Automotive Machining. Mike Mavrigian
Before you attempt a short-block disassembly, plan ahead. Instead of blindly removing items and scattering them in a pile, reserve a table or workbench to keep all parts organized, even if you plan to replace most or all parts. Also, it’s a good idea to take photos during disassembly. These will serve you well during reassembly, unless you are already very familiar with the specific engine design.
Drain all liquids including, engine oil and coolant, and dispose according to state and local guidelines. With the oil pan, water pump and all driven accessories, intake manifold, and flywheel removed, remove all rocker arms and pushrods. Organize all rocker arms and pushrods for original position so that you can determine the location for any unusual wear.
Remove all valve lifters. If flat-tappet lifters are used, remove them one at a time. If roller lifters are used, remove them one pair at a time if they are connected with a tie bar; remove them individually if their orientation is guided by “dogbone” guides. If you’re dealing with an LS engine, a plastic lifter “tray” guides a bank of four lifters; the tray is secured with a single bolt. If the engine is a GM LS type, rotate the crankshaft twice. This allows the cam to push all lifters upward to be held in the lifter trays, which eases removal.
Before tearing down a used engine, do yourself a favor and take plenty of photos as a record of parts and their locations. This can come in handy during organizing parts and during assembly.
Completely drain the engine of all oil and coolant. After heads are removed, rotate the engine upside down on your stand.
Certain OEM crank dampeners/pulleys require a special tool for removal. This LS crank pulley features tangs at each of the three spokes that accept a specialty puller. Never use a common pulley puller that engages onto the outer rim of the pulley, as this can distort the pulley or dampener.
Rods and pistons may be removed once the heads and oil pickup assemblies have been removed, but the crank dampener, front cover, and rear cover (if so equipped) must be removed prior to crankshaft removal.
If you plan to apply a show-quality paint job to the block, perform any surface smoothing and removal of casting burrs before the block is machined. This type of operation creates an enormous amount of metal particles and dust.
A power tool such as a pneumatic or electric impact wrench may be used for disassembly, but never during assembly. A power wrench makes faster work of disassembly.
Because you will likely replace all head bolts or studs, removal may be done by hand with a wrench or with a power tool such as a pneumatic or electric impact wrench. Although the heads on a V-engine are interchangeable bank to bank, it’s a good idea to label each head before removing, simply from a reference standpoint. Depending on the engine design, the heads may feature additional inboard, smaller-diameter fasteners near the top of the block decks, as found on LS engines. Before attempting to remove the heads, make sure that all fasteners that secure the heads to the block have been removed. Lift the heads from the block. The gaskets may be stuck, or the heads may be slightly stuck onto the deck dowels. If a head seems stubborn to remove, strike the head on its sides with a large rubber mallet to help dislodge it. Avoid hammering a screwdriver between the head and block deck because this can easily damage either deck surface.
Remove the crankshaft’s balancer. In most cases this is interference fit to the crank snout, requiring the use of a dedicated balancer removal tool that allows you to smoothly draw the balancer from the crank. Never strike the balancer with any object such as a hammer. The balancer must be pulled off, not pounded off.
Remove the front timing cover. Remove the oil pump and its pickup. If a windage tray is mounted to the block, remove it. Remove the timing system by removing the camshaft gear and the timing chain.
With the block rotated 90 degrees or so for ease of access, remove all connecting rods and pistons. Rotate the crankshaft at/near bottom dead center to gain the best access to an individual rod cap. Remove one piston/rod assembly at a time. Remove both rod bolts and remove the rod cap. Using your fingers or a plastic, brass, or aluminum drift, push the big end of the rod off the crank journal. Continue to push the rod and piston toward the deck until the piston rings have cleared the deck. Use your other hand to capture the piston, to prevent the piston and rod from falling to the floor. As you remove rod and piston assemblies, keep them organized if you plan to reuse the rod and/or piston.
When all rods and pistons have been removed, remove all crankshaft main caps. If the caps are not already labeled for position, do this now using an electric etching pen. Avoid using a hammer and number punch, as this may potentially damage the caps. Caps should also be labeled for orientation (which side of each cap faces forward) if not already marked. Before attempting to remove the main caps, make sure that all bolts are removed. Some blocks, such as vintage Ford FE big-blocks and late model LS engines, feature additional side bolts that engage caps from the outside of the block above the oil pan rails.
By hand, wiggle each main cap to dislodge it. Inserting a pair of used main cap bolts into the cap (but not into the block’s threaded holes) provides added leverage. Some main caps may feature a small notch at each side that allows you to dislodge the cap by using a flat-tip screwdriver leveraged against the oil pan rail.
With all main caps removed, carefully remove the crankshaft straight up, avoiding nicking the journals against the exposed edges of the upper main saddles.
Place the crankshaft in a secure location to ensure that it isn’t rolled or knocked off of a table or workbench.
After the crankshaft is removed, carefully remove the camshaft. With the crank out of the way, you have better access to the cam, allowing you to guide it out using both hands. Place the camshaft in a secure location to prevent it from being knocked onto the floor. If the cam is to be replaced or is worn, this may not matter, but if the cam is in good condition, you may choose to reuse it or you may be able to sell it.
Using a cam bearing tool and a heavy hammer, remove all old cam bearings. Remove the front number-1 cam bearing first, followed by the second, third, fourth, and fifth.
Work your way from front to rear. Remove all plugs from the block, including coolant jacket expansion plugs and all oil galley plugs. Depending on the engine, the smaller oil galley plugs may be small expansion plugs or threaded NPT (national pipe thread) plugs. Again, depending on the engine, NPT plugs may feature a female hex or a female square drive, so the appropriate wrenches are required. If a threaded NPT plug is difficult to remove, one trick is to heat the surrounding area in the immediate plug area with a torch until it glows. Then immediately apply a beeswax bar to the plug, allowing the wax to penetrate into the threads. This often frees the plug, enabling removal with a wrench.
When an engine block enters the shop, if the previous builder installed temperature indicators onto the coolant expansion plugs, check to see if the soft lead center of the indicator appears melted. This indicates that the engine experienced a severe overheating.