need to be bled. That means all the Air inside them has to be purged and replaced woth Oil. Do this by placing the Lifters in a Container. Stand them upright, the same way they will be positioned in the Engine.  Cover them with Oil then leave the Lifters like this overnight. You will see Air start to bubble out of them as they purge.


Cold Start Lifter Rattle:

Manuals for both Adjustable and Non-Adjustable valve gear in red/blue and black six cylinder Holden engines state that cold start lifter rattle will last for a few seconds and is caused by the lifter plungers being fully compressed by those valves that are being held open.

Cold Start Lifter Rattle References:

A reference for Non-Adjustable valve gear is on page 6-8 Holden HK Series Shop Manual Mechanical.A reference for Adjustable valve gear is on page 02-06 Improved Performance L6 and V8 Engines.

Further Noises:

Noises come in different sounds, and so can mean different things,
Hard rapping noise, It is usually caused by the plunger becoming tight in the in the bore of the lifter body, so the spring can’t push it back up to it’s working position, its usually associated with oil being too thick, or a build up of carbon, varnish etc, sometimes a small bit of dirt or metal can get caught between the plunger and the lifter body as well
Intermittent clicking, can be caused by a small bit if dirt caught between the ball check valve and seat, or improper adjustment, maybe a flat spot on the check ball itself
General noise throughout the valve train mainly due to lack of oil supply, or the improper lash adjustment
Moderate Rapping noise as a rule caused by high leak down rate, improper lash adjustment, or leaky check valve seat
As a rule if one lifter is in a bad way then your best bet is to remove them all ,for a good clean up and inspection,

Important Note:

When pulling the rocker assemble down, don’t mix the parts up, as they need to go back in the same location as from were they came from, so lay them out on a corrugated bit of cardboard, or in separate containers clearly marked, place them where they can’t get knocked over or mixed up, the same aplies to the lifters as well, as the plungers are not interchangeable, they are factory selected and fitted, so don’t mix them up, as they need to move free in the lifter body ,without excessive leak-down.

Removing Lifters:

Remove the distributor cap, place a clean rag over the dizzy body, remove the two side cover plates to gain access to the lifters, (you may need to replace the gaskets when refitting the cover plates), now loosen the rocker arm nuts, this will remove the tension on the push rods, you can now pivot the rocker arm free of the push rod, this will now allow you to withdraw the push rods, remember were they came from, don't mix them up
You now should be able to remove the valve lifters from there position, if you have a strong magnet then use it to pull the lifter up so you can get a grip on it to withdraw is from it's hole, remember were they came from, Note:there is no need to remove the rocker arms here at this stage
Photo by Jacks click to enlarge

Problem Removing Lifters:

Photo by Jacks click to enlarge, Burr here
Photo by Jacks click to enlarge

Because we have two faces contacting each other, (namely the cam lobe contacting the lifter base) this causes friction, which in turn causes wear on the cam lobe as well as the valve lifter base, as the cam lobe contacts the base of the lifter, being slightly con-caved
The base of the lifter is designed to have a slight concave surface which helps the lifter to turn and wear evenly as it is being in contact with the cam lob.
However over a period of time the wear on the lifter base will increase, thus the concave surface will get larger and spread to the edge of the lifter causing a burr
When this accrues it makes it hard to pull the lifter up out of the hole, so then the lifter will need to be removed by other means, sometimes the other means may mean damaging the lifter itself in order to get it out, but I should imagine that as the base of the lifter is some what worn,then one can assume the cam may need to be removed as well If the lifters need to be replaced because of the wear, then one can assume the lobs on the can shaft are worn as well , this is why one normally replaces the cam shaft when fitting new lifters, this is the proper way.

Valve Lifter Tool:

Photo by Jacks click to enlarge

You can also use a special Valve Lifter Tool, this tool fits into the groove where the retainer clip fits, so you will need to remove the clip, be careful doing this, block off open holes with a rag, as you don't want the clip falling into the sump.

The centre part of the tool is adjustable, as the shaft screws into the small block, this helps to spread the two small clip legs apart, so it can fit snugly into the retainer clip groove, you then can get a good grip of the lifter body and with a bit of luck you should be able to pull the little sucker out, this tool is not expensive, around the $11.50 mark, so might be worth trying especially if you have some that are hard to remove

(LINK : to removing cam shaft),

Rocker Assembly:

Once the Rocker Cover is removed ,you can see the workings of the Rocker Assembly, consisting of valves, valve springs as well as the rocker arms and the push rods
The valve action being up and down is controlled by two methods, the valve spring is used for closing the valve, whilst the opening of the valve is controlled by the cam action, as it pushes the push rod up to raise the Rocker Arm ,the Rocker arm in turn then pushes on the valve stem to open the valve.
Bridging these two assembly movements of the valve and the push rod actions, is the Rocker Arm, it is situated on a post with has an adjustable nut that can take up the Valve Lash between these two movement

===Pushrod Lengths:===

Submitted by WBJailwagon on Tue, 19/06/2007 - 10:58.

