Cam Wear?

[grannyknot]

Well, I could not think of a way to drill out the spraybar inlet where I could be 100% sure that the metal fillings could be cleaned out perfectly so I left it as it was and blew it out with carb cleaner and compressed air.

Once the engine catches I'm sure everything is covered with oil.

[Mark Maras]

I've used a torch tip cleaner to coerce some clearance in the oiler holes. I was surprised how choked the holes really were. 

[Chickenman]

I've used a torch tip cleaner to coerce some clearance in the oiler holes. I was surprised how choked the holes really were. 

I use the same tool to clean out my W/Washer nozzles... but great idea for the spray bar

[Chickenman]

To OP. One thing that I'm surprised has not been asked... what are you using for a Motor oil? Modern energy efficient Motor oils have the percentage of ZDDP ( high pressure Zinc and Phosphate additive package ) reduced so much,  that these " Modern " Energy Star oils cannot  provide enough shear strength for high performance Cams and higher pressure valve springs on older Valve Train designs. It is a HUGE industry wide problem on Vintage cars and Muscle cars with flat tappet cams or finger followers.

 

These new oils are barely adequate for stock cars. Only reason they work is that most new cars have Roller Tappets or Roller Finger  followers.

 

These days, you absolutely MUST research the oils  and use a correct formulation before you buy. Any oil rated SN or SM has vastly reduced ZDDP amounts and is inadequate on modded cars with any type of flat tappet or finger follower.

 

Pretty much any " off the shelf " Motor Oil under a 10/40 weight is SN rated. Start looking at the specialty oils with higher ZDDP concentrations for Vintage motors. I use Joe Gibbs Hot Rod full synthetic in the 10/40 weight, but there are many " Specialty " brands formulated for Vintage and HP engines.

 

More information can be found at BITOG ( Bob Is The Oil Guy ) which is one of the best no BS sites for all Lubrication information. Actual chemical engineers and Motor Oil researchers contribute to the site. Do some searching and you will find charts and recommendations for most popular motor oils with Zinc and Phosphate levels. But bottom line is...stay away from API SM or SN ( Energy Star ) rated oils. Especially if you have a high performance cam and stiffer valve springs. You have a Vintage car..you MUST use an oil formulated for a Vintage or High Performance engine.

 

http://www.bobistheoilguy.com/

 

There is also a very good oil article on the VW Vortex forum on recommended Motor oils for Big Turbo Engines.  This was a particularly  good Technical discussion thread with info on the whole ZDDP debacle. Turbo engines are particularly hard on Motor oils. 1.8T VW/ Audi engines have bucket followers that are sensitive to ZDDP levels, when you run bigger cams and stiffer Valve springs.

 

Well worth reading:

 

http://forums.vwvortex.com/showthread.php?5867396-Built-Engine-Big-Turbo-Heavily-Modified-engines%28aftermarket-cams%29-what-Engine-Oil&highlight=Big+Turbo+Oil

 

BTW...I'm " Chickenman35 " on that Forum

Edited April 13, 2015 by Chickenman

[Chickenman]

(Snip)

Can you just trade out one rocker for another? I thought the lobe and rocker had to wear in together.

I'm hoping that by improving the start up oiling that the lobe and rocker won't get any worse or am I just kidding myself?

Thanks,

Chris

Matching followers to lobes is more important on on designs that use a round tappet. Those are designed to rotate during operation. The Cam lobe has a slight taper mahined in to the face and the Lifter has a matching " Crown " on the face. Typical domestic flat tappet design. Lack of rotation will destroy those tappets in short order, that is why it is critical to match the lobes to used lifters.

 

The design of the Datsun L series engine  has no taper ground into the camshaft Lobe. As long as the cam lobe is in good shape, you can safely swap in another follower if necessary. A good used Nissan/Datsun follower is better than an off shore made  POS.

 

To OP: I would replace that follower ASAP. It's on the way out and failure is not far behind. You are already " galling "  the cam shaft lobe. I would also recommend either replacing that camshaft, or sending it out to a reputable Cam shaft grinder and have that Lobe " Micro-Polished ". It's saveable at this point... but eventually if you keep running it like that it will destroy the Lobe. If it's a HP cam and you have stiffer valve springs installed, do it NOW... not later.

