Engine Block Prep - Building Blocks

The pressure builds. The drive to perform efficiently ramps up. Failure of one aspect could be devastating. It's a lot to ask of an engine.

You're asking the same from your engine builder, who's charged with creating the key to propel your racing career. Whether you are a hobby racer or a professional, you are probably entrusting your success to a knowledgeable person who practices the craft of race-engine construction. After all, it's not what you have, but what you do with what you have. An experienced engine builder offers a competitive edge.

Chuck Jenckes works in the engine shop at Dale Earnhardt Inc. (DEI). The team goal is to win races and bring home a championship. With three NASCAR Nextel Cup cars in the fold and countless racing activities on their plate, the shop crews have to be perfect the first time and better after that.

"The first thing everybody thinks," says Jenckes, "is that building racing engines-whether it's Nextel Cup or, for what I know of, even Formula 1-is like a very dramatic, highly interesting business. The truth is, on an everyday basis, building racing engines is probably one of the most exacting, excruciating, if not almost boring, businesses. It's not excitement every minute. The actual process of assembling an engine is painstaking, and the level of detail you have to maintain is extremely high. It's rigorous, and it's not what people think. You're just out there every day making horsepower with everything you do. It all comes down to fundamentals.

"The interesting thing is that what makes a great Late Model Stock engine is probably a lot of the same things that make a great Nextel Cup engine-and that's attention to detail and making sure every detail is right to the extent that you have control over. The difference is that in a Nextel Cup engine, you have a lot more control over what you can do, whereas in the Late Model Stock engine, because of finances and resources, you may not have that control."

To create a quality engine, you must have the best possible block. This requires preparation and a certain understanding of what is being accomplished. "While the block itself doesn't make horsepower in the sense that there's no moving parts in the block, all the parts move in the block," says Jenckes. "The block is like a house. If the foundation isn't good, you can't have a strong, good house. With a racing engine, if you don't have an excellent block, then you don't have the foundation to have the power to make it better."

Block Inspection The first step in block preparation involves machining. "Make sure everything is in the correct place and that things are square and true, like the crank centerline and the cam centerline," says Jenckes. "Make sure the crank bore and the main journal bore are square, and that the line bore is properly done and placed."

Jenckes cites another area that's getting plenty of attention from today's engine builders: "There are attempts in all engines today to turn more shaft speed, so lifter plates are a huge issue. Are they placed correctly? Are they on the right centerline? Is the axis true? You check whether they are perpendicular to the cam or not and also the angle that they're indexed relative to that, and then the position of the lifter, left to right, front or back. All of those things are critical. If it's a roller motor, obviously the placement of the roller and how it's indexed against the camshaft-and if it's a flat tappet-is just as critical."

The crank centerline is a key element of the block preparation. "If you have an older block and you begin to bore it and set it up, you're actually moving the cam centerline and crank centerline closer together, but you compensate that with different caps," says Jenckes. "Actually, the boring and honing process will get you straight and true, but the point is, even if you aren't reindexing that bore, you need to check it. You need to make sure the journals are right. Don't assume anything. That's the key in almost all racing-engine preparation. Check every journal. Check everything. You have to check every bore of the mains. You need to check whether the crankshaft is square to the rest of the engine."