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Originally posted by KW:
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Originally posted by Ray H:
Well, for one thing, the steering committee that slogged out the protection recommendations for SM motor oils was composed of automaker reps as well as oil company reps (who make up the API - duhh...) No where were the aftermarket performance component people who manufacture wild profile camshafts operating with flat tappets and spring loadings that would stop an elephant mid-charge involved. I don't feel sorry for competitive racers who grind a cam down to a toothpick in short order if they use a passenger car motor oil never intended for such duty. There are specially formulated racing blends for their extended duty applications. Better yet, buy a cam/lifter kit that includes roller followers.
I think the SM oil is a big step down as far as oil performance. Now Amsoil has even re-labled some of the oils saying they meet the SM spec. I really hope this is not true or I'll have to re-think the oil I feed the 7 vehicles and 2 motorcycles sitting in the yard.
I have a suspicion that a major percentage of these so called flat-tappet cam failures are more related to the break-in or cam installation process than strictly to the reduced levels of ZDDP. Recall that the maximum Z and P levels were only reduced 20% from 5 years ago. I find it hard to believe that some critical point was passed with such a small change. And if a good cam lube grease with the proper amount of additives was slobbered on the cam, that 20% becomes a much smaller percentage change in the break-in oil.
Japanese manufacturers were concerned for their older engines in service that didn't have roller element valvetrains and conducted there own test. Those tests, which ran through a normally long OCI, revealed that wear didn't significantly increase in their older roller-less valvetrain engines until ZDDP levels dropped below .05%, thus the minimum of .06% was included in the SM/GF-4 spec where no minimum was specified in previous ones.
Further, I believe there have been a quite a few of these aftermarket valvetrain failures due to just bad parts like low quality overseas manufactured flat tappet lifters. However, when the SM/GF-4 spec came along the temptation to use it as the scapegoat was just to overwhelming and allowed some of these cam manufacturers to deflect the anger onto someone else.
Here's another example of misdirected blame. How many times have you seen amateur engine builders use Scotch Brite, Rolo Bristle, Soc Att, abrasive discs to clean up manifold gasket sealing surfaces after a cam and manifold upgrade? Nothing will kill new bearings and probably a new cam quicker if the debris from those discs get inside the engine. How much has this been advertised around the internet?
One last point. SM/GF-4 oils have to pass two engine tests which measure valvetrain wear, the Sequence IIIG and the Sequence IVA which are both roller-less valvetrain engines. Both tests run under very severe conditions for 100 hours and have lower wear limits than the SL/GF-3 specs.
I'll concede that if you have aftermarket flat tappet cam with an very aggressive lift profile and high pressure springs in a pushrod pig-iron engine, SM/GF-4 oil is not going to cut it for break-in, or for anything but a really short OCI. However, in all other cases, I just see a lot of irresponsible fear mongering going on.
Here's a blurb from Joe Gibbs Performance that is a more balanced in it's description and remedies for hi-po flat tappet cam engines. (Note that even his very high ZDDP content oil has cam failures.)
A technical bulletin from Comp Cams and the recommendation from Crower to use high zinc content oils for break-in of flat-tappet cams comes in response to the growing problem of cam failure during initial break-in. Joe Gibbs Performance MicroZol BR is the only fully formulated oil designed specifically for breaking in flat-tappet cams. The high zinc content formula has been used to break-in every flat-tappet Nextel Cup engine built here at Joe Gibbs Racing for the last 6 years. In fact, the development of MicroZol BR reduced the number of camshaft failures during break-in at JGR from 1 in 10 to 1 in 40. Proper preparation of lifters and cam lobes by polishing both the lobe and lifter foot aid the break-in process and further reduce break-in failures. It is also critically important to ensure proper parallelism of the cam lobe and lifter. For improved break-in success, we recommend that you use our Engine Assembly Grease to coat cam lobes, lifters and pushrod tips during assembly. Then use MicroZol BR petroleum based break-in oil during break-in. We also recommend that you use a tape of chemical polisher to improve the RA finish of your cams and lifters prior to break-in. Some companies sell pre-polished products, so you don't have to buy the equipment to do it in house. Again, there is no substitute for proper lifter to lobe geometry, so once you put the right pieces in the right places, you now have the right oil and assembly grease to protect you investment in time and hardware.
http://www.joegibbsracingoil.com/news/060316b.php
