I did a search and founds lots about what oil to use, but not much comment about zinc. So, some questions:

How many are adding zinc to their oil in older flat tappet engines?

Or, have you found an oil with enough zinc in it?

How much is enough?

What brands of oil or additive?

Thanks.

 

For me it was just easy to put Joe Gibbs Driven classic car oil in my truck as opposed to adding zinc.

 

I use Rislone Oil Supplement with Zinc/ZDDP Treatment as my first quart of oil at every oil chage for all my vehicles listed in my profile.

 

I use Valvoline VR1.

 

I don't worry about zinc. That wasn't added to the oil until the late 50s. It was added only to help the high revving high performance V8 motors with very stiff valve springs. I don't have an engine like that so no worries. For engine without a catalytic converter the diesel engine oils have a very good anti wear package. I run 15W-40 diesel oil in most of my old cars. My 37 has better hot oil pressure with the diesel oil.

 

I seem to remember reading somewhere rotella T (15w-40) has a decent amount of zinc in it. Hopefully someone can verify that.

 

Pretty sure I read on here that it used to but no longer does.

 

I have Brad Penn break in oil, straight 30 weight in my newly rebuilt flat tappet 223 six. Will stay with their high ZDDP oils. From what I have read the extra cost is cheap insurance to protect the investment.

Penn Grade 1 High Performance Oil

 

Rotella has far less zddp than it used to.

I run Redline brand additive in flat tappet engines, and roller engnes with very aggressive cams. Costs me 25 bucks a year for peace of mind. Probably a waste of money for most modern stock engines.

 

The zinc levels in oil have been reduced in order to stop plugging catalytic converters. This has been discussed and proven time and time again. Apparently a side effect of this thin layer of protection in the combustion chamber causes the cats to plug up pretty good.

Any oil currently made that has the same levels of zinc, now deemed bad for emissions vehicles, is not for sale by 99% of parts stores. VR1 may be the most common, but still has reduced levels. Using additives can be tricky. Unless you know how much you need, you are either going overboard or running low. Either way I am sure is bad (not saying it is or isnt, just assuming).

In my air cooled Beetle, I run Brad Penn. Never had issues with it.

In my fresh built flat tappet 289, I run Castrol GTX with no additives and no problems.

This spring, I am running all my vehicles and bikes on Amsoil exclusively.

Many old school mechanics I talk to have ran off the shelf oils with no additives with no issues. The real issue I believe after discussing this topic with many of these knowledgable people is something entirely different, not related only to reduced zinc levels in oil. What I personally believe is most entry level race cam companies have changed the alloy mix to save money, making cams cheaper to produce. My cam is an older cam that was in real good shape, so I kept it. Upon last inspection, no abnormal wear. Most of this information came from an extremely reputable source...since I don't grind or cut cams, nor do I know the metalurgy behind it. He does however.

 

Good points Fordman. It should definitely be pointed out that zinc is bad for many converter types. I have had the zinc conversation with a very reputable custom cam guy. He probably specs 20 hi perf custom cams a month. He has definitely seen failures among his customers, so his advice is going to be on the conservative side. I know he recommends Brad Penn and Royal Purple. I don't think he has seen failures with the other popular synthetics though but I am not certain.

I think you really need to know what your ramp rates and spring pressures are to make a decision. One size fits all advice is probably not prudent from me or anyone else. My mild cammed 53 with a 306 would probably be fine with any decent oil. My Mustang has ridiculous ramp rates and good springs. It is getting good stuff even though it is a roller motor.

The high end additive manufacturers do publish their zddp concentration levels so you can get your concentrations where they need to be. A little too much zinc is not going to hurt a car without a converter, which applies to most of us here.

 

This is a good read on the subject: Zinc and oils for older engines

 

Here is a pretty good one from Hot Rod (2009) that mostly just addresses flat tappet concerns.

Flat Tappet Cam Tech - How to Prevent and Fix Cam and Lifter Failure - Hot Rod Magazine

 

Thanks for that info fatfenders. I was always worried that I put in too much when I used the additive and either figured it would be hard on the bearings or oil pump perhaps. Ignorance is not always bliss!

 

You are wise to be cautious about dumping additives into oil. From what I have read, all additives are not guaranteed to properly disperse in all brand oil base stocks.