fuel and additive question

TerryH said:
The zinc has been gone a long time now; has anyone reported definitive harm done to Model A engines that do not use additives? Seems like I heard many experts say some time ago that only modern, higher performance engines were vulnerable. It would seem that by now problems would be surfacing.....none of my Model A friends have reported any issues due to it.
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The ZDP "controversy" (like the MMO and crap gas controversies) are likely to go on forever. Very few facts are involved in all of these...mostly opinions and anecdotal evidence.

The following is how I made my decision not to worry about ZDP. Newer oils do not contain as much ZDP as earlier oils, but other anti wear agents have replaced the ZDP that had to be removed since it poisoned cat converters. Note that ALL "Starburst" oils MUST be backwards compatible. In other words, they have to do as well or better in the certifying tests (including the valve train wear tests) as the oils they are replacing.

You can certainly make your own decision on this one. I've made mine and it may not be the same as yours. That's OK :)

The latest myth promoted by the antique and collector car press says that new Starburst/ API SM engine oils (called Starburst for the shape of the symbol on the container) are bad for older engines because the amount of anti-wear additive in them has been reduced. The anti-wear additive being discussed is zinc dithiophosphate (ZDP).

Before debunking this myth, we need to look at the history of ZDP usage. For over 60 years, ZDP has been used as an additive in engine oils to provide wear protection and oxidation stability.

ZDP was first added to engine oil to control copper/lead bearing corrosion. Oils with a phosphorus level in the 0.03% range passed a corrosion test introduced in 1942.

In the mid-1950s, when the use of high-lift camshafts increased the potential for scuffing and wear, the phosphorus level contributed by ZDP was increased to the 0.08% range.

In addition, the industry developed a battery of oil tests (called sequences), two of which were valve-train scuffing and wear tests.

A higher level of ZDP was good for flat-tappet valve-train scuffing and wear, but it turned out that more was not better. Although break-in scuffing was reduced by using more phosphorus, longer-term wear increased when phosphorus rose above 0.14%. And, at about 0.20% phosphorus, the ZDP started attacking the grain boundaries in the iron, resulting in camshaft spalling.

By the 1970s, increased antioxidancy was needed to protect the oil in high-load engines, which otherwise could thicken to a point where the engine could no longer pump it. Because ZDP was an inexpensive and effective antioxidant, it was used to place the phosphorus level in the 0.10% range.

However, phosphorus is a poison for exhaust catalysts. So, ZDP levels have been reduced over the last 10-15 years. It's now down to a maximum of 0.08% for Starburst oils. This was supported by the introduction of modern ashless antioxidants that contain no phosphorus.

Enough history. Let's get back to the myth that Starburst oils are no good for older engines. The argument put forth is that while these oils work perfectly well in modern, gasoline engines equipped with roller camshafts, they will cause catastrophic wear in older engines equipped with flat-tappet camshafts.

The facts say otherwise.

Backward compatibility was of great importance when the Starburst oil standards were developed by a group of experts from the OEMs, oil companies, and oil additive companies. In addition, multiple oil and additive companies ran no-harm tests on older engines with the new oils; and no problems were uncovered.

The new Starburst specification contains two valve-train wear tests. All Starburst oil formulations must pass these two tests.

- Sequence IVA tests for camshaft scuffing and wear using a single overhead camshaft engine with slider finger (not roller) followers.

- Sequence IIIG evaluates cam and lifter wear using a V6 engine with a flat-tappet system, similar to those used in the 1980s.

Those who hold onto the myth are ignoring the fact that the new Starburst oils contain about the same percentage of ZDP as the oils that solved the camshaft scuffing and wear issues back in the 1950s. (True, they do contain less ZDP than the oils that solved the oil thickening issues in the 1960s, but that's because they now contain high levels of ashless antioxidants not commercially available in the 1960s.)
Despite the pains taken in developing special flat-tappet camshaft wear tests that these new oils must pass and the fact that the ZDP level of these new oils is comparable to the level found necessary to protect flat-tappet camshafts in the past, there will still be those who want to believe the myth that new oils will wear out older engines.
Like other myths before it, history teaches us that it will probably take 60 or 70 years for this one to die also.

Special thanks to GM's Techlink
- Thanks to Bob Olree – GM Powertrain Fuels and Lubricants Group
 
Dick, what you call 'anecdotal evidence' I call experience. You yourself make your own decisions based on what has worked for you, i.e., your experience.

