EP additives, flat tappets, engine oil

[willyreid]

I know this is a bit off the wall, but I am curious about flat tappet engines where an actual wear issue exists. Sure, hardened cam/tappets is the usual answer for many engines with flat tappets, and likely they came with such. There are more than a few popular British cars I know of that appear to have flat tappet and cam wear in spite of any hardened parts that have come along since their initial introduction. The T-type MG's XPAG/XPEG engines seem to just have an inherent "defect" or call it what you will in design. The tappets and cam wears. Same for the MGB engines, though nowhere near as extreme as the XPAG/XPEG. Of course the typical discussion will include use of a high ZDDP oil to make the tappets/cam last as long as possible. Much debate on that whole topic and what defines the right amount. Seems there has been plenty of discussion on that already. Many say the oil did not even have ZDDP additives back in the late 40's or 50's. Whatever the case, there are still a lot of people running engines where they are concerned about such wear.

My question stems from something on a MG forum about that since the ZDDP is basically working to help between the flat tappet and cam to leseen wear, that means there is a big amount of "pressure" where they meet. That causes wear. I know about roller cams and all that and people would already do that if was cheap and easy. It is not. SO:

What about using something designed for Extreme Pressure like gear oil. It is loaded with EP additives, right? These cars are not subject to CAT converters or smog checks, and although EP gear oil of 90W would be about the same viscosity as typical motor oil, like 20W/50 people use in these engines, what would happen if you used something like that? There are all different kinds of weight gear oils, all different EP levels, at least GL4 and GL5 levels, not to mention multi weight gear oils. Why or why not? What would happen?

 

[OneEyeJack]

Don't put gear oil in your engine. You won't be happy with the results.

Instead use a motor oil that meets your requirements. Stick with motor oil, maybe try motorcycle oil.

Oil today is much better and camshaft/tappet wear should not be a problem.

 

[willyreid]

That's not much of an answer to the question. Thanks, but such an answer would work coming from an established expert in the field to someone who knows nothing.

I want an explanation of why or why not. I am not asking for advice, I am asking for information.

Oil today better? Yes I imagine it might be, and I am not talking about using 60 year old oil.

 

[OVERKILL]

Originally Posted By: willyreid
I know this is a bit off the wall, but I am curious about flat tappet engines where an actual wear issue exists. Sure, hardened cam/tappets is the usual answer for many engines with flat tappets, and likely they came with such. There are more than a few popular British cars I know of that appear to have flat tappet and cam wear in spite of any hardened parts that have come along since their initial introduction. The T-type MG's XPAG/XPEG engines seem to just have an inherent "defect" or call it what you will in design. The tappets and cam wears. Same for the MGB engines, though nowhere near as extreme as the XPAG/XPEG. Of course the typical discussion will include use of a high ZDDP oil to make the tappets/cam last as long as possible. Much debate on that whole topic and what defines the right amount. Seems there has been plenty of discussion on that already. Many say the oil did not even have ZDDP additives back in the late 40's or 50's. Whatever the case, there are still a lot of people running engines where they are concerned about such wear.

My question stems from something on a MG forum about that since the ZDDP is basically working to help between the flat tappet and cam to leseen wear, that means there is a big amount of "pressure" where they meet. That causes wear. I know about roller cams and all that and people would already do that if was cheap and easy. It is not. SO:

What about using something designed for Extreme Pressure like gear oil. It is loaded with EP additives, right? These cars are not subject to CAT converters or smog checks, and although EP gear oil of 90W would be about the same viscosity as typical motor oil, like 20W/50 people use in these engines, what would happen if you used something like that? There are all different kinds of weight gear oils, all different EP levels, at least GL4 and GL5 levels, not to mention multi weight gear oils. Why or why not? What would happen?


What makes you think the pressure levels in a flat tappet setup are EP level? The short answer is that they aren't, which are why EP additives aren't part of most commercial motor oils. I believe Royal Purple's XPR lineup has some form of EP additive (sulphated Ester) in it but generally it is reserved for places where EP actually exists, like in a differential.

 

[OVERKILL]

Originally Posted By: willyreid


I want an explanation of why or why not. I am not asking for advice, I am asking for information.



Gear oil is not formulated to deal with combustion byproducts, the heat experienced at the ring/wall interface, it can be corrosive to certain bearing metals depending on grade....etc. There are plenty of reasons to not run a gear lube in an application that doesn't call for one, but those are the primary ones.

 

[willyreid]

Originally Posted By: OVERKILL
Originally Posted By: willyreid
I know this is a bit off the wall, but I am curious about flat tappet engines where an actual wear issue exists. Sure, hardened cam/tappets is the usual answer for many engines with flat tappets, and likely they came with such. There are more than a few popular British cars I know of that appear to have flat tappet and cam wear in spite of any hardened parts that have come along since their initial introduction. The T-type MG's XPAG/XPEG engines seem to just have an inherent "defect" or call it what you will in design. The tappets and cam wears. Same for the MGB engines, though nowhere near as extreme as the XPAG/XPEG. Of course the typical discussion will include use of a high ZDDP oil to make the tappets/cam last as long as possible. Much debate on that whole topic and what defines the right amount. Seems there has been plenty of discussion on that already. Many say the oil did not even have ZDDP additives back in the late 40's or 50's. Whatever the case, there are still a lot of people running engines where they are concerned about such wear.

