So you think you can build engines? You've swapped out some head gaskets and maybe done a re-ring on your buddy's small-block, but now you want to build your first real engine, and you can't really decide if it's worth it to pass on any of the hundreds of crate engines out there on the nationwide interweb and invest in the tools you need to get the job done right yourself. What do you really need, and what is superfluous? And how hard can it be anyhow?
A good selection of brushes...
A good selection of brushes and gasket scrapers are worth their weight in gold or at least in bearing material. The number one cause of rebuilt engine failure is dirt or debris. If you think spending a half hour cleaning parts is good enough, then clean them all a second time to see if any more grit surfaces. Also, assume all brand-new parts are dirty-they usually are.
The fact that you made it to this paragraph indicates that you're still waiting for your flight to board, you shouldn't have had that shrimp-and-grits omelet for breakfast, and/or you are a die-hard gearhead ready for your next big merit badge.
The first step in deciding whether to take the leap into building your own junk is to figure out what all of the necessary stuff costs, and what you already have or could pilfer from your buddy's tool chest. Next, figure out whether you actually have the skills to use this stuff. If you feel confident that your work will be at least as good as some dude halfway across the country in a production shop and aren't afraid to boast "I built this in my garage," then it's time to get down to the nitty-gritty.
When you get started, it's always a good idea to preclean everything. If you can toss your engine in the bed of your truck and take it to the local car wash without the local EPA rep throwing you in jail, then that's a great place to power off years of leaky valve cover gaskets. Otherwise, spend an hour or so with a bucket of hot water, a couple scoops of Tide, and a good selection of brushes to peel off the scale.
If you're not measuring, you're...
If you're not measuring, you're guessing. At the bare minimum, a good dial caliper and some Plastigauge will get you in the ballpark. A 0- to 1-inch micrometer is good for wristpins and valve stems, a 1- to 2-inch mic is good for small crankshaft journals, a 2 to 3-inch mic for just about all other crankshafts, a 3- to 4-inch mic for smaller pistons, and a 4- to 5-inch mic for most big- and small-block pistons. A 12-inch dial caliper is good for measuring pushrods and the expanding calipers are great for checking cylinder head runner dimensions.
Unless you have an unlimited budget for machinery, you've probably already come to the obvious conclusion that there are some things that a machine shop is absolutely necessary for. Local machinists are a dying breed and can be a little finicky at times, but will appreciate you bringing them clean parts to work with and can be a treasure trove of information about whatever oddball engine combination you're putting together. Tell them exactly what you're building and what your goals are and they can often help with special valve jobs or cylinder honing finishes that will work best with that combo. The biggest tip regarding taking your stuff to a local machine shop is that when you say, "Take your time, I'm in no big hurry," they hear, "I don't have any money," and they slide your stuff to the side.
OK, so you had Big Al bore and hone your block, grind your crank, and do a valve job on your heads, and you're all geeked because it looks neat and shiny now. Regardless of whether they cleaned all that stuff after machining, you have to assume it's full of metal shavings. Back to the bucket of hot soapy water, running brushes through every orifice, wiping down the cylinder walls with lacquer thinner until a piece of white paper towel comes out clean, then laying out all your parts to start fitting everything together.
Checking bearing clearances, valvespring pressure, degreeing the cam, verifying piston-to-valve clearance, and setting up the proper valvetrain geometry may involve mocking up the engine several times prior to final assembly. By that time, though, you'll be intimately familiar with the innards of your engine and only then will the engine really just fall together.
Looking back after building your first real engine, you might have a different perspective on whether you would do this again. How much did you really save? Are you confident in your work? Could you do this again for a buddy and maybe make a buck? Was it really worth the blood, sweat, and tears for the pride of accomplishment, or would you just send off a check next time? Everyone has their own answer. What's yours?