How to Rebuild Pontiac V-8s - Updated Edition. Rocky Rotella

How to Rebuild Pontiac V-8s - Updated Edition

How to Rebuild Pontiac V-8s - Updated Edition - Rocky Rotella

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Remove the nut securing the rocker arm pivot ball with a 5/8-inch socket. Inspect the contact surfaces of each rocker arm and pivot ball for pitting or galling. Because the rocker arm and pivot ball wear in together and self-adjust to each other, it’s best to keep each pair united to prevent potential issues during future use. Like all pieces of the valvetrain, I prefer to keep the rocker arm assemblies in sequential order for inspection purposes.

      Professional Mechanic Tip

Valvetrain Organizer Image
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       A valvetrain organizer, such as this from Comp Cams, is an excellent way to maintain the order of the valvetrain components for each cylinder during disassembly. It allows for complete inspection of each complementing component after the entire valvetrain has been removed. The high-quality plastic tray is impervious to oil and solvents and cleans up easily.

3 Remove Pushrods and Lifters
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       Remove the pushrods and organize them in sequential order. Then remove and organize the lifters in a similar fashion. Two hands are required for removal, so use one to push the lifter upward and the other to lift it from the bore. Quickly inspect each lifter face for immediate signs of abnormal wear, such as grooving, pitting, or cracking. Organize them in a manner so each lifter can be inspected closely along with its corresponding lobe when the camshaft is removed.

4 Remove Cylinder Head Bolts
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       The 10 bolts securing the cylinder heads were likely torqued in a specific pattern during assembly. It generally includes working in a spiral pattern outward from the center bolt. A spiral pattern is not necessary for bolt removal during disassembly. I tend to pick an outside bolt, unloosening each as I work toward the center in a spiral pattern. The head bolts are very tight. I use a long 1/2-inch-drive breaker bar for maximum leverage and I squarely seat a quality 3/4-inch socket against the cylinder head to prevent rounding the edges. Some bolts on this 400 required noticeably less effort to remove than others, which possibly indicates improper torque during install or a head gasket that didn’t crush evenly. I recommend loosely reinstalling one or two head bolts. It keeps the cylinder head from falling off the block during the next step.

      Important!

5 Remove Cylinder Heads Image
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      Image Dowel pins locate the cylinder heads on the block. In most cases, you need to use a forceful upward tug to break the cylinder head free from any sealing compounds or corrosion. Place a pry bar into an intake port and smoothly apply pressure until the cylinder head pops up against the two remaining head bolts. If the cylinder head does not move after a fair amount of prying force has been applied, stop prying! Closely inspect for any hidden head bolts that may still be installed. Once the cylinder head is loose, remove the remaining head bolts and inventory them all, and lift the head up and away from the engine. I prefer grabbing the loose cylinder head near its exhaust ports and lifting it toward the center of the block, where I can carefully slide my fingers beneath and grasp it firmly. Fully assembled iron cylinder heads weigh nearly 60 pounds each, so be prepared. It can inflict damage and serious pain if dropped on your feet.

      Critical Inspection

6 Inspect Cylinders Image
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      Image Visually inspect the pistons and cylinder walls to gain an insight on the engine’s overall operating condition. The dish found on these pistons reveals that the engine’s static compression ratio was much lower than its original rating of 10.25:1. The heavy deposits indicate that oil was entering the combustion chamber and that irregular combustion was occurring. The cylinder walls have a defined ridge at top but otherwise look fine.

      Critical Inspection

7 Inspect Block and Head Gasket Image
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      Image Closely inspect the block deck and head gaskets for any signs of coolant and cylinder pressure seepage. If seepage is identified, there could be an underlying issue. If the head gaskets are in good condition, they can be reused if you’re on an extremely tight budget, but I strongly recommend using new, high-quality gaskets because a well-sealed head is essential. In this case, the coolant found leaking outward around this cylinder head bolt has clearly ruined this gasket. The leak was likely the result of an undertorqued head bolt, and we found several during cylinder head removal. Soot trails found between cylinders are further indication that the head bolts were not properly torqued.

       Special Tool

1 Remove Harmonic Balancer Image
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      Image Unbolt the water and fuel pumps, and remove the lower pulley from the harmonic balancer with 1/2-inch and 9/16-inch sockets. Inventory and set aside the hardware and accessories. You now have clear access to the harmonic balancer bolt, which should be extremely tight. I prefer a pneumatic impact wrench if compressed air is available. A very long 1/2-inch-drive breaker bar and a 15/16-inch socket can be used to remove the bolt, but crankshaft rotation must be prevented. Thread a long, hardened steel 1/2-inch x 20 stud into a flywheel bolt hole on the flywheel register. The stud locks the crankshaft when it contacts the engine stand so the balancer bolt can be removed.

       Critical Inspection

2 Inspect the Harmonic Balancer Image
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      Image On a Pontiac V-8, the harmonic balancer is used to damp harmonic vibrations, and not necessarily balance the front end of the crankshaft as its name suggests.

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