What about zinc?

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cruiser

cruiser

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Hi Guys/Gals. I have a very stock 1974 slant six engine in my 1974 Duster. Stock motor and heads, mix of town and highway driving. I change the oil about every 2500 miles. I use NAPA store brand 10W-40 oil in it year round, altho I don't drive it outside in our Minnesota winters. I just warm it up in my garage. The NAPA store oil that I buy is API grade SP, repackaged Valvoline oil (at half the price - $11.99 for a five quart jug). This stuff is way better than what we had back in the day when my car was new. In any case, does my car need zinc additive? I kinda thought that by 1974, they didn't need zinc rich oil any more. So I don't use racing oil with zinc, nor do I add zinc at my oil/filter changes. What do you think? Slant six Dan, if you're out there, please weigh in. Thanks all!
 
I think the zinc was/is primarily for engines with flat tappet cams (which your car has) but I don't think it needs a lot. In my flat tappet engines I generally use a product designed (or at least that is what they say) for older vehicles which I believe has some zinc in it.
 
70chall440 said:
I think the zinc was/is primarily for engines with flat tappet cams (which your car has) but I don't think it needs a lot. In my flat tappet engines I generally use a product designed (or at least that is what they say) for older vehicles which I believe has some zinc in it.
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You'll have to forgive me for asking, but what does "flat tappet cam" mean? I know I have solid ( non hydraulic) valve lifters that need periodic adjustment, but I really don't understand what a flat tappet cam is. Can you help? Thanks.
 
cruiser said:
You'll have to forgive me for asking, but what does "flat tappet cam" mean? I know I have solid ( non hydraulic) valve lifters that need periodic adjustment, but I really don't understand what a flat tappet cam is. Can you help? Thanks.
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Flat tappet=non roller lifters. In other words, what you have.

I like to run higher zinc content than what's "off the shelf" in anything flat tappet anymore. Just my personal preference. I can link to thousands of sites and tech articles that support my opinion, but you can also find information that says it's not needed.

My opinion is, the zinc content in oils when these cars were new(er) was much higher. The engineers didn't put it there on a whim.

I personally use Lucas 10w30 Hot Rod and Classic oil with 2400 PPM of zinc. I've broken in and run several flat tappet cams with it and not had a failure yet. The "ZDDP" compound is a combination of zinc and phosphorus and provides both additional anti scuff wear protection as well as extra cooling. There's real science and history behind it, it's not an opinion. It's scientific fact.

Flat tappet camshafts scrub the bottom of the lifters and the lobes making contact and need that extra protection. Some say once the camshaft is broken in with ZDDP oil or additive, after that, it's safe to run modern oils with much lower content. My personal opinion is to continue running ZDDP oil for the life of the flat tappet engine.

ZDDP was in the original oils for flat tappet engines and I believe that's what's best. That's my opinion and I stand by it.
 
I am not a slant 6 expert but I would have thought by 74 the /6 would be using hydraulic lifters? Anyway, there are basically 2 types of cams (as it relates to this discussion), a roller cam and a flat tappet cam. within these 2 "categories" there is solid and hydraulic in both styles.

On a flat tappet cam (solid or hydraulic) the base of the lifter rides on the cam lobe directly. The lobe raises the lifter up and down as it rotates and the came imparts this movement to the pushrods which in turn push (hence the name) the rocker arms which "rock" and open the valves.

On a roller cam, the lifter has a wheel in the base which "rolls" on the came lobe and does all the same things as the flat tappet cam.
 
There has been volumes written about this subject here at FABO. Use the search function and hold on.
 
70chall440 said:
I am not a slant 6 expert but I would have thought by 74 the /6 would be using hydraulic lifters? Anyway, there are basically 2 types of cams (as it relates to this discussion), a roller cam and a flat tappet cam. within these 2 "categories" there is solid and hydraulic in both styles.

On a flat tappet cam (solid or hydraulic) the base of the lifter rides on the cam lobe directly. The lobe raises the lifter up and down as it rotates and the came imparts this movement to the pushrods which in turn push (hence the name) the rocker arms which "rock" and open the valves.

On a roller cam, the lifter has a wheel in the base which "rolls" on the came lobe and does all the same things as the flat tappet cam.
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First year for hydraulic lifters was 1981 for the slant 6.
 
Goes to show you what I know about /6's... LOL I think I might have owned 1 or maybe 2 cars (out of like 140) that had a /6 but I know I never keep one very long. Not hating on them at all, just did have a lot of experience with them, I was much more of a BB guy.
 
