Marvel Mystery Oil - My test of MMO & mpg
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Originally Posted By: red7404
IMHO. if its metal to metal and moves it needs oiled. I.E. valve guides. which car maker makes the engine to lube the guides?
Sometimes I just wonder how I made it all the years and all the miles I have without using additives such as MMO. If my valve guides were being inadequately lubricated (assuming they need it at all), somehow I've managed to make it.
IMHO. if its metal to metal and moves it needs oiled. I.E. valve guides. which car maker makes the engine to lube the guides?
Sometimes I just wonder how I made it all the years and all the miles I have without using additives such as MMO. If my valve guides were being inadequately lubricated (assuming they need it at all), somehow I've managed to make it.
Originally Posted By: MolaKule
Originally Posted By: badtlc
Not to throw science into this discussion but that is a 17%+ increase in efficiency. You are obviously missing something in this experiment or purposely driving different to skew the numbers. There is no logical justification for that kind of increase.
Quote:
MMO claims it improves combustion and lubricates the fuel system.
Our detailed analysis of a few years ago showed that MMO contains a small amount of a chlorobenzene-type cleaner and some phosphorus that could act as a possible deposit scavenger when mixed in fuel, but nothing stood out that there is anything in it that could improve mileage.
Question: What component in a fuel system requires lubrication?
Fuel pump? Injectors?
Originally Posted By: badtlc
Not to throw science into this discussion but that is a 17%+ increase in efficiency. You are obviously missing something in this experiment or purposely driving different to skew the numbers. There is no logical justification for that kind of increase.
Quote:
MMO claims it improves combustion and lubricates the fuel system.
Our detailed analysis of a few years ago showed that MMO contains a small amount of a chlorobenzene-type cleaner and some phosphorus that could act as a possible deposit scavenger when mixed in fuel, but nothing stood out that there is anything in it that could improve mileage.
Question: What component in a fuel system requires lubrication?
Fuel pump? Injectors?
Originally Posted By: Brigadier
Fuel pump? Injectors?
Are you just pulling those out of the air or do you know somehow that they require lubrication but aren't getting it unless you use an additive? For your fuel pump example, how does the fuel lubricate the pump in the first place?
Again, how have I made it this long in my vehicles without the additive if those components were needing something they didn't have?
Fuel pump? Injectors?
Are you just pulling those out of the air or do you know somehow that they require lubrication but aren't getting it unless you use an additive? For your fuel pump example, how does the fuel lubricate the pump in the first place?
Again, how have I made it this long in my vehicles without the additive if those components were needing something they didn't have?
Originally Posted By: kschachn
Originally Posted By: Brigadier
Fuel pump? Injectors?
Are you just pulling those out of the air or do you know somehow that they require lubrication but aren't getting it unless you use an additive? For your fuel pump example, how does the fuel lubricate the pump in the first place?
Again, how have I made it this long in my vehicles without the additive if those components were needing something they didn't have?
Well, obviously I am not as automotively educated as you are, oh wise one........ Thank you for blessing us with your presence on this forum. Don't know what we would do without you.
But in case you haven't noticed, the engine in your Edsel is not the same as today's engines...
Originally Posted By: Brigadier
Fuel pump? Injectors?
Are you just pulling those out of the air or do you know somehow that they require lubrication but aren't getting it unless you use an additive? For your fuel pump example, how does the fuel lubricate the pump in the first place?
Again, how have I made it this long in my vehicles without the additive if those components were needing something they didn't have?
Well, obviously I am not as automotively educated as you are, oh wise one........ Thank you for blessing us with your presence on this forum. Don't know what we would do without you.
But in case you haven't noticed, the engine in your Edsel is not the same as today's engines...
Originally Posted By: Brigadier
Well, obviously I am not as automotively educated as you are, oh wise one........ Thank you for blessing us with your presence on this forum. Don't know what we would do without you.
But in case you haven't noticed, the engine in your Edsel is not the same as today's engines...
Lol. You make a statement, I ask you to back it up and you get snarky. It has nothing to do with education at all, it just has to do with the fact that I've never used any of those additives yet my fuel pumps and injectors haven't failed. That's all I was noting, is that not a valid observation?
