Flat tappet cam failures

[SteveK]

One of my coworkers who is really into vettes gave me an article today about a recent increase in cam failures in older cars.  This article talked about the "perfect storm" driven by a change in motor oil makeup. (additives)   

Not sure when, but some time ago this article talked about that fact that car manufactures were required by the EPA to provide 125,000 mile guarantees on catalytic converters.   It seems that the anti friction additives are instrumental in shortening the life of the catalyst in the converters.  The article makes it sound like the big car guys had to protect their converters and when they got the oil guys to reduce the additives, it required the manufacturers to go to roller rockers to avoid the friction. 

So here we are with our older cars who's cams and rockers need some serious anti-friction help while most of the new oils have specifically eliminated this type of additive.  The article named a number of diesel engine oils which still have the "good" additive in it. (less than before however)  It also said the jury is still out on synthetics since they have just not been on the market long enough to tell.   

Since I'm in the process of rebuilding the top of the head of my car due to a wiped cam, this all sounds pretty possible to me.   Anyone out there with an opinion?

[Norm]

A good solution for both older and high performance engines is to choose a motor oil that meets the new Heavy Duty (HD) Engine Oil specification CJ-4.  These products are designed for use on HD diesel applications but require a valve wear test to be passed as part of the CJ-4 approval process.  You can find these product by all of the major brand names and normally in a 10w30 or 15w40 viscosity.  Synthetic or conventional oils are another discussion. 

Since I work in the lubricant side of the business for a major oil company I won't go into discussions of why Passenger Car Motor Oils (PCMO) have evolved to the point that you reference in your post but a little research will confirm what I am saying about the wear protection built into the new HD CJ-4 specifications.

If you would like to discuss this in more detail I think I am going to be at the Houston Cars and Coffee this Saturday.  I don't know if I will have the Mercedes or my NSX but if the weather is good I should be there.

Norm

[bogeyman]

I use Shell Rotella 15W-40. The "oil guys" I have talked to plus my mechanic say that it has the best "shear factor".
I only can relay that from my personal experience, it seems to work really well.

[Jonny B]

Yes, the anti wear agent in modern oil, ZDDP (zinc dialkyl dithio phosphate) has been decreased due to the issue with the catalytic converters. The biggest issues are in the engines that are very high performance. Racing engines are especially susceptible to this. Auto Restorer magazine in the latest issue had a very good article about this and some reasonable approaches. You can add the ZDDP back in (there are several outfits selling this), Royal Purple is another option, as are the diesel oils as mentioned in the thread already.

[SteveK]

All, thanks for the feedback.  My mind is made up to go with the CJ4 spec oil before I crank up with my new cam, rockers and ball studs.   I'm chalking this one up to "you learn something every day"

Norm, not sure yet what Saturday brings.  If no golf game shows up I'll be at the Coffee and Cars with my 52 truck