From: 35 pickup (Original Message) Sent: 11/3/2002 5:29 PM
Hi All In my 35 pickup i am running a 53 merc engine. In my shop today we got to talking about the need for lead in the gas for valve cushion. I looked in the techo-site thinking there might be something there about it,but couldnt find anything. So i will ask the members. Do i need a lead additive in the flathead?? It has stock valves and if so what is the best to use?? Thanks in Advance. Lynn Barber Bay City Mi.

From: fearless Sent: 11/3/2002 10:01 P
I've heard arguments going either way, it all depends on whether or not your late model engine has hardened seats or not, they are the least popular engine in the line, that is 52-53. Lack of hardened seats may be one good reason, quality of build or iron alloy may be another reason..what with the "Korean Conflict" going on. I have read in Frank Oddo's book that when it comes to searching for a good engine to start a build-up one should avoid the last of the line....however the EAB heads do make for fairly high compression in stock form. My ole Granddaddy used to say that when he was a kid the gas was as clear as his whiskey, and it was "clear", just exactly when they started putting lead in I do not know, I do remember in my youth that 98 octane red-leaded ethyl was ruby red and smelled of sin. It was indeed put into the fuel to act as a cushion and had alot to do with higher compression ratios. Someone else may answer your question with more authority and knowledge just my 2cents....Dick

From: AlbuqF-1 Sent: 11/3/2002 10:19 PM
Back when lead was phasing out, Hot Rod Mag. did a very thorough test on engines to see the effects of unleaded. Also to determine what conditions resulted in damage to the seats on unleaded. (everyone had the same question as you).

The bottom line was, unless you're drag racing, pulling a heavy load constantly (i.e., a truck towing a trailer) or something similar that puts a lot of RPM's and a lot of heat (like where the exhaust starts to get red, running lean EPA-style mixtures), there was no big problem running unleaded in an engine without special seats. Are you running high compression or a blower or anything? That might dip you into the territory where hardened seats are needed.

From: Scotty Sent: 11/4/2002 1:51 AM
Lynn: This has been only MY experience. In 1971 I bought a new vehicle with notoriously soft valve seats. The svc manager suggested that I adjust the valve lash every three to four thousand miles. OK, I did it. That is until I had sixteen thousand miles on it and went back to the dealer with a burned valve. They fixed it for the cost of a tune up. More than fair. The up shot of this is that this rig is, to this day, my daily driver. How many times have I adjusted my valves? I average about once every two years. Over three hundred thousand very hard miles on a four wheel drive using nothing but regular gas with solid lifters, soft valve seats, one rebuild thrown in with stock components replacing stock components. I couldn't be more satisfied, but... like Albug F-1 asks, what will you be doing with your motor? Extended high RPM's (racing?) and little maintenance? Probably not, huh? Just the fact that you posted the question says you aren't into neglect of the vehicle. My opinion? Drive it and have fun doing it. If you do want to use an additive, someone here will most likely recommend the best one. Good luck, whatever you decide.

From: rumbleseat Sent: 11/4/2002 10:58 AM
I agree with fearless. The '53's I see all do not have hard seats. The seats are the block. I recommend installing hard seats on both intake and exhausts. Just my opinion.......... rumble seat

From: ole Sent: 11/4/2002 12:52 PM
Actually, tetraethyl lead was developed in the 20's by GM (Mr. Kettering, the designer of the famous '49 Oldsmobile 'Rocket' OHV engine, among others) and Standard Oil, only to allow the use of higher compression ratios, and NOT as a valve seat lubricant! Contrary to popular belief, the additive was actually very hard on cast iron exhaust valve seats, burning pits in the seats and valves, not to mention fouling s/plugs and creating deposits on the valve heads, etc. This was the reason for developing the hard alloys for use in valve seat inserts, as well as tougher alloys for exhaust valve heads, not the other way around. It was produced under the brand name 'Ethyl' by DuPont, added to gasoline and sold as leaded gasoline by the Ethyl Gasoline Corporation. In the 30's, it was finally sold as an additive to other gasoline companies. Since the re-introduction of unleaded fuel, much has been made of the disasterous results of unleaded fuel and 'soft' valve seats. Well, your cast iron seats would have a far shorter life if you were using leaded fuel! True, hard seat inserts will last longer than cast iron, but the question was it worth the expense of inserting a cast seat for unleaded fuel use in a normal use road engine? No, not really. Only if the cost is not a problem, or you're going to drive it hard, and put on a lot of miles. Otherwise, the cast seats will be fine.

