Engine Building 101 Chase, clean, and inspect all of the bolts and bolt-hole threads Bolt threads should be clean enough that you can screw and fully seat the bolt dry. If it hangs up, inspect and chase the threads, or replace the bolt Lubricate bolt threads before torquing. Never torque bolts dry Check all the dimensions three times Check all the torque specs three times-seriously Apply assembly lube lightly, as opposed to dripping wet Do not use Teflon tape on bolt threads; It can leak. Use a thread sealer Use high-temp RTV sealer on brass freeze plugs in the block and heads. Do this sparingly on bolt threads where necessary (e.g., wet decks, cylinder heads, screw-in rocker-arm studs, and intake manifolds) When using RTV silicone sealer on gaskets, use a thin layer that will not squeeze out. Excess sealer can break free and clog water jackets and radiators All engine parts should fit together with a comfortable fit (i.e., a nice, smooth fit with minimal effort). Marvin calls this a zero fit. A timing gear should slide right on the crankshaft or camshaft without effort-not loose and sloppy, just a smooth fit. If you need a hammer, it's too tight; if it can fall off, it's too loose. One exception is the harmonic balancer which has to be a press fit Piston-ring width controls engine friction and temperature. The wider the ring, the greater the friction and heat transfer. Run 5/64-inch width on the street because of long-term wear requirements, and 1/16-inch for racing because there is less long-term wear and friction concerns. Watch ring tensions also Cylinder bores shrink with heat; pistons grow with heat. Aluminum pistons grow at a rate of 3:1 compared with iron or steel. Keep this in mind when boring and honing for proper piston-to-cylinder wall clearances Forged pistons grow more with heat; cast and hypereutectic pistons grow less with heat Be attentive to crankshaft and camshaft clearances and endplay. If it's too tight, it will run hot, and it it's too loose, you risk instability Did you know you don't have to use gasket sealer on the oil pan gasket? Use sealer only to retain gaskets during oil-pan installation. Use sealer sparingly at gasket joints at the front and rear main seals Use engine oil on the cylinder walls during the final assembly. Never use synthetic oil during assembly, and absolutely no cam break-in lube Use engine assembly lube on main, rod, and cam bearings between the journal and bearing only. Dry between the bearings and block saddles Make sure all bearing-oil holes line up. Bearings don't always arrive from the factory properly machined Machining mistakes do happen. Inspect and cross-check everything Do a mock-up before assembly. Preassemble the long-block without the piston rings, and check compression and deck heights as well as piston-to-valve clearances. Check side clearances and end play also. Follow basic engine math and check compression ratio twice. While this takes time, it is necessary for engine-building integrity Be sure to degree the camshaft and check valve-timing events Blueprint the oil pump, checking rotor side clearances and relief valve for proper operation. Never trust an oil pump out of the box Always examine valvetrain geometry. Rocker arms don't always line up with valve stems. The rocker-arm tip needs to be dead center on the valve-stem tip at 50 percent of valve lift Blueprint the valve springs. File ragged edges smooth at both ends and spray them with graphite lubricant for reduced friction Did you remember to inspect all of the rocker arms? Rocker arms can arrive with flaws no matter how expensive they are. Pay close attention to snap rings, needle bearings, and rollers Inspect and dress all rocker-arm studs Apply GE's Glyptal 1201 to all unmachined iron surfaces for better oil drainback and to keep stray iron particles out of the oil Use main bearing cap screw-in studs instead of bolts for added strength Safety wire bolts where possible for added security With no exceptions, always use Grade 8 bolts in the build Ascertain proper head-gasket installation. Gasket end cooling passages always go at the rear of the block. Don't use sealer Dimple the intake gasket end rails for gasket security Do a five-angle valve job for improved airflow; never anything less than three-angle. Valve seat width affects valve temperature. Narrow seats (contact) makes the valve run hotter and wide seats run cooler. A good rule of thumb is .040-inch intake and .060-inch exhaust for racing, and .070-inch intake and .100-inch exhaust for street. A good compromise when doing both is .060-inch intake and .090-inch exhaust Lap the valves with a fine compound in 90-degree turns. Count the exact number of turns (e.g., 10 spins). This ensures a perfect 360-degree contact with the valve seat and a perfect seal Clean all assembly parts with mineral spirits. Identify them and put them in a plastic bag Use a magnetic oil-drain plug to pick up any stray iron or steel particles If using a cast-aluminum oil pan such as a Cobra T-pan, use GE's Glyptal 1201 on the inside surfaces to prevent leaks from porous aluminum and to keep stray aluminum particles out of the oil RTV or screw the rear-cam plug to ensure it doesn't leak
These pesky details may seem like overkill, but when reviewing the remains of a failed engine, it's no comfort to realize you should have sweated the details. Detail is of utmost importance in any engine build.