Adjustable Valve Gear

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Page created by T Nov 6th 2010:

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149, 179, 179X2, 161, 186, 186X2, 186S Adjustable Valve Gear. Note each Rocker Arm has its own support Stud and Nut. Image by Josh Lammi. Click to Enlargen
Failed Adjustable Rocker in a 186 Engine. Image by HGKingswood186. Click to Enlargen
Failed Adjustable Rocker in a 186 Engine. Image by HGKingswood186. Image by HGKingswood186. Click to Enlargen
173, 202, 2850 and 3300 non-adjustable Valve Gear. Note the Rockers share a common Saddle. Image by Mark Berner. Click to Enlargen

Adjustable Valve Gear:

This page describes the Valve Gear used on LC 138, 149, 179, 161, 186 and 186S Engines. These Engines had Hydraulic Valve Lifters and Adjustable Rockers. LJ 138, 173, 202, 2850 and 3300 Engines used Hydraulic Valve Lifters and non-Adjustable Valve Gear. The same Hydraulic Valve Lifters are used on 149, 179, 161, 186, 186S, 173, 202, 2850 and 3300 Engines.

Qute's Method For Setting Adjustable Valve Gear:

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

Qutes' Method For Setting Adjustable Valve Gear From Scratch:

If you have removed the head for any reason, follow this guide to the initialsetting of rockers on the motors with adjustable rockers. I'll assume you have left the dizzy in the vehicle and it istimed 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. TheRotor Button should really be pointing to a point that is 6 to 10 degreesBEFORE 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 isbest 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. When the nutsgets close to touching the Rocker with therocker touchingboth 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. 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 loadafter 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 aworking 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! :-))

Stripped Rocker Adjuster Nut. Photo by TUFFVB. Click to Enlargen.
Stripped Rocker Adjuster Nut (right). Photo by TUFFVB. Click to Enlargen.

Stripped Rocker Adjuster Nut (right). Photo by TUFFVB. Click to Enlargen.

Stripped Rocker Adjuster Nut (right). Photo by TUFFVB. Click to Enlargen.
Failed Rocker Arm. Photo by TuffVB. Click to enlargen.
Stripped Rocker Adjuster Nut (left). Photo by TUFFVB. Click to Enlargen.
Failed Rocker Arm. Photo by TuffVB. Click to enlargen.

Adjustable Nut Failure:

..... Just pulled the rocker cover off to check the valves and found number 3 cylinder exhaust rocker but has come loose and it's basically just sitting there. Surely this has to be the problem. End of submission by TUFFVB

Timing Check:

At top dead centre valves 1 & 2 will be shut. While 11 & 12 will be "on the rock" as in one almost closed and the other just opening. Also...when setting valves just watch the opposite cylinder. So.....with valves for number 6 on the rock, set number 1. To set cylinder 2 watch number 5. For 3 watch 4.....and so on


Noisey Lifter Rattle Diagnosis And Repair:

These steps are similar for adjustable valve gear. Use discretion to identify the differing steps.

1. Removed the Rocker Cover, started the Engine and used a length of plastic hose to listen at each valve stem for the noise.

2. Found the No 2 Inlet Valve had the problem.

3. Confirmed by levering out the lash with a screwdriver between the valve spring and the Rocker Arm. The rattle stopped with each levering and returned when the screwdriver was removed.

4. Shut down the engine and rotated the crank until the troubled valve was wide open. The valve spring held the lifter plunger compressed as we removed the retainer clip from the lifter.

5. Removed the No 2 spark plug to make crank rotation easier.

6. Equally loosened the rocker bolts on both valves and removed both rocker arms and saddle, keeping everything united.

7. Removed the faulty lifter - lift, tap down, rotate, repeat method.

8. When the lifter was high enough, placed an angled allen key into the lifter oil hole and pulled the lifter out with pliers.

9. Placed the lifter in a plastic bucket so no parts could fly apart.

10. Pressed the plastic tube of a carb cleaner can into the lifter oil hole and blew the lifter pieces apart. 11. The bottom of the inside of the lifter body was filthy with black contaminated sludge.

12. The check valve body was also layered with sludge and looked blocked.

13. Using pliers we levered the check valve off and removed the spring and check valve.

14. With all the parts now in the bucket we sprayed everything down with carb cleaner.

15. we inspected all the parts for signs of wear and found none, which included an inspection of the check valve for
roundness and absence of flat spots. It was OK.

16. We reassembled the lifter leaving it empty of oil so that the plunger could be easily compressed and the retainer clip refitted. If it had been oil filled, we would have had to resort to using the valve spring to compress it as in step 4.

17. Checked the Rockers at the valve end for wear marks and found them acceptable. Had we found grooves it would have been necessary to burnish the rocker faces flat.

18. We refit the pushrods, rockers, saddles and bolts to the engine and tightened the Rocker Bolts finger tight.

19. Ensuring both lifters were in the lowest position we began tightening the bolts a 1/8 turn at a time.

20. Naturally the inlet valve pushrod was easily rotatable because the lifter was empty, but the exhaust valve pushrod could not be made to rotate no matter how its bolt was worked.

21. After a while we opted to continue torquing the bolts equally to 23 ft/lbs.

22. We rotated the crank until the exhaust valve was wide open an let the valve spring compress the lifter for some

23. About 10 mins later we again rotated the crank until both valves were closed and found the
pushrod was free to rotate. The conclusion is that the exhaust lifter plunger had not been in the uppermost position
since 1974 and had jammed on some sludge.

24. After the No 2 plug was reinstalled and plug lead reconnected, we effected a start.

25. We flooded the centre of both rocker arms with oil to make sure they were lubed until each lifter was fully primed.

26. To be expected, the empty and repaired lifter rattled profusely, but seemed to quieten slightly every so many 10's of seconds as it filled with oil.

27. After repeatedly bringing the power up to 2,000 RPM and dropping back to idle the rattle reduced because the increase in oil pressure primed the lifter. Oil was soon flowing across the top of both rockers from each pushrod.

28. With the rocker cover back on the job was done.


Hydraulic Lifters

Rockers and Pushrods

Bubsy's Shed

Roller Lifters

Pushrods Rotating Video

Failed Adjustable Rocker Thread 1

Failed Adjustable Rocker Thread 2



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