to lead or not to lead.....

[71MACH-1]

google search made it more confusing.......

 

[PAPPY HAROLD]

GEE!!!! how did I get in this? After reading this I can only say my 460 heads from 71 had to have the seats changed it was previously softer seats.

 

[71MACH-1]

If I use lead substitute and don't " need" it....

Will it cause damage???

 

[Tnfastbk]

google search made it more confusing.......

LOL yeah I know

 

[Don C]

Tetraethyl lead was used to improve (boost) octane. After it was eliminated other compounds took it's place, some like MTBE was possibly worse than tetraethyl lead. A side benefit of lead was that it also lubricated valve stems and valve seats. If you don't have heads that were designed for non-lead you may at some point have to have hardened valve seats and valve guides installed. You'll know when you get valve recession (the seats worn down) until they no longer can seat properly.

If your car came with a catalytic converter it was designed for un-leaded gas, if it didn't have the converter, chances are you will have to have hardened seats installed, or use a lead substitute. I had them put in my '71 351-4V a few years ago. Mine were OK at the time, but I had serious valve recession on an early 70's 390 before that.

 

[goodnigh]

My quench head Cleveland 4V uses whatever they pump in California which contains alcohol and who knows what else at 91 octane.

It runs pretty good and has a newly rebuilt engine. Would love to try some of the 100 octane stuff they sell here and see what the

car was supposed to run like back in the day. The problem is it would cost $150 to fill my tank.

mike

 

[Tnfastbk]

My quench head Cleveland 4V uses whatever they pump in California which contains alcohol and who knows what else at 91 octane.

It runs pretty good and has a newly rebuilt engine. Would love to try some of the 100 octane stuff they sell here and see what the

car was supposed to run like back in the day. The problem is it would cost $150 to fill my tank.

mike

Its only money I paid 8 bucks a gallon for the 110 octane I bought.

 

[goodnigh]

My quench head Cleveland 4V uses whatever they pump in California which contains alcohol and who knows what else at 91 octane.

It runs pretty good and has a newly rebuilt engine. Would love to try some of the 100 octane stuff they sell here and see what the

car was supposed to run like back in the day. The problem is it would cost $150 to fill my tank.

mike

Its only money I paid 8 bucks a gallon for the 110 octane I bought.

So how did the car run?

Your Right, probably spent that much on beer and steaks watching

basketball this weekend.

mike

 

[marks73]

Rule of thumb has always been. If you are going to run strickly unleaded you will need to install bronz guides in the heads due to the unleaded eating the guides. Also, as I understand it ethynol is not in mid or high grade unless stated at the pumps. If your heads have not been rebuilt, use a lead additive. Better safe than sorry.

 

[72fastback]

I run a mixture of 94 octane and airplane fuel mix on mine once in a while and it does like the extra octane. MY wallet "not so much:-/" Also my 4v heads have been completely rebuilt with new seats and guides. So unleaded fuel is fine for it. But the higher octane helps to keep everything clean and eliminate pinging. I have a pretty rough cam so every little bit helps.

 

[Tnfastbk]

Its only money I paid 8 bucks a gallon for the 110 octane I bought.

So how did the car run?

Your Right, probably spent that much on beer and steaks watching

basketball this weekend.

mike

LOL like a Cleveland should

 

[droptop73]

I thought this was settled back in the early 80s.

The "problem" with unleaded fuels and non hardened valve seats is possible wear into the seats by the valve, called seat recession. There is a possibility of valve seat recession in a daily driven engine after 40 - 50k miles according to SAE studies done in the 70s. On production engines designed to go 100k+ that made hardened (actually a misnomer they are not hard just harder than cast iron) seats a necessity. On a collector car that will see maybe 5 - 10k miles a year at the most it goes to your comfort level.

So, to cut to the chase, you don't NEED lead substitute. No you don't NEED hardened seats. Most of us will never drive our cars far enough to see any valve seat damage from using unleaded fuel.

That being said I did put hardened seats in my heads 2 years ago because I had access to the tools and the seats at very little cost. I installed them myself. I certainly would not have paid machine shop rates to have this done. These are the first heads I have EVER put hard seats in. In over 35 years of building and driving classic performance cars I have never had a valve or seat issue from not running leaded gas.

 

[Wolverine]

That being said I did put hardened seats in my heads because I had access to the tools and the seats at very little cost. I installed them myself. I certainly would not have paid machine shop rates to have this done.

When I had my last motor rebuilt, I thought I was going to be charged $200 to redo the valve seats, or $150 to have hardened seats installed....your mileage may vary.

 

[goodnigh]

LOL like a Cleveland should

That must have been awesome

mike

 

[Tnfastbk]

LOL like a Cleveland should

That must have been awesome

mike

Will definitely put a smile on your face

 

[droptop73]

That being said I did put hardened seats in my heads because I had access to the tools and the seats at very little cost. I installed them myself. I certainly would not have paid machine shop rates to have this done.

When I had my last motor rebuilt, I thought I was going to be charged $200 to redo the valve seats, or $150 to have hardened seats installed....your mileage may vary.

Like I said I would never pay that much to repair a non issue.

 

[71MACH-1]

I thought this was settled back in the early 80s.

The "problem" with unleaded fuels and non hardened valve seats is possible wear into the seats by the valve, called seat recession.

Back in the "early eighties" i was 5

 

[Steven Harris]

The "problem", called seat recession.

Yeah - modern fuel definetly causes "seat recession". :s

 

[Wolverine]

The "problem", called seat recession.

Yeah - modern fuel definetly causes "seat recession". :s

Funny, my wife blames my seat recession on old age.

 

[scvol]

I run high test unleaded most of the time. We have a gas station that sells the leaded fuel and I can tell you mine runs a lot better on the leaded. Starts up better and idles like a dream with the leaded fuel not to mention love the way it smells.