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Am I being woofed??

2K views 15 replies 13 participants last post by  gemini86 
#1 ·
I am just getting my engine rebuilt (sbc 280 cam daily, driver) after a cam lobe flattened and all my bearings wiped, either from assembly problems or from cam pieces. This was after 4500 miles! Anyway, my mechanic says that he wants to use 15-40, I believe diesel oil with some king of break-in additive in the oil (costs 8$ per oil change) instead of plain ole 10-30 or 20-40 Castrol. He says this is because they have removed some additive from the oil that is needed for lubrication of flat tappet cams. Is this true, or is he covering for a poor breakin job?
 
#2 ·
comando57

I believe that if you will search this site there have been numerous discussions about using rotella diesel oil for break in. about 3-4 months ago in car craft (I think) they ran an article talking about the lack of sulfur and something else in gasoline oil due to emissions. diesel oil does not fall under this yet so it still has the additives in it. also they said racing oil still has them.
 
#9 ·
wrnchmaster said:
I don't think either one of you have a clue..back to basics :nono:
Actually, they are very clued in. With today's cam profiles, spring pressures, and less than cam-friendly oils, their advice is spot-on. I would add that a good (Crane) moly lube is essential on the cam lobes and lifter faces on assembly. Even when all the proper clearancing and checking is done, cams have a nasty habit of rounding of lobes if the lube isn't up to par.

I would spend some time checking out the posts on this and other forums concerning cam break-in procedures, etc., before making statements that make you seem uniformed.

:nono:

tom
 
#10 ·
It's not that zinc and phosphorous have been removed, they haven't. The percent by weight or PPM, has been lowered to meed new specs. So instead of say 1200 to 1500 PPM of Zn you may only have 700-800 PPM. That is why you use a diesel oil or an oil such as a 20/50 for break in which does not have to meet the latest specs.
 
#13 ·
The problems are happening long after break-in. Most of us use an additive during break-in, but then go to our favorite brand of motor oil and think that life is wonderful. Then we are devestated when the cam goes flat in in 2,000 to 5,000 miles. Point is the Rotella is needed at every oil change and not just during break-in period. Most racing oils are currently exempt from the reduction, and still have a sufficient supply of zinc. It looks like converters will be required on 2007 diesel vehicles, and this might be the end of the higher zinc content in the diesel oils next year. You can also use GM EOS additive to insure that your oil has sufficient zinc.
 
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