The Ethyl story is very interesting, and one I researched years back when I started collecting Petroliana. I recently found this site, for those who would like to read more about it... rodnut

From: Scotty Sent: 11/4/2002 2:00 PM
Nuts! Seconds after reading rumbleseat's reply, and having pretty well settled on at least hardened exhaust seats, if ever needed, Rodnut comes back with his thoughts and info. A lot of this "opinion" stuff can be brutal on my thought process. Now, both you guys are pretty sharp (read; intellegent, experienced, helpfull, and articulate-stroke, stroke, stroke) about these motors and associated needs, and although you seem to have differing views on this matter, I find it odd that neither of you even mentioned a "lead additive". Points from me on that. I've never used 'em and most likely never will. I fugure if a need arrises for something like that, there's something inherently incorrect with the mechanical components involved. My solution is to operate, monitor and eventually "fix what's wrong". Where does this leave Lynn, with his original question? As I read it, right smack in the middle of a decision, involving two opinions, expressed by two VERY experienced people. As rumbleseat says, in his recent post, his opinions differ with others. I guess if everyone's opinions were the same, we'd have to call 'em something else, huh? Anyway, I guess this post is just my thoughts spilling over onto this board. Almost every day I check in here and learn something, and I hope most others do too. Keep it up guys, I love reading this stuff.

From: dicker Sent: 11/4/2002 4:34 PM
Scotty, don't it just make your day when one of those guys and you know who I mean agrees with you, it don't matter if everybody else disagrees. Who else but one of these guys is gonna read about petrophelia? It is kinda awkward that Lynn never did get his question answered and I suppose once again it turns into a coin toss, although as was mentioned by most everyone "unless you are really going to run her hard, tow heavy loads, etc. do not worry about the lead additive or doing any additional unnecessary machining". Myself, I run everything I've got hard some of the time and just feel better knowing that my valve seats are up to snuff. The lead additives are not very expensive and if you do not put alot of miles on each year and it makes you feel good put em in, when I Winterize my engine I put in Sta-Bil and a good strong dose of Marvel Mystery Oil, partly because I love the way it makes the exhaust smell.....Dick

From: ole Sent: 11/4/2002 5:14 PM
Well, I kind of thought that one could make their own decisions on this 'lead additive' subject after reading the opinions and the factual archival information that was presented via the link. My opinion on additives? Unless you are using tetraethyl lead (really dangerous stuff by the way), you aren't using a 'lead' additive. There are lead 'substitutes' on the shelves at your local auto parts stores, but I tend to think that they're mostly snake oil (I wonder if snake oil has been tried as an octane booster?) so I don't bother with them. I could be wrong, but then I've never had a problem with unleaded gas with 'as cast' valve seats in any "normal road use" engine. If I'm going to run it hard; race it; abuse it, then yes- I go with hard seats. Lead 'substitutes'? No. Octane boosters? No. Build the engine to suit the intended purpose, and forget the 'additives'. If you're going to strictly race, build a race car and run race gas. If it's a street driven car, build it to run on available pump gas. If you're going to abuse it, install hard seats, etc. My opinion... rodnut

From: AlbuqF-1 Sent: 11/4/2002 6:01 PM
I meant to mention, I used a lead substitute (Wynn's, I think) in my '78 F150 (460/4-bbl, gets a lot of hard use) because it was a regular (leaded) gas engine, for about a year, because I was worried about it. The only change I noticed was that the carb got all goo'd up with an oil that looked remarkably like the additive. The goo was the same color as the Wynn's. Who knows what is in that stuff, like rodnut sys, it isn't Real Lead...


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