Does my 1974 455 need to run a Zinc additive in the oil?

 

Depends on what the level of ZDDP is in the oil you are using. Shoot for 1200 PPM or higher. That engine is flat tappet vs. a roller cam and lifter setup, ZDDP is beneficial for the flat tappet/lifter sliding on the camshaft vs. a lifter rolling on it.

Members will suggest specific oils, Rotella 15W-40 is a good start but I'd probably add a small amount of ZDDP to it.
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I think I have read that Rotella does not have as much zinc as it used to. I have used Valvoline VR1 Racing Oil in the 54 I had and in my 75 455 with no problems. I did not add any ZDDP.

 

According a major cam manufacturer it's best to buy a oil with the zinc already blended in rather than add zinc. TIFWIW.

 

These are what I use in my Oldsmobile.

 

That is exactly what I use tru-blu. I have used Wix filters for many years. NAPA Gold is supposed to be the same filter. I would never use a Fram filter. Way back they used to be good but not anymore.

 

Like the others have said . . . it is best to use an oil that already has the zinc formulated into it. There are several.
Valvoline VR1
Driven Hot Rod oils
Penn Grade
etc

 

Correct. And all cam companies today will tell you DO NOT use diesel oils as they have too much detergent in them.

 

Interesting, never heard that before, good to know.

Is the racing oil good for year round use? Wondering if their additive packages are good for occasional cruising and long down times.

What PPM of zinc if any do the cam companies recommend?

 

 

Interesting article in Jan 2024 Hemming's on ZDDP break-in oil.(Jeff Smith). It agrees with purchasing manufacturer blends. It agrees separate additives are a gamble.
Oil blending is a science that needs chemical analysis to provide useful data driven results.

Break in verses daily use:
Several companies offer specific break in oil EX: "Driven BR30." .
There are 2 types of ZDDP. Fast acting and slow acting, basically how quickly the zinc & phosphorous react is all important (on break in). Zinc dialkyl dithio-phosphate,,,ZDDP is a compound that is actually pushed into the lobe/tappet metal activated by heat.

Slow acting is good for over the road gas/diesels = long term protection = same for street driven flat tappet engines = not a great choice for break in.
Break in needs fast acting ZDDP to coat the critical wear surfaces within the first few minutes of cam break in. Over the road street driven engines need slow acting post cam/ring break in. 1200-1500 PPM of ZDDP seems to be the standard requirement to keep a flat tappet cam happy.

The reason ZDDP was removed was due to big brother(shocker) as it clogged the cats with ash from the combustion process.
30W non detergent high ZDDP oil is desirable as detergents if blended to aggressively will actually strip the ZDDP.

Rotella T Diesel 15w40 no longer offers enough ZDDP...because of....wait for it....big brother and whats decided is good for you. "JUST ENOUGH isn't enough.

Bottom line... with old skool flat tappet engines spend the money on high end blends mixed with 1200-1500 ZDDP like Schaeffer, Lucas, Amsoil etc.
I use Prolong with high zinc oil. Have done so for 35+ years. Zero wiped cams zero blown engines. I know I haven't built enough high horse blower engines lol.

 

I've never had any trouble running Rotella T4 15W-40 in my 71 or the 96.

 

Questions like this are the same as "what's your favorite color?" You'll get 40 different answers from 40 different people. ZDDP is a topic that you get 80 different answers from those 40 people. Some worry about it, some don't. Some have cam problems, some don't. So what's the real answer? Personally, I've never had an issue with any of my flat-tappet Olds engines over the years, even the 80s 307s with cats using Mobil 1 and Valvoline brands.

Today's oil blends are like anything else, tailored and engineered to more specific applications than ever before. It's no longer whatever the gas station has on the shelf that's 10W-30 is safe for your car. You got to educate yourself if you're serious about protecting your old cars. Hi lift flat tappet cams with high psi springs need to worry about it even more.

Run a high quality oil for the flat-tappet engines and a good filter and do your recommended oil/filter changes and you should be ok. Now, the part about high zinc, as well as high phosphorous, making catalytic converters ineffective faster is true. Not so much clogging, but coating the happy bits inside the converter keeping them from doing their job. So for those running cats, watch putting too much ZDDP and high phosphorous content in oils. It's usually not a problem with healthy engines, but if you run rich and lots of extraneous additive oils in a sicker engine, the catalytic converter could be affected. Regardless, there's only so much catalyst in the converters. So, no matter what, one day they'll quit doing their job anyway if they don't rust out first.

While Mobil 1 is great ubiquitous oil you can find almost anywhere, the ZDDP numbers are kinda shy as compared to others if that's what you feel is important. It's good for the ultra-modern engines as it isn't as horrendous to catalytic converters, but again, you gotta do your homework.

Here's a neat little write-up from a GM engineer about oil myths (Bob Olree, who sadly passed in 2017). Far be it from me to say, but I'm more than likely going to trust what a 23-year GM fuels and lubrication engineer says (and 17 years prior at Ethyl Research lab, makers of fuels additives) before anyone else that didn't specialize in lubrication.

Oils and ZDDP.fm (nonlintec.com)

 

Here's another brand to add to the list, especially if you live in a hot climate and want a little higher viscosity on the upper end of the multi-viscosity spectrum.