Just measured one from a 3.3 Black motor - 9inch (229mm approx),and one from a 186 - 9 1/8inch (232mm approx).

Cheers, Jeff. 

Pushrod Interchangeability:

There is only an 1/8 of an inch difference in the length of
the push rods i've used 202 push rods in a 186 just need to tighten them down a little more but worked fine

Valve Lash:

As the Rocker arm pivot's on the adjusting stem post, its imperative that any adjustment to be made only when the oil is at the correct working temperature, otherwise you will not get the correct clearance setting's so its imperative that the Oil Temperature be at working condition to make sure all the parts are fully expanded, thus avoiding false reading
Photo by Jacks click to enlarge
the working of the lifter

Adjusting Valve Lash:

Non-Adjustable Valve Gear:

For adjusting non-adjustable valve gear see Rockers and Pushrods. Now with the engine oil warmed up, the engine at idle speed, back off the valve rocker arm nut until it starts to clatter,now slowly turn the nut back down until the clatter just stops, this is what is called zero lash position.
Now turn the nut down 1/4 of addition turn, wait a bit for it to settle say 10 seconds or so until the engine is running smoothly. Repeat additional 1/4 turns, don't forget to pause for 10 seconds, do this until the nut has been tuned down from half to one full turn from zero lash position.Hope the above is helpful, if there are mistakes please advise me
Cheers, Jacks

Qute's Adjustable Valve Gear Adjustment Method:

 Adjustable Rockers Initial Setting (no offence but this is the basic version. There is a quicker one but this one has less room for error). There is an expanded Guide to the Initial Setting of Rockers below this section:Get motor to TDC on the Compression Stroke on number 1 cyl.Back off your rocker nuts for number 1 cylinder's valves until the rockers are loose. Then tighten rocker nuts on both valves for number 1 cylinder down until you cannot easily turn the pushrod by hand. Then tighten an additional ½ a turn.Turn motor over until Number 5 cyl valves are both closed and do the same on the valves for cylinder 5.Continue for cylinders 3, 6, 2 and 4 in that order.Replace rocker cover.Start motor and allow it to properly warm up (about 20 - 25 minutes at a fast idle which is 1,000 - 1200 rpm or a 10 - 15 minute drive).Stop motor and remove rocker cover.Remove rocker cover gasket from the rocker cover and place it in position on the head. Some people get an old rocker cover and cut the top out of it and then put this on the motor while doing the valve clearances as it makes a LOT less mess that way.Start motor and adjust idle back to specs (about 750 rpm for a stockie, as low as possible if you have a lumpy cam)Starting at the front of the motor (it doesn't really matter what order you do them in, I just start at the front and work back to the back...) back off each rocker in turn until it clatters (you'll know the sound when you hear it!). Then tighten the nut until the clatter JUST stops (a.k.a. Zero Lash).Then tighten the nut ¼ of a turn. Allow up to about 10 seconds for the motor to recover its composure then tighten the nut another ¼ of a turn. Holden recommend you tighten the nuts 2½ turns past Zero Lash which seems fine on a completely stock motor. If you have work done to your motor, about ½ a turn past Zero Lash works well and helps prevent the lifters getting pumped up too early.Follow the same procedure for the other 11 valves.Stop motor and replace Rocker Cover.Degrease motor and driveway under your car....Check oil level and top up as necessary.Beer O'clock...Cheers...Dave
Newer type Hydraulic Lifter dissembled. Photo by John Abbott.  Click to Enlargen.

Qute's Method for Setting Adjustable Rockers from Scratch:

