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@LotusElise What would cause this? I have three sets of used lost motion spring here at the house. Since I am installing new cams and new valvesprings , I figure it would be a smart thing to order new ones, all (8) cost $52.00. I have seen these things bending, breaking etc. on both forums, thus I am not going with used ones to play it safe. They are not visable when the valve cover is pulled off, the cams & rockers have to come out ot get a visual.
 

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Super Moderator
2002 DC5 Type S
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For those that do not know including myself, here are the meaning of these words:


tribolocial surface
The tribological surface is the result of the surface interacting with the environment. This interaction can take the form of a metal interacting with the environment to form oxides, nitrides, or hydroxides. Interaction with environments other than air can produce different surface films.

Hertzian pressure
Hertzian contact stress refers to the localized stresses that develop as two curved surfaces come in contact and deform slightly under the imposed loads. This amount of deformation is dependent on the modulus of elasticity of the material in contact.

austenitic steel
Austenitic steel is a type of stainless steel that contains austenite. It contains a high percentage of nickel and chromium, enhancing its ability to be formed and welded easily into any shape along with providing great strength and resistance to corrosion.
 

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Super Moderator
2002 DC5 Type S
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I thought of talking about a common basis 🤭. Sorry for that and thanks for clarification of it.

I may add the simple definition, coming from the prefix "tri" (lat. for three), there are three partners involved: two solid surfaces and a (separating) fluid in between those two. Tribologic is the science of friction, wear and greasing of friction partners in many kind like understanding the mechanism, forecasting and measuring wear rates and development of greasing fluids and pastes as well as protection layers.

It's a very complex science, especially on its application of a combustion engine. The complexity comes from the fact that it needs overlapping know how of kinematic, material, fluid mechanic, chemistry, thermodynamic. So you need an thermal and fluid engineer, chemist, material engineer and an mechanical engineer. It's very rare to have all in one person and it's even more rare to find one company altogether for the combustion engine. I was nine year in a ICE (internal combustion engine) development of the oldest company of the world producing ICE series for multiple applications: military, rail, marine, industry and commercial vehicles. The Leopard 2 engine is maybe the best known of them in the US. Even there you won't find someone who can combine all these areas as needed. It's always a share of everything in different deep dive qualities. I was one of them who were involved in failure related analyze, but there were specialists for different systems: valvetrain, crank drive and bearing and so on. None of them known everything and especially not the oil companies.

Pitting alone is complex, as the root causes are manifold and need deep dive know how down to chemical reaction basis background. So without any material investigation, e.g. SEM (scanning electrone analysis) where you can analyse the microscopic landscape and EDX (energy disperse X-Ray spectroscopy) the missing or added material content of a pitting structure, it is difficult to see it clearer. So my assumptions above are assumptions and no more.
I agree with you on the chemical reaction basis. In the industry I worked in we had weld procedures and processes for everything for many reasons. Certain chemicals are harsh to certain metals and will cause welds to crack and deform in three days time of being in service. Now in to relation to car engines like camshafts, the heat, friction etc. will make the process go faster. Thank you for sharing this knowledge with me.
 

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2002 DC5 Type S
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Hey man I was gonna ask, have you noticed any difference with the LMAs. As in their stiffness. Me and my brother noticed that K20A2, K24A2 and K20Z3 all have different feels. Do you think LMAs are made different?
They are all the same. For whatever reason the oem parts dealers charge a little more for the Z3. they are all the same part numbers
 
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