No two ppl are likely to have the exact same experiences. Forums are nearly useless since we are all posting our experiences, and few people are likely to change what they are already doing. That is fine with me. Most come on here and other forums with a preformed opinion and are looking for just one other person to agree with them. That way they can keep doing what they were already doing, and disregard the contrary opinions. Such is life.
The forum is loaded with topics that will never die, as you say oils, then antifreeze, timing, brakes, head re-torquing, gear oil, what red-line to use, water wetter, Evans coolant, paint prep, metal passivation, spark plugs, OD, babbitt, inserts, etc etc until nearly every thread has come into play
 
I think most of us will agree any auto oil nowadays is better than anything they had back then, and judging by the article above zinc didn't appear till after model a production. How many model a engines have we found that have worn out cams or tappets? I've been told the valve spring pressure is very weak when compared to modern engines that as long as they have any type of lube on the cam it will last forever. I use castrol 10-40 and dump some stp in there to make it extra clingy.
 
duke36 said:
ditto to Dino et al. Evidently zinc removed from oil because of havoc with catalytic convertors. Zinc additives study done by Porche Club sometime ago with recommendations for zinc products re; wear on flat -opposed 4 cyl's. STP had zinc in the red bottles but no longer sold in Cal. (EPA reg's), so any product with Zn may be beneficial.
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Duke-The STP oil treatment in the blue plastic bottle is still sold in Cali, never remember the red bottle though. On the blue bottle, it states it contains ZDDP.

How much is anyones guess......
 
Rich, the owner of Antique Engine Rebuilders, states in his video, zinc is needed for cast iron camshafts. Since Model A's use steel camshafts, he says it's not necessary to add zinc to a Model A engine.
 
Use additives, don't use additives, we could go on forever.

Whatever you feel you need to do to to get the A's on the road is fine.
 
For me the bottom line is whatever keeps my new motor alive and well, if engine builders recommend something and see how it stands up then they will recommend it the bottom line is if it is working great.
 
tbirdtbird said:
Dick, what you call 'anecdotal evidence' I call experience. You yourself make your own decisions based on what has worked for you, i.e., your experience.

No two ppl are likely to have the exact same experiences. Forums are nearly useless since we are all posting our experiences, and few people are likely to change what they are already doing. That is fine with me. Most come on here and other forums with a preformed opinion and are looking for just one other person to agree with them. That way they can keep doing what they were already doing, and disregard the contrary opinions. Such is life.
The forum is loaded with topics that will never die, as you say oils, then antifreeze, timing, brakes, head re-torquing, gear oil, what red-line to use, water wetter, Evans coolant, paint prep, metal passivation, spark plugs, OD, babbitt, inserts, etc etc until nearly every thread has come into play
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Totally agree! :)
 
duke36 said:
STP had zinc in the red bottles but no longer sold in Cal. (EPA reg's), so any product with Zn may be beneficial.
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Dino's A said:
Duke-The STP oil treatment in the blue plastic bottle is still sold in Cali, never remember the red bottle though. On the blue bottle, it states it contains ZDDP.

How much is anyones guess......
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Isn't the Red bottle a gas treatment and the blue bottle the oil treatment. Don't think you would need ZDDP in your GAS... :p:p
 

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tbirdtbird said:
Dick, what you call 'anecdotal evidence' I call experience. You yourself make your own decisions based on what has worked for you, i.e., your experience.

No two ppl are likely to have the exact same experiences. Forums are nearly useless since we are all posting our experiences, and few people are likely to change what they are already doing. That is fine with me. Most come on here and other forums with a preformed opinion and are looking for just one other person to agree with them. That way they can keep doing what they were already doing, and disregard the contrary opinions. Such is life.
The forum is loaded with topics that will never die, as you say oils, then antifreeze, timing, brakes, head re-torquing, gear oil, what red-line to use, water wetter, Evans coolant, paint prep, metal passivation, spark plugs, OD, babbitt, inserts, etc etc until nearly every thread has come into play
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I totally agree. I look over many of these contentious forum threads not for alternative methodologies, but to make sure I am not alone. However, I MAY change my ways I am the appear to be alone.

By the way, am I the only one using 2-cycle oil instead of MMO?:p
 
Ian when i used to race motorcycles we used a oil called klotz synthetic, we were always told to change the piston and rings after 4 races on our bikes 250cc 10,000 rpm water cooled engines. I did not follow that practice I went a half season on it plus all of the practice time and the piston and rings looked excellent when taken out it was a terrific oil not sure if it is still made also castor oil was used and will make your model a smell nice.
 
What ever happened to DA Speed Sport oil? That was the hot item back in my days of small high RPM racing engines.
 
Just to clarify , I have a couple of bottles left of the red bottled STP oil (not gas) treatment which according to my supplier was removed from store shelves. The red plastic bottle is identical to the blue one, which as Dino states is still available. I was told the amount of zinc in the red bottle was more, but who knows.
 
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