73Cleveland

Does anyone know of a site showing when the various engines started using hardened valve seats in the heads? I have done a lot of searching and can't come up with a definitive answer.

It looks like some sites I have seen in the past have varying views on what years the change happened.

I have a 73 Clev and am now thinking it may not have the hardened valve seats either.

Scott H.

That is a great question!

I thought it was '76 but I am finding information that conflicts with this.
For instance some Porsche engines did not have hardened seats until '84, other articles state '75.

Here is a quick read that touches on hardened seats.

http://www.vclassics.com/archive/octane.htm

If you do a search on google for "Hardened Seats" or "Stellite valve seats" you may find better info.

The one thing I do know from experience is if you don't cut the seats or lap the valves, you are good to go. If you have to cut the seats you will cut through the "work Hardening" that happened when they ran on leaded gas. There is not enough "cushioning" without the tetra-ethyl lead to keep the valves from pounding through the soft metal of the freshly cut seats. And this is what valve recession is all about.

I wonder if the MCA would know?

Look forward to a good answer on this!

Soaring

After reading several long articles on this, it appears that it is agreed by several authors on this subject, that 1971 was the first year that all cars were required to burn un-leaded gas. I would assume then, that the 1971 on engines all had hardened seats.

73Cleveland

Scott, thanks for the post!

It looks like different manufacturers started using hardened valve seats at different times. One site I found, (my link is on my notebook), said that the 351m/400 had hardened seats when introduced. I think those came into use in 74.

It's funny you mentioned Porsche as not having them until 84 and some list them in 75. I just saw samething about that over the last couple of days with Jaguars. I think this is at least in part determined by which country the cars are sold in. I'm looking up some things for a friend for his 98 Jaguar XK8 and found that the British didn't start requiring unleaded until many years after the USA.

I had the valves ground in my 73 Clev back in I think 98. Looks like my lead "cushin" is long gone! I've only put less than 4k on it since I got her back.

Are there any additives anyone could suggest that would help build this missing "cushion" back up?

saiuto

I don't know if it would help build the cushion back up, but you can buy lead substitute additives at just about any parts store (or gas station for that matter). At the least it would prevent any further wear. Only problem with that is you have to add some in every time you fill the tank.

Scott H.

Yeah, you are right, Information is all over the board on this stuff.

You can buy tetra-ethyl lead as an additive, or just buy leaded racing gas and do some mixing. But to be honest, unless you race your car a lot, or pull heavy loads for long stretches, I wouldn't get too excited.

Valve recession in a stock engine is a real long process. There are engines out there with 100,000 miles plus with soft seats that have been re-cut.

Worse case scenario is, you get valve recession to the point you bottom a lifter and start loosing compression.
You pull the heads, and put a set of 225 AFR's on. Or have your heads flowed (which would include new valve seats anyways).

Hey wait... I think I see where this is going?

"...HONEY!!!!!!! I've got "Valve Recession!!!!!" Quick, I've got to order new heads! Uh, Oh, might have to buy a new cam and lifters too. Awe man, That means a manifold and headers!!!! Really didn't want to have to do this sweetheart, but I guess that new sauna in the bathroom will have to wait."

Good luck man...let me know if it works

73Cleveland

Man, I'm splitting a gut here!!! Sounds like you have maybe thru a similar scenario before? LMAO!!! Something like this takes some time to work up to. I usually try to pay cash for things on the car anyway. Less explaining to do that way.

When I did my car I was pretty **** about being orig with everything. My only change was converting the 2v to a 4v. I changed, the heads, cam, intake & exaust manifolds, and a Pony Carb 4300 unit to the orig Ford components. If I had it to do over, (betcha never had that thought before), I would have went with a cam that would have kicked up the power a bit more. It runs great now but I keep thinking what if... Then I get yelled at for looking at more Mustang cataloges. It's got the stock 2.75 gears in it so I don't have a lot off the line for a Mustang but it really moves down the E-way.

