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lead-alternative for protecting valve seats

KayS

Well Known Member
this weekend i stumbled over something at a swiss gas station and the current discussion about G100UL came to mind. here's the stuff...

https://motorex.com/en-us/valve-guard--40918

they sold the bottle for 10 bucks or so. switzerland is not known for being an el cheapo country.

i am no engine expert and have no clue if lubricating valve seats is really needed and if so for what kind of engines that would apply.

but in case you think it's a good idea to lubricate your valve seats and in the future absence of 100LL... does anyone has experiences with that kind of product as an alternative to leaded avgas?

Kay
 
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Hi Kay,

Before you part with your hard earned cash, it may pay to read some of John Deakin’s articles. Here’s one to get you started, but he’s got plenty on engine operation, leaning etc.

https://www.avweb.com/features/pelicans-perch-55lead-in-the-hogwash/

Tom
RV-7

Tom:

Thanks for sharing.

Those that are old enough to remember lead in our car gas can remember the same scare tactics when TEL was removed from car gas.

Nothing happened to old car engines when we went lead free fuel.
 
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Tom:

Thanks for sharing.

Those of use that are old enough to remember lead in our car gas can remember the same scare tactics when TEL was removed from car gas.

Nothing happened to old car engines when we went lead free fuel.

The auto companies moved to different alloys for valves and seats when lead went away. I speculate that many engines of that era lost compression and either died early than they should have or had the valves replaced. I was barely a teenager, so not yet working on engines.

My guess is that Lyc moved to the then standard alloys for valves and seats in the 80's as the older stuff was probably harder to get.

Larry
 
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At one time auto cylinder heads were cast iron, and the seats were simply machined into the cast iron. THOSE seats depended on lead to survive. Early MGB's are an example.

As the lead went out, hardened steel valve seat inserts went in. [Or were retrofitted, like on my MGB]

As Lycoming heads were never cast iron (but rather aluminum), they always had to have a valve seat insert.
 
To add on to Blaplante's comment of old valves/heads.
I had an older chev van in the late 80's that we ran on propane. (dumb idea)
We tore the engine down at about 150,000 for overhaul cause of oil burn/leak problems.
The valves were very, very worn and the seats were gone. We actually got a different set of heads and had them machined for steel hardened seat inserts.
Propane is hard on valves. That said, Was it the lack of lead? or just the propane? It was the first time I\'ve ever seen valves worn out like that. And I've overhauled a few thousand of the older motors. A lot of times at only 60-80,000 miles too. They didn't seem to last very long.
Don't know, But, as said we have insert seats in our aircraft engines, So the lead lubrication question seem to be a moot point.
My I0-360 runs on Costco premium year in and year out.
With the SDS EM-5F fuel injection and ignition systems.
My three cents worth Art
 
TEL in fuels

Before you part with your hard earned cash, it may pay to read some of John Deakin’s articles. Here’s one to get you started, but he’s got plenty on engine operation, leaning etc.

https://www.avweb.com/features/pelicans-perch-55lead-in-the-hogwash/

Good article, as all of his seem to be.

OK: first off, I really miss the smell of 80/87 octane fuel! For all you younger folks, it had this pretty dark purple color and a very unique odor! :eek: 100/130 and eventually 100LL just not the same. And unleaded auto fuel: no competition!

I really can't remember when I started using auto fuel in my Cub but it "might" have been before 1982 when the STC came out. I was one of the first in line to get that STC. Now she flies with the placard allowing for the use of auto fuel....with no alcohol!

I could look at my log books to find out how many hours I have on auto fuel but it is likely over 1500. I have had several stuck valves but Continentals (and to an extent Lycomings) are famous for that. I have replaced one cylinder with an eroded exhaust valve seat but that might have happened with leaded fuel. I do slip 100LL in the tanks occasionally when other fuels are not available (and auto is becoming less frequently carried at airports) and check plugs for fouling at about 25 hours after.

I still run 100LL in my 160hp O-320 RV-4 but am not sure auto would have the octane to prevent detonation. It will be interesting to see where this all ends up. SOMEthing has to happen.......will happen.......

The picture is my younger (and skinnier) self fueling the Cub c 1982 or so....
 