Mobil 1 15w50 Full Synthetic
- 1300 ppm Zinc
- 1200 ppm Phosphorus
- Mobil 1 Specs sheet says specifically engineered for flat tappet applications
- Everyday price from Walmart $28 for 5 qt jug

 

This isn't meant to address what cam manufacturers are saying about too much detergent in diesel oils, it is just additional information.

FWIW, contacted Shell today and they advised that except for 5W-30 T6 Rotella, the other Rotella versions have 1200 ppm of ZDDP across the board.

 

thats funny..considering GM had some of the worst cam/lifter failure rates of any manufacturer, and then blamed it on the “new oil”

they even jumped on the band wagon and marketed their own cam saver additive

 

anyone try the Lucas Classic and Hot Rod oil? I run the Lucas synthetic motorcycle oil in my bike and have never had a problem with it.

 

I never used zinc oil or additives in my 71 350 which I ran all the way up until 2012 without any cam issues. Maybe Uncle Tony is correct, might be a good idea, but probably not necessary.

 

You should check out lake speed's videos on lubrication, its his specialty and he loves to talk on the subject. They put a list of oils that they recommended based on lab analysis.

 

Yeah, he is someone else I could consider advice from when it comes to lubrication as he does seem to know a lot, even though he does love to point out about how great he is every now and again. He is a certified lube guy, which is sort of an elite club, I guess. It's like having a doctorate degree for oil-heads. But, just like doctors, trust but verify. It's always good to get second opinions.

Lake did/does work for Driven Oil, so sometimes the bias would creep in, like he was doing a commercial for Driven oil. But still, GM lubrication engineers know their products' oil needs better than a general oil specialist, I would suspect. Not saying it's bad, just that someone developing racing oils may have a different viewpoint as to what's good for a specific GM car/truck. But it is another information source backed up with some tangible credentials.

One guy I'd very much be skeptical listening to is a guy who used to hang out on Bob Is The Oil Guy forum and that's a character by the name of "540 Rat". He espouses a boat load of information, without much context as to how it may be useful to car engines. All he does is an unverified extreme-pressure wear test, or so it appears. Not much else. But he is so full of himself. He's one of those guys that won't tell or show you exactly HOW he tests oil so nobody can prove/disprove him, but if he even suspects you don't agree with everything he says, then you are a hater and must be out to get him. Pretty low self-esteem, this one. Constantly looking for approval.

I've still yet to lose a cam or engine using good quality oils and filter, and doing the recommended oil change intervals. Maybe I've been lucky. To me, I'll take it.

 

I couldn't agree more, diesel oil was barely able to be sufficient when loaded with ZDDP because of the high detergents.

I use Zinc Replacement additive that's not ZDDP but instead a synthetic Polymer Ester that doesn't foul the base oil's chemistry. Made by Hy-per Lube, it's not expensive and has been on sale @ JB Tools for $9.62 per 12oz bottle (enough for 2- 5qt oil changes). (Full strength is overkill)

 

"Stock" engines , and that's a "maybe". Problems don't just show-up after an oil change - it's cumulative damage that takes it's toll !

 

https://www.jbtools.com/hy-per-lube-...dditive-12-oz/

 

It amazes me why anybody argues against zinc in oil. There is not that much price difference (if any) between Valvoline VR1 and other motor oils. To me it is peace of mind. Maybe my 455 doesn't need it but it sure as heck ain't going to hurt it.

 

I must agree Glen. The real argument should be in the filters used, ha. However I heard the Brad Penn motor oil is stupid $$, lol.

 

My thoughts exactly and even after posting what major cam vendors say about zinc additives versus blended oils some continue to promote additives. Why take the chance when the blended oils are about the same price when you buy the zinc additives and add to oil. I guess if you've never had a problem with additives why not take that chance.

 

Three questions...

Why wouldn't the diesel detergents be bad for the camshafts in diesel engines? I'm not disagreeing just throwing the question in the ring

Is racing oil good for the way most classic cars are used? Does it prevent corrosion etc. in the long term as the car sits for months at a time? That's not exactly racing.

And....at the end of the day the VR1 is probably way better than needed!

 

This thread makes me hearken to the days I first began driving my '67 4-4-2 in 1969. Boy, we had many heated debates over STP motor oil. If it was good enough for Mario Andretti & Richard Petty the $hit had to be great...many of us began using STP from that day forward.

 

I've been using that (10W-30) for about 12 years. Been very happy with it -- no hints of any failure. It's dino juice, though.

 

Same here. Been using it in two flat tappet classics for over 30 yrs. Never wiped a cam lobe.

 

That's a good oil but it's changed in the few years, not the same concentrations as years ago.

GM Delco 15W 40 Diesel oil does fine, a little additive with it.

 

Right, wrong, or indifferent..I use Amsoi Z-Rod 10w40. I'm fairly certain it has a Wix filter on it (usually I run STP, that's why I'm not sure) but remember years ago reading a filter comparison done by Herb McCandless. He swore Baldwin filters were far superior to anything else on the market. I personally haven't tried them, but know a few who have and so far have agreed.

 

Plenty of informative threads on this subject, bearing clearance stock vs race, heat of use , plenty to read if someone is interested.

​​​​​​Dulalec Ultra 15w40 has high concentrations