...and lack of need for reconditioning.
In Trotter's experience, particularly for the weekend racer, "I think the least expensive and easiest first step would be to coat the bearings. The reason is because they're easy to get to and you can even buy them pre-coated, including cam bearings. Cost-wise, if you're considering coating a set of rod, main, and cam bearings, you're probably looking at a total coating cost of about $100. A racer isn't going to see any additional horsepower from this but he'll easily triple the life of these bearings. Plus, it'll help crankshaft life and if there's a sudden oil starvation problem, he'll be less likely to damage the rods and crank."
Typically, in terms of engine parts, the next most popular components are the pistons. Once again, this operation is intended to extend cylinder wall wear through a reduction in friction, primarily as it relates to friction horsepower losses that net gains in torque at the crankshaft. Again, depending upon compression ratio, piston crown, and combustion chamber design, thermal barrier coatings on these surfaces may or may not be of significant benefit...but certainly can be in the proper environment.
On the immediate horizon, according to Trotter, "We're introducing a new finishing process called 'Super Micro Finishing' that is a combination of chemical and mechanical techniques intended to address post-machining surface imperfections." Actually, the process involved is designed to remove microscopic "peaks" or irregularities and residual stresses created on and in machined components where friction is a factor.
"Metal-to-metal contact creates friction that generates heat. The SMF treatment reduces friction and wear, increases part durability and improves corrosion resistance by removing a minimal amount of material, leaving an 'isotropic' or uniform surface finish of less than one micro-inch, in all directions," says Trotter.
Even after lengthy use, the coated pin (upper of the two shown) appears in virtually unuse
Finally and fortunately, consistent with the growth and availability of technical services and information on the Internet, it's possible to communicate with the various coatings materials and service provider companies on a direct basis. Many have technical staff on hand to respond to user questions, in addition to discussing specific customer needs and recommendations. It can't be overemphasized that communicating with your chosen source of materials or services is often critical to getting the right solution to your particular application.
In these two stories, we've attempted to provide you with sufficient background information and experienced-based suggestions from multiple sources, including the comments that follow below from the highly-respected master engine builder Keith Dorton. From this menu of topics, we're hopeful you'll feel confident in exploring the world of racing and high performance coatings.
Taken From Experience
His 40-plus years of building and testing record-setting racing engines clearly qualify Keith Dorton as a voice of experience. His willingness to share some slices from that store of knowledge stands to benefit readers of this magazine. You may want to take notes.
Coatings have been around for decades. When did you first decide to use them in your work?
We've always had to look at things from a performance versus cost perspective. Of course, most of Circle Track's readers do this as well, so I think we're all pretty much on the same page. So this is how I first began looking at coatings, and I think it was sometime during the 1980s.
At the time, we were primarily doing what today are called Cup engines. I believe they called them Grand National engines back then. I knew some people who were getting into coatings and our first experience was with coated engine bearings. Coated bearings would essentially double the cost of these parts to my customers, and I wasn't yet convinced it was worth the investment. But I committed to give it a try.