Automotive Engine Performance Coatings and Treatments

Professional racers have used internal engine component coatings for more than 20 years. These coatings offer increased horsepower, reliability, and engine longevity. They are not, however, intended for everyday commuter engines (since the cost likely isn’t justified). Instead, these coatings should be considered for high-performance street and racing engines only, where power and engine life needs to be optimized.

 


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Current coatings on the market deliver enhanced thermal control, improved lubrication, and oil-shedding. Depending on the type of coating and the area in which the coating is applied, the benefits can include increased power, component durability, or both.

 

This group of parts helps to illustrate heat barrier and anti-friction coating applications. The examples shown here include high-temperature thermal-barrier coatings on head chambers, piston domes, turbo housing, and headers; anti-friction coatings on skirts, valvestems and bearings; and heat-release (or shedding) coatings on valvesprings. (Photo Courtesy Swain Tech Coatings)

This group of parts helps to illustrate heat barrier and anti-friction coating applications. The examples shown here include high-temperature thermal-barrier coatings on head chambers, piston domes, turbo housing, and headers; anti-friction coatings on skirts, valvestems and bearings; and heat-release (or shedding) coatings on valvesprings. (Photo Courtesy Swain Tech Coatings)

 

Coating Types

Suppliers typically offer four types of coatings for high-performance engines: low-friction, oil-shedding, thermal-barrier, and heat-emitting. Each has its own set of parameters for use.

Thermal Barrier Coatings

Also called ceramic coatings, they act as a shield to prevent heat from passing into a part. For instance, a thermal barrier coating on a piston dome prevents combustion heat from being lost beyond the dome. This prevents heat from dissipating through the dome, causing the piston to expand. If there is a barrier coating, combustion heat is greatly reduced, and does not sink into the piston and cause expansion. Since the piston doesn’t expand as much you can then run a tighter piston-to-wall clearance.

 

The set of pistons in this shot have had only the domes treated to a ceramic thermal barrier coating.

The set of pistons in this shot have had only the domes treated to a ceramic thermal barrier coating.

 

Precoated engine bearings, that is rod bearings, main bearings, and cam bearings, are now available already coated from various bearing manufacturers.

 

If the combustion chambers are also coated, combustion heat stays in the chamber and promotes more efficient use of thermal energy. To aid in this, the valve faces can also be coated to help seal the heat in as well as to prevent excess heat from traveling up the stems.

If the exhaust path is coated, combustion heat is contained inside the exhaust path. This prevents loss of thermal energy and adjacent areas from being subjected to excess heat. Coating the exhaust ports and outside of the exhaust manifold also creates a scavenging effect, contributing to more-efficient exhaust flow. In essence, the combustion energy and heat stays in a more-contained path, doing its job, instead of being allowed to sink into surrounding areas, where it does nothing but waste energy.

Anti-Friction and Oil Management Coatings

Anti-friction coatings provide a low coefficient of friction between two moving surfaces and serve to retain surface oil between moving parts. This oil is applied to components, such as bearings and piston skirts. It’s exactly what you want at bearing and skirt locations.

Oil-shedding coatings provide a slick and non-porous surface treatment to aid in slinging oil off a component. A shedding coating applied to connecting rods and crank counterweights prevents unwanted oil weight from clinging to the surfaces. As a result, parasitic drag is reduced as the rotating assembly whips through the air and a mechanical advantage is realized.

 

In addition to piston dome coating, the same high-temperature heat-barrier coating may be applied to the combustion chamber, all valve faces, exhaust valve throats, and exhaust valve ports. This completely encapsulates the combustion stream path. (This head was coated by Dart.)

In addition to piston dome coating, the same high-temperature heat-barrier coating may be applied to the combustion chamber, all valve faces, exhaust valve throats, and exhaust valve ports. This completely encapsulates the combustion stream path. (This head was coated by Dart.)

 

MAHLE Clevite, for example, uses a polymer-based moly-graphite coating on its performance bearings.

MAHLE Clevite, for example, uses a polymer-based moly-graphite coating on its performance bearings.

 

An oil-shedding coating is extremely useful for crankshaft counterweights, allowing oil to more quickly depart from the counterweight surfaces. This reduces the drag that exists because of clinging oil, which in turn reduces parasitic power loss.

