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lead additive-yes or no?


wildcatsrule

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This probably has been covered in the past, but I'll go ahead and ask, since there seems to be conflicting opinions. Can you run unleaded gas safely in an engine that was designed for leaded? Or is it best to put in a lead substitute? I have a '68 Wildcat with 22,000 orig. miles. I have been using a product called "instead-o-lead" that you add when you fill up. I know that when an engine is rebuilt, it can be reconfigured to safely run on unleaded, but since my engine is still original, can I safely forgo the additive, or should I continue using it? David

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Guest Mr. Solutions

David

My 2c worth...

The short answer:

Use a substitute / additive for long distance driving, as the engine gets warm enough to warrant the additive. For city driving the engine temperature doesn?t get warm enough, so not worth while. And this is the way I have been driving my '51. But if using the stuff gives you a warm fuzzy feeling, then use it!

The long answer:

- Are you using hardened seat valves? If yes, then don't add an additive.

- Lead was added to fuel for 2 reasons: stop pinging and stop VSR (valve seat recession) Pinging was pretty much cured by the 50?s by means of other engine advances, so this left VSR? Only excessive, and I stress this, excessive heat, as in long distance driving, causes valve seat recession, and then only in a car that doesn?t have a properly functioning cooling system. City driving, with its short trip nature of start, stop, on, off cycles doesn?t warrant this extra expense, as the engine hardly ever reaches a temperature than can cause VSR.

Some tell you that their Buick doesn?t require it, others do, all from experience. This leads me to believe that Buick used semi-hardened (if not hardened) valve seats in some models?, or it may simply be the quality of the steel being used! Of interest is to note that the VW Beetle on the other hand, used hardened seat valves from day one in the mid-1930?s, mainly because economic sanctions against Germany after WW1 forced them to run unleaded fuels!!!

Hope this helps things a little.

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  • 10 months later...

At the Buick engine presentation that Denny Manner did at the Centennial meet in Flint, he mentioned that Buick was able to delay the use of hardened valve seats on their motors in the early 1970s (when unleaded fuel became the "norm") due to the fact that they did not use valve rotators and DID use nickel steel valves. Other GM divisions obviously didn't spec the nickel steel valves for their motors and others also used valve rotators too.

As stated, light load uses aren't hard on valve seats anyway whereas max load, higher speed conditions will ruin a set of non-hardened heads in about 12,000 miles (from Chrysler research in the early 1970s). As Denny stated, we don't drive our vintage cars like that (and 12,000 miles would take many years to accumulate, typically).

With that little mileage on the car, it could well be that there is some residual lead in the fuel tank anyway.

There are different kinds of additives. One is sodium based and the other one is oil based. I found this in an RV magazine on the valve seat deal about 10 years ago. Sodium is better, of course, but the best long term fix is hardened inserts for that kind of use (high load, high speed, many miles at a time).

In general, for the way we typically use the cars, there probably would be no real need for tearing something apart that is working fine as is. Quality fuel might be more of a concern (and maybe changing the rubber in the fuel lines to be more compatible with the newer fuels we have) to me for a vehicle of that age and miles.

Just some thoughts,

NTX5467

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My 67 GS has over 100000 miles,a lot of it at hiway speeds,even pulling a trailer & I never add lead. It runs as good now as when I bought it.I ran a lot of 455 test engines doing power development & after a few runs I would pull the heads and clean carbon off the pistons & valves.Hard to believe how much carbon comes from leaded gas.When we switched to unleaded the carbon cleaning was over.I got rid of the carbon by breathing it. Norb

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  • 2 weeks later...
  • 7 years later...
Guest johnhunt3055

I am making this project on oil based small engine car but what we have put in my car that it will give us around 30 miles per hour and burn the fuel only 50% as compared to earlier one. Now I want to know what effects could possibly come after mixing it with lead.

lead answer @ leading ways

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Why did no one mention the need for a zinc additive to avoid damage to the cam shaft. I have read something about that, and my engine builder put in a quart of oil in my '53 which has zinc in it. It's called ZZD Plus and can be found in Valvoline and several other brands.

Bill

Edited by BillMadden (see edit history)
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When this thread started in 2003, the zddp levels were NOT an issue as "SL" rated oil was still available, or prior forumations which later led up to "SL".

