Benifits and purposes of coating engine parts

[El_Diablo]

Well, im sure you guys all know there are a lot of different coatings out there and more than a few "treatments". Lately I have been looking into a few of these and have been trying to figure out what I want to do and where in my engine i want to do it.

The purpose of this thread is to pretty much gain a bit more insight on what these coatings do and to list out the possiblities for these coatings and treatments.



The few key points i would like to focus on are heat resistance, lubricity and durability aswell as what these processes can do to help keep you engine together over the long haul.

First off, Titanium Nitride Coating-
Some of the benifits and features i have found listed on various sites are:

• Wear resistance
  Maintaining sharp edges or corners
  Prevent galling, seizing or cold-welding
  Decreases friction
  Resists corrosion
  Withstands high temperatures
  Extreme hardness (Harder than carbide)
  Lubricity
  Resistant to nearly all chemicals
  Heat resistant

Now, moving on to implementation aspect of this coating. One possible use is coating the block for increased durability. Another possible option is use in internal turbo assemblies.

Now for the questions this thread was meant to try and answer. How well does this work? What are the other possible uses? Will the increased lubricity and hardness help your block stand up to years of high performance pounding?



To add to this, here is a little more information on the material-

Titanium nitride (TiN) is an extremely hard (~85 Rockwell C Hardness or ~2500 Vickers Hardness or 24.5 gigapascals)[1], ceramic material, often used as a coating on titanium alloy, steel, carbide, and aluminum components to improve the substrate's surface properties.

TiN has excellent infrared (IR) reflectivity properties, reflecting in a spectrum similar to elemental gold (Au). Depending on the substrate material and surface finish, TiN will have a coefficient of friction ranging from 0.4 to 0.9 versus itself (non-lubricated). Typical formation is a face-centered cubic crystalline structure with a roughly 1:1 stoichiometry. TiN will oxidize at 600 °C (~1100 °F) at normal atmosphere, and has a melting point of 2930 °C.

-Taken from Wikipedia.Org

Also, just a side note-
There will be plenty more to come in this thread and i will slowly add the different treatment offerings availible, this is only the first of an installment of posts on this subject.

[El_Diablo]

Cryo Treating

Cryo Treating or "Cryogenic Tempering"-
Benefits and features:

• Increased dimensional stability
  Stress relief (Especially for aluminum, titanium and composite materials)
  Improved wear
  Abrasive resistance
  Reduces Distortion
  Increased toughness, fatigue and impact resistance
  Creates a denser molecular structure, resulting in a finer contact surface area that reduces friction, heat and wear
  Does not cause dimensional changes

Aditional Information-

The process completes the austenite to martensite transformation that occurs during heat treat in steel alloys. Heat treating increases hardness in tooling, while post-heat treat cryo processing with a mild draw increases hardness by an additional 1% - 2%.

The process uses Liquid nitrogen to cool parts from room temperature to –300F at a rate of ½ to 1F per minute for maximum stress relief. Then, maintaining the parts at –300F for 18 to 36 hours completes the austenite transformation. The more carbon in the material, the colder and longer the parts are kept at low temperature, according to the customer’s specific needs. After the “cold soak,” the parts are returned to room temperature at ½ to 1-minute rate. Usually, three heating and cooling stages (called a “triple draw”) are included, depending on the material, with a one-hour hold at the temperature extremes.

Cryo processing also is used to stabilize aluminum and titanium, since they are often hard to handle during machining. In aerospace applications, cryogenic tempering conditions the metal in aluminum optical benches, so that large temperature variations can be tolerated with minimal distortion. Once a part has been cryo treated, additional cryogenic processing will not usually make any difference.

Gears in transmissions, cast iron or forged items also can benefit from processing. When the military tested cryo treating helicopter gears in the 70’s, they found that the process improved durability and reduced noise, which turned out to solve several problems in combat. Noisy working environments are improved through cryo treatment by providing greater longevity and safety for gears and moving parts.

Race car owners and drivers are always looking for any performance advantage. In cryogenic treatment of their cars’ parts and engines, if one of the materials in a metal-to-metal contact surface is carbon-bearing, it is a good candidate for cryo treating. This is especially true if it has already been heat-treated.

-Taken from "One Cryo"

Recomended Treament From "Metal-Wear"-

Engine
Virtually every engine part will respond to cryogenic processing. In general, it is best to treat the engine disassembled.

Block
Treating the block and piston rings helps assure better ring sealing, which raises torque and increases engine life by reducing wear on the cylinder bores. Treating the block also reduces distortion of the block during machining and running. Blocks should be treated after all heavy machining is done and before final boring and honing. It is beneficial to treat both aluminum and cast iron blocks. Sleeved blocks and cylinders (for instance, Harley Davidson cylinders) should also be treated.

