Lead lubricates the valve stems?

[54Illinois]

While watching the motor run thru the side of the block, I noticed there is no oil hitting the valve stems.  Lead from the gas lubricates them correct?

 

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CDEQFjAB&url=http%3A%2F%2Fwww.39olds.com%2Flubrication.htm&ei=HCphUqCjKKGwygGM9oHAAQ&usg=AFQjCNF66F1QkZejAYkQmDk4sglTmBpaHA&bvm=bv.54176721,d.aWc&cad=rja

[Merle Coggins]

There is no lead in gas anymore. The valve stems are lubricated by splash oil. You won't see anything splashing around at idle, but at higher RPM there will be enough to take care of it.

[greg g]

Well it actually not a splash system.  There are holes in the connecting rod bearing caps that are designed to direct a stream of oil toward the valve gallery during rotation.  as the hole aligns with valve area a small stream of oil is directed there much like a squirt gun firing as it passes by.

[wayfarer]

Waaay back in the old days...lead was used for two functions, raise octane and cushion the valve seats.

[desoto1939]

Yes the lead was used to cushion the vale sets, But Chrysler engineering was a step ahead of the other manufacturers from what I have read and have been told.  They used hardened value seats in their engines.  So this is why our engines do not have to worry about the use of unleaded fuel.

 

If you had the engine rebuilt then they should have used hardened valve seats.  If you do not have bill and a list of the items that were replaced it will be a hit or miss situation.

 

All older engines when being rebuilt should get the hardened valve seats.

 

So the lead in the old gas that was being sold was an extra benefit to our cars.

 

Am I correct in my assumption.  If I am not correct please let me know so I have the knowledge.

 

Thanks,

 

Rich Hartung

[greg g]

Some how this seems counter intuitive.  Only the exhaust valve seats in mopar 6 were made of hardened material.  If the job o the lead was to cushion the valve / seat interaction, wouldn't it seem to make sense that the seat be made of less hard stuff???  The hardening of the seat has more to to with heat than with a comfortable seating of the valve that could easily be addressed by the strength and or tensioning of the valve spring. Lets look at the valves in operation.  The intake valve gets a nice cooling flow of a relatively cool mix of air and fluid droplets,all over its large and exposed backside, as the incoming combustion charge rushes past.  This cooling effect even gets enhanced through wind chill factor, then it snuggles up against its non hardened seat which has also been treated to the cooling elixer,on its front as well as a nice flow of coolant on it underside. Then it gets closed by a spring of given strength.  Bump open, cooled, snapped shut, rest against a nicely cooled seat.  All is good. The exhaust valve gets its face cooled momentarily as the air fuel charge enters the cylinder, but then this turns into a steam bath as the volume gets compressed, and if that weren't bad it enough the stuff explodes, then as the valve opens, the hot nasty stuff rushes past the valve and it friend the seat. heating both front and back of the valve and top of the seat, then the valve snaps down on the seat combining both hot surfaces together.  Now while I am sure a little residue might have mad this a bit more tolerable, what ever amount there was of it was freakin' hot too.  So my considered opinion was that the hardening of the exhaust valve seats had more to do with protecting against heat erosion than it did with how comfortable the valve/ seat interface was.  And thanks to Walter P to thinking it was better to engineer a preventative feature, then to rely on the application of an outside factor by a third party.  How much money did Henry pocket through saving 8 bucks per engine from 32 through 53.

 

And to the question about lead lubricating the valve stems, wouldn't most of it not get into the valve guide any way??

Edited October 18, 2013 by greg g

[TodFitch]

Remember that the L-6 engine was designed in the early 1930s when use of lead in gas was quite low. Thus the hardened valve seats from the factory.

 

Lead content really climbed after WW2 which lead to a number of things like new engine designs with higher compression ratios, wide spread adoption of overhead valve designs which could achieve better flow at high compression ratios and and lack exhaust valve seat inserts.

 

It also lead to other things outside the automotive realm in areas of public health but I think that not in the scope of this forum.

[Don Coatney]

Every thousand miles Gulf crest does the trick.

Keeps your engine running slick as a whistle.

 

I am sure many here recall the transition from leaded fuel to unleaded. What I never understood was how the petro companies could remove lead and charge a higher price for unleaded. I would think that loss of an ingreadent would reduce the price. but that was not the case.

 

http://www.youtube.com/watch?v=KoGg6YP8Wl8

[54Illinois]

There is no lead in gas anymore. The valve stems are lubricated by splash oil. You won't see anything splashing around at idle, but at higher RPM there will be enough to take care of it.

So letting the engine idle, is bad for the valves and springs?

[TodFitch]

So letting the engine idle, is bad for the valves and springs?

Coil springs don't need lubrication.

 

I suspect there is enough of an oil film on the valve stems and the loads on them are low enough at idle that there is no issue.

[wayfarer]

Although coil springs don't require a lubricant, the oil does act as a coolant, and valve springs get very hot in operation.

[austinsailor]

 

I am sure many here recall the transition from leaded fuel to unleaded. What I never understood was how the petro companies could remove lead and charge a higher price for unleaded. I would think that loss of an ingreadent would reduce the price. but that was not the case.

 

 

An old timer I talked to when unleaded came out was even more perplexed - he said they upped the price back when they put lead in, now they are raising it again to take it out.