My question stems from something on a MG forum about that since the ZDDP is basically working to help between the flat tappet and cam to leseen wear, that means there is a big amount of "pressure" where they meet. That causes wear. I know about roller cams and all that and people would already do that if was cheap and easy. It is not. SO:

What about using something designed for Extreme Pressure like gear oil. It is loaded with EP additives, right? These cars are not subject to CAT converters or smog checks, and although EP gear oil of 90W would be about the same viscosity as typical motor oil, like 20W/50 people use in these engines, what would happen if you used something like that? There are all different kinds of weight gear oils, all different EP levels, at least GL4 and GL5 levels, not to mention multi weight gear oils. Why or why not? What would happen?


What makes you think the pressure levels in a flat tappet setup are EP level? The short answer is that they aren't, which are why EP additives aren't part of most commercial motor oils. I believe Royal Purple's XPR lineup has some form of EP additive (sulphated Ester) in it but generally it is reserved for places where EP actually exists, like in a differential.


OK, so what are you saying? Flat tappet is nowhere near EP pressure? So what is your point? Why would EP (too much EP protection) not work with less pressure? How often is a differential in need of full protection? Get my point?

 

[willyreid]

Originally Posted By: OVERKILL
Originally Posted By: willyreid


I want an explanation of why or why not. I am not asking for advice, I am asking for information.



Gear oil is not formulated to deal with combustion byproducts, the heat experienced at the ring/wall interface, it can be corrosive to certain bearing metals depending on grade....etc. There are plenty of reasons to not run a gear lube in an application that doesn't call for one, but those are the primary ones.


Can be corrosive at combustion? Can? So that means some gear oil is fine but others have been poisoned so they wont work in an engine, or the various additives in some gear oil may or may not be such that they may or may not damage a certain type of combustion area? I appreciate the replies so far, but sorta could be taken as boilerplate oil industry answers so far.

 

[MolaKule]

Quote:
...what would happen if you used something like that? There are all different kinds of weight gear oils, all different EP levels, at least GL4 and GL5 levels, not to mention multi weight gear oils. Why or why not? What would happen?


What would happen? Overkill has provided you with the correct answer.

First, you don't need EP additives in a motor oil, you need anti-wear (AW) additives.

Secondly, the kind of EP additives found in gear oil would form acids that would cause corrosion, due to the heat of combustion and moisture in an engine.

Simply because lubricants may be similar in viscosity does not mean they have the proper additive package for that specific application.

And tone down your S*******S responses.

 

[Shannow]

Might be just the gear oil I had at hand, and the motor oil I chose, but I once for giggles mixed them and started heating them (sort of a backyard D6922)...it reacted with some bubbles, and what looked briefly like slivers of soap floating around behind the bubble trail.

I was a little shocked, shouldn't have been surprised but I was.

 

[willyreid]

What additives to cause acid that regular oils do not have? Or do you mean lack of additives forming acid? Is not the cause of wear in these high wear flat tappet engines caused by pressure, or what would you call it?

 

[willyreid]

Originally Posted By: Shannow
Might be just the gear oil I had at hand, and the motor oil I chose, but I once for giggles mixed them and started heating them (sort of a backyard D6922)...it reacted with some bubbles, and what looked briefly like slivers of soap floating around behind the bubble trail.

I was a little shocked, shouldn't have been surprised but I was.


Likely already too many fusil oils in the system, eh?

 

[MolaKule]

Gear oil additives contain sulfur-phosphorus chemistry such that this chemistry reacts with combustion temperatures and moisture not found in a closed differential.

Engine oils contain special anti-oxidants, alkaline detergents/dispersants, and metal inhibitors to reduce acid formation at high combustion temperatures.

ZDDP is an anti-wear agent that forms a plastic film to combat wear in high pressure areas. About 1200 to 1500 ppm of phosphorus and zinc (from ZDDP) is all you need for those highly loaded areas.

Improper heat treating of cam lobes and tappets will usually cause accelerated wear.

 

[Diego3336]

I honestly think you will never have the answers you want. At least not here.

Of course there's must have a scientific answer to your question, but I don't think anyone besides the oil formulators can answer them to you basically because I guess anyone here doesn't knows what the oils have and at what concentration.

If you had a bunch of MG engines to run a wear test using every gear oil available, maybe you could have some answers based on the good and old trial-and-error method. But the fact that these stock engines are available for decades and still nobody can make them reliable despite tons of attempts should give you a clue.

