FC Holden Valve Timing

[John G]

Hi,
I purchased an almost completely restored FC sedan a couple of years ago. I've finished off the restoration - Chrome, Rubber floor mats, some interior trim, sunvisor, Rear venetians and a host of minor mechanical and electrical items and now have a nice FC for club runs etc.
The one thing that annoys me though is getting rid of the tappet noise - at idle it is not too bad but at 1000 to 1500 rpm there is a distinct clatter in addition to the tappet noise.
I have had the rockers re-faced and the valve clearances have been done with engine hot and running to .008 inlet and .012 exhaust.  When the rockers were re-faced, we noticed some wear in a couple of bushes but thought it was not too bad.  The oil bleed in the central bush has been blocked to try to increase oil flow through the shafts and through rocker bushes.
However, given the annoyance factor, I am at the stage of pulling off the rocker gear and giving it a close check re clearances and replacing where necessary.  I have been told I may be wasting my time but the FC I had back in the late 60's was very quiet and I want to try getting the tappet noise reduced - my time, my money.
I haven't had to do much of this work in recent times so would welcome some helpful hints in addition to what I intend to do.

Dis-assemble rocker gear, clean all oil passages, measure shafts for wear, measure rocker bushes ID for wear, replace what appears to be worn and on reassembly, check and replace fibre washers at central bush.  Given that it may be difficult to procure new shafts and rocker bushes, I may get a used rocker assembly from a friend in my car club and interchange components to build a good rocker gear assembly.  Any comments?

Does anyone have any hints to make the job more a success?

Regarding valve timing (and ignition timing), I was taught that No 1 cylinder is at the front of the engine ie. closer to the radiator.  However, since having this FC, I have heard people quoting No 1 cylinder being closer to the flywheel.  What is correct?

For the initial setting of the valve clearances to enable the motor to run and take to running temperature before final adjustment, can someone give me a foolproof and simple procedure for the initial valve clearance settings?

A response on these questions would be much appreciated.

John   

[ardiesse]

John,

A simple initial procedure for setting valve clearances is -
Turn the engine over by hand until the timing mark is lined up with the ball on the flywheel, and number 1 cylinder at firing instant.
Release the locknuts on number 1's rockers. Turn the adjuster down until there's no lash (this corresponds to finger-tight with a screwdriver).
Back the adjuster off a sixth of a turn for the inlet valve.  Hold the adjuster in this position and tighten the locknut.
Back the adjuster off a quarter turn for the exhaust valve.  Hold the adjuster in this position and tighten the locknut.

Work your way through the firing order: 1-5-3-6-2-4, turning the engine over a third of a turn each time.  The firing instant is when the opposite cylinder's valves are rocking: when the exhaust valve is almost closed and the inlet valve has just begun to open.
Adjust 1 with 6 rocking.
Adjust 5 with 2 rocking.
Adjust 3 with 4 rocking.
Adjust 6 with 1 rocking.
Adjust 2 with 5 rocking.
Adjust 4 with 3 rocking.

By the way, this procedure is almost exactly right for final valve clearance setting, when the engine's properly up to temperature.  But instead, adjust the clearances with the engine idling.  As long as you can cope with a dancing screwdriver and 5/8" ring spanner, that is.  Loosen the locknut and wind the adjuster in until the engine begins to miss.  Then back the adjuster off a sixth of a turn for inlets and a quarter turn for exhausts, and tighten the locknut.

Then, it's helpful to get a stethoscope (or a length of small-diameter tube) and listen to the rockers at the valve stems.  You'll be able to hear some of them make a tick-tick-tick or nack-nack-nack sound.  In the loudest cases, wind the adjuster in a little more until they're quiet.

You need to make sure that your clatter at 1000-1500 rpm really is valve-train noise, and not (say) bottom-end.
In the same spirit, check that you don't have sticking valves or bent pushrods.

Worn rocker bushes don't in themselves make for valve-train noise.  What they do do is starve number 1 cylinder's rockers, particularly the exhaust, for oil.  But you've already shoved a self-tapping screw in the oil bleed hole.

Other hints: Over time, the ball-end of the adjuster wears and develops a "nipple".  Grind or file this off.
Double-check that the rocker arms have been refaced correctly.
Clean the sludge out of the rocker shafts, but you shouldn't have to disassemble the rocker assemblies.  Just make sure that oil flows out of all twelve rockers when the engine's running at fast idle or above.
Check that your rocker shafts are a tight fit in the pedestals.  If the pedestals are difficult to twist on the shafts, they're OK.  Shafts loose in the pedestals is a perennial FX/FJ/early FE problem, but not so much FC onwards.  (By the way, if you are going to pull your rocker assemblies apart, heat the pedestals up with a blowtorch to just above boiling when you refit them to the shafts.  Work quickly, and they'll slide straight on.)
If your valve-train makes noise at 1000-1500 rpm, that's usually a give-away that the cam followers are pitted at the base.  You might have to pull your followers out to inspect them.  Replace as necessary.

Rob

[John G]

Hi Rob,
Thanks for your response.  Can you please give me an answer in regard to location of No 1 cylinder.
John

[Errol62]

1 is at the front and 6 at the back John
Cheers
Clay


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