lead-alternative for protecting valve seats

[scsmith]

Originally Posted by lr172

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.

[BobTurner]

Originally Posted by Roadjunkie1

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! 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.

[flyride]

Originally Posted by Roadjunkie1

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! 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.

[flyride]

Originally Posted by BobTurner

115/145 was also dyed purple, but not commonly available since WW II.

I remember it being available at the pump in the late '80s at some west coast airports that hosted firebombing companies.

[BillL]

Originally Posted by abwaldal@gmail.com

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.

[abwaldal@gmail.com]

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

[gasman]

Originally Posted by BillL

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......


Notice the Butane tank.

https://www.curbsideclassic.com/blog...-wimpy-diesel/

[Dan 57]

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.

[KayS]

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.

[Triumph1974]

Originally Posted by Dan 57

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