Grinchia

When I bought my '68 7 years ago, I was able to order a case of Lead Supreme (now called Octane Supreme 130) online, and was in the habit of adding a pint or two to each tank of 93 octane gas for extra protection against knocking and to help cushion him my valve seats. I finally ran out, and when I searched online yesterday, the stuff is "temporarilly out of stock" everywhere, even direct from the manufacturer. Is there another real lead based additive out there? Does it even really matter? Are the 'lead substitute' octane boosters of any use in valve seat protection, and do they have any potential negative effects on my engine and fuel delivery system? If all else fails, I can go to our little municipal airport and get a few gallons of leaded aviation fuel to add to each tank, but that is kind of a pain. On my fresh rebuild the compression ratio is now down to just below 10:1, and the cam has significant overlap, so I may be good to use plain old premium gas, but I'd feel better confirming this somehow. Who knows enough to help me out here?

zwede

There really is no need for TEL. When you had the engine rebuilt, did they install hardened seats? If they did, TEL serves no function at all. If they did not, I still wouldn't bother. By the time you get any significant valve seat recession it will be time for another engine rebuild anyway. Only time TEL really helped was for small engines pulling heavy loads for long times (like towing).

Yes, there are many negatives with TEL. First of all it is HIGHLY toxic and has been proven to cause brain damage, especially in young people (keep far away from kids!!!!). It also leaves deposits on your spark plugs and will make them misfire earlier (you have to change plugs more often).

Grinchia

The machinist (very experienced guy) was happy with the state of the non-hardened valve seats, and did not recommend replacement with hardened seats, so they stayed. It is NOT a small engine, and will not be used for towing

Sounds like I should be okay to forget about it and have fun driving. I should note that in probably 5 000 miles on the old plugs, I never needed to replace them, so perhaps I wasn't adding enough lead to make much difference anyway.

capevettes

You don't need a lead additive for your 68. I have been running my 61 (10.25:1 383), 65 (327/350 11.0:1), and 68 (427/390 10.25:1) for years with no problems on 93 octane pump gas.

7T1vette

The only reason to use TEL in your car would be to alleviate "spark knock"...pre-ignition. If you can run no-lead fuel in your car and not get any knocking, you don't need it at all. If you DO get pre-ignition knock, you can try de-tuning your engine or put in other additives which emulate higher octane performance.

If you don't have 11:1 or higher compression ratio, you probably don't need more than 93 octane fuel. If you do have a high-compression engine, you might consider putting a thick head gasket under the heads or changing to some aluminum heads.

mrvette

RONG!!! i'ts a flat out lie, dunno your information source but it's pure

What in hell you think?? ever tinkerer and kid from the 40's++ is brain dead after handling leaded gas?? much less doing engineering work landing us on the MOON???

what sort of green weenie propaganda are you reading man???

don't mean to thread hijack, but I simply can NOT let this go by....

Mike Ward

I think you've just incriminated yourself by providing proof.

FRSTR90

If you do not have hardened valve seats... I would keep adding the lead.. Not trying to knock any of you guys who posted not to worry about........ but, if chevy along with all the other car manufacturers thought it was necessary to add hardened seats because of the unleaded fuel then obviously there is a reason. Just think about the extra work that goes into putting those hardened seats in, that slightly raises the cost per engine(or per car) and when you are building millions of cars a year that becomes pretty expensive.

Google - Max Lead 2000 (this is also a tetra-ethal lead additive)

Mr.Vette - I, too, agree with you. You can spot an old carb'd engine anywhere today because they usually run soo damn'd rich... now if you imagined every single car being carb'd, pollution would be out the @$$. Add lead to the mix... Im sure EVERYONE today, from their late 40's on up would all have neurological damage..

mrvette

Look, I have, like many of my friends, been playing with engines, cars, bikes, lawnmowers, go carts for over 1/2 a century....I come from the Wash DC area spent 53 years in that region, except '70, in DFW Texas area....