 

And you certainly do not want to wear through the surface hardening of the Cam Lobe (   only a few thousandths thick ).  Once you do that you hit softer metal underneath and the Lobe will fail VERY rapidly. You do not want " Chilled Iron " filings running all through your motor. That can destroy a complete engine. Catch it now and correct the issue while you still can. 

Edited April 13, 2015 by Chickenman

[Zed Head]

My impression has been the zinc additives are necessary for break-in, to build up a smooth case-hardened wear surface, but the cams and rocker arms do fine with today's common no-zinc oils after a proper break-in.  I've been using common oil for ~30,000 miles on my current high mileage stock engine, from a 78 280Z, and did the same with my old 76 engine for about 25,000 miles.  I did use  5 quarts of Rotella once on the 76 engine because it was on sale.

 

Most of the cam problems happen with new or reground cams, shortly after break-in.  Often, it's with the zinc-additives.  There seems to be a general problem with the way cams and rockers are ground today.  Makes you think that there's a bad specification out there that everybody is using, or the factory cams have a subtle profile to them that is important for long life.  Like the fact that lash is typically higher one side of a lobe than the other.  Maybe the grinders, cam or rockers, are grinding to a shape that applies to much pressure on a certain spot.

[Chickenman]

No that is an incorrect impression. It is not just during breakin that ZDDP is required. It is required in sufficient amounts throughout the lifetime of the valvetrain.

 

Z- cars have a very stout  valve train design with very well matched metallurgy. That is the only reason why we haven't seen more problems with our valve trains. But we are borderline none the less.

 

The reduction of Zinc is wreaking havoc in all forms of Vintage and High Performance cars. Even brand new Vehicles are having problems with the lack of ZDDP. VW/Audi are having HUGE problems with their direct port fuel injection cars.

 

They have a high pressure ( 1,000 + psi ) Mechanical fuel pump that is driven of an eccentric lobe on the cam. They used a DLC ( Diamond Like Coating ) bucket lifter instead of a roller lifter to actuate the mechanical pump. Guess what?? ..they're all wearing out because even with the DLC coating, the buckets cannot survive at the reduced ZDDP levels. Huge warranty issues for VW/Audi and other engine designs that use this type of HP Fuel pump actuation. VW trying to keep it all hush, hush. But they are seeing failures in all Global markets WITH factory approved oils.

 

Joe Gibbs Racing has a video on why you need ZDDP in Vintage and High Performance engines. It's a bit " Hokey ", but any Professional engine shops all know these facts are true. And if you follow NASCAR, JGR was the first to develop it's own custom engine oils in the late 1990's to fix a problem that Chevy was having with lifter failure ( Nascar mandates flat tappet cams.. no roller cams allowed ).

 

Pay particular attention to the Valve Spring pressures that API uses in it's testing!!!

 

https://www.youtube.com/watch?v=lQ6NXXLZA3A&feature=youtu.be

 

BTW, it's worthwhile reading all of their Tech articles.

Edited April 13, 2015 by Chickenman

[Chickenman]

Another good Tech bulletin to read is the one on High Temperature High Shear issues with new API standard motor oils.

 

http://www.drivenracingoil.com/news/dro/training-center/latest-tech-bulletins/hths-tech-bulletin-september-2012/

 

BTW, I'm linking to JGR Driven oils just because it has factual information and in a no BS language that the average gearhead can understand. . I'm not a JGR " fanboy ". I use what is best for my engines. ( I use Rotella T6 5w-40 full synthetic in my Audi..because it is an HDEO that works well in Turbo engines and it's HTHS properties are extremely high )   You'll find the same tech info at Redline, Motul, Amsoil, and most importantly... all of the major aftermarket camshaft companies such as Lunati, Isky, Comp Cams, Edelebrock etc.

Edited April 13, 2015 by Chickenman

[Zed Head]

No that is an incorrect impression. It is not just during breakin that ZDDP is required. It is required in sufficient amounts throughout the lifetime of the valvetrain.