70chall440 said:
Goes to show you what I know about /6's... LOL I think I might have owned 1 or maybe 2 cars (out of like 140) that had a /6 but I know I never keep one very long. Not hating on them at all, just did have a lot of experience with them, I was much more of a BB guy.
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I understand completely. I'm the opposite. I've had over 400 vehicles, most with V8s of some sort. I've just fell in love with the slant 6 and going to keep messin with um. Most fun I've ever had with a car.
 
Mobil 1 lists the zddp content (which is what you're really after) for every flavor that they make.
Review it, and see if you can find published info for your preferred oil choice.
It's supposed to be more critical in a new cam application, but I had tons in my 360 and it still wiped 2 lobes. I'm a roller cam man, now, but I don't know if that's even an option for slant 6's
 
RustyRatRod said:
I understand completely. I'm the opposite. I've had over 400 vehicles, most with V8s of some sort. I've just fell in love with the slant 6 and going to keep messin with um. Most fun I've ever had with a car.
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Such a car *****....
 
As far as the “start and let it warm up”, unless you can take it out and drive it, it’s best left alone for the winter. IMHO.
 
cruiser said:
Hi Guys/Gals. I have a very stock 1974 slant six engine in my 1974 Duster. Stock motor and heads, mix of town and highway driving. I change the oil about every 2500 miles. I use NAPA store brand 10W-40 oil in it year round, altho I don't drive it outside in our Minnesota winters. I just warm it up in my garage. The NAPA store oil that I buy is API grade SP, repackaged Valvoline oil (at half the price - $11.99 for a five quart jug). This stuff is way better than what we had back in the day when my car was new. In any case, does my car need zinc additive? I kinda thought that by 1974, they didn't need zinc rich oil any more. So I don't use racing oil with zinc, nor do I add zinc at my oil/filter changes. What do you think? Slant six Dan, if you're out there, please weigh in. Thanks all!
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Imo -The worse thing that you can do is "warm up" your car instead of driving it. The motor never completely gets warm and this builds condensation from the motor all the way through to your exhaust. (recall the condensation running out of your tailpipe) The best thing you can do is keep the battery on a Tender and only start the car unless your going to drive it.
 
A56 said:
Imo -The worse thing that you can do is "warm up" your car instead of driving it. The motor never completely gets warm and this builds condensation from the motor all the way through to your exhaust. (recall the condensation running out of your tailpipe) The best thing you can do is keep the battery on a Tender and only start the car unless your going to drive it.
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Somebody give this man a medal
 
A56 said:
Imo -The worse thing that you can do is "warm up" your car instead of driving it. The motor never completely gets warm and this builds condensation from the motor all the way through to your exhaust. (recall the condensation running out of your tailpipe) The best thing you can do is keep the battery on a Tender and only start the car unless your going to drive it.
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A56, that's a great point, and it's well taken but there's one problem with it. I just can't leave my car alone all winter long here in Minnesota. I've nicely finished out my garage - sheetrocked and painted walls, painted floors, gas furnace in the ceiling, six foot deep mechanic's pit in the floor. Once my Duster is waxed up and clean, it looks so good sitting there that I just have to start it up and run it. I've set up the slant six totally stock, so when it's cold and I start it up it runs on the high idle setting before I kick it down. The air bypass door in the air cleaner intake opens up to provide warmed air to the carb off the exhaust manifold. The engine starts transferring coolant to the reserve tank, the temp gauge comes up to the full operating temp and stays there. For some inexplicable reason, I just love watching this process unfold even though I can't back it out of the garage because there's two feet of snow out there. The best part is listening to that lovely solid lifter motor run at high idle, then kick down to a butter smooth idle. So yes, I can see your point, but I just can't resist the temptation to warm it up every few days. You look forward to small things like this when you live in a frozen tundra all winter long. Anyhow, there's my lame explanation. Show's how sick I am.
 
