What is a good zinc additive for engine oil and how much to use when the car uses 5 quarts? Is it cheaper to get conventional oil and add zinc or get oil with it already in? Will adding zinc to an engine that may not need it do any harm? New to the whole zinc in oil thing, sorry if it sounds like a few stupid questions.

Oh boy, you're opening a can of worms. It's easier (I don't know if cheaper) to get oil with high zinc. I used Valvoline VR1 Racing Oil upon the recommendation of a local Mopar engine builder who I trust. It's available at all my local auto parts stores. And, you'll find a lot of people with flat tappet/non roller cams use it and recommend it. If you decide to go with additive instead, the additive will tell on label how much to use. Good luck.

It's best to buy oil with the right amount of zinc in it rather than add any additive. There are a couple of oil testing sites that report that oil additives do not always have the intended affect. Apparently, sometimes additives clash with the oil and actually lowers the total zinc.

Nowadays, it seems no one recommends any additive for all oils.....except the additive dealer. Some do help in some oils, some times. But it is a real challenge to sort it all out.

Just buy the right oil. And I like the VR-1, too. It's what I run in my flat tappet Hemi.

There are multiple oils on the market that already have the higher zinc quantities and are specifically formulated for our flat tappet cammed engines. I like amsoil products, however there's joe gibbs, brad penn, valvoline, etc.

I seem to recall reading that indiscriminately adding zinc products to your oil can be detrimental if you overdo it. That too much zinc can cause pitting and some other chemicals that come along with these additives can cause issues if overused. Calcium levels in the additives or something if memory serves.

I would also add, that if you have stock cam/valve springs, any oil oil will be fine.

What enginees need the zinc additive?

I've used the GM EOS which used to come in a tin can (~1 pint iirc) & now is in a plastic bottle along with "regular" oil but agreed that it would be the best to use a tailor made zinc equipped oil such as one of the ones mentioned. I used to use Rotella diesel oil & it was changed (different labelling on the white plastic bottle and they lowered the zinc) but it still has some in it. I hear www.bobistheoilguy.com is a good read on the subject.

Oils with high zinc ratios are required for initial start up and brake-in for engines with old style non roller camshafts.

I use the small blue plastic bottle from STP

There isn't just one zinc-phosphorous compound that is used in motor oil. There are many. Mixing them may result in the two additive packages reacting to each other and precipitating out, leaving you with less ZDDP than the original oil started with.

Another factor to consider and is activating temperature. The different compounds react at different temperatures and have been selected by the oil company technical staff to fit a particular use.

The next factor is detergent level. Race engines come apart all the time so the oil has much less detergent. This frees up some surface for more of the zinc compound to attach to. But our engines tend to stay together longer, also are not driven enough to get oil hot enough to drive out moisture. Moisture acts as a catalyst and causes formation of different molecules, like varnish. So in a street rod type of car one needs much more detergent.

If price matters, I suggest using a good fully synthetic oil designed for your typical usage and running it twice as long. The cost difference will be negligible. Most of us are throwing away several quarts of perfectly good oil every year by changing the oil at the "magic" 3000 miles. I challenge you to run oil for 6,000 miles and send it to Blackstone Labs or similar for analysis. It doesn't cost that much. Nearly every time you will get back an OK to keep using the oil. Shoot, over the road trucks go for 100,000 miles or more between oil changes. Their duty as far as loads on bearings and cylinder walls is much higher than 97% of our rides.

I prefer Joe Gibbs Driven because they have done the research. Others can be just as good, but how can you tell?

R.

Brad Penn gets the nod within a lot of the Mopar world in these parts...

I've been using it for years...


I change it every 2500, or so...

Just like I have for the last 20 years...


Overkill???

Matter of opinion...


Takes me longer and longer to rack up the 'change' miles as time goes by...


Fresh oil and filter makes sense for such a long amount of dormant time...

I like the viscosity of a mineral oil when it's static...


I fog it(as they do in the marine world)for the winter...

Same Here !!!!!

I used to use one bottle of ZDDP with an oil change. Then I changed to Brad Penn with no additives.

100k per oil changes on OTR big rigs?! Ok, but how deep are the oil pans? I would never go 10k miles on my gas motor oil changes, but do it willingly on my cummins. Why? 4-5 quart oil pan capacity vs 12 quart capacity. More oil volume means longer till the same PPM of harmful exhaust contaminates to turn the oil acidic, and more longer till the film strength starts to break down because it's not cycled through the bearings/engine loads as frequently.

How many hours are on the engines at 100k miles vs how many hours on your average daily driver that sees lots of idle and stoplight duty?

I work for an oem class 8 manufacturer and I BELIEVE the norm for big rig oil changes is more like 12-25k miles. I KNOW the capacity of most big rig engines is in the range of 9-10 gallons

The place I used to work for had 35K PMIs.
They used regular Chevron 10-30, not a 15-40 diesel oil like Rotella or Delvac.
Most went 1.4-1.5M before they sold them off. Maybe 1 in 25 needed a "infame" before it reached the 1.5M goal.

I use regular 10-30, brand is determined by current lowest price. I add a bottle of ZDDPlus like Y07 posted above, only because I have a supply of it. Once it's gone, I'm going with one of the oils with correct Z-P in it.

http://lucasoil.com/products/engine-oil-additives/engine-break-in-oil-additive-tb-zinc-plus

- EM

I do maintenance for a heavy duty truck/trailer fleet. Company units get oil changes at 35-40k miles, most owner operators do the same. A couple guys who run synthetic aren't stretching theirs any further either. However it's worth noting a lot of trucks these days have two or three oil filters and they all take around 40 quarts to fill. With the environment they see, it would be tough to compare them to cars.

Ok, here's the details. I have a 70 Monte Carlo that gets stored in an unheated unit for the winter. I change the oil as soon as it comes home and right before storage (overkill, maybe, but that's what I do). I use Valvoline 10W30 and a Wix oil filter. I do not know the engine internal specifics since I didn't do any engine work when I got the car or since. I bought the car in 2005 and have done this every year. Depending on how many miles I drive, I may change it again in the summer. I doubt I go over 3,000 miles in a year.

Quick search on O'Reilly online shows VR-1 10w30 and it's not much more per quart.