I well remember reading none other than the Wash Post rag back then that it took 10% more crude/gallon on refined gas for the elimination of lead....10% more crude over 40 years now is a total boatload of crude oil....

and what did we gain for all that increased import?? 9/11??.....

play the % game here now....10% when we pumping X% of our own crude oils...and then they want a 10% SURcharge?? where do we think that stupid move comes from.....

show me ONE POSITIVE thing that eliminating lead from gasoline has done for this or any other country....but I demand SOLID SCIENTIFIC PROOF, not some green weenie/Huff post site...

The ONLY thing that has been a positive development on engine/fuel management has been DPFI, and that has nothing to do with fuels so much as ELECTRONICS.....

as in chips, and transistors....

and we could run at 17-18 to one A/F ratios, apparently, according to a old poster here ...Norval.....

but not with the EPA over our shoulders.....at any rate, FI is obviously the way to go....some of you may know that my old '72 shark is a more modern FI car...with overdrive...

zwede

Lead causes a specific kind of brain damage that shows up primarily as aggression and violent rage.

Rate of violent crime started decreasing a few years after leaded gas was eliminated and has continued to decrease as the damaged kids died off.

7T1vette

Hmmmmm.... A strong desire to revert back to 'leaded' gas... No concern about the environmental effects or for brain damage to 'gas sniffers'... Prone to tirades and unsolicited rage... I think I'm seeing some pattern here.

Mike Ward

Chevrolet never put separate machined hardened seats in the heads- that's an aftermarket trick. Instead, the cast iron head was induction hardened in the seat area, a quick and dirty process that cost next to nothing.

Corvettes never suffered from valve recession due to lack of lead, not back then, not now. Dump trucks and Dad's wagon pulling a house trailer up a mountain did. Since the foundry had no idea which engine a head was going to end up on, all of them got induction hardened.

Mike Ward

And disjointed ramblings on discussion boards are common effects too.

roscobbc

TEL can be simply ingested in to the body by just spilling on to the skin - you will then suffer from lead poisoning - just as many people would have done ingesting other heavy and toxic materials in the engineering/automotive/marine/plumbing/electrical/in fact ALL industries many years ago before health and safety laws took off - and just like developing countries are doing NOW.

whitehause

All the toxic shock talk aside...........I would recommend adding at least a fuel stabilizer. The ethanol in today's gas really draws the water in, and since many of us don't run our cars a lot, that is one measure that I think is almost a necessity to help prevent rusty tanks and lines.

Rich's'78

and the other drawback to TEL was that it was not added to gas as pure TEL - it had alkyl halides added to the HC formulation. When they burned they generated, amoung other things, HCl and HBr which corroded the sh8t out of the exhaust pipes / mufflers. Before I swithched to unleaded in the '80s I had to replace my whole exhaust system every 3 years! My father in law worked for Texaco refining for 35 years and explained this to me.
The beauty of TEL (from the refiner's point of view) is that it it is a catalytic octane improver so a little does a lot. To get the same increase in octane in a gallon of gas you need a lot more branched HCs (like i-Oct) and that cost a lot more for the refinery to produce.

Grinchia

I didn't mean to ignite a firestorm hear about the environmental and health effects of lead! I'm a physician, I am familiar with the effects of lead on the system, and I have not desire to get on a rant. The only two solid pieces of information I'll drop in are that back in the 70's, the average blood lead level in kids in the US was 15 ppm...today it averages less than 3ppm. Some of that could have been due to lead paint and other lead sources I suppose. Lead is definitely neurotoxic among other things, but you're not going to die from spilling a little lead additive on your skin

I am not going to worry about lack of lead additive, but I may try and track down some of that max lead 2000 stuff.

Thanks all!

c69vete

Google Jack Podell. He has the MAx Lead 2000

68/70Vette

Another symptom is that lead poisoned people write angry, ranting and raving posts.

If you can't find TEL, can you buying racing gasoline in your locality? Drag racers are a prime customer. I can buy it locally, I think the last I bought was 110 octane. Higher octanes are available. Also, the high octane gasoline is available either leaded or non-leaded. But ...........its' $$$$$. I think I paid $10 a gallon. (And that's with no road taxes!) One or two gallons in a tank of pump gas may give you the boost you want.

My 68 350/327 10.5:1 ran OK on 91 pump gas.

roscobbc

If I am suffering from lead poisoning - will I weigh more because of the additional lead in my body ?