As with everything I do, trust but verify.
You want to build a "cost effective" motor. It is ok, admit it. Everyone LOVES saving money. Shopping for an engine in a junkyard can help you... but before you haul home that shiny "new" power plant from the salvage yard, there are a few things you should do (and need to know).
What is the purpose of this motor going to be? You have quite a few choices: high performance, daily driver, original restoration? Having a clear idea of what role your engine is to fill once you find the perfect power plant is important.
2.) What parts are available for that engine?
350 SBC? No problem- the parts market for SBC's is huge, which translates into less cost for you. What about a high performance Buick 455 Roadmaster? You better have a line on some parts, and expect to pay a premium for the rarity of the parts.
. Educate yourself on different block, head, and crank castings. Know what year engines are most desirable, and from what donor vehicle(s) you can expect to find those engines. Be sure to have a pretty good idea of what you should expect to pay for your particular engine, too.
4.) Set a budget
. Now that you know what engine you are looking for, what your engine's purpose is, and the general parts availability for it, set a general parts budget. This is easier said than done since you don't yet have the engine and know what condition things are in. Using common sense will aid you with coming up with some numbers. At a minimum, expect to buy all new bearings, gaskets, and piston rings.
5.) Be Observant
. Bring a good flashlight. Look for the most desired donor vehicles and engine castings. Pay close attention to details. If willing, have the yard pull the engine from the vehicle. Remove the carburetor, valve covers, and oil pan to check for obvious signs of problems and damage. Inspect the intake manifold plenum runners and exhaust ports in the heads for rust. Use your flashlight to inspect the valve train and rotating assembly for obvious issues. Try and spy the underside of the pistons for heat scorching. Pull the spark plugs and check for fouling. If you can, remove the heads and check the combustion chambers and valves. If there are no major issues or apparent damage, then you likely have a decent junkyard engine.
6.) Understanding importance of machining
. Now that you have your junkyard engine, you need to strip it to the bare block and have it machined. You may ask, do I have to have it machined? YES! If you want a reliable engine that runs well, do not skimp on this step. At a minimum, have your block hot tanked, flushed, decked, line honed, and cylinder honed. This will run between $300-$500+, and is worth every penny.
7.) What to bring, and terminology
. At a minimum, you will need to bring the bare block, crankshaft, one of the main caps with bolts, the new main and connecting rod bearings, the new piston rings, a piston, and connecting rod. Depending on your build and the amount of machine work you are having done, you may need to bring additional parts. Your machinist can help you with this. Now that you have all the stuff there, you need to know what services you are asking for...
- Hot Tanking- Refers to a process in which the block is placed in a hot tank and cleaned of surface corrosion, grease, and all the other nastiness that accumulates in and on an old engine.
- Decking- Refers to the machining of the top of the block where the cylinder head(s) are bolted. Decking ensures a new, perfectly flat surface for the head gasket to mate to.
- Line Honing- Refers to the machining of the bottom of the block and main caps to align and size main bearing bores.
- Cylinder Honing- Refers to the machining of the cylinder walls to ensure a smooth, new surface for the new piston rings to seal to.
- Flushing- Refers to the cleaning of all the journals in the block of old oil and debris.
. Machining is done? Paint the block! You can paint the block any color you like using a high temperature engine enamel paint. I have heard very good things about Eastwood's products. Make sure you mask off all the freshly machined surfaces and accesses to internals prior to painting.
. Now you are ready for the fun part- reassembly! After all your hard work,planning and preparation, your engine has been transformed from a junker to a jewel.