So "today's" engines need fuel pump and/or injector lubricants? For the fuel pump specifically what components are in contact with the fuel that need lubrication?
Well, obviously I am not as automotively educated as you are, oh wise one........ Thank you for blessing us with your presence on this forum. Don't know what we would do without you.
But in case you haven't noticed, the engine in your Edsel is not the same as today's engines...
Lol. You make a statement, I ask you to back it up and you get snarky. It has nothing to do with education at all, it just has to do with the fact that I've never used any of those additives yet my fuel pumps and injectors haven't failed. That's all I was noting, is that not a valid observation?
So "today's" engines need fuel pump and/or injector lubricants? For the fuel pump specifically what components are in contact with the fuel that need lubrication?
Originally Posted By: kschachn
Originally Posted By: Brigadier
Well, obviously I am not as automotively educated as you are, oh wise one........ Thank you for blessing us with your presence on this forum. Don't know what we would do without you.
But in case you haven't noticed, the engine in your Edsel is not the same as today's engines...
Lol. You make a statement, I ask you to back it up and you get snarky. It has nothing to do with education at all, it just has to do with the fact that I've never used any of those additives yet my fuel pumps and injectors haven't failed. That's all I was noting, is that not a valid observation?
So "today's" engines need fuel pump and/or injector lubricants? For the fuel pump specifically what components are in contact with the fuel that need lubrication?
Um, did you notice the question marks in my post? I guess not.....
Both the fuel pump and injectors are electro-mechanical devices and are in contact with the fuel. I am not privy to the intricacies of the designs, but it seems pumping a fuel containing anywhere from 10% to 85% of a solvent, might need some help in lubrication. After all, fuel used to have lead in it as a lubricant, remember?
And along these lines is the upper cylinder with the rings. Ethanol is a solvent and strips away the lubrication...
Originally Posted By: Brigadier
Well, obviously I am not as automotively educated as you are, oh wise one........ Thank you for blessing us with your presence on this forum. Don't know what we would do without you.
But in case you haven't noticed, the engine in your Edsel is not the same as today's engines...
Lol. You make a statement, I ask you to back it up and you get snarky. It has nothing to do with education at all, it just has to do with the fact that I've never used any of those additives yet my fuel pumps and injectors haven't failed. That's all I was noting, is that not a valid observation?
So "today's" engines need fuel pump and/or injector lubricants? For the fuel pump specifically what components are in contact with the fuel that need lubrication?
Um, did you notice the question marks in my post? I guess not.....
Both the fuel pump and injectors are electro-mechanical devices and are in contact with the fuel. I am not privy to the intricacies of the designs, but it seems pumping a fuel containing anywhere from 10% to 85% of a solvent, might need some help in lubrication. After all, fuel used to have lead in it as a lubricant, remember?
And along these lines is the upper cylinder with the rings. Ethanol is a solvent and strips away the lubrication...
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The way things are made today I have no argument for the above stated. Every little bit of help you can get to supplement the longevity of these throwaway systems designed to empty your wallet. Could easily be the difference in spending $2,000 in vehicle maintenance over 150k miles or $10,000. Lots of sealed and connected components nowadays that make it nearly impossible to save money working on new cars being a diy savy person. The parts are made of cheaper materials and being exposed to solvents. Seems they have a plan to siphon all the money they can. Just my piece sorry for the rant but I find piece of mind adding a little MMO to my fuel. Isn't hurting anything so don't be so critical of each other. Share your experience with it or lack there of and thoughts on it. Not cram your opinions down each others throats and expect them to change their mind. Unless I missed something this forum is about sharing knowledge and ideas.
Even if I was sure that MMO was doing good things for my engine, I won’t use it it the fuel because of the tricresyl phosphate (TCP) additive in it. It is a quite toxic chemical and given that it’s in the fuel, it gets spewed out of the exhaust, spreading all over the place.
https://en.m.wikipedia.org/wiki/Tricresyl_phosphate
https://en.m.wikipedia.org/wiki/Tricresyl_phosphate
MolaKule
Staff member
Originally Posted By: Brigadier
Fuel pump? Injectors?
