WAYNE, PA.- Shining his work light into the deepest recesses of a Ferrari F512 M’s engine bay, Tim McNair takes note of minor flaws that will warrant closer attention. There’s an oily smudge on the intake plumbing, chipped paint where red shows through on the black chassis tubing, a damaged sticker on an ignition coil — typical signs of use in a 30-year-old car — and all readily dealt with.

Making them right won’t be a problem for McNair, whose credits include preparing a Ferrari Enzo that was awarded a perfect 100-point score at the Cavallino Classic, where the brand’s cars are evaluated by judges.

But the wrinkle-finish paint on the engine is another matter. That color, silver, and in that finish with an attractive crinkled texture found on many Ferrari engine castings, simply isn’t available in a quality that satisfies him.

For McNair, owner of Grand Prix Concours near Philadelphia, it’s all in a day’s work. His livelihood is making sure that collector cars arrive at premier competitions as perfect as possible. Far removed from the casual bucket-and-sponge routine of an owner preparing for the local cars and coffee, the stakes of McNair’s work run much higher. His subjects will be scrutinized at formal events like a concours d’elegance, a beauty showcase typically featuring classics revived by seven-figure restorations.

So when a client gives him a car to prepare, he cleans, polishes and corrects flaws. With judges — likely including experts steeped in the minutiae of just what type of hose clamp or headlight bulb is correct for that year and model of vehicle — working to exacting guidelines, a concours demands precise preparation. To be a best-in-show contender, a car must be more than spotless; it needs to be factory-accurate in myriad details.

Time to call in a specialist.

That’s the niche McNair occupies. His decades of experience have accrued since his start as a 15-year-old, progressing through his time as a Mercedes-Benz technician and now providing high-end show preparation.

McNair takes his skills and encyclopedic knowledge of classics and race cars — as well as fastidiously organized cases of cleaners and obscure spare parts — to the garages and workshops of collectors, applying the finishing touches to cars that have already been refurbished or, in some cases, preserved in near-original condition.

“I’m the 2 percenter,” McNair says, emphasizing that his focus is on covering the post-restoration fine points, the crucial details that separate winners from the also-rans.

His portfolio includes a mastery of how a modern Ferrari should look, inside and out, yet it also ranges from an 1885 Duryea to a 2024 Bentley Continental GT Speed Edition 12. For his clientele of historically significant vehicles, McNair likens his work to that of an art conservator, an appropriate parallel for handmade creations worth millions. Each one presents challenges to preserving originality: Factory finishes can be fragile, and there are likely to be numerous materials in use, each requiring different cleaning agents and protective treatments.

The value of a top concours contender frequently runs into the millions of dollars, and expert restorations of rare models regularly reach seven figures. The costs of refinishing trim alone can be striking: McNair notes that a 1931 Duesenberg Model J at Reimel Motor Cars in Wayne, Pennsylvania, has $100,000 worth of chrome plating in adornments like its grille and bumpers.

Even wrapping up that last sliver of work ahead of a major concours can require 40 to 60 hours of labor, for which he charges $150 to $250 an hour. The goal, McNair says, is to “ship it done.” Ideally, when the car comes out of its transporter at the event, all it needs is to be wiped clean of dust.

The particular advantage McNair brings to clients whose vintage machines vie for honors in top-level competitions is decades of experience as an official at concours, including Pebble Beach in California and Amelia Island in Florida. He knows what the judges will be looking for.

“Getting it right starts with research,” he notes, tracking down documentation like period photos — color images from the period are the ultimate source — and manufacturer build sheets, all to bring a car to the “as delivered” state. For exclusive European brands, certification from the automaker’s historical programs is sometimes available, verifying installed options, paint color and upholstery materials — even down to the part number stamped on a suspension arm.

With the available historical resources in hand, the guide for work to be done becomes the checklists used by judges. These work sheets are a reminder of the items that must be operable — horn, wipers, turn signals — and guide McNair’s work. Judges use them to log the overall condition of the car as well as to note any mechanical flaws. Points are then often deducted.

Before the car can be cleaned, visible flaws are addressed. This is where experience is most valuable. A Sharpie is not the right touch-up (a noted rookie shortcut) for a black finish, for example, because the texture and sheen will not be correct — and will jump out to a judge’s critical eye. Chips can be repaired with paint used by model builders, often available in exact matches for factory colors.

Details like the wrinkle finish in the Ferrari engine compartment can be a greater challenge. McNair has not found a satisfactory silver in that texture, so he paints the removed parts with a red wrinkle paint, then a plain silver paint. Even that requires special precautions: If there are painted inspection marks left from factory assembly, they must be preserved.

The question of what constitutes proper surfaces — matte or gloss, whether paint is authentically imperfect or beyond what it looked like from the factory — is a major issue at a concours, where sensitivity to overrestoration is acute.

“The first step in getting it right is knowing what it should be in the first place,” says Eric Peterson, manager of Leydon Restorations in Lahaska, Pennsylvania. “That may require a deep dive into any documentation on the car and knowledge of what was used in the time period: chrome, nickel, zinc or cadmium plating, for example. Even then, there will be questions about what is overrestored.”

Preparing the surface is no less of a hand-wringing choice, explains Peterson, who also is a concours judge.

“Some processes can dull the finish of bare metal,” he says, “so we have to rely on experience in choosing among techniques like soda blasting or vapor honing to achieve the desired finish.”

“The takeaway,” he says, “is that judges are looking closely, and if a finish is incorrect, they’ll be wondering what else is wrong.”

There is also an understanding by judges that cars will be driven onto the show field and that they may have covered miles in the tours and road rallies that often accompany these events.

“An entry should be well prepared for concours judging, but that doesn’t mean surgically clean,” says Ken Gross, a Pebble Beach judge. “Judges are not there to intimidate, but they can see the difference between honest dust and outright neglect.”

McNair’s kit to solve those problems holds cleaners and polishes as well as microfiber cloths. A degreaser used in restaurants to clean range hoods, SD-20, works well on engine-oil accumulations without damaging the surface underneath. And he uses black cotton swabs made with bamboo shafts that are less likely to break than white drugstore swabs with cardboard shafts.

McNair is clear that his role goes only so far. One wealthy client was so pleased with the revival of his car’s leather seats that he asked for the leather chairs in his home movie studio to get the same treatment. McNair obliged, but that was not the end of the requests: Could he treat the owner’s Ferragamo loafers as well, to keep them from getting soaked by the predawn dew on the fairway at Pebble Beach?

Those shoes were seen with beads of water shimmering on their surface at the concours d’elegance there a few weeks later.

This article originally appeared in The New York Times.