Applied to the underside of...
Applied to the underside of the piston, this coating is intended to reduce the reciprocating weight by repelling oil quicker than an untreated part. Courtesy of JE Pistons
Q: Have you ever experienced any problems using coatings?
Wells: Not at all. In fact, we've even experimented with coating exhaust ports, along with rod and main bearings. My feeling is that if you ever happen to experience any oil starvation problems, the coated bearings will probably help prevent parts damage, especially the crank. And because I've not wanted to trust my ability to coat bearings, primarily because my concern about clearances, I've used companies that do this on a commercial basis.
Q: If you were to suggest the first place in an engine that would yield immediate benefits, where would that be?
Wells: I think the first place would be to coat piston crowns and skirts. Well, maybe not so much the skirts but crowns and combustion chambers, primarily to help retain heat and make more power. I'm sure there's more there that we've not yet looked into, mainly because our initial reason for using the coatings was to solve an oil temperature problem. I'm certain this has added life to the affected parts, too. In fact, I would probably include the valve faces, especially the exhausts.
Based on his 35 years working with and developing a wide range of coating materials and applications, I chose to share some comments recently made by Leonard Warren. While his views are from the perspective of Tech Line, they nevertheless represent a voice of experience, particularly in the field of motorsports, and clearly include his involvement with the circle track community.
"Over time, many have looked at coatings as a Band-Aid rather than a genuine solution to specific problems. Certainly today, this is a mature technology. I say this based on the fact that outside the motorsports industry, coatings are recognized and accepted as a technological solution to often complex problems. Plus, and this may come as a surprise to some people, the OEMs are currently using various coatings in both general automotive and heavy-duty truck applications. The fact that some of these type coatings are also being used by the F1 teams is further evidence of its global acceptance among some of the best funded teams in competition.
"Confusion exists to a degree because of all the new 'coatings' entering the fray. Surface modification systems using high impact impingement, vacuum deposition, ion impingement and vapor deposition, and chemical treatment (these are variations on anodizing) are just a few. In some cases, the equipment can run into the high six- or even seven-figure costs. Each has its advantages. Where the market needs to focus attention now is not on the 'next' cool coating idea but in evaluating each type of system. Examine the application's needs, ability to handle all the environmental issues found in racing, the overall cost-to-benefit ratio, and potential downsides."
Essentially, there are "coatings" and there are coatings. By purchasing precoated parts, you make the assumption manufacturers have done their homework in selecting the best coating technology for the application. And there's nothing wrong with that. There are clearly some excellent products available. However, whether you elect to take this path or decide to apply coatings yourself, becoming familiar with the basic categories of coatings applicable to a motorsports environment will help eliminate problems derived from either a lack of information or just plain oversight. Talk to the sources and make your selection decisions accordingly.
Lubricating oil can only perform within its inherent limitations Unwanted and/or improperly-distributed heat in an engine is a natural phenomenon and partially a function of power level. Friction horsepower losses are a fact of life. In short, the high mechanical loads and stresses derived in a racing engine are that, in addition to the notion rust and corrosion are ever present. How you deal with these issues should very likely include the benefits of applicable coatings materials. Band-Aids, they're not. Potential solutions to problems, they can become.