Race Engine Building - 10 Steps To A Better Engine

When we want to learn the important details of any operation, we can always rely on the experience of someone who makes a living doing it. This idea holds true when it comes to building and/or rebuilding race engines. Those who have done it a hundred times have found that things can, and often do, go wrong. By listening to them and following their instructions, we can avoid some common pitfalls.

Although this is not intended to be a complete engine-building guide, it will point out some of the simple, but dangerous, things sometimes overlooked that can affect the amount of useable horsepower and engine life.

Most, if not all, of the tips and procedures are the result of problems that have occurred and solutions that have been worked out by expert engine builders and tuners. If you discover just one tip that saves your engine, the time spent reading this will be well worth the effort. Let's get started.

1Engine TearDown Most often, the engine-building experience begins by tearing down a motor. This might be one built and used last season or one purchased from a junkyard. Regardless, attention must be paid when disassembling the motor. There are clues as to possible pre-existing problems, and if we are attentive, we can locate problem areas and fix them before investing money in new parts.

The rod and main bearings are an area where potential problems associated with restricted oil flow, binding, or improper clearances can be seen. Aside from a spun bearing or the obvious signs of galling or burning of the bearing surface, look further if one or more bearings are a different color than the others. This may be an indication of restricted, not blocked, oil flow. One or more bearings may be running hotter than the rest, and failure is imminent.

When a problem such as this is detected, take extra time to inspect and clean all oil passages. Another area is the felt torque on all bolts removed. If one or more bolts are already loose or take less effort than the others, the threads may be stressed in the block, or warping of the block or head may have occurred from overheating at one time or another. While the block or head may have been thought to be OK as is, you may now consider having it surface milled to make sure it is a truly flat surface.

This step is fairly obvious to most engine guys, but always mark the rods, caps, and pistons as to the original location as they come out of the engine if you intend to reuse them. You can stamp them by number, or those who don't own a number stamp kit can use an age-old method. Using a punch, make a series of dents to represent the cylinder number for the rod/piston combination and the end cap that goes with those as well as the main bearing caps. Use one dent for "1," two dents for "2," and so on.

2Block and Head Preparation Prior to assembly, the block and heads will be cleaned by acid-dipping or other means to remove all of the old paint, sealants, and oil deposits that remain. It's now time to think about what machine work is needed before assembling the motor.

A limited amount of machine work may improve your chances of success with this motor. Usually the shop where you get your motor acid-dipped can also mill the block and heads, align-bore the block, and recut the valve seats for you. Price those jobs and see what you can afford. The areas of valve seats and alignment are well worth the cost and effort.

If you have several bolt holes that show worn threads, make sure to have them repaired by someone who knows how. Pay attention to those areas, not just before assembly of the motor.