PROJECT 51: Rocker Arm Assembly. The rocker arm assembly mounts to the top of the cylinder head, and converts the upward push from the cam into the downward push needed to open the intake and exhaust valves. When the car is traveling at 58 MPH each rocker is opening its valve 1000 times per minute. That requires a good supply of lubrication. (Top speed for the car is considered to be about 78 MPH, by the way.)
As mentioned in an earlier post, Brutus had choked off part of the oil supply to the top of the engine in order to falsely increase the oil pressure on the gauge. The result was excessive wear in the rocker-arm bearings and on the rocker shaft. In several of the rockers the bronze bearing material had worn through to the steel base metal, and the polished steel shaft had worn as much as .015". The maximum bearing-to-shaft clearance is supposed to be .002" (as a reference, a human hair is about .003").
Fortunately, I can buy replacement bearings for all of the rockers, and also a new shaft. (I am continually amazed at the number of parts that are still available for these cars!)
If all goes as promised, I should finally have the engine block, the cylinder head, and the crankshaft back from the machine shops today or tomorrow, and I can start the reassembly of the engine. (Those parts have been at the shops since before Thanksgiving!)
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| Rocker assembly on the engine. |
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| Rocker assembly ready to be disassembled. |
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| Rocker showing bearing worn through to base metal. |
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| Rocker arm showing .015" step. |
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| Another view of the step. |
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