This article is intended to give a complete procedure for the rebuilding of a Ford 5.0 or 302 cubic inch engine. Follow these procedures in their entirety and the finished product will be as good, if not better, then the original. The cost will be close to 1/3 of a new or already rebuilt engine and last 200,000 miles plus. You will be proud of the quality you have produced.
Tear the engine down to the bare block. Make sure that you replace the rod caps on the same rod that they came from. Make a box, or better yet, get a milk carton and mark it for the relation to the cylinders. You want the rockers to go on the same spot they came off of since they have developed a wear pattern.
Take the short block, the heads, crank, and the pistons to the machine shop. This is what you want to tell them to do:
A] Hot tank the short block. This will clean out the years of sludge and rust buildup in the engine and clean out all the oil passages that are not accessible so that you restore the oil pressure to new.
B] Magnuflux the block for cracks, bore it 30 thousandths over, install the cam bearings and brass freeze plugs. The brass plugs are pennies more but will not rust out like steel.
C] Do a valve job to the heads to include new valve springs, knurl or replace the valve guides, reseat the valves, install new bronze valve seats for the unleaded fuel only if needed, surface the heads, check them for cracks before the work is done and, finally, you want Ford umbrella seals for the valves instead of o-rings. The umbrella seals are a metal cover-like a thimble with the rubber inside. They last longer than o-rings.
D] Check the crank for cracks and see if the journals need to be cut for smoothness. If the machinist says that they need to be cut, ask how much needs to be cut. If he says anything over ten thousandths, then you want a new crank. Cranks come with a tough ride on the journal surfaces to make them hard and difficult to scratch. Once the machinist cuts over ten thousandths off, he has removed the toughride. The crank will scratch and groove much easier when the oil is dirty and reduce the life of the bearings by at least 30 to 40 percent.
E] Install 9.5:1 flat top hypereutectic pistons on the rods and size them to the crank. Over time, the rods swell out at the studs, causing the rods' journal caps to be out-of-round and exert uneven pressure on the bearing.
F] Get the main and rod bearings that the machinist has determined for your crank as well as the rings for the pistons.
Wash the block with dishwashing soap to get all the fillings and residue from the boring process out. Blow it off with an air gun and then spray WD40 silicone on the block's interior surfaces to prevent rust. Wipe off any excess.
Turn the block upside down and install the main bearings. Coat them with STP oil treatment on the surface side prior to installation of the crank.
Install the crank gently so as not to gouge the bearings. Install the bearing caps in their proper order by the numbers on the caps. Torque them down in two progressions starting with 40 foot pounds and then to the recommended torque. Always start at the middle cap and work outward in both directions. Once installed, check for end play due to a bad or undersized bearing by using a screw driver and force it back and forth. There should be barely any play. Now, install the rear main seal with a little engine oil on the lip of the seal. Turn the crank to insure it rotates smoothly.
Submerge all of the lifters in oil for at least two hours to get all the air out, and charge them with oil prior to their installation.
Turn the engine upright for the installation of the camshaft. Install the cam pulley on the cam and coat all the lobes with STP. Very carefully install the cam so that you do not damage any of the cam bearings.
Install the timing chain after dipping it in oil and wiping it off. Make sure that the timing marks are aligned. Install the timing cover with the use of a light coat of RTV on both sides of the gasket.
Install the rings on the pistons using a ring installer for the two top compression rings. It is very important to install the rings in this manner: the ring gaps must be opposite of each other and away from the side of the piston's pin. Starting at the bottom ring's groove, install the first of three oil rings. The first oil ring is solid, and the gap should be ideally 30 degrees away from the piston pin. Now, place the spring spacer ring with the groove opposite the first ring. Install the third solid ring with the gap 30 degrees off the pin opposite of the bottom ring. This entire procedure is to eliminate any possibility of blowby. Install the second ring (with the dot up) with the ring installer keeping the gap in the middle of the piston away from the pin and opposite the top of the last oil ring. The last ring is installed in the same manner but opposite the last rings installed.
Coat the cylinder wall with STP. Install the rod bearings on the rods one at a time and put a piece of hose on the rod bolts so you don't scratch the cylinder walls. Put STP on the bearings. Install the ring compressor on the piston so that the bottom of the installer is just lower than the ring. Pour oil on the rings before installing the ring compressor. Look at the piston top and make sure that it is in the correct position---it should face forward to the front of the engine. There is usually a mark on top of the piston toward the front. Also, make sure the piston is on the right side by the orientation of the rod to journal. They will only fit one way or the rods will be to tight. Each piston rod must face the side of the journal with broad side toward the journal. Install the pistons, making sure the rings don't come out of the compressor while you install them. Put STP on the bottom bearing and make sure the cap goes on right by being sure the crimped edges of the bearings are on the same side. Torque the rod caps to the correct torque.
Replace the accessories in the reverse order they came off.
