Worn Rocker Arms
by Norman Nock, British Car Specialists
Originally published in the Austin-Healey Magazine, January 1994
Worn rocker arms have been a problem with six- cylinder Austin-Healeys. This problem shows up in many ways:
Valve cover leaks at gasket, name plate rivets and hold-down bolt seals.
Oil spurting out of engine up to 12" when oil filler cap is removed with engine running.
Oil in rear air filter. This is caused by oil spurting into the valve cover breather and traveling along the hose to the air filter.
Oil on the exhaust. Same cause as #3 but the leak is much worse.
Car burns oil and smokes. At freeway speeds, spurting oil hits the inside of the valve cover then passes down the valve guides.
Low oil pressure. Cause is same as #5.
If you think you could have a worn rocker arm assembly, remove your valve cover when your engine is at operating temperature, speed up your idle and look for oil spurting out of the holes on top of the rocker arms. Rocker arms in good condition will only have a slight seeping from the small hole in the top and from the bush of the rocker arm.
Rebuilding Rocker Arms
If this is the case, and oil spurts up when the car is running, remove the rocker assembly and strip it completely. Inspect the shaft for wear on the bottom, as shown in photo I. If you should find your worn shaft looks just like the one in the picture, you'll need a new shaft and 12 bushes. Both are available on special order. Remove rocker-adjust screws to clean threads, press in bushes, drill oil holes and ream to fit shaft.
Completed installation should look like photo 2.
Grind valve to rocker arm face as per photo 3.
Next, inspect the threads on the pedestal where the banjo bolt is attached. If it is in good condition, fit the pedestal to shaft first and then fit the banjo bolt into locating hole on shaft. Do not remove this bolt until assembly is bolted onto cylinder head. Rocker arm assemblies are available with the chromed used shafts, I prefer a new shaft and bushes. Complete assemblies are available.
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