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Head and inlet coatings. Worth it or fantasy?

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Head and inlet coatings. Worth it or fantasy?

Post by ctwg60 on Tue Apr 07, 2009 3:17 am

I was thinking of getting the inlet manifold coated to reduce heat absorption from the exhaust heat and then found myself browsing the other coatings, specifically the inlet and exhaust port internal coatings. I can't imagine they'd make a great deal of difference but thought I'd ask you guys.

Here are some links...

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I was going to burnish some tungsten disulphide in to the piston crowns, bores and combustion chamber when I install the new head just to reduce friction and allow combustion heat dispersion, don't suppose it could do any harm now the engine is fully bedded in, well in a few more km anyway.

Tks

Chris

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Re: Head and inlet coatings. Worth it or fantasy?

Post by JNLRacing on Tue Apr 07, 2009 11:53 am

Yes coatings help but for a normal application a lot of them are overkill and you wouldn't see a noticeable difference. Also remember if you coat the intake mani to stop heat getting in. Then any heat absorbed from the head can't get out either it's a two way balance. Much better of getting rid of the heat by stopping the exhaust from expelling it. However they dont gaurantee their coatings on FI cars if you read the small print due to the extremes of temperatures.

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Re: Head and inlet coatings. Worth it or fantasy?

Post by ctwg60 on Tue Apr 07, 2009 1:04 pm

Mmm just another one of those things people talk about but not necessarily a benefit.

Still going to burnish in the tungsten disulfide power I have, with a little methanol. Can't really go wrong with that one and should help engine longevity and potential knock.

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Re: Head and inlet coatings. Worth it or fantasy?

Post by mrbeige on Tue Apr 07, 2009 1:18 pm

What about ceramic coatings? They can resist extreme heat.

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Re: Head and inlet coatings. Worth it or fantasy?

Post by JNLRacing on Tue Apr 07, 2009 11:56 pm

ctwg60 wrote:Mmm just another one of those things people talk about but not necessarily a benefit.

Still going to burnish in the tungsten disulfide power I have, with a little methanol. Can't really go wrong with that one and should help engine longevity and potential knock.

#PLease do not do that the tungsten disulfide was designed as a lubricant for preventing seizure in moving components like sliding pins, cog driven assemblies etc. It wont resist temperatures over 400celsius, and will prevent the rings of your pistons bedding into the bores properly. It is not designed for engine application. You can get the side of your pistons chrome moly coated for reduced friction in the bores but that wears of anyway over time. If you want to do anything when your headis of give the bores a fresh hone and chuck a set of rings in.

mrbeige wrote:What about ceramic coatings? They can resist extreme heat.

Camcoat are ceramic coatings it's just they have a disclaimer as a lot of race teams with FI engines have had issues. Personally I use a local company that does Zirconia plasma coating as follows

Zirconia based ceramics are used in heat insulation applications as thermal barriers to improve efficiency and service life of components in high temperature service. These materials are generally plasma sprayed over an appropriate bond coat. Stabilisers such as magnesia, ceria, calcia and yttria are alloyed with the zirconia to help minimise phase transformation that can cause volume changes within the coating, which can in turn lead to coating cracking during service. Key applications are graphite trays used for sintering of carbide, gas turbine hot section components, diesel engine piston crowns and seats.

They use it on the inside of ovens that exceed 1400celsius in temperature. Coat the outside of your exhaust mani with it and that's about it. If you have a turbo do the mani, exhaust housing and downpipe. Keeps the heat of the exhaust out the engine bay and keeps the exhaust gases flowing faster and more efficient.

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Re: Head and inlet coatings. Worth it or fantasy?

Post by kevhaywire on Wed Apr 08, 2009 1:43 am

I'm still waiting to be convinced by coatings tbh. The parts coated with it that I've seen still radiate heat into the engine bay. I can put my hand on a fibreglass wrapped downpipe with the engine running (not for long though!!) and not get burned. Can't do that with a ceramic coated downpipe. Although I guess it's largely down to the quality of materials and how well it's applied?

As for insulating turbine housings, I had an interesting chat with a good tuner and he says GTxxxxR turbos don't like being insulated. The oil gets too hot and thin and bearing life suffers. I note turbo manufacturers never coat their housings or supply them with jackets, so I'm inclined to take his word for it.

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Re: Head and inlet coatings. Worth it or fantasy?

Post by ctwg60 on Wed Apr 08, 2009 3:31 am

JNLRacing wrote:#PLease do not do that the tungsten disulfide was designed as a lubricant for preventing seizure in moving components like sliding pins, cog driven assemblies etc. It wont resist temperatures over 400celsius, and will prevent the rings of your pistons bedding into the bores properly. It is not designed for engine application. You can get the side of your pistons chrome moly coated for reduced friction in the bores but that wears of anyway over time. If you want to do anything when your headis of give the bores a fresh hone and chuck a set of rings in.

As I say the engine has already bedded in and will be more so by the time I come think about doing this, engine was rebuilt about 6 months ago. On Cam Coats website they recommend WSX (Tungsten Disulphide) for valve guides, piston liners and cylinder bores. They describe it as an "Extreme temperature lubricant which can withstand load to 350,000 psi. Simply buff onto surface requiring lubrication."

Going to get a rocker cover done by them to see how they operate as they are local to me I'll talk to them about it when I'm in there. I understand what your saying about the rings and the bores, it doesn't make much sense being a lubricant coating when your running thin oil and cross hatching the bores to bed the rings in but with it being tungsten rather than molybdenum it's a lot tougher and I guess it is such a thin layer it allows the crosshatching to still do it's job after all it's the rings bedding into the bores not vice-versa. I don't know I'll have to do more research. A little knowledge and all that!

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Re: Head and inlet coatings. Worth it or fantasy?

Post by ctwg60 on Tue Apr 14, 2009 1:38 am

OK so a little more research reveals that WS2 cannot withstand 650˚ so it not suitable for FI engines. Oh well.

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Re: Head and inlet coatings. Worth it or fantasy?

Post by dirtytorque on Tue Apr 14, 2009 3:44 am

at least you have satisfied your own curiosity.
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Re: Head and inlet coatings. Worth it or fantasy?

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