Injectors need a cleaning component but as to lubrication, no, because of its design. It is basically an electromagnetic popitt valve.
A fuel pump, like a water pump, has sealed bearings so no, those don't need lubrication either.
Fuel pump? Injectors?
Injectors need a cleaning component but as to lubrication, no, because of its design. It is basically an electromagnetic popitt valve.
A fuel pump, like a water pump, has sealed bearings so no, those don't need lubrication either.
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Originally Posted By: kschachn
Originally Posted By: red7404
IMHO. if its metal to metal and moves it needs oiled. I.E. valve guides. which car maker makes the engine to lube the guides?
Sometimes I just wonder how I made it all the years and all the miles I have without using additives such as MMO. If my valve guides were being inadequately lubricated (assuming they need it at all), somehow I've managed to make it.
I agree - how did we manage? I tried MMO in the Impala a few years ago, and I think I noticed a very small increase of MPG on a long trip - probably because my wallet was lighter! LOL!
Seriously I tried it with an open mind, and saw NO increase or decrease either way. Maybe my cars are too "new" to qualify for it's magical benefits.
On the other hand I only use top tier gasoline to start with, so maybe that has something to do with it. But it's fun watching the fan boys sing it's praises!
Originally Posted By: badtlc
Not to throw science into this discussion but that is a 17%+ increase in efficiency. You are obviously missing something in this experiment or purposely driving different to skew the numbers. There is no logical justification for that kind of increase.
I agree 17 plus percent increase seems a little hard to believe. My Impala usually get 30 MPG on the freeway - so I should have seen about a 5 MPG increase? Hard to believe!
Originally Posted By: red7404
IMHO. if its metal to metal and moves it needs oiled. I.E. valve guides. which car maker makes the engine to lube the guides?
Sometimes I just wonder how I made it all the years and all the miles I have without using additives such as MMO. If my valve guides were being inadequately lubricated (assuming they need it at all), somehow I've managed to make it.
I agree - how did we manage? I tried MMO in the Impala a few years ago, and I think I noticed a very small increase of MPG on a long trip - probably because my wallet was lighter! LOL!
Seriously I tried it with an open mind, and saw NO increase or decrease either way. Maybe my cars are too "new" to qualify for it's magical benefits.
On the other hand I only use top tier gasoline to start with, so maybe that has something to do with it. But it's fun watching the fan boys sing it's praises!
Originally Posted By: badtlc
Not to throw science into this discussion but that is a 17%+ increase in efficiency. You are obviously missing something in this experiment or purposely driving different to skew the numbers. There is no logical justification for that kind of increase.
I agree 17 plus percent increase seems a little hard to believe. My Impala usually get 30 MPG on the freeway - so I should have seen about a 5 MPG increase? Hard to believe!
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My MG gets 4 oz. of Stabil and 4 oz. of MMO on every tank(12 gallon tank).
I've not noticed a gas mileage increase. This is about as low tech of an engine as you can get(short of being a flathead-it is at least OHV) and mine's pretty "tired" with about 100K on it and some known ring issues. I also use it for upper cylinder lubricating properties, and as an added benefit I've noticed that I seem to have fewer issues with stuck floats and/or needle valves(I use to have one stick open occasionally). I guess the latter does improve gas mileage since I don't have gasoline leaking out
FWIW, the upper cylinder lubricant thing probably isn't as big of a deal as I swapped the head last year(I pulled it for a valve job and found a crack) and of course the redone head I bought had hardened exhaust seats. If my head hadn't been cracked, I would have redone it with stainless exhaust valves and hardened seats. I opted for a "small chamber" head, which bumped my c/r to 9.5:1(stock is 8.8:1) and as a result I always run top tier premium. I could run it on mid-grade, but running premium lets me up the total mechanical advance to 35º BTDC(the "standard" with a factory "high compression" engine run on regular is 32º total mechanical advance) which gives me a bit more power down low and also helps the gas mileage a bit.
