How to Build a Chevy Engine

This article is directed toward the individual with a basic mechanical knowledge and will provide the most important information and steps to the successful rebuilding of a Chevy engine. Following these steps will result in an engine that is as good or better than the original.

Instructions

1. Tear the engine down to the short block, then take the short block (the engine block without the heads, oil pan and other accessories), heads, crankshaft and pistons to the machine shop. Tell the machinist that you want the short block hot tanked, bored 30 oversized, magnafluxed for cracks, with brass freeze plugs and new cam bearings installed.

2. The heads need to be checked for cracks, new or reconditioned valve guides, the valves need to be reseated, new springs with Ford umbrella seals need to be installed, and the head resurfaced. Use the Ford umbrella seals because Chevy provides only o-ring seals while the Ford seals look like a sewing thimble: metal with the rubber inside and a spring for tension.

3. Have the crankshaft checked for cracks at the journals and for straightness as well as clean the ungrooved surfaces. Also have the machine shop mic (measure with a micrometer) the journals to get the exact size for the bearings. If the machinist says that the crank needs to be turned, ask how much must it be cut down. Crankshafts have a tuffride material on the journals to make them extremely hard so that dirty oil or other contaminants are not as likely to score the crank and bearings. This tuffride is only about the first ten-thousandths of an inch, so if he says more than ten must be removed, there will be no more hardness in the journal and the life of the bearings is greatly reduced.

4. Have the rods resized for the crank since they tend to spread apart with high mileage at the rod bolt ends and would provide uneven wear otherwise.

5. Get a new set of pistons, preferably hypereutectic, which are inexpensive but give superior service life. Have the machine shop install the pistons on the rods. Also get the exact oversize on the boring job so you can get the right size pistons and rings. Also have the machinist mic the crank even if it's new so that the main and rod bearings will be perfect.

6. Put the engine short block on engine stand and wash with dish detergent and water to get all the filling out of the block. Blow the block dry with an air gun and spray the inside of the block with WD40 and wipe off any excess.

7. Turn the block over and install the main bearings and coat them with STP oil treatment. Install the crankshaft and the bearing caps with the right sequence -- watch the numbers so they go on the right spot.

8. Install the cam sprocket on the cam and lube the lobes with STP then install the cam. Install the timing chain and make sure that the marks line up. Install the timing chain cover.

9. Pour STP into the oil pump so that it will get a prime fast. Install the distributor shaft and the oil pump. Turn the engine over to upright and lube the cylinder bores with STP. Submerge the lifters in a can of oil and let them sit for at least two hours so they will relinquish all the air and pump up.

10. Install the piston rings on the pistons using a ring installer for the two top rings. Make absolutely sure that all the gaps are staggered and away from the piston pin. Install the rod bearing on the first piston and lube it with STP, then pour oil on the ring surfaces and install the ring compressor. Install two pieces of hose on the rod bolts so they do not scratch the bore. Install the piston. Make sure that the pistons are properly orientated with the notch on the piston facing forward and the rod end toward the front or back of the journal. Install the rod cap with the notches on the bearings on the same side and torque to specs.

11. Install the harmonic balancer and pulley and bolt to ease the turning of the crank. Turn the crank and make sure there is no binding. Install the rest of the accessories in order of removal and remember to torque the head using three stages of torque starting from the middle moving outward in an X pattern so as not to warp the head.

Tips & Warnings

• Remember to never attempt to start the engine without disabling the ignition and fuel and turning it over for at least 30 seconds to prime the oil pump and get oil to the bearings.