An oil-shedding coating is extremely useful for crankshaft counterweights, allowing oil to more quickly depart from the counterweight surfaces. This reduces the drag that exists because of clinging oil, which in turn reduces parasitic power loss.

 

An oil-shedding coating applied to connecting rods serves the same purpose: to reduce parasitic power loss caused by unwanted oil clinging to the surfaces. After all, the engine doesn’t need oil on the exterior surfaces of the crank and rods for lubrication, so by promoting oil departure from these surfaces, we reduce unnecessary drag, which helps to free-up horsepower from the rotating assembly.

An oil-shedding coating applied to connecting rods serves the same purpose: to reduce parasitic power loss caused by unwanted oil clinging to the surfaces. After all, the engine doesn’t need oil on the exterior surfaces of the crank and rods for lubrication, so by promoting oil departure from these surfaces, we reduce unnecessary drag, which helps to free-up horsepower from the rotating assembly.

 

Oil-shedding coatings also prevent hot oil from clinging to the stationary wall surfaces, and this helps reduce radiated heat, promoting much faster drainback to the sump. Interior walls include roof of valve covers, oil pan walls, (some) dry sump pans, and the underside of V-type engine intake manifolds.

A thermal-barrier coating can also be applied to the cover exterior. This coating combination helps to reduce radiated cover temperature while preventing oil from clinging to the cover roof and walls, allowing oil to scoot back to the moving parts where it’s needed.

The oil pump is an often overlooked but vital component. Applying an oilshedding coating to the oil pump gears and passages allows the pump to more efficiently move oil, which reduces the amount of oil that clings to the passage surface areas. An oil-shedding coating lets oil move through the pump faster and reduces the amount of oil that hangs around by sticking to passage walls.

Heat-emitter coatings promote the release of heat. Common applications for this specially formulated coating include valvesprings, with the coating intended to prolong spring life.

Piston Skirt Coatings

The moly coating’s true benefit is reduction of friction, which prolongs part life and reduces operating friction, and it naturally frees available horsepower. A moly skirt coating is not specifically designed to reduce heat, but because it reduces friction, heat is potentially reduced as a direct by-product. A moly skirt coating improves cold-engine startups; the moly coating prevents skirt scuffing that might otherwise repeatedly occur in that situation.

Many approaches can be used to reduce friction with the cylinder bores, including synthetic oils, plasma-moly ring faces, oil retention grooves in the skirt areas, plateau cylinder-wall finishes, etc. All of these methods have merit, but so does coating the piston skirt areas with a long-wearing high-lubricity material.

 

All of the coating shops offer thermal barrier dome coating and anti-friction skirt coatings. Here’s an example of a piston treated with a thermal barrier coating on the dome and moly-coating on the skirts.

All of the coating shops offer thermal barrier dome coating and anti-friction skirt coatings. Here’s an example of a piston treated with a thermal barrier coating on the dome and moly-coating on the skirts.

 

Commonly, this is a molybdenumbased application applied to the skirts in an average thickness of about .0005 inch per side, which might provide about a .001 inch increase in piston overall skirt diameter. Since the moly is applied in such a thin layer, no additional boredimension changes are required. In other words, you should hone the cylinder to the size dictated for proper piston-towall clearance for a non-coated piston. Whether you’re installing non-coated or coated pistons, the finished bore size is identical. Do not compensate for the added moly coating when finishing your bores.

Forged piston applications typically run a .005- to .006-inch clearance, which does not change if you opt for moly-coated pistons. If you plan to use hypereutectic pistons that require a .001- to .0015-inch clearance, for example, finished bore size is not enlarged to compensate for the coating layer. With hypereutectics, the skirt coating might actually create what first appears to be a nearinterference fit of the piston to the bore. This is not a concern because any excess moly is sacrificed during initial runs, and mixes with the engine oil in a completely compatible fashion. So install and run them. If you overhone by .001 inch in an effort to compensate for the moly coating, you simply defeat the benefit of the tighter and more efficient clearance.

 
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Coating Sources

Many engine bearing manufacturers offer anti-friction coatings as standard or as an option.

Mahle Clevite offers its TriArmor engine bearings already coated with a moly-graphite treatment in a low-friction PTFE polymer base.

Dart Machinery has a full array of coatings, including moly-based anti-friction coatings, synthetic ceramic and traditional aluminum-based thermal barrier coatings, oil-shedding polymers, molyTeflon coatings for bearings, Teflon-based air-enhancement coatings for intake ports, etc.

