I've read on various sites where some people add a bottle of GM EOS with their oil when doing the initial break-in of a new motor. BUT, I read on the bottle that it is to be used as an assembly lube not as an additive. Hmmmm?
I can remember when GM spec'd the stuff for break-in but they have obviously chnged their position. I think it's because modern oils don't need extra additives.
If you properly lubed the cam and lifters and your engine was machined and cleaned properly then you shouldn't need it. Cam breakin is the most critical part to be concerned about. The lifters get there lube from oil splash so whatever's in the pan won't reach them for several seconds on start up. That's why you have to lube those surfaces with the clinging lubricant on assembly.
Make sure your distributor is in correctly and the carb is set up so it starts and runs right away. Most flat cams come from extended start up sessions.
Verify the pushrods are twirling.
The problem is compounded with Kendall oil that is no longer green and the EOS that no longer has zinc in it. Kendall will tell you that nothing has changed (B.S.) we used to drain the oil and it would still be green after a couple of races, the new stuff looks dirty after 50 laps.
So, since you cant break in the camshaft on synthetic, Green Kendall and EOS was the ticket for not hurting the cam in the first five minutes (along with 1.2 rockers) back in the day.
I read in the new Car Craft magazine that several camshaft makers have been having lots of returns on camshafts for loosing lobes on breakin. It seems some of the newer oils have a lower level of zinc. I guess that provides some of the protection that stops camshaft wear. I believe that Crane Cams were the first to figure it out. Is this something new or old news I just heard about?
Its pretty much old news now. I think the EPA mandated removal of zinc from many products. The biggest loss to me was the loss of zinc in GM EOS. I've got some of the old stuff left, but when its gone thats it. There was a father son Ford drag race team from Washington state named Van Cleve, they were other worldly in their performance, I once saw them add 2 cans of EOS to a fresh unrun motor they were dropping in, I did some research after seeing that.
I read that too and was intrigued because we've had a discussion on root cause of cam lobe failures. If the lack of zinc in oil causes lobe failures why isn't everyone having lobe failures? Sounds like a shred of truth being stretched into a new urban legend. Remember the doom scenarios's when lead was taken out of gas?
I'll have to ask around and try to find out what's true and what's not.
My theory is that roller camshafts don't need the same additives as a flat tappet camshaft? Do any of the newer cars have a flat tappet camshaft? I think that flat tappet camshafts are mostly used by rebuilders and it's easy to blame failurs on a small shop or a shadetree mechanic. When you rebuild an engine every five or ten years you are an easy target for the reason why the camshaft fails. It could be a rumor or a reason.
I'm guessing that some premature cam failures might be caused when the lifters used don't have the stellite slug on the bottom (flat lifters only). It seems like zinc was a band aid of sorts for soft lifters that got them turning and got through the break in without killing the cam. I was having so much trouble at one point, I'd use some #80 grit sandpaper and scuff the bottom of the stubborn lifters to get them to turn in their bores while I rotated the cam with a speed handle,(no pushrods or chain of course). I only did this on motors where a stellite lifter was not available.
The "lack of zinc" is old news.Seems it coats the ox sensors on new cars so most oil companys have reduced the zinc content,Mobil 1 has none.
The break-in is important.We assemble,break-in and race 3 oil changes with 20w50 Kendal GT1 to inpregnate the cams,followers and other parts then switch to 10w40 Mobil 1.The link gives a little insight into this situation. http://www.micapeak.com/info/oiled.html
The new Hot Rod Mag has an article about Cam Break in and problems the Cam manufactures have been plagued with.
They recommend Diesel Oil during Cam break in. Apparently due to emission standards oil companies have been forced to take out certain types of lubricants, however Diesel Oil and Off Road racing oil still contain this lubricant that Cam companies like to see during break in. They recommended using Rotellla T diesel oil
I dont just break in cams on Rottella, I run it all the time in my nova, my pickup and my motorcycle. When breaking in cams I also add a bottle of GM oil additive.
I work at a truck dealership and see engines go a million miles running this stuff so it must be pretty good.
Besides still having zinc for the added prevention of metal to metal contact, it has higher detegent levels and really keeps the insides of your engine clean, and because most all heavy duty diesels have gear trains for running the cams it has additives for gear lubrication for the tranny in my motorcycles.