The Stovebolt Site Forums The Shop Area Engine Shop Zinc Needed ?

I was reading Patrick's catalog, and he says that all oils have insufficient zinc could ruin a cam very quickly. Has this been the experience of the Stovebolters?

A zinc additive seems to be necessity for cam/lifter break-in.

Zinc in standard engine oil does not sem to be necessary but it does not hurt. Some diesel oils supposedly have higher levels of zinc.

http://cranecams.com/uploads/breakin/548e.pdf

The "zinc" mentioned is zinc dialkyl dithiophosphate or ZDDP for short.
It aids lubrication in sliding/rubbing contact applications like cam/lifter contact.
Obviously the harder this contact the more important is the lubrication layer or oil film, so it is pretty minimal in our older engines at low rpm and light spring pressures--compared with heavy spring loading and max rpm for performance.
Cam grinders once included with the cam or recommended the use of EOS (engine oil supplicant)for their cam breakin--dip the lifters and anoint the cam during assembly then dump the rest in the crankcase.
EOS was marketed by GM and contained a heavy dose of zddp and ????--came in a pint can and was later changed to a quart can.
I don't think GM supplies anymore but WallyWorld and FLAPS will have a ADVERTIZED equivilent on the shelf.
Most premium motors oils once contained zddp before the heavy restrictions to protect cat converters etc limited it.
A WAY to easily identify the more desirable oils with zddp is to look closely at the nickel-sized circular product spec label on the container.at the top of the circle will be the oil design ratings like SF-SE-CC-CE etc. but what we are looking for is in the bottom part of the circle.if you find "energy conserving" the zddp has been left out--if the lower half is blank ZDDP is present.
Max zddp will be found in diesel engine oils(perfectly acceptable maybe even preferred ),racing oils, small engine oils, and motorcycle oils.
Our old engines are not terribly sensitive in my opinion.

All very good information from Bob. Older engines already broke in need very little additive, but you will not hurt a thing adding some if you feel better about it. Diesel oil has been cut back just as the automotive oil has, so don't assume a engine is protected just because its diesel oil. Almost all racing oils still provide the need protection. Heavy valve springs, extreme lobe designs, and high rpm are what really need the additives. The old inlines with 80 to 90 lb. valve springs will last a life time with out it. Some race springs can have over 400 lb. with the valve open, you can see where that might wear a cam out!!!!

Joe

The first few minutes of operation on a new cam is the critical time when extra lubrication and/or ZDDP is necessary. The wear pattern between the cam and lifters is being established during that time, and the absolute worst thing that can happen is to allow the engine to idle. Lots of oil is being thrown off the crankshaft and connecting rods at higher speed, so the cam and lifters are being flooded with oil splash. I've seen race cams get worn out in the first few minutes of operation when the break-in procedure was not followed.

I like to get the engine in as good a state of tune as possible - - - -valve adjustment, ignition timing, coolant level, etc. as close to correct as possible so the engine fires up with a minimum of drama. As soon as I see good oil pressure, I bring the RPM up to around 2,000 and hold it there for 20 minutes or so. Monitor the coolant temperature closely- - - -it's not uncommon for trapped air in the cylinder head to cause an overheat condition during the initial run-in, so avoid that possibility at all costs. After 20-30 minutes of fast idle, the engine can be slowed down and final adjustment tweaks can be done if desired. That's also a pretty good time to do a hot retorque on the cylinder head, final valve adjustment check, etc.
Jerry

....I have NOT purchased any EOS from GM lately but I have "heard" that they once again carry it on the shelf. Perhaps in response to the very problems we're talking about. Joe and Jerry is dead on.

..Jerry, I like your comments about having everything right before starting to avoid the "DRAMA" on start up. The first few minutes is definitely critical. I recently seen the lobes on a 600HP plus Camaro that was about as round as you can get. "David" learned his lesson the hard way. No wonder the engine was "skipping".

ZDDP is one of the things they are taking out of modern motor oil as a concession to emissions control it poisons the cat.
There are still a few oils out there that have high enough ZDDP content to keep the old engines happy like Vavoline VR1 that's what manny run in the MG engines, but then that's just getting happy at 3000 rpm as opposed to a 216 that is topping out in that range.
It's better if the oil has some ZDDP for nonroller style lifters, if you look hard enough you can find oil with some in it.

This is one of those things that comes up form time to time on on forums where you have old style engines.