How to Rebuild the Small-Block Ford

CHAPTER 1

BEFORE YOU BEGIN

Building an engine is a golden opportunity to know exactly what’s inside. Think of your engine as a blank canvass, ready for liberal doses of oil, paint, and creativity.

Rebuilding an engine can be a very rewarding experience. It’s a golden opportunity to start anew, with fresh components and perfectly machined surfaces married together in blissful harmony. When you build an engine, you become familiar with what the engine is. There is no wondering here—you know exactly what you have under the hood. You can start an educated performance tuning and maintenance program that will allow your new engine to live for a long time. Contrary to the old 100,000-mile (or less) theory of engine life, well-built engines can live 200,000 to 300,000 miles with regular preventative maintenance and a civilized driving technique.

Why do engines live longer today than they did years ago? Much of the improvement is centered around better lubrication technology, lead-free gasoline, electronic engine control, overdrive transmissions, and a host of other elements that make life easier on the engine. Likely the single greatest benefit for engines today is unleaded gasoline. In the 1980s, car buffs were very concerned over the loss of lead in gasoline. There was fear that unleaded fuels would harm valve seats and cause premature engine failure. The valve seat part is certainly true. If you drive a car everyday using unleaded fuel and iron valve seats, it will wind up needing a valve job. Big deal. That is the only sacrifice you’ll have to make using unleaded gasoline. The benefits are far more numerous—a cleaner engine, cleaner air, longer exhaust system life, and certainly longer engine life.

Engines also live longer because companies like Mobil have developed synthetic lubricants that offer excellent staying power, longer service life, and cleaner operation. If you run Mobil 1 in your small-block Ford, change it with great regularity every 5,000 miles, and use a Wix or Motorcraft oil filter, you can achieve 200,000 to 300,000 miles on a rebuild. We offer no guarantees because every engine, and every driver, is different. If you run your engine hard, it won’t live as long. If you consistently forget to change the oil, it won’t live as long. If you let it get out of tune, it may not live as long.

To build an engine that will serve you for thousands of miles, you have to know what you have to begin with. All the best machining technique and highest-quality parts are worthless if you have a flawed casting or forging that will fail when the engine is fired up. This is why the teardown is as critical as the build up.

When an engine arrives at the machine shop, there are many unknowns that become discoveries as we knock the engine apart. We would quickly learn we needed a block, new valves and guides, and more.

Before you can begin on your engine project, you have to be committed to what you want the engine to do, and be willing to stick with that plan. What’s the most severe treatment you intend to throw at this engine? How will you use this engine most of the time? And, the most important question – how much do you have to spend? How you intend to use the engine is directly affected by how much you have to spend. Tight budgets call for a whole lot of common sense, which means knowing how to make the most of your money.

Building a small-block Ford costs anywhere from $1,200 to $15,000, depending on your expectations. A mild-mannered, easy-to-live-with small-block Ford you’re going to use everyday can be achieved for $1,200 if you do most of the work yourself. And, if you take good care of it, including the use of Mobil 1 synthetic engine oil, you can easily achieve between 100,000 and 200,000 miles. If you expect to spin it to 9,000 rpm on a road-race course, circle track, or drag strip, you can expect to spend $15,000 in parts and labor. How much do you have in the checking account? More importantly, how much engine do you actually need?

We are all guilty of bench-racing ego, and many of us build way more engine than we actually need. It sounds so good during a boast fest with your buddies. We all like to talk up our engine build plans. But why spend more money on an engine than you have to, especially if you’re going to build it for the daily commute or weekend cruising? Pleasure cruisers don’t need H-beam connecting rods, steel cranks, and forged pistons. And they don’t really need aftermarket cylinder heads with expensive port work, either. They need the very basics of what Ford provided in the beginning, plus improvements that will make them peppy, reliable engines they can count on for years to come.

Daily drivers and weekend cruisers need only have the small-block they had to begin with, plus reliability improvements like hardened exhaust valve seats, high-volume oil pumps, roller camshafts, high-performance valve seals, bronze valveguides (or replacement of the valveguides entirely), new valves, high-tech gaskets and seals, hypereutectic pistons, electronic ignition, and more. Your goal with a mild street engine is to make it as reliable as you can make it while pumping up the power a bit.

If you intend to do some weekend drag racing, you need to decide how fast you want the vehicle to be and what you can afford. The quarter-mile times you are seeking are directly proportional to what you have to spend. Racing engines take a lot of effective planning and a realistic approach. In the racing world, there is no such thing as compromise. You have to be prepared to spend wisely and go after the best bang for the buck. Cutting corners with a racing engine is foolish. If you try to save a few bucks, you could wind up spending a fortune later when the darned thing blows up. You have to think of a racing engine like you would an aircraft engine. There’s no compromising with an aircraft engine – because airplanes can’t just pull over and call a tow truck. When racing engines fail, like aircraft engines, they typically fail catastrophically. So let’s dive right in with realistic expectations about budget and limitations.

