Unleaded versus leaded gas

[JCF350]

Re: Unleaded versus leaded gas

Lincoln Mercury??

"http://cgi.ebay.co.uk/JADA-TOYS-1-24-OLDSKOOL-1951-LINCOLN-MERCURY
-SILVE-GREY_W0QQitemZ180193812277QQihZ008QQcategoryZ47194QQcmd
ZViewItem"

 

[Texasmark]

Re: Unleaded versus leaded gas

Man (Folks) this is just moving right along.

Back in those days, I drove to school in a '51 merc with the V8 flathead and overdrive and "Davis" brand, white wall tires (hot dogs for that day), from where else, Western Auto. Will never forget it. You could get to speed, let off the accelerator, wait for the thump, and cruise, almost soundlessly in overdrive. All you could hear was the purr of the Davis' rollin on the road and the Merc was a road cruiser; nice and soft riding in the big plush seats. Loved it.

Mark

 

[jay_merrill]

Re: Unleaded versus leaded gas

Strictly speaking, I think it was a Mercury. He and all of his buddies used to call them "Lincoln Mercurys" so I guess I got used to that name over the years.

Anyway, here it is, minus the custom work:

"http://www.torinocobra.com/images/1951Mercury2DR.jpg"

 

[JCF350]

Re: Unleaded versus leaded gas

I personally do not believe the whole "unleaded valve recession" theory and I have never seen it proven in even the slightest fashion. I used to work in a cylinder head specialty shop where we did rebuilds as well as custom work for high-performance applictions ranging from circle track dirt cars to big block drag boat--I even worked on the Accel Performance drag boat. I never saw one case of valse or seat recession attributed to lack of lead in the fuel. However, we sold a lot of hardened seat jobs and laughed all the way to the bank. There was nothing wrong with doing an upgrade--and it IS a good upgrade--just it wasn't as necessary as people believed.
--
Stan

Usually the exhaust valve burnt from not closing before seat recession took place. The damage unleaded fuel caused in engines is well documented in tests done by manufacturers and other engineering organizations.

 

[MikDee]

Re: Unleaded versus leaded gas

My uncle had a dark blue 51' Merc back in the day, I always liked the styling. I think the issue with high octane gas, and aviation gas is, because it was so slow, and longer burning, combustion byproducts going out the exhaust valve were extra hot, taking it's toll on the exhaust valve, & seat.

 

[SuperNova]

Re: Unleaded versus leaded gas

N/M

 

[SuperNova]

Re: Unleaded versus leaded gas

Usually the exhaust valve burnt from not closing before seat recession took place. The damage unleaded fuel caused in engines is well documented in tests done by manufacturers and other engineering organizations.

Such as?

 

[JCF350]

Re: Unleaded versus leaded gas

Get your books here
"http://www.wiley.com/WileyCDA/WileyTitle/productCd-186058358X.html"

"http://ci.nii.ac.jp/naid/110002356391/en/"

"http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=5212414"


A very good non-engineering oriented description of what happens.

"http://www.rroc.org.au/library/unleaded/chapman.html"



Also note that 1960's model engines and earlier had almost no problems with unleaded fuel until they had a valve job done and hardened seats were not installed (the residue left from the miles of driving with leaded fuel left enough on the valve and seat to prevent damage). Cutting the valve and seat removes this coating, hence the need to install hardened seats (and some cases harder exhaust valves).

 

[tx1961whaler]

Re: Unleaded versus leaded gas

You posted this 3 times in 2 different forums. EXTREMELY bad form.

Q - What grade of fuel should I use in my motor?
A - Current recommendations are to use a minimum of 87 octane, 89 octane is preferred. There is no additional benefit from using higher-octane fuels, in fact they may cause hard starting conditions in hot weather. If you have an older motor and the owner's manual requires premium fuel, here's why:
When these were built, the best oil available was TCW-2 rated, and did not contain the additive package (detergents, carbon preservatives, etc.) which our current oils (XD-30, XD-50 and XD-100) contain today. In that era, premium fuel contained the additive package that helped prevent the formation of internal engine deposits. That's why premium fuels were preferred at the time. Ultimately, in the late 90's the federal government mandated fuel refiners to use the same additive package in all grades of fuel and the premium fuel requirement was dropped.

evinrude.com