In some respects, the whole camshaft wear issue has, in my orientation, been somewhat overstated with respect to STOCK engines with OEM (new or used) camshafts in them. The reason the rebuilders and such started having issues with camshaft wear were due to the fact that they were not using OEM camshafts, but aftermarket or "replacement" camshafts. As things have progressed, most of the camshaft issues were with non-OEM camshafts and camshafts with higher lift and higher valve spring pressures than stock engines used, even the HP ones. This would be, basically, racing engine applications. Later, some of the aftermarket camshaft manufacturers (including Comp Cams who originally brought the camshaft wear and "SM" oil issue to our attention) have begun to market camshafts with more Parkerizing on them (which they didn't have initially). The Parkerizing is an anti-wear coating to help the camshaft get through the initial fire-up and run-in/break-in time. Remember, too, that it was highly recommended to use GM EOS to pour over the camshaft lobes before you fired the engine on a camshaft change? The GM EOS was there to be a high-pressure lubricant for the lobes until they could get enough "splash" lubrication from the crankshaft (NOT the same as how the earlier Chevy 6-cylinders used dippers rather than an oil pump).

The original CompCams recommendation was either "synthetic oil or Rotella T" motor oil. Contrary to some popular beliefs, the current CJ-4 diesel oils still have a LOT of zddp in them, although they also carry a "SM" gasoline engine rating, especially in normal "dino" oil. There are some synthetics which meet VW approvals, which also have an "SL" rating which usually have about 1000ppm of zddp in them. In a dino oil, that might be a little borderline for some, but in a synthetic, that's plenty of zddp as some VW diesel engines use a camshaft lobe to run their injection pump. Without the correct oil, they have camshaft wear issues too.

Consider, too, that the whole zddp addition to motor oil didn't happen until engine horsepower started climbing due to higher-lift camshafts and stiffer valve springs to allow 6000rpm engine speeds with such camshafts. This post-dates your 1952 vintage vehicle by several years, exclusive of the normal rpm range of your engine. In this respect, considering that current motor oils are of a superior base stock and additive package (anti-wear and detergency) than the prior "MS" rated oil, it could well be that ANY modern motor oil would do just fine and keep your engine running for a very long time--especially with a synthetic motor oil and a modest amount of zddp.

Also be aware that zddp is NOT the only anti-wear additive in the additive package. As emission control longevity has become a big issue with current motor oil specs, plus additional fuel economy, titanium has emerged as the new motor oil additive. Kendall GT first embraced titanium a few years ago and Castrol has recently come online with it too. To meet the current GF-5 specs, the motor oil has to show a certain amount of fuel economy increase in order to meet that spec. It might be a minimum of .03% compared to the GF-4 spec "energy conserving" motor oil, but it is still an improvement through decreasing internal engine friction with the motor oil itself. That would mean the oil film would need to be stronger and more slippery, which would most probably relate to "less engine wear" in the process.

Also be aware that GM also still builds crate motors with flat tappet camshafts in them, which are spec'd to use "SM" oils. BUT, they also have OEM-produced camshafts in them too. In many cases, though, they've already been "fire tested" at the engine plant and have already done their camshaft break-in time on the engine stand.

As things have progressed, CompCams and other camshaft makers have not introduced their own anti-wear motor oil additives. And CompCams also has their own line of motor oil now. Of course, this protects their interests in selling camshafts. Other "old car" motor oils have sprung up too, in the mean time, but there might be mixed results from them. If you want to see what's in "virgin motor oil", head over to - Bob is the Oil Guy, click on "Virgin Oil Analysis" and it'll bring up a forum where people have paid to have their "virgin" (as opposed to "used") motor oil analyzed by a noted laboratory. There, in all of its detail, will be the list of how much of what's in there, including zddp and moly and titanium. That particular forum has about 50 pages in it, so there's some good archived data in there.

As I mentioned, the whole zddp issue first surfaced in the rebuilder industry rather than in the OEM side of things. A rebuilder, typically and with all due respect, will use a "replacement" camshaft rather than pay the extra money for an OEM unit from Ford, GM, Chrysler, or whomever. One reason those camshafts are significantly less expensive is that they most probably didn't get the same thickness of Parkerizing on their camshaft lobes, which was not an issue when normal motor oils had over 1000ppm of zddp in them. It's also been noted that the greatest need of zddp is in the initial life phase of the camshaft. Even back then, it was highly recommended that one can of GM EOS was added to the initial oil put into the engine, which would augment the anti-wear additives with a tougher oil film being splashed onto the camshaft lobes.

Your engine, your money, your judgment call . . .

Respectfully,

NTX5467

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  • 4 weeks later...

After talking with Denny Manner, an expert on Buick engines, I stopped using lead additive, as it has a tendency to foul out spark plugs. The Wildcats with their original engines are running just fine without "instead o lead."

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Guest Kingoftheroad

I use a lead additive once in a while with no regularity. My nailhead is unaffected by todays fuels with or with out a lead additive. I probably won't buy any more lead substitutes for my old Buick.

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