Engine building should always begin with a mental blueprint of how your engine is going to be built. Are you going to collect the castings and parts yourself and build the engine? Are you going to begin with a manufactured short-block or long-block? Are you going to opt for an engine kit? How you approach your engine build beforehand determines the outcome. Crate short- and long-blocks are an excellent choice that can save you a lot of money if you know and trust the builder. Regardless of who the builder is, all crate engines must be checked in great detail before you install them in the vehicle.

Engine building projects begin all sorts of ways. Sometimes, we stumble upon an engine like this one, with no idea of its condition internally. The problem here is whether or not we have found an engine that has already been rebuilt. Rebuilt engines that are worn out typically have 4.030-inch bores. Small-block Fords can be bored out to 4.040 inches, but we discourage a 4.060-inch bore size. It’s always a gamble until you remove the cylinder head and measure the bores.

Build for a Mission

If you want to save a whole lot of money, plan your engine realistically and don’t overbuild. Engines for the daily commute don’t need steel cranks, H-beam rods, and forged pistons. They don’t need an 850-cfm carburetor either. Plan your engine for exactly the driving you intend to do – and leave the bench racing and boasting for the dreamers down at the drive-in.

Engines built for daily commuters, for example, don’t need pure-race technology inside. They need to be planned and built for reliability and economy. This doesn’t mean you have to sacrifice power. Using a nodular-iron crankshaft, heavy-duty I-beam rods, and hypereutectic pistons nets you reliability and performance. If you want an aggressive camshaft that will give you power, seriously consider a roller hydraulic camshaft with .500-inch lift or less. Go for duration and good valve overlap. A high-lift camshaft (above .500-inch) will beat the daylights out of your engine’s valves and springs – which hurts reliability. For more on choosing a cam, check out Chapter 3.

Performance and reliability are always about compromise. To get reliability, you have to give away some performance. To get a lot of performance, you have to give up a certain amount of reliability. It’s always a tradeoff. It is up to you to determine how far to go in either direction.

Any time you can buy a crate engine for $800 to $1,200, you’re not going to get the same value you would from an engine built from the ground up at a local machine shop. Buying a low-buck crate engine means really cheap cast pistons, rings, bearings, and the like. It can even mean .030-inch oversize pistons in some bores, with .040- or .060-inch oversize pistons in others. We’ve seen this enough times to know it is a matter of practice with the low-buck engine builders. They cannot afford to lose the value of a single core block. So, they fudge the rules a bit, taking some bores to 4.040 and 4.060 inches in order to save a block that should otherwise be scrapped. This means variations in compression ratio from bore to bore that most people probably wouldn’t notice. But, it is something you need to be mindful of during your engine build planning. Don’t waste your money on an engine built this way. All bores must be uniform in size without exception. Bearing sizes may also vary too, which certainly isn’t as critical as bore size. For example, .010-inch oversize on rods and .020-inch oversize on the mains is not a big deal.

Critical Inspection

Engine building projects are best started with hand-picked castings and forgings. Look to mass engine builders and parts houses for castings. Always opt for a matched set of heads and block, meaning the same casting numbers and similar date codes.

Another important question for the budget mass-production rebuilder is, do they dynamic balance the bottom end? Not all builders do. Dynamic balancing is critical to smooth operation. The automakers and mass-production engine builders do dynamic balancing to some degree. Pistons, rods, and crankshafts are weight-matched to get them as close to specs as possible. Pistons must weigh within a reasonable amount of each other. So must connecting rods. But this really isn’t dynamic balancing. It’s a crapshoot with your time and money. We like pain-staking dynamic balancing – with pistons and connecting rods that are precision balanced and adjusted for uniformity. We want piston and rod assemblies that weigh exactly the same as the crankshaft counterweights and flywheel counterweighting. Any irregularities in balancing can induce unhealthy vibration. You may not even feel that vibration. But, your engine will. Vibration is destructive and will bleed life right out of your engine.

While we’re on the subject of vibration, it’s important to remember there are two types of offset balance with small-block Fords. Small-block Fords are externally balanced, which means we have to balance the flywheel and harmonic balancer to the crank, rods, and pistons. They should not be balanced separately. Small-block Fords built prior to 1982 have a 28-ounce offset balance dialed into the flywheel (manual transmission) or the flexplate (automatic transmission). When Ford came out with the 5.0L High Output V-8 in 1982, this offset balance went to 50 ounces, due to heavier connecting rods and pistons. The 50-ounce spec has been the standard ever since.

