The Stovebolt Site Forums The Shop Area General Truck Talk unleaded gas

I was talking to a couple of guys yesterday about leaded gas vs. unleaded gas. They stated that I should be adding a lead additive to unleaded gas. They said that the leaded gas acted as a lubricant to protect the valves. They said if I continue to run unleaded gas it would burn up the valves on my 42 with the original 216 motor. any thoughts?

I have heard the same thing. I have also heard form the guys on this site that after many thousands of miles the lead is impregnated in the valve seats and will lubricate for years to come even with out lead in the fuel.

If you are using this as a daily driver I would consider a lead additive. If occasional use is your thing you might not need it..But I am sure others with more knowledge will pipe in soon.

Rich

btw..that is one snappy lookin rig you got there.
Rich

Do a search. This has been discussed a lot. BTW you'll be OK on unleaded unless you work your engine hard for extended periods.

It would be a lead substitute because I don't think they can sell the old tetraethyl lead of "Ethyl" high-test gasoline.

Some have advised to just use the no-lead. If the valves burn, replace them with hardened valves and/or seats. My engine man said that only one of them - the valve or the seat - needs to be hardened.

I was offered the same advice...To burn no-lead
I was told that hardened seats is what it will take...So I will use a lead substitute for now.
Bill B.

my 57 235 had 50,000 on it when I got it, never been opened up, I've put BOUT 35,000 more on with unleaded .... loaded, stop n go, flat out highway, whatever - still runnin like a swiss watch

Bill

the gas we get today is some strange stuff ive seen some very strange things happen to valves a flat valve become cupped a valve burn small and go inside the head i have a 67 283 and use instead of lead my valves are fine all older machines i run lead sub in and i should have run it in some of the newer motors i would have saved some valves the gas is hard on new and old motors they need all the help they can get iv been using gas stablizer it realy works in motors that set around

I would not be so concerned about the lack of lead in the gas, as I I'm about the lack of ZDDP in the oil. I've lost 3 350 chevy motors in last 3 years due to lubracating problems on the flat
tappit motors. Trying to settle now with Pennzoil.

Is my memory this bad? I was a kid in the 70s, but I thought gas was more orange than it is today. Nowadays when I pour gasoline into my lawnmower, it looks dang near colorless. I know blends have changed a lot over the last 30 years, but did the color change too, or just my memory?

Bill

It changed,no color added unless Sunoco still tints theirs Blue yet??

Like mentioned before...If you work your engine hard, you probably want to run a lead substitute.

IMO Here is what I would/wouldn't do.

I would run unleaded without additives. This works for me because I use a newer vehicle for working, and I use my Stovebolts for pleasure.

I wouldn't run out and do a hardened seat valve job just because I wanted to work the old Stovebolt. I would run it until I needed a valve job, and THEN consider the hardened seat valve job.

With regular driving (not hard work), I would expect a 10-25% decrease in the life of the original seats using unleaded gas. That's 10K-25K miles in 100K miles.

Considering the costs of a hardened seat valve job, I wouldn't bother with hardened seat replacement (unless I'm already having a valve job). I would use a lead substitute until a valve job was needed "IF" I were overly concerned about my valve/valve seat life, and I didn't mind the hassle of adding to the gas, or the price of the lead substitute.

Bottom line? Run lead substitute......

1. if it makes you feel better.
2. if you plan on "working" the truck.
3. if the cost of hardened seats and a valve job isn't in the cards for you right now.
4. if you question whether or not you need a lead substitute.

Otherwise, if you can live with shorter valve life, and replace the seats when a valve job is needed, run unleaded.

Just do what makes you feel more comfortable.

All of this is very true. It is necessary to have hardened valve seats if you want to run unleaded fuel. Otherwise it will burn the valves. A lead substitute can be purchased at any auto parts store or even a wal-mart for that matter. I am not sure on the statement made by rustbucket53, on whether you need to use it for occasional use. The way I look at it, lead substitute is relatively cheap, only needs a cap full to a tank of fuel and is probably worth the investment if it means I might lose an engine. I run it with every fill up in the Chevelle, and will with every fill up in my 50 when it is finished as well.

Most auto parts stores sell a lead additive,not very expensive.

I pulled the head on my Bobcat loader last year after 25 years of hard running. I can't remember exactly how many years we haven't been able to buy leaded gas, but it has to be around 15. I expected to see the valves pounded half way through the cylinder head, and instead I found a small piece of carbon had lodged between the seat and the valve and the head and valve were in perfect condition.
I have always used a gas additive that does not state that it compensates for non leaded gas, and always thought it would just prevent valve guide wear. I can't say whether or not this additive was the reason that the seats looked this good, but I can say that this engine has worked very hard on no lead gas, has soft seats, and no harm was done.
I have been running a F#$^ big block for the last 8 years with soft valve seats on no lead gas. I have taken many long ( up to 2000 miles / trip ) holidays with this car, and the engine is still running great.
Bottom line, I worry about the problem, but it hasn't happened to me.
Bob

i add lead additive about every 3 tanks in my 49, i also do the same for my D-17

My 1944 Ford 2N tractor get a shot of lead additive every 5th or so fill up.

After following this thread for a couple of days now and reading past discussions there seems to be a whole bunch of He said, She said, this and that, observations but not to much science behind most of it.
So being the curiosity seeker that I am, I did a little, mind you a little searching on the web. There is so much information on the subject available on the web that one could spend a week reading about it. I found this one article interesting and very educational.
http://en.wikipedia.org/wiki/Gasoli...;q=no%20lead%20gas%20and%20old%20engines
Bottom line sure looks to me like an additive would be a pretty good idea if you want to avoid problems down the road with your unmodified vintage or classic engine no matter how you drive it. I know all three cylinder head that I have encountered in my latest task have exhaust seats in pretty bad shape. I can’t say for sure that it was the elimination of Lead from the fuel that caused it but I would bet it was a contributing factor.
Denny Graham
Sandwich, IL

Denny, was it the seats bad or the guides?

I have seen more valve seats beat out by improper valve lash than anything else. If you are doing a build, definately go w/hardened seats.

The builders I talked to all recommended to stay away from hardened seats, unless you use the motor really hard.

I also heard about poorly installed seats that came loose eventually!

I used CD-2 lead substitue for the first few years on my daily 235, but haven't added anything to the gas in many years now with a fresh head.
I would stay away from any additives in fuel and oils with an engine that runs well without any issues.

I'm also not worried about hardened seats on my current 261 rebuilt.

Accually BeaverThe guides weren't all that bad, the seats were just heavly eroded in to of the heads and it was just starting in the third. That one must have had some valve work done to it recently because there was one exhaust valve that was different than the others.
Now sweat thar, both the heads that I have out being worked on are haveing seats installed along with new guides. I would agree with ya on the adjustment issue. I'd venture to guess that more than one valve adjustment has been done with the engine cold.
Denny Graham
Sandwich, IL

Thanks for all of the imput. I will add a lead additive from now on. Why take the chance? The 42 should be road ready in about a month. I can't wait after all it's been a 7 year restoration.

If you want to be safe - install hardened seats by a skilled pro and get a warranty.

How well lead-substitutes really work is anybody's guess.
When I used this stuff for years and then stopped and drove for another few years - the only difference it made was saving me $$ which brought my gas expenses down.

I've used Marvel Mystery Oil in my gas as a top cylinder lubricant for years now and haven't had any problems. I can't say if it's the oil or the fact that I don't run the tar out of my oldies. At any rate, the oil has never hurt anything.