Valve Train
Cryogenic Processing reduces wear in the valve train. This assures the valve timing remains constant. One of our pickiest engine building customers tells us his valve lash does not change during break in when he uses cryo'd parts. Reed Cams agrees with him, as they offer cryogenic processing as an option on their camshafts and lifters. We see a lot less wear on solid lifters, and less breakage on roller lifters. Treatment of push rods changes the harmonics of their vibration, which helps prevent valve float. Our customers also report much longer rocker arm life. Treating the valves, guides, keepers, and retainers assures minimum wear in this area and minimum breakage, which results in reduced sticking and more accurate timing. Treating valve springs allows our customer much longer life. One Remax series racer changes springs once a year, where his competitors change theirs every other race. At $400.00 to buy a set of springs and $48.00 to cryo treat a set, you can see the economics. He consistently runs in the top ten.

Rotating Assembly
Cryo Processing reduces wear and breakage of crankshafts. Two major racing crankshaft makers cryo treat their products as part of the production process. Cryo treating cast crankshafts greatly reduces wear and breakage. Cryo treating bearings helps to increase their life and reduce instances of cracking. Connecting rods respond to cryo by an increase in life and toughness. Dyer's Top Rods cryogenically treats all of its connecting rods and is known for having one of the toughest rods in the market. Pistons resist detonation longer when treated, and also distort less in use. Piston pins wear less. Piston rings seal better, vibrate less, and last longer.

Now for the questions. Is this process compatible with other treament types? If so what is the process that should be followed for multiple coating parts?




As before, additional information and questions about other coatings will be addressed at a later time.

[bszopi]

Once this thread gets a little more along, I'd like to compile the info for a site article...

[El_Diablo]

thats what i actually plan on doing for a couple other sites i belong to

[El_Diablo]

Ceramic Coatings

Here are a few types of ceramic coatings i have found availible to the automotive industry-

• Thermal Barrier
  Anti-Friction
  Oil-Shedding
  Thermal Barrier Coatings for Exhaust Systems
  Anti-Corrosive and Salt-Shedding

The most common applications for ceramic coatings are on the exhaust system, manifolds, and headers. When ceramic thermal barrier coatings are applied to exhaust manifolds or headers, they provide two advantages. They protect the headers from rust and corrosion and also reduce heat loss, which translates into higher power output.

Some "Ceramic" coatings that come standard on headers are actually less than .002" thick, while others tend to stay around the .002" mark. Swain coatings is one of the alternatives that i have found that are after more than just looks. Their "White Lightning" coating is applied about .015" thick and from what I have witnessed is a far superior thermal barrier.



Pistons can also increase their performance characteristics with ceramic coatings. Coating the piston's crown and top will cause heat reflectivity, driving a percentage of any detonation energy back into the fuel burn zone, to increase fuel burn efficiency. It will also lower carbon buildup, which reduces detonation quality, as it builds up on the piston's crown and increases the risk of detonation damage to the piston crown surface. By protecting the crown and land diameter surfaces, it will allow for a leaner fuel mixture.

Piston skirts can be coated to create an excellent dry sliding surface during engine start-up and will help eliminate skirt slap during initial engine run-in. Using a dry coating will fight against scuffing and abrasion of the piston skirt during its stroke travel inside the engine block cylinder. The inside of the piston can also be coated with an oil-shedding coating to cut parasitic drag and return oil to the sump faster. Ceramic coatings can also be applied over the piston ring contact face of OEM hard chromium, which provides lowering friction between the ring face and cylinder inner bore surface scuffing, and also improves wear resistance.

Here is some additional information on what Ceramic coatings are capable of when used in an engine-

http://www.powermachineservice.com/power_machine_services.htm

[El_Diablo]

any questions, comments or answers?

[RedBird]

well, here's a link to an article about a treatment i found out about a couple days ago, and the people i've talked to about it seem to think it could be big. read through it, it's pretty interesting.

EDIT: i guess you could use the link, haha

http://www.findarticles.com/p/articl...7/ai_n14823010

[Fiero Brick]

Should I point out the thread I started in regards to the Mikronite finishing process, or keep that to myself? :P

Coatings and new finishing processes are all very interesting and promising. Particularly now that I hear of some OEM useage of them.

[El_Diablo]

the more info the better

[gectek]

so does anyone know of a good cryo place to treat some of the internals

[El_Diablo]

http://www.300below.com

http://www.metal-wear.com

http://www.300degrees.com/

had a link to a really cheap place but unfortunetly the link is on my other computer which i cannot acess right now

[gectek]

cool, so what would be better for treating the heads then, the coating that sappy offers for the thermal barrier or the cryo treating alone, or do you think both of them could be used on the head without any flaking or bonding issues

[SappySE107]

cryo treat a head? hmm, intersting but I dont know that it will do anything for you. Cryotreating is supposed to make wear resistance go way up and surface finish for machined parts. Neither of those really matter to heads.

[gectek]

its not supposed to heat up as much either and have better grain qualities a presume, by compacting the molecules, there are a few articles to back up their claims, but then they start bashing each other, so i really have no idea about that one. but they are very interesting. on all 3 of the sites that diablo posted

[El_Diablo]

i dont see any problems with doing both treatments, im planning to cryo pretty much my whole engine for strength reasons and i know i'll be using a few of the offered thermal coatings from swain coatings if i get the chance

http://www.ws6.com/cryo.htm

i have also come across information regarding an example of the same tolerences kept after racing and pretty much abuse of the engine for more than 15k miles in an aircooled vw engine... if it can do that for them it should help us keep some amazing specs on through the life of our engines