to lead or not to lead.....

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71MACH-1

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I am still wet behind the ears. I have a 65 cadillac convertible that takes leaded gas....

what does my 71 mach 1 with a 351C take?

LEADED OR UNLEADED GAS??

thanks

 

71MACH-1

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lead substitute.............................

 

Valhallo

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Is there any leaded gas any more:huh: I have a hard time just finding 100% gas here:mad:
I think there are 4-5 stations in the entire state of Utah that will pump non-ethanol fuel. :dodgy: Every time I fill up, I just get a little bit sad. I have to stroke the hood and say "I'm not doing right by you..." :(

 

71MACH-1

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no one has answered my question...do I NEED lead substitute or not.....

 

Widowmaker00

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I just run regular gas in my car, but it is a '72 with lower compression.

 

Widowmaker00

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I have a quick related question, sorry to jack your post.

What would make an engine require leaded fuel?

I had a '57 Chevy with a 265 V8 that ran fine on regular gas...

 

sm3570

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I may be way off base, but I thought that higher compression engines needed leaded fuel so they wouldn't get detonation or SOMETHING like that. I'm sure Chuck or Pappy or someone will set me straight, as usual.

 

thundertc64

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Tetraethyl lead (a colorless, oily, poisonous liquid), commonly called "lead," was used as a gasoline additive for automobiles made between the mid-1940s and the end of the 1970s. There were several reasons for adding lead to gasoline. First, lead improved the way that gasoline burned. Second, it reduced or eliminated the "knocking" sound caused by premature ignition in high-performance large engines and in smaller, high-compression engines. Lead also provided lubrication, which prevented the close-fitting parts of the engine from chafing against one another. or the valve seats taking a beating

 

Widowmaker00

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Tetraethyl lead (a colorless, oily, poisonous liquid), commonly called "lead," was used as a gasoline additive for automobiles made between the mid-1940s and the end of the 1970s. There were several reasons for adding lead to gasoline. First, lead improved the way that gasoline burned. Second, it reduced or eliminated the "knocking" sound caused by premature ignition in high-performance large engines and in smaller, high-compression engines. Lead also provided lubrication, which prevented the close-fitting parts of the engine from chafing against one another. or the valve seats taking a beating
Ah, I figured it was something along those lines. I would imagine engines with upgraded ignition systems, better cylinder head design, computers, etc. eliminated the need for lead, at least in high performance applications.

 

thundertc64

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I believe somewhere around 69-70 some automakers started to change over to hardened valve seats but from what i gathered not all engines got them , i add it to mine to be on the safe side until i decide to pull heads and have the hardened seats installed

 

Valhallo

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no one has answered my question...do I NEED lead substitute or not.....
I only put lead substitute in my fuel when I'm going to be pushing my engine. When I'm doing my daily driving I use unleaded. You can never be to safe I guess, but judging by the capitol NEED I'm getting the vibe you'd rather not.

 

hyena429

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I have a quick related question, sorry to jack your post.

What would make an engine require leaded fuel?

I had a '57 Chevy with a 265 V8 that ran fine on regular gas...
All of them will run great for a while..The problem is..Some of the older preformace cars have soft valve seats...So it would run on regular unleaded gas...But down the road it will eat the valve seat away..And you will loose compression and need to rebuild the head...Reason why alot of older high proformace heads get harden valve seats put in later on...Low compression motors back then got hard seats to burn crappy fuels....So unless it was performance...You wont have much issue...But cars like our years of mustangs..Mmmm yes...Alot of the 4v heads got soft seats and unless they been changed should watch out..And should have lead additive....I even seen a freinds truck..A 1974 ford truck with a 460 in it...He had the motor rebuilt and come to find out ..Even it had soft seats.

 
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Born an I-6, spent the teenage, 20 and 30 years as a 302, but at 40 will reach full potential as a 351C.
Regarding VALVE WEAR...

My understanding, at least regarding Fords, is they prepared for unleaded fuel in the 1960's.

As a very wide and general rule, 1970 engines(build date) and later are all able to run stock with unleaded fuel because the heads were built for them.

However, as most people who have rebuilt their engines know, the exhaust valve seat takes a tremendous beating. Everyone I know who has rebuilt an engine with 100+k miles on it and installed exhaust valve seats in their heads. This was even the case(at least in my experience) for people who rebuilt their engines prior to 1969.

Warning....facts & politics to follow....Alcohol in fuel is one of the biggest government scandals of all time. It doesn't make economic sense, it doesn't make environmental sense...it only makes political sense.

I will stop there.

 

hyena429

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Regarding VALVE WEAR...

As a very wide and general rule, 1970 engines(build date) and later are all able to run stock with unleaded fuel because the heads were built for them.
I hear a few rigs got soft valves to watch out for all the way up too 1976 in some models...I know for a fact some chevy motors 1974'ish 350's have soft seats..And i heard the same with ford...like my buddies 1975ish ford with a 460..When he rebuilt the motor...Its turned out too have soft ones in it...But im really not sure if that was original motor or not with that truck...lol...But i read its kinda hit or miss

 
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