Proper Engine Building Techniques Engine Builder

Proper Engine Building Techniques - A Lasting Impression

Any time you build an engine, or have one built, you must define the intended use of the engine, which will determine the minimum quality of parts necessary. Since this engine is an all-out race piece, we'll be using some of the best parts on the market to build it. Also remember that even at the top level of performance, there are still equivalent parts made by competing companies. In these cases, the engine builder generally uses his or her personal experience, choosing the part based on parameters like weight, dimensional accuracy, application, etc. The one way we don't choose our parts is by price. While it is true that some of the best parts are expensive, it's also true that highest-priced parts aren't always the highest quality, or could be overkill for an engine that makes only moderate power.

Accurate machine work is also vital to the power and durability of a high-performance engine. You can assemble your engine with the best parts in the world, but if the cylinders aren't round, the decks aren't square, or the valve guides have too much clearance, it won't make the power you expect it to or last as long as it should. In a street car, this isn't often apparent as initially two engines with vast differences in quality might seem to make similar power. However, in six months, a year, or two years, the engine built with higher-quality parts and accurate machining will still be running strongly and consistently, while the other engine may smoke, burn oil, perform poorly, or not run at all. In racing applications, the lesser engine quickly makes itself apparent by a lack of power, requiring constant maintenance, or by spilling its guts and oil out the bottom (or sides) of the oil pan.

In our part of central Florida, we use Auto Performance Engines for their machine shop services. Owner Kevin Willis runs a clean shop, has high-quality, updated equipment including a Superflow engine dyno, and he's not scared to tell us something isn't right even if he knows we won't be happy. These qualities are also possessed by the shops in our AMSOIL/Mopar Muscle Engine Challenge, and should be what you look for when choosing a machine shop to perform your work. Don't assume just because a shop builds off-brand racing motors that they have the equipment like torque plates for Mopar engines so they can perform your work properly. This is an area where you don't want to cheap-out. Performing machine work to the highest standard takes extra time, and a shop doing such work will replace tooling more often to ensure accuracy, but the money you'll spend upfront will certainly be worth it when your engine provides years of good service.

Assembling the engine also requires a special touch, patience, and a certain amount of precision tooling. Just as importantly, the assembly area must be clean as well as all of the engine parts and tools. Before you use your socket set to tighten any of the fasteners inside an engine, think about where your tools have been. If you were just crawling in a gravel driveway tightening the muffler clamps on your '78 custom van, you don't want to transfer that dirt and rust into the engine you're building. This is one of the many reasons to either have clean, dedicated engine building tools, or to have a professional build your engine for you. If neither of these options is possible, we suggest completely cleaning the tools in a parts washer or with brake cleaner, then soap and water, just like the engine components.

Now that we've told you why it's important to use the proper parts, accurate machining, and proper assembly techniques, let's get busy building this big Hemi. Follow along and you'll certainly learn a trick or technique that you can apply to your next engine build. And if you're planning to have an engine shop build your next engine for you, this article should give you the information you'll need to choose a shop properly.