But really, what you are asking is not so different than ask why anyone shouldn't put canola or diesel on the sump as both of them are oils after all...

 

[Torrid]

Honestly I'd stick with the 20w50 specified by MG. I have a buddy that owns an MGB and we've had many extensive discussions of use of fluids regarding the car. He uses 20w50 GTX. He said the main failure point he's seen mention in the cars is the gear box. The issue is that MG specified 20w50 in the gear box and diff too and apparently the gear box is extremely notchy with 20w50 and most use a transmission fluid to cure it.

Most 20w50s are pretty beefy in the ZDDP department.

 

[MolaKule]

Originally Posted By: Diego3336
I honestly think you will never have the answers you want. At least not here.

Of course there's must have a scientific answer to your question, but I don't think anyone besides the oil formulators can answer them to you basically because I guess anyone here doesn't knows what the oils have and at what concentration.




I am an oil formulator and I know what is in each type of lubricant and in what concentration.

His question was answered with a scientific response.

But first one has to ask and respond in a civil manner.

 

[willyreid]

Originally Posted By: Diego3336
I honestly think you will never have the answers you want. At least not here.

Of course there's must have a scientific answer to your question, but I don't think anyone besides the oil formulators can answer them to you basically because I guess anyone here doesn't knows what the oils have and at what concentration.

If you had a bunch of MG engines to run a wear test using every gear oil available, maybe you could have some answers based on the good and old trial-and-error method. But the fact that these stock engines are available for decades and still nobody can make them reliable despite tons of attempts should give you a clue.

But really, what you are asking is not so different than ask why anyone shouldn't put canola or diesel on the sump as both of them are oils after all...


Actually I think all it would take is some testing in just about any internal combustion engine to find out about any effects. Wear is caused by the "pressure" as two surfaces rub against each other, like a tappet on cam or hypoid gear on gear. Yes sulfur the common EP additive and sulfur could possibly be damaging when minute amounts burned, but then again most anything might be damaging when burned. As I mentioned in the original question, 90w gear oil and 20W motor oil about the same viscosity, so nuts to your peanut oil. Not relevant, but cute.

 

[MolaKule]

Originally Posted By: willyreid

Actually I think all it would take is some testing in just about any internal combustion engine to find out about any effects. Wear is caused by the "pressure" as two surfaces rub against each other, like a tappet on cam or hypoid gear on gear. Yes sulfur the common EP additive and sulfur could possibly be damaging when minute amounts burned, but then again most anything might be damaging when burned. As I mentioned in the original question, 90w gear oil and 20W motor oil about the same viscosity, so nuts to your peanut oil. Not relevant, but cute.


Wear is caused by not having the proper lubricant between two surfaces.

We're not talking about just "burning" sulfur we're talking about chemical reactions between certain chemicals at high temperatures in the presence of moisture and the forming of acids.

And as I stated before, simply because two lubricants are nearly the same viscosity doesn't mean they will react the same in different units.

Quote:
but then again most anything might be damaging when burned.


We're not talking about just burning anything, we're talking about the reaction chemistry of different oils in different applications.

Quote:
Actually I think all it would take is some testing in just about any internal combustion engine to find out about any effects.


Then run pure GL-5 gear oil in your engine and let us know how it works out.

 

[dave1251]

Originally Posted By: Diego3336
I honestly think you will never have the answers you want. At least not here.

Of course there's must have a scientific answer to your question, but I don't think anyone besides the oil formulators can answer them to you basically because I guess anyone here doesn't knows what the oils have and at what concentration.

If you had a bunch of MG engines to run a wear test using every gear oil available, maybe you could have some answers based on the good and old trial-and-error method. But the fact that these stock engines are available for decades and still nobody can make them reliable despite tons of attempts should give you a clue.

But really, what you are asking is not so different than ask why anyone shouldn't put canola or diesel on the sump as both of them are oils after all...


Houve respostas muito precisas às suas perguntas.

 

[willyreid]

I was talking 90W in the original question. But since I am in LA and you in AZ I could see 140w, but you would need to not let it get cold.

High temp or burning you said rings.

 

[MolaKule]

Originally Posted By: willyreid
...So far sounds like just boilerplate from the oil industry to get people to buy what they want them to buy...


Interesting in that I have not seen anyone try to sell willyreid anything.

But then again, ignorant argumentative people always attempt to bring up side issues that have no bearing on the original discussion.

Pressure is force divided by area or P = F/A willyreid. Mechanical force attempts to squeeze an oil film down to almost molecular distance separations.

AW additives such as ZDDP and certain polymeric esters produce plastic films when reacted with ferrous surfaces in order to keep these metal parts separated and to reduce wear.

Again, you don't use EP additives in an engine to prevent wear. You use AW additives.

Now this is in direct contradiction to willyreid's original and incorrect asumptions and statements about what happens in the real scientific, un-mythical world of physics, chemistry, and mechanics.