Keith Dorton is no stranger to the readers of this magazine and in numerous categories of motorsports. For 46 years, his Automotive Specialists has been a reliable and leading source for both engines and components applicable to racing. His store of experience and knowledge is both extensive and practical, so this month we'll treat you to a recent discussion with him on engine building and his perspective on how many young racers may become active on circle tracks.
Circle Track: Let's talk about specific areas in the building of what we'll call a reliable and competitive "weekend racing" engine, as you've discovered over time addressing a wide variety of these type applications. Are there certain components or systems you consider more critical than others?
Keith Dorton: The first consideration is to identify the specific application and environment in which the engine will be operated. For example, if the application is a heat race and 30-lap main event situation, how you view the requirements will be different than if it's a qualifying, practice, and 250-lap main. And actually, it's much easier today to fashion an engine for just about any application because of the broader availability of quality parts than in years past. It hasn't been very long ago when you either had a basically stock piece or a very expensive piece, but now we have a broader range of good, quality parts.
More to your question, the rotating assembly is a critical system. I think the way you should choose these parts is best accomplished by talking directly to parts manufacturers. Many of these companies have active technical services, either by phone or Internet, that can and do provide good information during the parts selection process. Once a potential customer has outlined the intended use of an engine, it's possible to get helpful advice. These are not parts you can skimp on, and there are some quality rotating assembly parts that today can be bought very reasonably.
KD: These are additional parts you don't want to skimp on. The place to start here is to identify and take advantage of the parts you're allowed to run, according to the rules. I mean, if you're able to run a good, used shaft rocker arm assembly, I'd definitely favor that instead of a new set of "floppies." Skimping in the area of the valvetrain can definitely bite you in the long run. Again, based on allowances within the rules, choosing these components can be helped considerably by talking to your choice of parts manufacturer.
CT: Turning to the topic of assembling parts, are there any particular aspects of this that need to be considered and discussed?
KD: Two things come to mind. The first is that it's critical to take all the proper measurements. Clearances, concentricity, piston-to-valve, piston-to-head are among the more important areas to consider. And I'd recommend going through these measurements more than once and writing down all the information.
It's somewhat like the "measure twice and cut once" approach, except in engine building I'd consider measuring twice to be the minimum. It's pretty tough to correct a measurement mistake once the engine is running. Once again, I'd use the parts manufacturer as a source of information because it's reasonable to think he knows more than the builder, at this point. Beyond asking about clearances, I'd also inquire about coatings, oil, and things like that.
Over time, at least in our business, we've had customers that do ask these types of questions, but they do it too late, and that can be expensive. I don't know exactly why they didn't ask sooner. Maybe they were ashamed or too proud or thought the question was too simple. But from our perspective, that shouldn't be the case. I mean, no matter how simple or crazy a customer may think his question is, that's just his opinion. Any question at all deserves a straight answer, and that's how we've always operated. Put another way, there really aren't any dumb questions.