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The auto companies moved to different alloys for valves and seats when lead went away. I speculate that many engines of that era lost compression and either died early than they should have or had the valves replaced. I was barely a teenager, so not yet working on engines.

My guess is that Lyc moved to the then standard alloys for valves and seats in the 80's as the older stuff was probably harder to get.

Larry

All my old Volvo B-18 and B-20 engines continued to run 300,000 miles after the lead went away. Cast iron heads, three-angle valve seats cut into the iron. No issues. Cams still had to be replaced at 150k miles, but that was never a lead problem. What I saw was that everything inside the engine was cleaner, including the valve stems. I don't think there was any loss of service life or performance to old engines at all.
 
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OK: first off, I really miss the smell of 80/87 octane fuel! For all you younger folks, it had this pretty dark purple color and a very unique odor! :eek: 100/130 and eventually 100LL just not the same. And unleaded auto fuel: no competition!
....

I think maybe you sniffed a bit too much of that gas!
80/87 was dyed a faint red color, and was basically 100LL with 4 times less lead. It was available in the early 1980's at LVK and we ran our low compression 182 on it, no problems. But it smelled just like 100LL.
I wonder if you meant 82UL? It was a lead free product, dyed purple, available for a few years in the last century.
115/145 was also dyed purple, but not commonly available since WW II.
 
OK: first off, I really miss the smell of 80/87 octane fuel! For all you younger folks, it had this pretty dark purple color and a very unique odor! :eek: 100/130 and eventually 100LL just not the same.

I seem to recall 80/87 being red, 100/130 being green, and 115/145 being the purple gas. The latter did definitely have a unique smell but I think it was probably from brain cells dying.
 
Definitely the Propane

To add on to Blaplante's comment of old valves/heads.
I had an older chev van in the late 80's that we ran on propane. (dumb idea)
We tore the engine down at about 150,000 for overhaul cause of oil burn/leak problems.
The valves were very, very worn and the seats were gone. We actually got a different set of heads and had them machined for steel hardened seat inserts.
Propane is hard on valves. That said, Was it the lack of lead? or just the propane? It was the first time I\'ve ever seen valves worn out like that. And I've overhauled a few thousand of the older motors. A lot of times at only 60-80,000 miles too. They didn't seem to last very long.
Don't know, But, as said we have insert seats in our aircraft engines, So the lead lubrication question seem to be a moot point.
My I0-360 runs on Costco premium year in and year out.
With the SDS EM-5F fuel injection and ignition systems.
My three cents worth Art
Propane has a much higher flame temperature than gasoline and natural gas. It is the temperatures of the combustion that killed the valves. One project in my engine design assignment was development of a propane and natural gas conversion for CAT 3208. In lab testing/validation we could barely get natural gas to meet the durability but not even close with propane. Valve erosion. plug life, and piston temps were more significant challenges compared to NG. I recommended we drop the project, management agreed with review.
 
Propane power

Well there ya go.
I guess I won't be experimenting with Propane in my next plane project.
Ha Ha Ha!!!
I knew something was amiss with the totally trashed valves. I was/am and always will be a mechanic not an engineer.
The boys called me "FIXIT" for a reason I guess.
Art
 
Propane has a much higher flame temperature than gasoline and natural gas. It is the temperatures of the combustion that killed the valves. One project in my engine design assignment was development of a propane and natural gas conversion for CAT 3208. In lab testing/validation we could barely get natural gas to meet the durability but not even close with propane. Valve erosion. plug life, and piston temps were more significant challenges compared to NG. I recommended we drop the project, management agreed with review.

Propane has been a very successful motor fuel if the conversion was done correctly. Every propane dealer in the country powered their delivery trucks with propane.

I powered my 67 mustang (289) for over 250K miles on propane with no issues. The oil would be as clean when drained as it was when poured from the can. Plugs lasted forever.

Propane weighs 4.2 lbs per gallon so power was reduced by 10% and mileage, the same. But at 20 cents per gallon, I put up with it.

The engineers had no problem designing a butane / propane powered truck back in the 40's......

butane.JPG
Notice the Butane tank.

https://www.curbsideclassic.com/blo...tt-gas-engine-more-power-than-a-wimpy-diesel/
 
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does anyone has experiences with that kind of product as an alternative to leaded avgas?

