The Stovebolt Site Forums The Shop Area Engine Shop Reformulated Engine Oil

Hello!

I've heard a lot of talk lately about the reformutation of engine oils. From what I've heard the new oils are missing additives that older engines need. Does anyone have information on this?

Randy Baumann,

Lots has been written on this subject, and many folks opinions based on misunderstood info! Here is my unprofessional take on the topic.

You are probably referring to Zinc, which is a extreme pressure additive added to motor oil. I think it is shown as ZDDP in the list of ingredients, and the levels have been reduced to help auto makers achieve emission requirements.

This additive isn't critical in any engine you would find in a old Chevrolet car or truck. Most of these engines were produced when the oil of choice was non-detergent which had few anti-wear additives.

The lack of this zinc can be a factor in the cam lobe/lifter interface of a new engine with high performance (stiff) valve springs. This area can wear rapidly, transfer material and generally fail in very short order if a metal to metal situation is allowed. It's a smearing/shearing zone and requires something to keep it lubricated until the surfaces wear and polish to each other.

Some of the API diesel rated oils contained sufficient amounts of ZDDP to satisfy this cam/lifter problem area, but I understand even those oils are having their levels of zinc reduced.

There are aftermarket additives that will solve this problem.

These are hot-rod, big cam solid-lifter engines with big valve springs or dual valve springs. Most engines with flat tappet cams aren't effected. Most modern engines use roller cams so this critical boundary zone doesn't exist.

That's my take on this often hot topic.

Stuart

atomarc:....."most engines with flat tappet cams aren't effected" ......

I think so?! I would say especially them!
A local shop just recently ruined a nice rebuild job by putting in oil that did not have the proper Zinc additive and I personally felt the lifters which were dipped out real bad and also the cam lobe was practically round. All this happened in very few miles.
Randy, if you do a search on this you will find seveal posts about this problem and I remember one that I personally started because of the engine failure I just mentioned. The thread got pretty long and is FULL of info.

I tend to agree with Stuart on this one. I've checked with several very experienced machinists I know, they don't buy all of the flap either. Most of the failures that's been seen all have a few things in common, they were all fresh rebuilds, and they all had some sort of aftermarket cam. It really points more to improper assembly, incorrect break in, or low quality parts. I work in the auto reapir industry, we put the "low zinc" oil in flat tappet engines all the time. I have yet to see one fail. BTW, I just went to some training on oil manufacture and testing. I can't say for other companies, but Valvoline uses a FLAT TAPPET engine to do their cam wear test.
Not wanting to start anything, just my own opinion based on experience.

Achimpmunk,

My post only reflects what I have read. I have no first hand experience with a cam or lifter failure due to lower levels of zinc in motor oil.

The articles I read, which were authored by cam manufacturers and major oil companies stated the only area of concern for this was a brand new cam install which involved new, high pressure valve springs...a hot rod engine.

After the initial break-in period, after the lobe and lifter face wore to each other and were polished, the need for extra protection was no longer needed.

I feel safe in saying there never was a stock Stovebolt engine that came anywhere near needing a zinc rich oil.

Stuart

Longbox: don't worry. Nothing is getting started. I actually enjoy all the opinions. I know that a couple "performance" companies put out a letter about this but feel a lot of it was perhaps due to poor quality on their part and it was "CYA".
Nevertheless, right or wrong, I would recommend doing as I have always done and that is use a quart of EOS (GM's Engine Oil Supplement) when starting up a new engine. Simply because todays companies try to "cheap up" a part and you never know what changes they have made!
I've worked on cars most of my life,evem at a dealership "many" years ago and have spent some time at my brothers shop. He built racing engines for over 25 years and you can probably imagine some of the stuff he,and myself, seen happen to engines!

The thread about a year ago about the zddp in oil was a good one but things change "regularly" with the formulations and even down to the color of the dang oil bottle.
It seems I remember a lot of folks going to Rotella because of this but BEWARE. Even the "diesel" oils were reformulated a while back. There is also a couple brands that "tout" having the zddp in it but can't remember them at the moment!

My own personal choices are Valvoline and Castrol but AFTER the break in most any oil will do the job if proper maintenance is done on the vehicle.

It's relatively easy to tell which oils still have adequate levels of zinc in them. Look for the API service symbol on the oil container. If it says SL or lower it has plenty of zinc. You'll notice the sample is SM which has the lower level of zinc. I've read that some of the oil companies are going to introduce specialty oils for flat tappet engines but have only personally seen one so far. Many here use Rotella but I've noticed that it is now rated SM too (at least all I've seen here). I've started buying farm fleet oil at the local farm store because it still is SL.

Alvin, you are right about the stovebolt engines not needing much zinc. It has been the new cams and lifters with high spring rates thats eating the cams. A stock 6 cyl with 40 to 50lb valve springs isn't going to need much protection, the EOS GM sells will do the job.
The real problem is the radical cam profiles they are using now, most makers try to get as much lift as fast as they can, so the ramps are really steep. To keep the lifter on the cam, really heavy springs are needed, 200 or more pounds, so now you can start to see why the extra protection is required. A few of the cam makers recommend soft spring for a break in period or at least removing the inner springs.
Dad and I recommend the Brad Penn racing oil (web search for it), our local dyno shop won't run a engine with out it. Its the old Kendell oil reformulated but still a very high zinc content, if not the highest. I also don't like the Rotella's, they are to thick and have a funny smell to them. Thick oils wear the cam/distributor gears to fast and is hard on cold start ups.

This is my opinion, so feel free to throw it out. Joe

Interesting comments! I've been building "performance-enhanced" engines for over 40 years, starting back in high school with a flathead Ford V-8 that used various leftover parts from the family dirt tracker. Since then, I've run competition sports cars, a few (thankfully!) drag race engines, street machines, tractor pull engines, and a couple of hotrod boats. 1/4-mile dirt tracks are still my favorite, however. Nothing beats the sound of a dirt tracker running on alcohol with a gear-driven roller cam, and wide open exhausts. Some racing associations outlaw the roller cams, so we have to run flat tappets with triple valve springs andc extreme seat pressures to handle the RPM when a driver breaks the tires loose to power through a turn. I distinctly remember our driver's comment back in the mid-50's about RPM after a gear change one night- - - -"Well, hoss,- - - -it's runnin' 6,000 down the straightaway, and 6,200 in the turn!" He was talking about a 300 cubic inch Ford flathead with a 4 1/8" stroke, and 3 main bearings!

Cam break-in is very critical on those engines. I use a set of stock valve springs for startup, and run the engine at 2,500 RPM for at least 20 minutes before pulling the heads and installing the racing springs. I've seen too many round-lobe camshafts to do it any other way! After the initial break-in, it's pretty uncommon to see a worn-out cam, even on a full-house race engine.
Jerry

I 100% agree on using EOS for break in, it's an exellent product. Proper break in is the key, as well as proper assembly.