 

When you have exhaust ceramic-coated headers, pay attention to the collector area. If the header has a bolt-on flange, there’s no need to mask off anything. However, if the collector has a slip-on end, ask the coating shop to mask off a sufficient area, since the thickness of the coating can result in a too-tight slip-on fit. (Photo Courtesy Swain Tech Coatings)

When you have exhaust ceramic-coated headers, pay attention to the collector area. If the header has a bolt-on flange, there’s no need to mask off anything. However, if the collector has a slip-on end, ask the coating shop to mask off a sufficient area, since the thickness of the coating can result in a too-tight slip-on fit. (Photo Courtesy Swain Tech Coatings)

 

Ceramic thermal barrier coating is ideal for turbocharger housings. This increases efficiency and helps to reduce underhood temperatures. (Photo Courtesy Swain Tech Coatings)

Ceramic thermal barrier coating is ideal for turbocharger housings. This increases efficiency and helps to reduce underhood temperatures. (Photo Courtesy Swain Tech Coatings)

 

Dart’s coating offerings include the following:

  • DCIMOS2TeflonSkirtCoating
  • DC2 High Temperature Reflective Heat Barrier for thermal barrier applications on piston domes, combustion chambers, valve faces, exhaust ports, etc
  • DCB-3 Engine Bearing Coating (a moly/Teflon based material with highload/non-stick properties for bearings
  • DC-4 Lubricating Pigments for wear and load capacity in applications such as valvesprings, oil pump gears, valvestems, timing gears, camshafts, and other friction related areas
  • DC-5Oil Shedding Coatingfor shedding parasitic oil from connecting rods, crank counterweights, windage trays, inside oil pans and valve covers, etc
  • DC-7 Anti-Corrosive Protectant to protect surfaces from weather, gasoline, alcohol, nitro methane, brake fluid, etc.

In a turbo application, according to Swain Tech Coatings, a heat-emitter coating provides benefit to an oil-cooled, bearing turbo. A stellite coating on the turbo impeller shaft (which can experience 1,650 degrees F) reduces shaft wear and acts as a solid film lubricant while providing the needed hardness to protect the shaft.

Swain offers three different thermal barrier coatings, including the standard thermal barrier coating (TBC), Gold Coat, and White Lightening. TBC is used in most applications for piston domes, combustion chambers, valve faces, exhaust valve backs (radius), and exhaust ports. Where higher temperature extremes are encountered, such as in nitrous oxide or turbocharged applications, the Gold Coat version may be applied, which simply yields a higher thermal-barrier capability for these extreme situations.

 

Cryogenic Stress Relief

This process stress relieves a crankshaft, reduces the chances of warping an aluminum head, and prevents distortion in a block bores.

Cryogenic treatment involves freezing engine parts to make them stronger. The tool-and-die industry regularly uses this approach to temper and extend the life of steel tooling components.

 

Cryogenic metal tempering requires a specialized, computer-controlled cryo tank that uses liquid nitrogen, in which components are exposed to temperatures at approximately –400 degree F. The pieces are cooled in a slow, controlled manner, then allowed to come back to ambient temperature in a controlled process. The engine block in this photo was removed from the tank only for the photo. Notice the white frosty surface, resulting from the frozen part exposed to room temperature.

Cryogenic metal tempering requires a specialized, computer-controlled cryo tank that uses liquid nitrogen, in which components are exposed to temperatures at approximately –400 degree F. The pieces are cooled in a slow, controlled manner, then allowed to come back to ambient temperature in a controlled process. The engine block in this photo was removed from the tank only for the photo. Notice the white frosty surface, resulting from the frozen part exposed to room temperature.

 

What Does It Do?

In a nutshell, cryogenically tempering (deep-freezing) a metal part, makes the internal structure more uniform, more durable, and stronger.

The process of cryogenic freezing changes the structure of the metal being treated. Inside the metal, areas of weaker, potentially brittle deposits called austenites may exist. These are flaws that create the potential for cracking. Cryogenics changes these areas into harder, more uniform martensites. The process also creates a vast distribution of very fine carbide particles throughout the metal.