I doubt if I'll put 700 miles a year on the car. I'm going to more cruise-ins & went to MIS on Aug 6. That's the longest road trip I've been on (an hr drive each way) on with the car since I got it back from the resto. So if I can get many thousands of miles I should be good to go. (except with the discussion with the wife about needing mods!)

As I get time I'm going to try to get more info about what had hardened seats & when they first apeared. I'll post back with that when I have more info!

6mustang6

HAHAHAHAHAHAHAHAHAHA You devil you.

Soaring

You guys are mixing apples and oranges regarding European built cars and U.S. built cars. Remember, the Europeans didn't have the EPA breathing down their neck as did the Yankees, and that happend in the late 60's. Here is a blurb from one of the articles I was talking about.
Tetra-ethyl Lead
Early engines had a lot of problems with loss of compression due to rapid valve wear. the valve surface just didn't last very long. In 1935, the Ethyl corporation started marketing a fuel additive to gasoline refiners which made the valve surfaces last much longer. It was known as "tetra-ethyl lead", or just plain "lead". It also increased the octane rating of the fuel. What it did was coat the surface of the exhaust valve with lead. This acted as a high temperature lubricant, slowing down the transfer of molecular sized particles from the face to the seat. The way it worked, was it coated everything that got really hot, with lead. It also coated the piston, combustion chamber, spark plug, and exhaust system, with lead. This lead powder was an abrasive, so it caused the rings to wear prematurely. It was also caustic, so it caused the spark plugs, and exhaust systems to wear out prematurely. Lead powder also got in the oil, contaminating it prematurely, requiring more frequent oil changes. In short, the lead helped the valves last longer, at the expense of the rest of the engine. It also meant gasoline refiners didn't have to refine their product as precisely, they just had to add lead to it.
It became apparent, by scientific research during the 1960's, that lead was also an environmental hazard. It got into the atmosphere from car exhaust, was absorbed by the clouds, and therefore the rain had lead content. The lead contaminated rain fell on the grass which absorbed it. The cows ate the grass, and we drank the milk the cows produced. Tests on humans revealed an alarming level of lead poisoning, and it was causing learning disabilities, and birth defects. Something had to be done! Every lifeform on earth was being contaminated by car exhaust. The newly formed Environmental Protection Agency (EPA) in the United States, started putting pressure on the car manufacturers to build engines that didn't require leaded fuel, and in 1971 cars built in North America, no longer needed lead in their gasoline.
As of 1975, most north American cars came equipped with catalytic converters in their exhaust systems. Catalytic converters convert carbon monoxide and unburned hydrocarbons, two pollutants in the exhaust stream, to carbon dioxide, and water. They do this by passing the exhaust gas through pellets, or a ceramic honeycomb, of platinum and palladium which is glowing red hot. Because lead coats everything that gets hot, it coats the catalyst too. The converter is useless after one tankful of leaded gas. If the car is equipped with an oxygen sensor, it too becomes useless after one use of leaded gas.

69FECoupe

Just a point of information. I've only owned two brand new cars in my lifetime. The first was a 73 Gran Torino Sport with a 400. It ran on regular leaded gas. The next was a 74 Mercury Capri (German) with a 2.0 OHC. It also ran on regular leaded gas. My sister also bought a new Mustang in 73 (351C 2bbl.) and it also ran on regular leaded. American cars were not required to use unleaded until the advent of the catalytic converter in 1975. My dad bought a new Cougar in 75 and it indeed was an "unleaded fuel only" car as it had dual cats. Leaded gas was still available but the nozzle would not fit into the fuel filler on a cat equipped car. As for hardened seats, GM started advertising that their vehicles could run on unleaded gas, if you so desired, in 1974. I'd guess that Ford, Chrysler and AMC (remember them?) followed suit. IMO, I would not assume any head was equipped with hardened seats unless it was a 74 or newer.

Here is something interesting to keep in mind. Amoco premium has always been lead free. We used to call it "white gas". I was wrenching for a living in the late sixties/early seventies and never once heard of someone burning a valve from using Amoco.