Mike Terry

I know for years we all had to put a Lead additive in our car so we would not have valve problems. That or we has the valves hardened in our cars because there was not enough lead in the gas for our motors. Now in 2017 have they made enough improvements that we do not have to put lead in the gas we buy now??

phil2302

From what I have come to understand it really doesnt matter hardened valve seats or not. I drive my 66 a decent ammount and I have been using lead free ever since they banned TEL in fuel and havent had any issues.

SDVette

You are venturing into one of the "twilight zone" topics here...

Some claim valve seat recession was an over-blown and rare condition.. occurring on heavy load applications only.. in racing and truck motors.

Some still do add lead even for street driving, just as a precaution.

Let the follies begin.......

warrenmj

I've had my '66 L79 for 16 years and it doesn't have hardened valve seats. I drive it about 2000 miles a year and don't add any lead additives and have never had any problems. The car has 100k miles on it now.

wmf62

lead is not required, period (with a few possible exceptions..., and we don't fall in them...)

Bill

capevettes

Over 300,000 miles on my 65 L79. No hardened valve seats. No issues. The new gasoline has plenty of octane. One thing I noticed, when they transitioned to unleaded, my plugs burned much cleaner.

Mr D.

Lead in my gas tank, don't use it or need it.

GTOguy

Haven't put in lead additive since lead was removed almost 40 years ago. The only lead I use is TEL for my '65 GTO, to boost the octane. Keep in mind that lead was introduced to gasoline in the '20's to increase octane. Valve seat protection was simply a bonus. Have not had any issues with newer gas other than low octane and poor economy due to the addition of alcohol in my state. As well as increased boil-off at higher temps. It definitely is inferior to the old gasoline, but we're stuck with it if we want to buy it at the pump and not out of a 5 gallon tin at the speed shop.

Critter1

I agree with the other replies. Hardened seats are definitely not necessary for cars like ours that see somewhat limited mileage. It's a waste of money and the procedure has trashed a lot of good heads over the years.

The "hard seats" thing is just a money maker for engine rebuilders that tell you that you must do this or no warranty on the rebuild. Just like block decking and line boring. Don't buy into the BS.

Instead, spend the money on deck plate cylinder honing with an automatic feed precision hone.

Mikado463

if one is that worried you can always add a splash Av gas from your local airport. Back in my snowmobile racing days that's what we ran

Robert61

I think most can agree that the manufacturers add nothing if it's not necessary. They have used hardened seats in everything since 73. It's definitely no BS. While you very well may gotten away with it or get away with it the facts are that unleaded fuel causes micro welding of the valve face to the seat. The lead was used to lubricate the valve to keep this from occurring. cars that are only driven a few miles at a time probably can get by without the seats but anything used for pulling loads or driven a lot wood need the seats. Ask any machinist they've seen the results and know what and why. They don't just suggest it to make money. I oversaw a pretty good size shop in the 70s and 80s and had my own shop til the early 90s. I did a set of 993 casting 350 heads for a guy once he said I don't need them. It didn't last any time before the seats eroded into the heads. I do think heads that have been run a long time will live better than a set with a fresh valve job.

SDVette

I agree with Robert. Manufacturers needing to warranty engines for 36k-60K miles are not saving the costs of hardened seats.. and you know they have crunched the numbers.

For most of us cruising around 1k-2k miles a year, it probably doesn't matter. We'll be dead before any significant recession occurs.

Yes, there are those who've been running unleaded with no issues for 10's of thousands of miles. But it's statistics... My aunt Millie smoked 3 packs and drank a 1/5 of Vodka every day, and lived to be 95.... but I don't recommend it.

On my 1970 LT-1, I add a splash of this both for valve lubrication, and raise octane as the 11:1 CR does not like the 91 California premium.




I'm not a metallurgist.. maybe one will chime in.. But I believe metal gets hardened in operation..??? Perhaps as long as that process happens with lead present, you can then safely switch to no-lead on these old heads? That would explain both the long-term success of some people, and the short term failures of others - specifically after doing a fresh valve job....????

Food for thought.

wmf62

here we go again...

Bill

Frankie the Fink

I put hardened valve seats, screw in rocker arm studs and guide plates in the '66 Mustang Fastback I raced and autocrossed for years and no issues. I sold that car in 1998; have run all my classics since without hardened valve seats, no issues so far. That's Mustangs, Chevelles, Corvettes, Camaros, etc. My biggest bugaboo with modern gas is the boiling point. Its the bane of the old carburetors and mechanical fuel injection. In the hot south, in summer, every classic car is 'on the edge' with modern gas and some run fine with no issues, others have perc/vapor lock problems.

The horror stories I read about exhaust valve seat recession are from companies selling additives.

My dual quad '61 ran fine on pump 87 octane; my '63 will give it up when cruising on a hot day and I coast to the side of the road feathering the gas pedal to keep the motor alive. I run 93 octane and have also used ethanol-free 91 octane.

I've tried everything including spacers, insulating the fuel line, carb tweaks. What gets me is that its the lil ole factory 250hp with a single WCFB carb on it. Running with the hood popped open seems to help a bit but I hate doing it.

I have a freshly built, numbers matching carb put together with the best, most pristine parts from 4 other carbs and I'll swap it on when the weather gets warm and we'll see what happens.

The fight continues this summer...

wmf62

it's a bit 'unsightly', but it seems to help... (helps keep the heat out of the cabin too,,,)

Bill

rfn026

Here we go again.



Richard Newton
Gasoline 101

wmf62

some fires you can NEVER put out....



Bill

Frankie the Fink

I've found running synthetic oil, with a Petronix, a spin on oil adapter, DOT 5 brake fluid and radial tires completely solves the problems with modern gas.

I can't explain it...I just know it works...

Jackfit

Same car 66, same mileage , same results...

Had to change plugs 3 or 4 times a year 45 years ago....

Now...really never , but I do every 10,0000 miles just because..

Jack

GTOguy

Frank, in all seriousness, a vapor return system for your fuel might do the trick. My '67 GTO came with one from the factory, and it sure keeps the fuel cool. There is a large fuel filter that has a main outlet to the carb, and a 1/4" outlet that goes back to the fuel tank, so the fuel is always circulating. This is a small steel line in tandem with the main fuel line, mounted alongside/inside the frame. Probably a PITA to try to install, but they work pretty well. The issue is that the volatile alcohol laced fuel is formulated for pressurized fuel injection systems, not our ancient carburetors.