The Cryogenic Unit

Advanced Cryogenics uses the –300 Cryo-Processor, and has conducted an enormous amount of research in the field of cryogenic tempering of engine parts. For purposes of R&D, Advanced Cryo maintains its own test car, a modified D.I.R.T. race car with a Chevy big-block 467-ci bowtie engine. The block is .060-inch over, fitted with Chevy aluminum heads and produces a compression ratio of 13.5:1 and a dyno output of 650 hp. The engine runs on alcohol and lives at 7,200 rpm.

 
A wide range of components can benefit from cryogenic tempering, including blocks, heads, rods, cranks, cams, rockers, and brake rotors. (Photo Courtesy 300 Below)

 

A wide range of components can benefit from cryogenic tempering, including blocks, heads, rods, cranks, cams, rockers, and brake rotors. (Photo Courtesy 300 Below)

A wide range of components can benefit from cryogenic tempering, including blocks, heads, rods, cranks, cams, rockers, and brake rotors. (Photo Courtesy 300 Below)

 

“When we began the testing program with this motor,” noted co-owner Joe Troya, “Constant attention to valve lash adjustment was needed. After the entire engine assembly was cryo’d, we’ve noticed that cylinder and ring wear have been dramatically reduced, and lash adjustments are almost a thing of the past; everything stays so much more stable.” In addition to the engine block, heads, and all internal parts, the Advanced Cryo team has also started to treat and test the car’s suspension and brake parts in the same fashion.

In all, the Advanced Cryogenics’ racetesting program has involved the treatment of some 15 engines, in D.I.R.T., Busch Grand National, NASCAR, and a few SCCA road racing applications. They’re also performing cryo testing for a few aftermarket engine parts manufacturers.

Benefits

Cryogenic treatment finds internal flaws missed by external Magnaflux bench detection. However, an internal pocket flaw may actually cause the part to snap open during freezing. Certainly, most engine builders agree that it’s better to find a bad part during testing rather than discovering the problem in a running engine. In other words, if the part is badly flawed, this process may break it.

With this process, the tensile and ductile strength of the part is improved, an obvious benefit for items such as connecting rods and head bolts. Cryogenic treatment also improves the bond of a weld, by producing a more uniform metallurgy structure.

Since this treatment stabilizes the metal, it reportedly improves the machinability of the part. It is a one-time, permanent process that changes the metal structure throughout the part. Once a part has been cryogenically treated, there’s no surface layer to break through during future machining. The only materials that don’t benefit from Cryogenic treatment are plastics (fiberglass, ABS, various composites) and engine bearings. “The process doesn’t hurt those parts, but it just doesn’t seem to help either,” says Troya. He’s treated blocks, heads, pistons, rings, cams, lifters, valves, pushrods, connecting rods, valvesprings, head bolts, retainers, crankshafts, flywheels, and even frozen spark plugs.

The electrical conductivity of the plugs was increased measurably as a result of the process. “The go-kart guys really notice the difference,” he noted. Although the process creates a slightly higher Rockwell hardness, that isn’t the real directive. Cryogenic processing benefits a part by stabilizing the metal structure, creating a stronger molecular grain pattern throughout the metal.

 

Vibratory Stress Relief

Vibratory stress relief involves inducing a controlled series of vibrations to metal components (in this case, engine components). This process provides an effective and non-destructive method of achieving stress relief, which results in longer life and increased component stability. Bonal Technologies (to my knowledge, the only provider of this technology) designs and manufactures a complete system for subharmonic stress relief.

Two forms of stress can exist within a metal part: mechanical and thermal. Subharmonic vibratory stress relief (VSR) is a method that relaxes metal (commonly known as Meta-Lax), but only for the metal part’s thermal stress, leaving the mechanical stresses unchanged.

Vibrating a part relieves any stresses that were created due to the heat involved in welding, casting, machining, or forging, but it does not alter the metal’s strength.VSR doesnot generate heat and doesn’t alter the part’s hardness. As a result, VSR is safeto use on a repeated basis.

How It Works

Let’s say that you have a part rated with a strength of 50,000 psi. Because of internal thermal stress that may be present, the actual strength of the part might be reduced by 20 percent (for example). If the part is heat relieved in an oven, the internal stress is relieved but the part might now only offer a strength of, say, 45,000 psi due to the softening created by the heat. (In contrast, VSR removes internal stress while maintaining the metal’s full 50,000-psi strength.)

