Lube-Tips Newsletter [mailto:
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Above is a handy little news letter I used to get when I was working with pumps. I still get it because it contains good general application information about lubrication. Below is a rules of thumb that was posted in the news letter for cold weather (actually any temp.).
"The pour point is the lowest temperature at which an oil will flow. This property is crucial for oils that must flow at low temperatures. A commonly used rule of thumb when selecting oils is to ensure that the pour point is at least 10 degrees C (20 degrees F) below the lowest anticipated ambient temperature."
So going off of that it's just as we all know as it gets colder you need to lower that first number on the multi-vis oils and as it gets hotter it needs to come up. In a nut shell, if the viscosity is to high for the oil to "poor" (bottom number i.e. 5W, 10W, etc.) it wont flow on startup and the oil wont get through the engine fast enough, if it's to low on the second number (30W, 40W, etc.) it wont protect when it's hot. If you guys running in the colder areas it very important to look at that bottom number in the winter.
Another thing to remember is that your oil pressure is very critical to bearing life, going to low or to HIGH can cause premature bearing failure. To low and the oil wont get there to lube and cool things and to high it starts eating up bearings and blowing seals. Everyone jumps on the high volume oil pumps. Not always a good idea! For example: If you look in any old Chilton's manual you will see that up until 1970 Chevy ran oil pressures as high as 62lbs but in 1971 the oil pressures drop to 40lbs across the board. That is because after extensive testing Chevy found that the higher pressure was actually wearing the bearings out to fast. If they lowered the pressure they still got the protection required and increased bearing life on top of that. Remember that it isn't really the pressure that keeps your engine safe it is the ability for the oil to resist breaking down under shear load and heat. I have seen a GREAT example of this when two of my buddies got an old Ford Galaxy for $50 bucks and after beating the crap out of it on the farm for a few days put the rear axle up on jack stands, started the car, put a brick on the throttle, and let the car run until it died. It took 2hrs at WOT and on top of that they had drained the oil first! That was COOL!
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Originally posted by screamingchief:
But NONE of the cam makers will warranty a cam broken in using sythetics,after the cam (or a fresh engine) is broken in it is fine to use,synthetics actually work too good for any parts that have metal to metal contact to allow proper break-in,they will not allow a proper wear pattern to form on mating parts.Every gear company I've come across recommends using std gear oil for breaking in gearsets for this very reason.
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This is very true. If your breaking in an engine a good rule of thumb is to use a straight 30W oil. This will let the parts "lap" in. Of course follow the cam manufacturers break-in procedure to the tee! After the engine is broken in you can use the synthetics or whatever your choice is.
Here is a little tid bit of info. The guy that is doing the work on my car has a chassis dyno. His son did a little experimant one day and put Mobile on in his 2002 Z28 (that's what he normally ran) and than ran it on the dyno. He pulled the car off the dyno and changed the oil to Royal Purple and put it back on and tested it again and gained 2hp. I have seen this kind of test done on TV of course but and I always wonder about seeing a 2hp gain on a chassis dyno. I would think that was SO FAR inside the margin of error on that machine that you wouldn't know if there really was a change.
Uneasyrider