Guest Torquemonster Posted July 29, 2007 Share Posted July 29, 2007 This has got to be the slipperyest question out there. My 1970 MC 400sb with 70,000 miles. it's tight & runs strong. I replaced the cam and all related valve train parts a few years ago. The heads or bottom end were never touched. I broke it in with conventional oil and have been running a Synthetic blend figured I would get the best of both. But I keep hearing that the Shell Rotella is best compared to going to a FUll Synthetic because of the additive package?? Why is Shell better for engines built "back in the day" compared to my 96 Impala SS that recomend Mobil One. Please give me the all dirt. It's ready for an oil change and if i'm going to change I can do it now. Thanks for the advice. Link to comment Share on other sites More sharing options...
Guest Rice Racing1 Posted July 29, 2007 Share Posted July 29, 2007 First off the federal gov has mandated new lower zinc levels in diesel oils for 2007. The level is still higher than normal gas engine oil. The deal with the zinc level is this, in flat tappet engines it acts as a hi press lube for the lifters. It is being done away with due to the fact the zinc burn off plugs cat convertors over time and since no modern production gas engine uses flat tappet cams any more it is not deemed needed by the gov and oil makers. As for mobile 1 in a hyd roller equipt engine its ok. Won't do a thing for wear on a flat tappet cam though, the lobes will wear just as fast on mobile 1 as they will on the $1.57 a quart cheap crap from wal mart!! The only syn oils with high zinc levels are the true racing syn oils like royal purple racing the $12 and up a quart stuff! Good old Valvoline racing oil has the highest zink levels period and it is availible in 10/30,10/40,20/50 and straight 30,40,and 50 weights. Not all stores carry it you may have to order it by the case and it will state on the bottle for off road use only due to the zinc level. Ignore that and go with it! From an Engine builders stand point I would like to see everyone with a flat tappet or hyd roller cam running the Valvoline racing period! BEST conventional oil on the market bar none!!! You guys with solid roller setups the true racing synthetics or Valvo racing is your onlyt choice if you whish your bearings in your lifters and rockers to survive! As far as the additive package in a full syn oil, unless its a full racing version it's no diff than the reg new api spec dino stuff. Mobile 1, any of the blends, any of the Q syn's are just exp normal oil in older cars, or any flat tappet engine or anything with high valve srping pressures! Don Link to comment Share on other sites More sharing options...
Guest Torquemonster Posted July 29, 2007 Share Posted July 29, 2007 Goood Morning Don So if I understand your reccomending Valvoline Racing oil as a first choice, Great! as the higher zinc levels will protect my Monte's engine, I will try and get it. I know you said Valvoline Period, but would the shell Rotella an acceptable second choice? Better than the syn/blend I have been running? Frank Link to comment Share on other sites More sharing options...
Guest Torquemonster Posted July 29, 2007 Share Posted July 29, 2007 Thanks Don Just picked up Valvoline 20-50w VR1 Racing oil at my local parts store. Going to go get on my cardbord recliner in the garage and change it. Thanks again for the great advice. Frank Link to comment Share on other sites More sharing options...
stangeba Posted July 30, 2007 Share Posted July 30, 2007 Don, What is dino stuff? Any reference to Sinclair oil and their mascot Dino the dinosaur? I ran Sinclair oil for the first 5 years on my Monte. Bruce Link to comment Share on other sites More sharing options...
Guest Rice Racing1 Posted July 30, 2007 Share Posted July 30, 2007 The Dino ref is for all natural crude based oils. don Link to comment Share on other sites More sharing options...
stangeba Posted July 30, 2007 Share Posted July 30, 2007 OK, that's cool. I collect Sinclair stuff so I had to ask. Bruce Link to comment Share on other sites More sharing options...
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