Yes, I have only been using the stuff for about a year now…

Trying to run my O-360 purely on Mogas or car gas, I’ve had a case of stuck valve whilst others were pretty tight in their guides.
Reamed up to lowest tolerance and all ok, but now using this very additive hoping for prevention… my next SB388C might tell some truth. Or not.
 
Dan: you had the stuck valve using mogas? i was under the impression that stuck valves are more a problem caused by leaded avgas.

at least the manufacturer promises to "prevent" deposits and maybe that could help you in this regard.
 
Yes, I have only been using the stuff for about a year now…

Trying to run my O-360 purely on Mogas or car gas, I’ve had a case of stuck valve whilst others were pretty tight in their guides.
Reamed up to lowest tolerance and all ok, but now using this very additive hoping for prevention… my next SB388C might tell some truth. Or not.

Hi Dan, I just started collecting data on sticky valves.....if you would like to contribute info, please send it to valvedata@protonmail dotcom. (the dot is a .com)

Thanks,
Paul
 
Dan: you had the stuck valve using mogas? i was under the impression that stuck valves are more a problem caused by leaded avgas.

Yes, I've had. And I also had it on a C-90 engine using only MOGAS as well.

Back to this one... checking compressions this Spring, I found 1 cylinder showing 0, nix. One of the exhaust valve was found almost impossible to move, all ok once the guide was reamed. And this was at 330h into the 400h of the SB388C...

Paul, yes I've seen your thread. As someone else commented, I doubt it will be conclusive in any way. I've had stuck exhaust valves on different engines, C-90/O-320/O-360, flying AVGAS or MOGAS or mixed, at different typical power settings.
One factor which most of us, inclusive myself, miss, is the material those valve guides are made of, the answer might be there...
 
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Mickey is probably closer to the mark. Given Dan's experience, it's unlikely that lead is the cause. More likely oil is frying onto the stem or guide or both.
 
Read Mona’s STC instructions

My Mogas STC instructions for my old A65 powered Cub say to run one tank of leaded gas every 25 hours to add minimal lead to various parts of the engine. Any time running 100LL I add TCP.

Flying around the South East we don’t have much pump mogas at airports and no UL fuel yet.

Looking forward to 93UL or 100UL coming to airports across the country!
 
and CHTs could be factors

Yes, could be... the stuck valve cases I had were on different engines which I ran completely differently.

And if we take Marvel Oil, and other additives into account, and oil grade and the position of the stars, could be too...
I'm now heading towards the kitchen, luckily the machine's always plugged in :D
 
Why not use 2 cycle synthetic oil instead of Marvel Oil? It is made to be mixed with gas, lubricate everything in the engine and will not foul plugs. My airport golf cart runs well at 220 to 1...
 
Amazingly on this month's "ask the A&Ps" podcast Mike Busch did recommend MMO for noisy lifters - perhaps it will help for stuck valves?
 
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In researching for another topic, I stumbled on to this document on the Conti website: http://continental.aero/xpublications/xservice bulletins/eci archives/si88-7-1/

Page 5 has some information on Mogas and valve seats. I'd question a couple of the statements made here but it still makes for interesting reading.

One does wonder if Lycoming and ECi seats are very different material though as the doom predicted here on a diet of Mogas doesn't seem to be taking out Lycoming seats. I think Pete Howell has over 2600 hours on his now...
 
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2 Cycle Oil Flashpoints

Why not use 2 cycle synthetic oil instead of Marvel Oil? It is made to be mixed with gas, lubricate everything in the engine and will not foul plugs. My airport golf cart runs well at 220 to 1...

Typical 2 stroke engines do not have valves. The oil added to the fuel is for bottom end lubrication.
2 stroke oil flashpoints vary from less than 200F to over 500F. Most are below traditional aircraft engine CHT normal operating range.
I’ve seen many 2 stroke oils leave very gummy and sticky deposits on exhaust port variable timing mechanisms in modern 2 stroke motorcycle engines.
Perhaps adding 2 stroke oil as a top end lubricant in an aircraft engine will greatly increase the possibility of sticking valves.
 
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