cruiser said:
A56, that's a great point, and it's well taken but there's one problem with it. I just can't leave my car alone all winter long here in Minnesota. I've nicely finished out my garage - sheetrocked and painted walls, painted floors, gas furnace in the ceiling, six foot deep mechanic's pit in the floor. Once my Duster is waxed up and clean, it looks so good sitting there that I just have to start it up and run it. I've set up the slant six totally stock, so when it's cold and I start it up it runs on the high idle setting before I kick it down. The air bypass door in the air cleaner intake opens up to provide warmed air to the carb off the exhaust manifold. The engine starts transferring coolant to the reserve tank, the temp gauge comes up to the full operating temp and stays there. For some inexplicable reason, I just love watching this process unfold even though I can't back it out of the garage because there's two feet of snow out there. The best part is listening to that lovely solid lifter motor run at high idle, then kick down to a butter smooth idle. So yes, I can see your point, but I just can't resist the temptation to warm it up every few days. You look forward to small things like this when you live in a frozen tundra all winter long. Anyhow, there's my lame explanation. Show's how sick I am.
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You're not sick, but a man who loves his car!
 
cruiser said:
A56, that's a great point, and it's well taken but there's one problem with it. I just can't leave my car alone all winter long here in Minnesota. I've nicely finished out my garage - sheetrocked and painted walls, painted floors, gas furnace in the ceiling, six foot deep mechanic's pit in the floor. Once my Duster is waxed up and clean, it looks so good sitting there that I just have to start it up and run it. I've set up the slant six totally stock, so when it's cold and I start it up it runs on the high idle setting before I kick it down. The air bypass door in the air cleaner intake opens up to provide warmed air to the carb off the exhaust manifold. The engine starts transferring coolant to the reserve tank, the temp gauge comes up to the full operating temp and stays there. For some inexplicable reason, I just love watching this process unfold even though I can't back it out of the garage because there's two feet of snow out there. The best part is listening to that lovely solid lifter motor run at high idle, then kick down to a butter smooth idle. So yes, I can see your point, but I just can't resist the temptation to warm it up every few days. You look forward to small things like this when you live in a frozen tundra all winter long. Anyhow, there's my lame explanation. Show's how sick I am.
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I'm not to far south of you and I start mine up a couple times each winter (usually during a January thaw) and drive it around the lot to lube up the transmission and rear end. I don't get it out on the street with all the salt. I usually wait for a couple spring rains before getting it out on the streets in the spring.
 
For long term storage use



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I know in my slant (totally stock), I used 15-40 heavy duty diesel oil. That stuff has all the vitamins and minerals that you need. Keep in mind I did not run it very long, however every one of my old hot rod friends run this stuff with a half bottle of lucas motor honey and have run them like that for YEARS.
Also, it'll never hurt to run zinc additive in an old engine if you are scared of flattening a cam, it does not hurt to put zinc in it.
 
shittyslant6 said:
I know in my slant (totally stock), I used 15-40 heavy duty diesel oil. That stuff has all the vitamins and minerals that you need. Keep in mind I did not run it very long, however every one of my old hot rod friends run this stuff with a half bottle of lucas motor honey and have run them like that for YEARS.
Also, it'll never hurt to run zinc additive in an old engine if you are scared of flattening a cam, it does not hurt to put zinc in it.
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Not anymore. The ZDDP was reduced a few years ago. About the same time converters were required on diesels, I believe. About 2004.
 
I run diesel oil and also add a bottle of lucas additive with each oil change. Might not be necessary but its cheap piece of mind.
 
RustyRatRod said:
Not anymore. The ZDDP was reduced a few years ago. About the same time converters were required on diesels, I believe. About 2004.
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Yes, but they still have some stronger detergents and other chemicals that are just better than the car oil ones. That is why I used the lucas stabilizer with it. Zinc is really just an extra lubricant, so I just I used the lucas as the lubricant instead.
That is also why I said if he is uncomfortable with that, zinc additive will never hurt.
 
shittyslant6 said:
Yes, but they still have some stronger detergents and other chemicals that are just better than the car oil ones. That is why I used the lucas stabilizer with it. Zinc is really just an extra lubricant, so I just I used the lucas as the lubricant instead.
That is also why I said if he is uncomfortable with that, zinc additive will never hurt.
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Which is why I prefer oil with ZDDP already in it. Look up Hyper Lube ZDDP additive in the clear bottle. Read the back label. It clearly says "Contains no zinc or phosphorus". So you have to be careful when buying additives. Rather than be careful, I just choose oil with ZDDP already in the mix.
 
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RustyRatRod said:
Which is why I prefer oil with ZDDP already in it. Look up Hyper Lube ZDDP additive in the clear bottle. Read the back label. It clearly says "Contains no zinc or phosphorus". So you have to be careful when buying additives. Rather than be careful, I just choose oil with ZDDP already in the mix.
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that is what I am going to do with the 318 when I get the cam in there. the Valvoline I think it is 15-20 racing oil with ZDDP in it already. expensive as hell though
 
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