I know that I'm probably also "double dipping" by using both Stabil and MMO since I know that Stabil is also MOSTLY kerosene. Still, I'm not giving up on using it since since I know it prevents fuel oxidation, and I rarely fill the car up more often than once a month(and I also never know if I might have a mechanical problem or a stretch of bad weather that stretches a tank to 2 or 3 months).
I've not noticed a gas mileage increase. This is about as low tech of an engine as you can get(short of being a flathead-it is at least OHV) and mine's pretty "tired" with about 100K on it and some known ring issues. I also use it for upper cylinder lubricating properties, and as an added benefit I've noticed that I seem to have fewer issues with stuck floats and/or needle valves(I use to have one stick open occasionally). I guess the latter does improve gas mileage since I don't have gasoline leaking out
FWIW, the upper cylinder lubricant thing probably isn't as big of a deal as I swapped the head last year(I pulled it for a valve job and found a crack) and of course the redone head I bought had hardened exhaust seats. If my head hadn't been cracked, I would have redone it with stainless exhaust valves and hardened seats. I opted for a "small chamber" head, which bumped my c/r to 9.5:1(stock is 8.8:1) and as a result I always run top tier premium. I could run it on mid-grade, but running premium lets me up the total mechanical advance to 35º BTDC(the "standard" with a factory "high compression" engine run on regular is 32º total mechanical advance) which gives me a bit more power down low and also helps the gas mileage a bit.
I know that I'm probably also "double dipping" by using both Stabil and MMO since I know that Stabil is also MOSTLY kerosene. Still, I'm not giving up on using it since since I know it prevents fuel oxidation, and I rarely fill the car up more often than once a month(and I also never know if I might have a mechanical problem or a stretch of bad weather that stretches a tank to 2 or 3 months).
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Geez, I been using MMO for about 50 years. Good for some stuff, not for others. Never had any luck as fuel additive ...
Barryman B-12, now that works well as a fuel additive. But it gets pricey if you are doing full can per fill-up ...
Barryman B-12, now that works well as a fuel additive. But it gets pricey if you are doing full can per fill-up ...
IF and only IF your vehicle was short tripped or neglected previously will you see an MPG increase of 17% +/-.
Amazing how so many people get stuck on the numbers and miss the whole point that MMO, as well as some other additives, do help OLDER OR NEGLECTED engines regain their original parameters, such as oil consumption, fuel consumption, and sometimes even performance.
Case on point.
I bought a super clean car, but mechanically it was abused and neglected. It was consuming 1qt of oil per 100 miles, and was getting 20mpg at best. After some MMO in oil and in fuel my numbers improved to 1qt per 5000 miles, and 27mpg average (32mpg hwy). Factory parameters for that vehicle are 22mpg city and 29mpg hwy, with oil consumption of 1qt per 1000 miles considered normal, per the manufacturer (Toyota 1ZZ-FE engine). As you can see I exceeded the normal numbers with the help of MMO.
Question: Will everyone see a 5mpg increase and 98% oil consumption improvement if they use MMO as directed?
Answer: No. Unless your engine has been previously neglected and is in need of some cleaning.
Amazing how so many people get stuck on the numbers and miss the whole point that MMO, as well as some other additives, do help OLDER OR NEGLECTED engines regain their original parameters, such as oil consumption, fuel consumption, and sometimes even performance.
Case on point.
I bought a super clean car, but mechanically it was abused and neglected. It was consuming 1qt of oil per 100 miles, and was getting 20mpg at best. After some MMO in oil and in fuel my numbers improved to 1qt per 5000 miles, and 27mpg average (32mpg hwy). Factory parameters for that vehicle are 22mpg city and 29mpg hwy, with oil consumption of 1qt per 1000 miles considered normal, per the manufacturer (Toyota 1ZZ-FE engine). As you can see I exceeded the normal numbers with the help of MMO.
Question: Will everyone see a 5mpg increase and 98% oil consumption improvement if they use MMO as directed?
Answer: No. Unless your engine has been previously neglected and is in need of some cleaning.
