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

atomicjoe23

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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?
 

1audiohack

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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

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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

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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
 

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atomicjoe23

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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!!!
 

jeff

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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. :mad:

Aloha
 

ChromolyKid

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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

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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

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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/FlatTappetCamTechBulletin.pdf
 

atomicjoe23

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I didn't take into account spring pressure. . .I guess that and how aggressive the lobe profile is (and maybe if you have hardened lifters?) are the two biggest contributors to camshaft lobe wear
 

jeff

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Seriously? Run whatever oil you want. When the lifters are destroyed and the cam goes flat in your recently rebuilt motor you can pat yourself on the back for a job well done.

Aloha
 

atomicjoe23

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Seriously? Run whatever oil you want. When the lifters are destroyed and the cam goes flat in your recently rebuilt motor you can pat yourself on the back for a job well done.

Aloha

. . .little harsh there don't you think?

. . .I'm just trying to learn from you guys. . .plus it's not a rebuilt motor, more like freshened up ever so slightly. It's a $200 used motor out of a '79 K-Blazer (but less than 100K miles). . .all I've done is replace all the gaskets, paint it, and replace the intake manifold and carb.

If it eats the cam and lifters it, then it eats the cam and lifters. . .lesson learned and not that expensive of a lesson either, a cam costs about $150 and lifters are about $50, so for $200 I've got a new cam (something I plan on doing in the future anyway). . .although I do plan on using the zinc additive. I was just stating that I thought it curious for it to be such a big deal about the zinc and in 15 years of driving I've never used it or even heard about it before outside of an occasional reference to new cams, but never for regular everyday use.

I'm asking you guys because you have more experience than me and I hope that by asking I can avoid the mistakes that others have made ahead of me. . .and I take the advice that I get, but I'm entitled to ask questions to clarify. . .the internet is like TV, you can't believe everything your hear (read. . .)
 

63chevyll

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this is easy,
run whatever oil you want with a 1 can og BG MOA and you will be fine,

also, you wont always be able to tell if a lifter is good or bad by just looking at the bottom.

they are slightly convex and you wont be able to see it with your eye, when the wear they become flat, then mushroomed

I buy MOA by the case at Napa or Advanced auto parts. It has been prooven stuff and i have proof!!!! THE STUFF WORKS VERY WELL PERIOD!!!!!!!!!!!!!!!!!!!!

http://images.google.com/imgres?img...&prev=/images?q=BG+MOA&hl=en&gbv=2&tbs=isch:1
 

rich1

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does anyone have any experience with amsoil and flat tappet motors. I talked to my amsoil guy and he said it worked well, but I would rather hear from someone less biased. I use the signature series 0w-30.
 

philofab

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Motors that are older have all the surfaces work hardened from use. New stuff is still really soft, so an anti shear agent is required (zink). If your building a performance motor save yourself time and money and install a roller cam.

I run 20-50 Rotella T with a zink additive in everything I own. Not good for the cat but I don't care.
 

scottm

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Rich1, what is your application? Is the amsoil youre talking about a street oil or race only? All DOT rated street oils do not have enough zinc, even if its a full synthetic. Real race oils, conventional or synthetic have enough zinc, but no detergents or anti-corrosion agents, which street engines need. I know of two good options for street flat tappet engines: get any dot oil you want and add a zddp supplement, or use 4-stroke motorcycle oil, which has the right amount of zinc and detergents. Iether way it will be about $4-5 per quart.
 

rich1

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Rich1, what is your application? Is the amsoil youre talking about a street oil or race only? All DOT rated street oils do not have enough zinc, even if its a full synthetic. Real race oils, conventional or synthetic have enough zinc, but no detergents or anti-corrosion agents, which street engines need. I know of two good options for street flat tappet engines: get any dot oil you want and add a zddp supplement, or use 4-stroke motorcycle oil, which has the right amount of zinc and detergents. Iether way it will be about $4-5 per quart.

I am about to swap in a 350 SBC crate motor. It is the 290 HP version that I am going to upgrade to 420 HP using Edelbrock performer RPM kit. The motor already has 3k miles on it, but the edelbrock kit uses a new cam, complete heads, intake, and carb. This motor is going into my race truck that I do drive on the street very rarely. Being in Texas, it is somewhat street legal. Why would it matter if it is used for street or race? Are you refering to the emissions or the application? Maybe cat conv? It does not have any smog equipment whatsoever.The amsoil dealer tells me it is their race oil, but I do not know. I have been using it in my 302 sbf motor with good results, but it is a roller. I basically want to know what oil to use for breaking in the new cam and valvetrain, and then what oil to use for racing. Keep in mind, I do have a working relationship with Amsoil. Not free oil, but very wallet friendly.
 

scottm

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Those edelbrock kits work great! The issue is how you drive the truck. Race oil should only be used in high maintenance race-only engines. If you drive the truck around on regular errands and quick beer runs like a normal car, race oils are a mistake. Whenever an engine is run without getting fully warmed up, condensation from combustion blow-by builds up in the oil resulting in corrosion, oil/water emulsion and sludge formation. Street oil has detergents and corrosion blockers that normal cars need to fight off these problems. Race oils do not have these additives because they lead to chamber deposits that can cause detonation. I say get amsoil dot-rated street oil and use a zddp additive for your cam. I have a flat tapet cam in my race truck too, but I run a lot of shortcourse races and I dont want to change 12 quarts of $10 race oil after every 30 minute race. So I run Redline full synthetic street oil with Torco zddp additive, and change it every 300 to 500 race miles.
 
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