If you’re having a hard time understanding this 28- and 50-ounce offset issue, you aren’t alone. In the old days, the 289 High-Performance V-8 had a slide-on counterweight that went on the nose of the crankshaft. This counterweight offset the additional weight imposed by larger 3/8-inch connecting rod bolts. The same can be said for the 428 Super Cobra Jet, which also had a counterweight to offset heavier connecting rods and bolts. The Boss 302 had this extra weight incorporated into the wider harmonic balancer. Beginning in 1982, Ford infused this added weight into the flywheel/flexplate to offset the even heavier connecting rods and bolts.

Where this 28- versus 50-ounce offset issue becomes challenging is when you’re shopping for bottom-end engine parts. Your small-block Ford must have the proper offset balance to keep vibration in check. This means you need a 28-ounce offset flywheel or flexplate if you are building a pre-1982 302. To do this right, you have to know what combination of parts you have. Keep in mind that your machine shop can balance your rotating assembly to 28- or 50-ounce. The choice is yours. Just make sure you know which it is when it is time to buy a flywheel/flexplate and harmonic balancer. A 28-ounce offset flywheel on a 50-ounce offset engine will set up an ugly vibration. The same is true for a 50-ounce flywheel on a 28-ounce engine. Make sure you have a cohesive package.

Crate engines can be a good value if you know what’s inside them. Not all crate engines are created equal. If you are considering the $800 short-block from a discount auto parts store, carefully consider this decision. If you’re building a rarely driven show car, low-buck short-blocks and long-blocks might be a good value. If you’re building a driver, opt for something better. Don’t be fooled by nameplates. Just because it is a Ford remanufactured engine does not mean it is any better than the $800 to $1,200 discount mill. Verify what’s inside first.

On top, it’s important to understand what kind of valve work you are getting for the money. Are you getting 16 new valves with hardened exhaust valve seats? Or are you getting valves grabbed from a huge barrel with hundreds of other used valves? Are you getting new valveguides or are you getting bronze guides? Are they knurled? Or did the builder forget all about the valveguides and cheat with just a fresh set of seals? These are important questions to ask the budget crate engine builder. Rarely driven show cars don’t need hardened exhaust valve seats, but aggressively driven engines need hardened exhaust valve seats, new valves, and guides.

Low-buck budget engines you can buy from national auto parts discounters are not going to be up to the standards you might be expecting. Based on our experiences with remanufactured engines, a lot depends on what you have to spend and how you intend to drive the vehicle. The occasional weekend driver or trailered show car can get away with a low-buck budget engine from AutoZone, Kragen, or Pep Boys, unless you’re date-code and casting-number conscious.

If you don’t care about date coding or having the correct castings, the discount store crate engine is a nice deal for under $1,500. These crate engines are built by outside contractors, but the same is true for Ford Authorized Remanufactured engines. If you buy a Ford Remanufactured engine through your local Ford dealer or classic car parts house, you are getting the same kind of engine sold through AutoZone, Kragen, CarQuest, or Pep Boys. Ford’s standards may be higher, but not by much. You’re getting the same kind of warranty – about 90 days to 12 months – depending on the company.

Of all the crate engines and kits we’re familiar with, we like the engine kits you can order from Performance Automotive Warehouse and Coast High Performance. Engine kits enable you to see what you are getting before the mill goes together. When it’s already assembled, you have no idea what’s in there. Both Coast High Performance and Performance Automotive Warehouse give you the best parts available in their engine kits. Of the two, Performance Automotive Warehouse offers the greatest value for the money because it sells so many of these engines and kits.

Where these engine kits (and all others) need close scrutiny is in the area of machine work. It doesn’t hurt to check the new parts when they come out of the boxes. All components should be thoroughly examined by a qualified machinist that you trust. Cylinder bores, line-bores, decks, and the like need to be checked prior to assembly. Disassemble a cylinder head one valve at a time and inspect the seats and guides.

Crate engines and kits are the easy ticket to completion, but there’s a great sense of self-satisfaction that comes from building your own engine. Look to a seasoned, qualified machine shop to do your machine work. See to it that everything is properly measured – twice – just to make sure.

You should do this because mistakes do happen with even the best manufacturers and distributors. These days, mistakes happen with greater frequency because the marketplace has become very competitive. Manufacturers are under great pressure to build these engines and kits for less money. As a result, flawed parts slip through unnoticed. So does sloppy machine work because it is all about volume – and profit. We have seen camshafts that don’t match the cam card (mispackaging or poor manufacturing technique). And, we have seen remanufactured blocks with mis-sized pistons and bearings.