Originally Posted By: MolaKule
Our detailed analysis of a few years ago showed that MMO contains a small amount of a chlorobenzene-type cleaner and some phosphorus that could act as a possible deposit scavenger when mixed in fuel, but nothing stood out that there is anything in it that could improve mileage.
Question: What component in a fuel system requires lubrication?
What is the base liquid Mola. Kerosene? How about the viscosity? Thanks Mola
Our detailed analysis of a few years ago showed that MMO contains a small amount of a chlorobenzene-type cleaner and some phosphorus that could act as a possible deposit scavenger when mixed in fuel, but nothing stood out that there is anything in it that could improve mileage.
Question: What component in a fuel system requires lubrication?
What is the base liquid Mola. Kerosene? How about the viscosity? Thanks Mola
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Originally Posted By: Vladiator
IF and only IF your vehicle was short tripped or neglected previously will you see an MPG increase of 17% +/-.
Amazing how so many people get stuck on the numbers and miss the whole point that MMO, as well as some other additives, do help OLDER OR NEGLECTED engines regain their original parameters, such as oil consumption, fuel consumption, and sometimes even performance.
Case on point.
I bought a super clean car, but mechanically it was abused and neglected. It was consuming 1qt of oil per 100 miles, and was getting 20mpg at best. After some MMO in oil and in fuel my numbers improved to 1qt per 5000 miles, and 27mpg average (32mpg hwy). Factory parameters for that vehicle are 22mpg city and 29mpg hwy, with oil consumption of 1qt per 1000 miles considered normal, per the manufacturer (Toyota 1ZZ-FE engine). As you can see I exceeded the normal numbers with the help of MMO.
Question: Will everyone see a 5mpg increase and 98% oil consumption improvement if they use MMO as directed?
Answer: No. Unless your engine has been previously neglected and is in need of some cleaning.
Sounds about right. My explorer is/was my wife's. Lots of cold starts and hammering on it right away because with kids your always late. 260,000 miles is enough to cause some build up along with inadequate maintenance. Not worry I wasn't the one neglecting it. Runs like a top now and MMO will continue to run through it.
IF and only IF your vehicle was short tripped or neglected previously will you see an MPG increase of 17% +/-.
Amazing how so many people get stuck on the numbers and miss the whole point that MMO, as well as some other additives, do help OLDER OR NEGLECTED engines regain their original parameters, such as oil consumption, fuel consumption, and sometimes even performance.
Case on point.
I bought a super clean car, but mechanically it was abused and neglected. It was consuming 1qt of oil per 100 miles, and was getting 20mpg at best. After some MMO in oil and in fuel my numbers improved to 1qt per 5000 miles, and 27mpg average (32mpg hwy). Factory parameters for that vehicle are 22mpg city and 29mpg hwy, with oil consumption of 1qt per 1000 miles considered normal, per the manufacturer (Toyota 1ZZ-FE engine). As you can see I exceeded the normal numbers with the help of MMO.
Question: Will everyone see a 5mpg increase and 98% oil consumption improvement if they use MMO as directed?
Answer: No. Unless your engine has been previously neglected and is in need of some cleaning.
Sounds about right. My explorer is/was my wife's. Lots of cold starts and hammering on it right away because with kids your always late. 260,000 miles is enough to cause some build up along with inadequate maintenance. Not worry I wasn't the one neglecting it. Runs like a top now and MMO will continue to run through it.
Originally Posted By: Brigadier
Both the fuel pump and injectors are electro-mechanical devices and are in contact with the fuel. I am not privy to the intricacies of the designs, but it seems pumping a fuel containing anywhere from 10% to 85% of a solvent, might need some help in lubrication. After all, fuel used to have lead in it as a lubricant, remember?
And along these lines is the upper cylinder with the rings. Ethanol is a solvent and strips away the lubrication...
Like as already been mentioned in answers here, there is no lubrication required for injectors nor fuel pumps. And leaded fuel did not have the lead in it for lubrication it was there to increase the apparent octane rating. Even the fears of valve seat recession were never realized.
Ethanol does not strip away the lubrication any more than does plain gasoline. Oil is more soluble in gasoline than in EtOH.