The vibration process searches for the harmonic peak of the workpiece by vibrating it. The peak is where the piece tends to create the maximum harmonic disturbance, just as a tuning fork vibrates when subjected to a force or a fishing rod whips and vibrates when dynamic force is present.

The vibration process searches for the harmonic peak of the workpiece by vibrating it. The peak is where the piece tends to create the maximum harmonic disturbance, just as a tuning fork vibrates when subjected to a force or a fishing rod whips and vibrates when dynamic force is present.

As a harmonic disturbance is sent through the workpiece, those signals are sent back to the system’s controller (via the transducer). The force inducer is then automatically adjusted to vibrate the workpiece in a frequency range that begins just before the peak. This energy area at the base of the peak is where maximum energy dampening occurs. Sending these adjusted (or tuned) vibrations through the workpiece removes stress.

According to Bonal Technologies’ president, Tom Hebel, “We first find the harmonic peak to establish where the subharmonic area is. We then induce vibration at that frequency until the part stabilizes. It’s as though the part tells you that, up to a point, it can dampen the vibrations on its own; but beyond a certain point, it can’t. This process shifts the harmonic peak to its natural location, from an artificial frequency to a stressfree frequency.”

Conventionally, if you find the harmonic peak, you might add weight to dampen that vibration. With VSR, you relax the metal in order to alter the harmonics that can take place. Thin of a stressed engine component as a musical instrument that’s out of tune.VSR brings the part back into tune.

 
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Benefits

Hebel cited a simple experiment that helps to illustrate the benefit of VSR: “A local industrial machine shop was curious about the concept, so we performed a demonstration using a solid aluminum bar, 2 inches in diameter and 36 inches long, supplied by the shop. They cut the bar in half (two 18-inch sections). We Meta-Lax treated one section only. The shop then machined each bar section on a lathe, by exactly the same amount.

“Each section was then measured for distortion. The untreated section distorted (warped) by .020 inch along its length, while the treated section moved a mere .002. The dramatic increase in metal stability was obvious.”

Thermal stresses can also be induced as a result of distortion immediately after grinding, welding, or machining. This creates a tendency to prematurely crack. Hebel advises that the optimum time to vibrate the part is immediately before the final machining phase (just before the last task that could cause distortion). All four types of stress relief (heat treating, cryogenic freezing, vibratory relief, and natural seasoning) address the issue of thermal stress. VSR offers an advantage because it’s faster and doesn’t affect mechanical stresses. You already know that a stress-relieved part distorts less during use. When a relieved part is trued during machining, it tends to retain this trueness. For machining advantages, the process reportedly reduces machining time and reduces distortional effects during machining.

If the part distorts less during use, wear is reduced and engine efficiency is enhanced. A quality stress relieving helps to keep bores round and decks flat, something that every performance-engine builder strives for, and is central to the blueprinting goal.

How to Use It

A VSR system includes a force inducer (this unit attaches to the workpiece and applies the vibrations), a transducer (this sends a feedback signal from the workpiece to the control computer), and a control console unit (computer). System prices start at around $7,000 and canclimb as high as $35,000, depending on size and application. Some controller units offer an analog readout, while others provide digital information and a hardcopy plotting printout. The object is to transmit the programmed vibrational forces to the engine part(s).

This stress relief system can be used on-site as a portable setup, or in the shop as a permanent fixture. The force inducer can be attached directly to the piece being treated. For example, the inducer can be clamped to a bare engine block, or even a complete engine assembly, while on a stand or even in the vehicle. As a nonportable shop system, the workpieces are clamped to a heavy steel-platform table.

If a number of parts are to be stress relieved at the same time, all of the parts can be mounted to the precision steel table. A block and cylinder heads can be bolted to the table, and smaller items such as a crankshaft, connecting rods, valvesprings, etc. can be secured to the tabletop by means of accessory brackets and clamping fixtures. As long as the vibrations can be transmitted to the engine parts (by direct attachment to the force inducer or by being rigidly mounted to the tabletop with the force inducer secured to the table), the vibrational force is able to affect the engine parts’ metallurgy.

Portable systems have been successfully used by race chassis builders. While a race car tubular chassis is being welded, or even after welding has taken place, the portable force inducer is bolted to the chassis. The resulting vibrations stress relieve the tubular network, reducing the chance for frame fatigue and failure. Portable setups have even been used at race sites on completely assembled engines.

