What are your opinions on whether or not to use an additive for unleaded gas in our trucks designed to run on leaded gas? Thanks.

 

If you plan to drive it a few thousand miles or more per year and the heads have never been redone then they probably need it. Have hardened seats installed and forget the additive.

If you don't plan to drive it much then the additive won't cost much.

What truck/engine do you have?

 

One factor is how you drive. Extended high speeds, and towing especially, is said to accelerate valve recession. The additives aren't going to do much, and would get expensive really quick.

 

It's a '59 with the 223. I bought it in January and it's going to sit in the garage 5-6 months every year because I'm in NW Wisconsin. So far this spring/summer I'm averaging a couple hundred miles per month. I have rarely gone over 60 mph-it's winding pretty tight at speeds over 60 and the front end needs some work-it's also a little too thrilling to drive then!

 

It might be interesting to see the MSDS and determine what's in those "lead substitutes"; afaik there are no true lead additives available. I'd be inclined maybe to run Marvel's in the fuel.

 

If you are in Canada (which you are not) then there would be no worries as Canadian gasoline is still has MMT in it to help combat valve recession.

There are some true tetraethyl lead additives on the market such as Octane Supreme 130 but really it is only needed in high compression high performance engines.

A couple hundred miles a month it going to take an awfully long time (like many many years) for the valves to recede
Ford's do not have the same level of issue with valve recession as GM did Ford used a bit better cast iron and typically will hold up much better.

So to be honest I would not worry about it. By the time you have issues (it is going to take years and years) and by not using an additive you will have more than saved the cost of having the heads rebuilt by the time they need done..

 

Dcmania,
Have you popped the valve cover off and checked the condition of the valve tips and rocker arm tips? If the heads have never been done these parts may be pretty beat up by now. If these parts are all okay then I'd say keep on driving. If they need work then you might want to get it done before worse things happen.

 

Thanks for your insight, guys.

 

In my opinion, using a zinc additive or classic car oil with zinc and other anti-wear additives in it is a must, if you still have flat-tappet lifters and the original camshaft. Of course if you don't drive it very much, it's not going to matter that much, but the engine is still going to wear slightly.

Many people like to argue whether or not additives work as good as the classic car oils with zinc, but either will work ok. Right now in my 223 I'm using an additive, even though I've only put a couple hundred miles on it, and I'm going to use an oil with zinc and anti-wear additives made for classics next oil change.

 

Well OK, but what's your opinion on the lead substitute additives and hardened valve seats?