 

Impressions are, by their nature, not incorrect.  They are the result of what the person has experienced.

 

Anyway, I've seen all of the writing on why people with old cars need to buy expensive oil.  My point is that many, many, many of us don't use zinc additives on our old cars, and our cams and rockers are fine after many,. many, many miles.  And, in addition, I've seen many accounts of people who used zinc additives during break-in, on essentially stock systems and still wiped their cams and rockers.

 

When you collect all of the real world accounts, not just the theory, and do the math, reality doesn't match the theory.

 

A poll would be interesting, to see how many people are running common oil on the their stock engines, and for how many miles.  Compared to a poll of how many people have wiped a new cam lobe and/or rocker pad, while using zinc additives.  If you wanted precise numbers.

[grannyknot]

Chickenman,  I use diesel oil in my older cars and bikes, it still has adequate  levels of ZDDP and I add some of this stuff with every oil change,http://www.acdelcochemicalcatalogue.com/view_picture_description.php?prod_id=15&start=0&page=1&search_frn=Lubrifiants&search=Lubricants

 

The description doesn't list ZDDP but there is lots of in there.

 

I buffed up the cam lobe and rocker and removed most of those marks so now I'll pull the valve cover every 300 miles and have a look.

Chris

[Diseazd]

My guess is that if a new camshaft is destroyed on start up, it's probably more from a lack of lubrication flow than the type of oil. I've never had a problem with camshaft break in, but I make sure I fill the oil pump with oil before installation to insure it's primed.....also coat lobes and rockers with heavy zinc break in lube. If Isky recommends VR1, I'm going to use it.......may not make a difference, but I don't want to find out that it does.

[Chickenman]

Impressions are, by their nature, not incorrect.  They are the result of what the person has experienced.

 

Anyway, I've seen all of the writing on why people with old cars need to buy expensive oil.  My point is that many, many, many of us don't use zinc additives on our old cars, and our cams and rockers are fine after many,. many, many miles.  And, in addition, I've seen many accounts of people who used zinc additives during break-in, on essentially stock systems and still wiped their cams and rockers.

 

When you collect all of the real world accounts, not just the theory, and do the math, reality doesn't match the theory.

 

A poll would be interesting, to see how many people are running common oil on the their stock engines, and for how many miles.  Compared to a poll of how many people have wiped a new cam lobe and/or rocker pad, while using zinc additives.  If you wanted precise numbers.

Not trying to argue with you..but you're trying to re-invent the wheel. The evidence of adverse ZDDP reduction on flat tappet cams is already well documented ad-nauseum. If you choose not to believe it, that's your choice. As for myself, I have seen plenty of older flat tappet engines destroyed by using these new " Energy Star " motors. Mainly in Detroit Muscle cars but also a lot of Vintage British cars. It was an issue 10 years ago and still is today.

 

I doubt that a Poll will reveal much in this particular case. The stock Nissan L series valve train has excellent metallurgy. That is a proven and documented fact. And it's going to have a very small data pool. And if you use a 10/40 wt or higher motor oil you will probably not run into the problem as these are not considered " Energy Star " classification.

 

The problems are rampant in Forums outside of Nissan/Datsun, in engines that use flat tappet cams, such as GM, Ford, Pontiac, Chrysler VW/Audi etc. Those are the ones that are full of failures directly due to ZDDP reduction. And there are literally Millions of data points out there. I've seen enough first hand and trust the advice of the Professional engine builders that I deal with to convince me. Mind you, I've been an Amsoil user for over 20 years.. but even Amsoil has recently changed and it's oils aren't as good as they once were.

 

As far as theory vs actual fact? I trust the results of independent oil testing laboratories such as Blackstone Labs. And white papers by SAE and technical articles on Motor oils by Race Car Engineering, Race Car Tech, Race Car Engine,   David Vizard, Joe Gibbs Racing, my engine building shops  and others.

 

With respect, just because you or a small sampling of people don't have a problem does not mean the problem doesn't exist

Edited April 14, 2015 by Chickenman