The bottom line is that there is no lubrication required nor needed in an engine that is not already being provided, all the reasons you give are myths.
Both the fuel pump and injectors are electro-mechanical devices and are in contact with the fuel. I am not privy to the intricacies of the designs, but it seems pumping a fuel containing anywhere from 10% to 85% of a solvent, might need some help in lubrication. After all, fuel used to have lead in it as a lubricant, remember?
And along these lines is the upper cylinder with the rings. Ethanol is a solvent and strips away the lubrication...
Like as already been mentioned in answers here, there is no lubrication required for injectors nor fuel pumps. And leaded fuel did not have the lead in it for lubrication it was there to increase the apparent octane rating. Even the fears of valve seat recession were never realized.
Ethanol does not strip away the lubrication any more than does plain gasoline. Oil is more soluble in gasoline than in EtOH.
The bottom line is that there is no lubrication required nor needed in an engine that is not already being provided, all the reasons you give are myths.
Originally Posted By: kschachn
Like as already been mentioned in answers here, there is no lubrication required for injectors nor fuel pumps. And leaded fuel did not have the lead in it for lubrication it was there to increase the apparent octane rating.
Yes, TEL was initially added to increase the octane rating(not sure why you say "apparent") but its effect on valves is real and well documented.
Exhaust valves run very hot for a couple of reasons(funneling hot exhaust gasses and no benefit of fuel/cold air flowing over them to cool them) and opening and closing against a plain cast iron seat will "micro weld" every time the valve closes. When the valve opens, this has to be broken and material is slowly lost from the valve face. This is what causes valve recession. It usually will hold for a while, but once recession sets in badly, the valve seat goes pretty quickly-I've seen seats move a 2-3 thousanths every few hundred miles.
TEL breaks down and causes lead to "plate out" on the valve face and seat. Since it's "squishy" it helps the valve seal, cushions its closing, and is sacrificially pulled off in each micro-weld event.
BTW, I've heard old mechanics talk about how Amoco "White"(which was always unleaded) would leave behind a sparkling clean engine that needed valve jobs about twice as often if the car was exclusively run on it.
For 1975 and later M/Y cars(US, first year of catalytic converters), most makers using cast iron engines went to a short term fix of induction hardening the valve seat. This worked, but the hardening was thin enough that it would be gone as soon as someone lapped the valves. Of course, the permanent fix is to machine out the valve seat area and fit a seat made of Stellite or similar material. I know cast iron engines are a dying breed, but presumably all have this from the factory now(and aluminum engine heads have always been had separate valve seats).
Like as already been mentioned in answers here, there is no lubrication required for injectors nor fuel pumps. And leaded fuel did not have the lead in it for lubrication it was there to increase the apparent octane rating.
Yes, TEL was initially added to increase the octane rating(not sure why you say "apparent") but its effect on valves is real and well documented.
Exhaust valves run very hot for a couple of reasons(funneling hot exhaust gasses and no benefit of fuel/cold air flowing over them to cool them) and opening and closing against a plain cast iron seat will "micro weld" every time the valve closes. When the valve opens, this has to be broken and material is slowly lost from the valve face. This is what causes valve recession. It usually will hold for a while, but once recession sets in badly, the valve seat goes pretty quickly-I've seen seats move a 2-3 thousanths every few hundred miles.
TEL breaks down and causes lead to "plate out" on the valve face and seat. Since it's "squishy" it helps the valve seal, cushions its closing, and is sacrificially pulled off in each micro-weld event.
BTW, I've heard old mechanics talk about how Amoco "White"(which was always unleaded) would leave behind a sparkling clean engine that needed valve jobs about twice as often if the car was exclusively run on it.
For 1975 and later M/Y cars(US, first year of catalytic converters), most makers using cast iron engines went to a short term fix of induction hardening the valve seat. This worked, but the hardening was thin enough that it would be gone as soon as someone lapped the valves. Of course, the permanent fix is to machine out the valve seat area and fit a seat made of Stellite or similar material. I know cast iron engines are a dying breed, but presumably all have this from the factory now(and aluminum engine heads have always been had separate valve seats).
