Engine-building tends to be a mystery for most of us. We're baffled by the tricky math that goes with machine work. And sometimes we're stumped when it's time to buy parts, not to mention assemble an engine. So what to do? Well, listen up, because it's time to go back to school--engine-building school, that is. We're not necessarily going to show you what to do here, but what not to do when building and setting up an engine. Some of these great ideas come from our own past heroic failures and faux pas-and yes, we did learn from them. We also received help from Tom Naegele at D.S.S. Competition Products, Jon Enyeart at Pony Carburetors, and the fine folks at Crane Cams. Thanks, guys!
When it's time to disassemble an engine, we tend to get sloppy because it's dirty work. But you must be organized from the start. Don't throw all of the parts in one big box and hope for the best later on. Inventory your parts and keep them in proper order. If you're going to reuse any parts, they must go back in their proper place; only a few of us put them back where we found them.
We get this one mixed up a lot: dynamic balancing. Small-block Fords were externally balanced two ways from the factory: 28-ounce offset and 50-ounce offset. Get this one wrong and we won't need to talk about dashboard chatter-you'll live it. Small-block (260, 289, 302) Fords manufactured prior to 1982 were 28-ounce offset-balanced. When reciprocating weights (rods and pistons) became heavier in 1982 with the 5.0L H.O. engines, offset balance increased to 50 ounces. This means you can't use a 5.0L H.O. flywheel/harmonic balancer on your pre-'82 260, 289, or 302. It also means you can't use a pre-'82 260, 289, 302 flywheel/harmonic balancer on a 5.0L H.O. Small-block Fords are externally balanced, which means the flywheel and the harmonic balancer must be balanced with the crank, the rods, and the pistons.
Most often, engines die due to valvetrain failure. Many of us have a tendency to install pushrods and rocker arms without checking the harmony between the rocker arm, the pushrod, and the valvespring beforehand. The folks at Crane Cams recommend that you take the time to check the harmony prior to fire-up. The rocker arm must sit squarely on the valve stem, and it should be relatively level in relation to both the pushrod and the valve stem. With the valve fully open (at peak lift), the rocker arm tip should be clear of the valvespring retainer. Overlook these basic tasks and they can bite you in the-well, you know.
Checking The Deck
Only a few of us check the cylinder head and block deck surfaces for trueness. Warpage in these areas can cause a blown cylinder- head gasket, leakage, or both. Make sure you check these surfaces and mill as necessary.
It's such a simple issue, but we've screwed up the engine's head gaskets more than any other head gaskets. Engines overheat when we install their head gaskets backward. FRONT means front on every application. Head gasket cooling passages must be positioned at the back of the head/block in order to have coolant flow throughout the entire engine. If the passages are positioned in front, coolant doesn't circulate to the rear of the engine, thereby causing major hot spots.
Only a few of us thoroughly clean our engine castings during a rebuild, but oil and coolant passages must be thoroughly cleaned, no matter how long it takes. Crusty water jackets and clogged oil passages are engine suicide if they're not checked during an engine build. When you check water jackets, ascertain that all freeze plugs have been removed; ditto for oil galley plugs.
Know what kills fresh engines? Dust. When you're assembling an engine, make sure it's wrapped in a plastic bag when you're not working on it. We've witnessed early engine failure because engines were left uncovered by hobbyists and machine shops alike. Dust finds its way to the bearings, the cylinder walls, and the moving parts, which causes premature wear and tear, so cover it up!
You know the old saying, "Never enough time to do it right the first time, but plenty of time to do it over." Quite often, we're guilty of being eager to get the car finished and get into it. But in being eager, we miss important details that would take seconds to accomplish and save us a lot of grief. Naegele recommends you check bearing clearances twice. Go back and retorque the rods, the mains, and the heads thrice, marking each bolt head with a marker as you go. You'll sleep better if do you.