 

Hard Cylinder Coating

This is an application of an optimized deposit of dispersed nickel and a uniform inclusion of hard silicon carbide particles, known today as Mahle’s patented Nikasil.

According to Mahle, with a roughness average of 15 Ra, typical Nikasil-coated cylinders can operate at higher temperatures with less wear. This allows clearance from cylinder wall to piston to be optimized to better control oil consumption with lower ring tension, for a reduction in friction. This coating also provides superior heat conductivity and allows increased oil retention during cold starts.

Benefits

The performance benefits of the Nikasil coating include low wear rate, low operating noise, thermal consistency, and faster ring break-in. When selecting honing stones, the rule is: the harder the cylinder surface, the softer the bond of the stones.

Nickel is oilafilic, which means that oil is attracted to it, resulting in a constant oil layer. Another benefit is Nikasil’s uniformity and repeatability. For teams with multiple engines, this greatly reduces any variances between cylinders and between engines.

 

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Nikasil and similar coatings are electro-deposited. Ceramic coatings are similar. For example, Perfect Bore uses a 16-percent silica-carbide particle in the 2- to3-micronrange,with a balanceof nickel. A number of engine builders are seeing their work run two or three races without the need for honing during a freshening rebuild, with only the need to merely run a silica carbide brush for minor touch-up. Some engines have run several thousand race miles without being rehoned.The current trick is to hot hone to minimize bore distortion to eliminate potential blow-by.

For racing applications, this hard coating provides the opportunity to run tighter wall clearances. Wear resistance is higher, cylinder wall lubricity is better, and wear is minimal. In a Winston Cup engine application, a cleanup of only .0002 inch might be required following a grueling 600-mile race, allowing even the original rings to be reused.

These hard coatings really don’t offer a performance benefit in terms of gaining increased power. The benefit lies in being able to run tighter clearances and a substantial gain in engine longevity.

Honing the Coating

According to extensive research conducted by Sunnen Products, Nikasilcoated cylinders should be honed with diamond stones. Hard cylinder coatings can be applied to the bore (in iron and alloy blocks), but coated cylinder liners are more popular. If the bores have been coated and now must be recoated as a result of wall damage, the block must be shipped away, which eats time. Coated liners allow the engine builder to much more quickly refresh a block in his shop.

With chrome coating, it is more likely to hone through the chrome (potential of fracturing of the plating) due to any distortion of the cylinder in the areas adjacent to the head bolt areas, even with a dry torque plate. Nikasil and similar coatings don’t share this potential problem since they’re not as brittle as chrome.

 

The force inducer generates the vibrations that are transmitted to the work piece. This inducer is clamped to a steel worktable upon which the parts are secured.

The force inducer generates the vibrations that are transmitted to the work piece. This inducer is clamped to a steel worktable upon which the parts are secured.

 

Nikasil, on the other hand, is very consistent for thickness and hardness uniformity. Because Nikasil allows tighter clearances and its oil retention is much higher, you can get away with creating a smoother finish. Typical Nikasil cylinder finishesare in the Ra range of6 to10.

Rings

It’s absolutely critical to use the correct type of rings in conjunction with Nikasil-coated cylinders. The top ring is typically moly or PVD; the second ring is ductile iron. Chrome rings cannot be used (including oil control rails) because chrome and Nikasil react to each other and result in scuffing. So just run plasmamoly top rings, ductile-iron second rings, andunplatedoilrails.Ringseatingoccurs very quickly. Nikasil and other cylinder coatings are applied to aluminum or iron walls (on parent bores or on liners).

Typically, the coating is about .008 inch and can be sprayed on between .012 and .015 inch thick. This type of coating visually appears to be chrome, very shiny and difficult to scratch. In order to touch up Nikasil in order to re-ring, a 150-grit aluminum-oxide stone usually suffices, just to clean and remove any high points. However, if you find excessive wear or if new sleeves are to be installed, finishing requires a 500-grit diamond stone.

Cost

For a four-cylinder block, cost could typicallybe around $750 for coating the metal bores, or $200 per liner if you need sleeves. Coated liners for an eight-cylinder block may run about $1,600.

Nikasil and similar coatings are highend processes for builders with the budgets to handle the expense. However, when you consider the reduced inventory required for blocks, cranks, rings, etc., and the extremely minimized need to rehone, the initial investment quickly pays for itself.

 

Written by Mike Mavrigian and Posted with Permission of CarTechBooks

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