Regular Gas

your fine as long as it doesn't ping

I had my valve seats replaced with hardend seats so unleaded is fine.

I had an old jeep that required leaded fuel and used the STP lead subst*tute and never had any problems.

    I also believe that the old leaded gas you could run your timing higher without pinging for the same octane rating as unleaded. If I recall, the lead causes the gas to burn slower compared to straight unleaded of the same octane, making it appear as a higher octane. Any comments?? Im not totally sure.

                                      Jeff...

Lead (tetra-ethyl lead) was a cheap way to get the octane rating higher. When lead was outlawed, they started using more expensive alcohols and ethers (like MTBE--which I think was banned recently also).
Fuel is assigned the octane number by how much it makes a test engine knock. 89 Octane rating makes the test engine knock as much as a mixture of 89% Iso-Octane (a very good fuel) and 11% Heptane (a poor fuel). 93 Octane would knock as much as a mixture of 93% Iso-octanne amd 7% Heptane.
I run 89 octane now. Before the price of fuel went up so much, I ran 93.

I think you could run that '88 on unleaded without problems. All that lead you are adding does not all burn and leave via the exhaust, some of it stays around and collects on things (like spark plugs).

Seems to me that by '88 Ford would certainly have been assemblying heads with hardened valve seats.

I have read studies that showed leaded fuel was only necessary on engines designed to use leaded fuel under severe operating conditions...something a marine engine qualifies IMHO. But, the studies also conclude that if you only add lead each third to sixth tankfull then you get all the protection necessary as the lead is collected on the valve seats and takes some time to wear off.

Seems to me there was a thread on this many months ago, try a search and see what we all had to say about it back then.

Yeh, I understand what you are saying and cannot really argue with you or fault you. And, I agree, marine engines work hard all the time.

Anecdotally (sp?), my friend has a '86 2001 that has the original engine and he has never used a lead subst*tute in the 5 years he has owned the boat...no signs of problems.

This what I think, but cannot prove: Boat/engine manufacturers are slow to change their documentation or recommendations even as the technology changes. I find it hard to believe that any Ford manufactured cylinder head in '88 (or even a few years before) did not have hardened valve seats.

Ford seemed slow to give up the ghost on leaded fuel for some reason. I don't think Chevy or other engine manufactures were as stubborn. I always thought it was a political move on Ford's part.
I do know the incidence of children with high blood lead levels significantly dropped off in states as they switched to unleaded fuel.

I found this thread interesting,thought I'd throw my .02 in.The octane rating on gas pumps is derived from 2 different numbers,it's an average of the research octane and motor octane.The research octane number comes from a low compression low rpm test using a comparison fuel,the motor octane number comes from a higher compression,higher rpm test using a comparison fuel.The average of the two gives you pump octane(R+M divided by 2)as seen on the pump.Iso-octane and heptane are used in place of lead.Iso-octane increases the octane rating,heptane has an octane rating of zero,but helps determine the burnability of the gas.If you run a higher octane fuel than you need,you are wasting your money,if you run too little octane,you're damaging your engine.
   All of this is affected by alt*tude,temperature,ignition timing,compression ratios and engine load,spark plug heat range,etc.
   MTBE is still avail. in the northeast,but not for long.It absorbs water,burns hotter,and causes lean air/fuel ratios,and it can lead to fuel system deterioration(as any type of alcohol will).
As far as I know,Ethanol is produced by fermentation and is not recommended by any manufacturer in quant*ties above 10%.

   Sorry for such a long post,but it's pooring here and I'm bored to death.I hope this information is useful to someone.

     MIke

if the engine hasn't had any head work then with it being a 74 the lead sub would be wize atleast every other tank full.

dchris17 wrote: You can't run E85 (85% methanol, 15% gas) in a traditional gasoline engine without modifications.

Do you have any idea what the mods are? I'm guessing that the ethanol will damage rubber parts in the carb, but what about the hard parts? If the engine is fuel injected, I would think exhaust sensors and a different computer would be the only change. Is there such a thing as a E85 compatible carb? I would think that due to the higher octane rating, compression and timing could be pushed pretty far for some nice performance gains.

I would think almost certainly yes. However, there is always a slight chance that the rebuilder simply reground the valve/valve seats and left them in place. But, my thoughts are if the engine needed rebuilding, then the valve seats were probably shot anyway and needed replacing so they were.

My wife's '02 Suburban has a flex Fuel Engine just because that is what was on the lot with everything else we wanted. I am looking at the window sticker now and the engine is not listed as an extra cost over the base vehicle cost, so if true, why arn't all the engines flex fuel? Incidently, we have never put any alcohol laced fuel in the burb simply because I have never seen any. So, I have this engine that can run cheaper fuel, but no place to buy it....typical!

My oppinion on putting E85 in a boat is do not do it. 10% alcohol, probably ok, but watch for rubber deterioration in the fuel system. You would think that all fuel system rubber components are manufactured these days to be tolerant of alcohol fuels, but who knows! Be safe!

Almost all gas sold today has 10% ethenol in it so if you think you have never ran alcohol in your engine, you have and just don't know it. Flex fuel cars have been on the market for several years, and you may not see a charge listing for the engine, usually it's a different base price/model and you have to look at the top of the window sticker to tell the differnce.

Well look at what is on the Fox News website today....Home made ethanol

Here is an excerpt from the article:
"Ethanol already is routinely added to gasoline in New York, Connecticut, California and the Midwest, and makes up about a third of the gas sold in the U.S., according to Kristin Brekke, a spokeswoman for the Sioux Falls, S.D.-based American Coalition of Ethanol.

Finding E85 gas is more of a problem. The 30 or so states with public E85 fueling stations are mostly in the corn belt."

   Actually,I think that ethanol is not what we have in gas in Maine.MTBE(methyltertiary butylether)yes,that's actually a word,is a product of crude oil.MTBE has been banned in most areas due to health issues,but in the southern counties of Maine they still sell it.It's got a shelf life of about 60 days and is only good for burning brush after that.I think most fuel systems designed now take this stuff into consideration and the labels on the boats are more of a C-Y-A thing.It's not likely ethanol will chew through your fuel system in a week,but you guys with older boats should inspect that stuff more frequently.My new boat has a sticker right next to the fuel filler that says"do not run any fuels containing alcohol".I guess I'll have to siphon that nitromethane back out of the tank

   You would have to double(approximately)the jet sizes,probably advance timing-alcohol has a longer burn lag time.I would guess by altering the pulse rate you would be accomplishing the same thing.Would it be worth it?Double the consumption.I'm not real familiar with pricing,etc on that stuff.Is the only real advantage not having to let oil companies control your life?iI guess that itself would make it worth it alone!