I say apparent as that was the way I was taught in college, and if you Google the term it is in use. Generally the base octane rating is how the fuel under test compares to straight iso-octane (and comparatively against heptane) with no additives, and then when antiknock additives are added it increases the "octane" rating, which isn't due to the base molecules but instead the additive. I've always seen that listed as the apparent octane rating in literature or descriptions. So although the end result is the same (a printed octane rating on the pump label) it distinguishes between the actual octane rating of the hydrocarbon base and the observed performance of the finished fuel in the test engine.
And yeah, there is no need for lead whatsoever in today's automobile engines and no need for additional lubrication. Even if you did have an old engine that had soft seats there's no indication MMO would provide the same benefit as lead to reduce the welding you mention. My point being that lead wasn't there just running around "lubricating" stuff in the engine. If anything it was largely a detriment and caused other issues which were eliminated with unleaded fuel.
Originally Posted By: bunnspecial
Yes, TEL was initially added to increase the octane rating(not sure why you say "apparent") but its effect on valves is real and well documented.
Exhaust valves run very hot for a couple of reasons(funneling hot exhaust gasses and no benefit of fuel/cold air flowing over them to cool them) and opening and closing against a plain cast iron seat will "micro weld" every time the valve closes. When the valve opens, this has to be broken and material is slowly lost from the valve face. This is what causes valve recession. It usually will hold for a while, but once recession sets in badly, the valve seat goes pretty quickly-I've seen seats move a 2-3 thousanths every few hundred miles.
TEL breaks down and causes lead to "plate out" on the valve face and seat. Since it's "squishy" it helps the valve seal, cushions its closing, and is sacrificially pulled off in each micro-weld event.
BTW, I've heard old mechanics talk about how Amoco "White"(which was always unleaded) would leave behind a sparkling clean engine that needed valve jobs about twice as often if the car was exclusively run on it.
For 1975 and later M/Y cars(US, first year of catalytic converters), most makers using cast iron engines went to a short term fix of induction hardening the valve seat. This worked, but the hardening was thin enough that it would be gone as soon as someone lapped the valves. Of course, the permanent fix is to machine out the valve seat area and fit a seat made of Stellite or similar material. I know cast iron engines are a dying breed, but presumably all have this from the factory now(and aluminum engine heads have always been had separate valve seats).
And yeah, there is no need for lead whatsoever in today's automobile engines and no need for additional lubrication. Even if you did have an old engine that had soft seats there's no indication MMO would provide the same benefit as lead to reduce the welding you mention. My point being that lead wasn't there just running around "lubricating" stuff in the engine. If anything it was largely a detriment and caused other issues which were eliminated with unleaded fuel.
Originally Posted By: bunnspecial
Yes, TEL was initially added to increase the octane rating(not sure why you say "apparent") but its effect on valves is real and well documented.
Exhaust valves run very hot for a couple of reasons(funneling hot exhaust gasses and no benefit of fuel/cold air flowing over them to cool them) and opening and closing against a plain cast iron seat will "micro weld" every time the valve closes. When the valve opens, this has to be broken and material is slowly lost from the valve face. This is what causes valve recession. It usually will hold for a while, but once recession sets in badly, the valve seat goes pretty quickly-I've seen seats move a 2-3 thousanths every few hundred miles.
TEL breaks down and causes lead to "plate out" on the valve face and seat. Since it's "squishy" it helps the valve seal, cushions its closing, and is sacrificially pulled off in each micro-weld event.
BTW, I've heard old mechanics talk about how Amoco "White"(which was always unleaded) would leave behind a sparkling clean engine that needed valve jobs about twice as often if the car was exclusively run on it.
For 1975 and later M/Y cars(US, first year of catalytic converters), most makers using cast iron engines went to a short term fix of induction hardening the valve seat. This worked, but the hardening was thin enough that it would be gone as soon as someone lapped the valves. Of course, the permanent fix is to machine out the valve seat area and fit a seat made of Stellite or similar material. I know cast iron engines are a dying breed, but presumably all have this from the factory now(and aluminum engine heads have always been had separate valve seats).
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