 If you have removed the head for any reason, follow this guide to the initial setting of rockers on the motors with adjustable rockers.
Hydraulic and Solid Valve Lifters. Click to Enlargen. Photo by HQ_SS.
I'll assume you have left the dizzy in the vehicle and it is timed fairly correctly. If you have also removed the distributor, you can still use this method to set your rockers' adjustment but determining TDC on the Compression Stroke for Number 1 cylinder is a harder job.  If you have built the motor from scratch, you shouldn't need to be reading this... :-) Remove Spark Plugs (makes it SO much easier to turn the motor over by hand), the dizzy cap and plug/coil leads. Turn motor over until Number 1 cylinder is on TDC (Top Dead Centre) on the Compression or Firing Stroke. This can be reasonably judged by the rotor button in the dizzy pointing to the notch in the dizzy's body that signifies Number 1's Spark Plug Lead position. The Rotor Button should really be pointing to a point that is 6 to 10 degrees BEFORE the notch (depending on your initial timing setting). If it is pointing at the position where Number 6 Spark Plug Lead normally sits, you have to turn the motor over some more... Check the position of the timing mark on the Harmonic Balancer (only REALLY trust this is the H-B is new) for more confirmation of the piston's position. Once you are REALLY sure you have Number 1 cylinder on TDC on the Compression Stroke, we can commence initial setting of the Tappets.
Hydraulic and Solid Valve Lifters. Click to Enlargen. Photo by HQ_SS.
Put the first 2 Push-rods in their respective holes in the head and allow them to slip down (NOT drop!) until they are resting on the lifters. If you are re-using the Pushrods, ensure they go back into the same hole they were removed from AND they are also pointing in the same direction as before (same end up) It is best to mark this or work out a system to know this when you disassemble the motor. Put the first 2 rockers on the studs (once again, the same rocker on the same stud it was removed from initially). One end of the Rocker will have a ball socket looking bit on it. This is where the push-rod pushes on it.  Screw the rocker nut onto the stud and start winding it down.
A view down the inner sleeve of an Hydraulic Lifter from a 173 Engine. Scoring in here can limit the Lifter's ability to adjust properly resulting in the Valve being held open or the clearance not closing up with Valve rattle resulting. Click to Enlargen. Photo by John Abbott.
When the nuts gets close to touching the Rocker with the rocker touching both the push-rod AND the valve, use your free hand (the one you WERE using to hold yourself off your paintwork) to "twirl" the push-rod between your thumb and index finger.
A view down the inner sleeve of an Hydraulic Lifter from a 173 Engine. Scoring in here can limit the Lifter's ability to adjust properly resulting in the Valve being held open or the clearance not closing up with Valve rattle resulting. Click to Enlargen. Photo by John Abbott.
Tighten the rocker nut down until you JUST cannot twirl the pushrod. Then tighten the rocker nut an additional ½ a turn. Turn the motor over until Number 5 cylinder is on TDC on its Compression Stroke and repeat the above process. Then repeat the above for Numbers 3, 6, 2 & 4 cylinders in that order.  Replace Rocker Cover, Dizzy Cap and Leads (plus anything else you removed from it earlier) and it is safe to start your motor.  It is not advisable to use lots of revs/throttle or put the motor under load after this initial adjustment. Just start the motor and set it to a fast idle speed (about 1,000 to 1,100 rpm) for 20 minutes to warm it up properly. This assumes you have a working thermostat - it WILL take LOTS longer if you have removed your thermostat. Once the motor's temperature has normalised (the actual motor NOT the water/coolant), you can then do the final adjustment as noted in the previous section. Then, and only then, do you get to drive the damn thing! :-))  

Identifying Solid and Hydraulic Lifters:

When the lifters are already in the Engine here is an easy way to identify which is which. 
Belated info I realise ...Hydraulic Lifters:
With the engine stopped, set a valve to the fully closed position and with its required clearance, then tighten down the adjuster until the valve is slightly open.Wait 2 mins. If the valve is closed and the pushrod can be rotated by your fingers the lifter is hydraulic (it has ramped down).Solid Lifters:
With the engine stopped, set a valve to the fully closed position and with its required clearance, then tighten down the adjuster until the valve is slightly open.Wait 2 mins. If the valve is *still* partially open and the pushrod *cannot* be rotated by your fingers the lifter is *solid* (it has *not* ramped down).T 

===V6 Roller Lifters:=== 

Roller Valve Lifter as used in a V6. Click to Enlargen. Photo by HQ_SS.

VL Lifters:

Valve Lifter as used in a VL 6. Click to Enlargen. Photo by HQ_SS.
Valve Lifter as used in a VL 6. Click to Enlargen. Photo by HQ_SS.
Holden 173 Engine disembled.  Note this 173 has Adjustable Rocker Gear. A standard 173 uses Non-Adjustable Rockers. Image by Bubsy. Click to Enlargen.
Adjustable Rocker Gear on a 186 Head. The Hold Down Nuts are called Posi-locs. Image by Bubsy. Click to Enlargen.
    SICKHG on Mon, 20/04/2009 - 14:30. They are posi-locs they allow you to be able to adjust your rockers then lock them up with the allen key in the top. seems wierd someone would put them on std rockers though, they normally come with rollers.Cheers
Adjustable Rocker Gear Head fitted to a 202 Engine. Photo by Besty123. Click to Enlargen.
Rocker Cover with the Top cut off makes for adjusting Rocker Gear without dropping Oil everywhere. Photo by Dusty. Click to Enlargen.


Rockers and Pushrods

Bubsy's Shed

Roller Lifters

Pushrods Rotating Video

Rockers and Pushrods



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