What's the story with zinc and camshafts???

[atomicjoe23]

What's the story with the zinc?

I've heard people mention using "zinc" when breaking in a cam twice now on this forum but I've never heard of it before now (not that I've installed any new cams before though. . .so I'm not calling BS, I'm just not familiar with it). . .

. . .I've got several engine rebuild books and I DVR every episode of PowerBlock TV and Gearz and I don't ever remember them mentioning it before either.

What does the zinc do. . .beside the obvious "protect the cam". . .shat specifically does the zinc do to protect the valvetrain?

The only thing I've heard is to coat the cam lobes, lifter faces, and pushrod tips with assembly lube and to lube the cam journals and lifter sides with engine oil.

If I run engine break-in oil will this have the zinc in it? or is something separate I have to get?

[SPONSOR]

Membership in the largest desert racing community has its advantages - Participate in Forum Discussions - Send and Receive Private Messages - Maintain Public Photo Albums - Access to Groups - User Profile in our Social Network - Increased Access to more Sub Forums - Reduced Online Advertisements Join our community today

[1audiohack]

Zinc is one of the few extreme pressure addatives used in conventional engine oil. Molybdeum and phosphorus are a couple of others. The E.P. in gear oils are not soft metal and few are yellow metal friendly.

Zinc is a disolved soft metalic that is great for sliding hard metal to hard metal interfaces like flat tappet lifters on camshafts. It has been removed from virtually every HMO engine oil as it reduces the life of catalytic converters by plating them (with zinc) like leaded gasoline will with lead. It has even been removed from the diesel oils, like Delo 400 is now Delo 400 LE, no metalics.

Engine oil has changed! If your engine oil does not state that it has zinc in it, you can bet it does not. That's one of the reasons almost all newer engines are roller cams. There are addatives like ZDP or racing oils like Joe Gibbs that have all the good stuff in them. Some of the more expensive oils like Schaeffer's use highly processed molybdeum (the clear stuff) that protects very well. Moly is one of the most expensive oil addatives, most oils now just go without.

[atomicjoe23]

So I could just grab a bottle of zinc additive and toss it in. . .then prime the engine to get it mixed up really good before I start the engine?

Is one bottle enough (although I'm sure the additive bottles tell you how much to add it would be nice to know ahead of time)?

Thanks for cluing me in!

[jeff]

GM has a special break in lube that can be added to conventional oil.
http://www.summitracing.com/parts/NAL-88862586

I learned the hard way on a BBC in my boat that a reduction in ZDDP (zinc), not a total elimination of zinc, can cause lifter and cam lobe failure. It was an expensive lesson in motor oils and how they've changed over the years. Diesel oils like Rotella with the CJ-4 spec generally have higher ZDDP levels than "Gasoline Engine Oils" but it's nowhere near as high as the old CI-4 spec. Some guys are still using certain Rotella oils as a low buck alternative to the racing oils. I decided to rebuild the motor with a roller cam to prevent future problems from occuring. Whatever you do, don't fire your new motor until you get the right oil in it! A quick Google of "high zinc racing oil" should give you plenty of options.

Aloha

[atomicjoe23]

Thanks for the heads up!

Does it make a difference if it's not a new cam, but only new lifters. . .I would think not, it would make sense that you still have to wear the new lifters to the cam. . .

That picture is scary!!!

[Shawn M.]

Break it in just like you would if it was a new cam including the zinc content of the oil.

[jeff]

That picture is scary!!!

You should have seen the lifters! I saved two of them as reminders. This was an engine that had maybe 100 hours on it when the cam and lifters took a dump. Reformulated oil ruined an otherwise excellent running motor.

Aloha

[ChromolyKid]

I have a bit of experience with this as I recently rebuilt a 350 with a flat tappet cam, and all I can tell you is that the zinc is absolutely 100% necessary for a flat tappet cam, EVERY oil change. Put a bottle in every time because your lifters will mushroom if you don't. Glad I sold that turd flat cam and bought a full roller with the money

[atomicjoe23]

I totally believe you guys, but at the same time I'm scratching my head. . .I pulled the lifters from this engine and they had very little wear. . .they definitely weren't mushroomed. . .and I can guarantee that the previous owner wasn't adding zinc every oil change.

I believe that it's necessary for cam break in (whether that's a new cam and lifters, or just new lifters) but every oil change? I don't think many people do that.

I'm just curious here. . .

[scottm]

Good advice given in this thread. Yes street oil has less zinc and phosphorous now, and its not enough for a flat tappet cam. And yes there are millions of ft engines still running around without enough zinc. The key is valvespring pressure, rpm, and wether its already broken in or not. All new ft cams have to be broken in with a special oil like Joe Gibbs Breakin or regular oil with an additive, like gm EOS or the stuff from ZDDPlus.com. I use a Torco additive I get from my machine shop, but its hard to find. All real racing oils (non dot) have enough too, but they are very expensive and do not have normal detergents and stuff that street engines should have. Regular trucks and cars with low perf cams in normal driving may not ever have a problem, but they probably will eventually. I always use a supplement in my ft engines from now on.

http://www.zddplus.com/
http://www.compcams.com/Base/pdf/Fla...chBulletin.pdf