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- When it comes to the world of engine building, there's a wide range of information, products, and processes that you need to understand that go further than just the task of machining and assembling an engine.
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In this section of the course we're going to discuss some of this additional information.
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00:17 |
We'll discuss terms, products, and processes, that we receive questions about, and we'll discuss them in detail so that you can understand what they mean, why they may be selected, and what the potential advantages or disadvantages are.
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00:32 |
We'll get started by discussing engine coatings.
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00:36 |
Coating the engine internal components is quite a large segment of the aftermarket industry, with several standalone companies offering this service as well as many of the engine component manufacturers offering it as an option.
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00:50 |
There's a huge amount of confusion surrounding the value of coatings and what they can offer, so in this section we'll discuss these coatings and what advantages they may offer you.
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01:01 |
While there are a wide variety of coatings available, we'll focus on three of the most popular, which are thermal barrier coatings, friction reducing coatings and coatings that promote oil shedding.
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We'll start with thermal barrier coatings, which are most often applied to the crown of the piston, but these can also be applied to the combustion chamber of the cylinder head.
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01:24 |
Internal combustion engines are notoriously inefficient with the majority of the energy content of the fuel being converted to heat and sound.
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01:34 |
The thermal barrier coating is designed to reflect heat back into the combustion chamber rather than it being transferred into the piston crown.
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01:43 |
The intention here is that it can increase exhaust gas velocity and improve scavenging of the exhaust gases.
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01:51 |
I think many novice engine builders expect a coating like this to be some kind of magic bullet that will help save their engine from a meltdown if the tuneup is unsafe.
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02:02 |
And in my experience that's just not the case.
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02:06 |
I've personally built engines both with and without thermal barrier coatings and I've not been able to pick up an advantage when it came time to hit the dyno.
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02:16 |
That's not to say that these coatings aren't worthwhile, however I feel that the magnitude of gain that you're likely to see is going to be quite small, so you need to factor this in with the cost and decide if it's worthwhile to you.
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02:31 |
Next we'll discuss friction reducing coatings which are typically applied to the skirts of pistons.
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02:37 |
A reasonable amount of potential engine efficiency is lost to friction between the engine components.
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02:43 |
So it makes sense that anything we can do to reduce these frictional losses, has got to be an advantage.
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02:51 |
These anti friction coatings can also help reduce the likelihood of galling between the piston skirt and the cylinder wall during operation.
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03:00 |
Anti friction coatings are one of the coatings that I do regularly run, as I see the advantages being worth the relatively small additional cost.
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03:10 |
You do need to check with the coating manufacturer as some of these coatings will affect the required piston to bore clearance.
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03:18 |
Lastly we'll discuss oil shedding coatings.
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03:21 |
These coatings promote oil flying off of the product rather than sticking to the surface.
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03:28 |
In turn this reduces the reciprocating mass of the part, as we're now not moving such a large mass of oil.
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03:35 |
This isn't a coating that I've personally had the opportunity to test, however I'd expect that the sort of gains you're likely to see through its application would be minor at best.
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03:47 |
This is one of those coatings that I'd consider for a maximum effort race engine, where we want every aspect working in our favour, and the additional cost isn't a concern.
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03:59 |
It's equally well suited to tightly controlled race classes where you want every possible advantage working in your favour and you're limited in what other modifications you can use.
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