that will be helpful

 

+1 for wanting to switch to RP

 

I wasn't saying that synthetic was bad for our cars. I was just saying that "I didn't know" if it would be okay for us to go 15k-20k between changes. Maybe we can, maybe we shouldn't.I'm not sure. I just don't want anyone to to do any damage based onthe success I havewith my modern car.
I don't doubt that some brands are better than others. But I bet the difference in them is very minimal.

 

im not happy with the fact that RP doesnt meet the latest specifications for oil. why is that? i dunno.

i swear when i spent like 3 hours gathering technical date from each manufacturers site redline oil was superior to every other brand, with mobil 1 coming in at a close second.

that being said, i still use pennz dino in the II and pennz full syn in the 06gt. its never let me down yet - so why change.

btw, there are links to the oil filter comparison page around here somewhere - the motorcraft filters are actually among the best made.

 

American Iron motorcycle magazine did a series of articles on oil back in 2000. They interviewed the Mobil-1 engineer who developed their 'motorcycle' specific oil. (I think that is a bunch of B.S. IMHO) but it WAS a very informative article. It is THE bit of information that changed my mind about synthetic oil in a low stress, normal temp range engine. I came away from those articles knowing that if your engine oil did not see more that 250 Degrees nfor VERY extended high stress periods that you could not beat Castrol GTX. The engine test they quoted used a 3.8 v-6 with oil temp controlled at 300 degrees @ 3000 rpm at WOT and after 62 continuous hours of this ordeal the 20-50 Harley-Davidson (I've been told it is SUNOCO) oil solidfied.
Now, ask yourself...do YOU see 300 degrees for 62 hours @ WOT under enough load to keep the rpm at 3000? Didn't think so.
CASTROL 20-50 GTX. If it's good enough for 1,000,000 miles in a M-B 380 SEC, it's good enough for me.

 

IIRC, the latest automotive oil spec calls for reduced concentrations of zinc and some other extreme pressure additive (EPA reasons). RP (and a couple of others including oils for trucks) are out of spec on the high side on this.

BTW, too much EP to pass the latest spec is a good thing, if you're breaking in a new flat tappet cam. On edit, I'd probably continue to run something with a more-than-new-spec amount ofEP in it if I was running a flat tappet cam that called for valve springs much heavier than OE or otherwise produced a large force going over the noses of the lobes.

Norm

 

I have a 1992 Chevy Silverado...5.7L V8 with 237,000 miles on the drive train.
Nothing has ever been done to it.
When I bought the truck, it had 192000 on it, and a big Amsoil sticker on the air cleaner.
The P/O said he was the 2nd owner, and he bought it with 112000 on it, and the 1st owner used Amsoil, he however did not. He had switched back to Valvoiline 10W30.
I run the same oil today, but with that said, this engine dosnt show any signs of wear, it dosnt burn oil, it dosnt use oil, and it get 17mpg...which is good for a truck this size for 1992.
I dont use Amsoil, but I hold it in high regard. I contribute the condition of this engine to it.

 

im leaning towards the shell rotella or possibly the pennzoil 15-40 diesel oil (i need to find out if it contains the higer levels of zinc) for the II when it goes back together. the 06gt gets 5-20 which scares the hell out of me, but all the new hondas and fords are coming with it and if they are comfortable using it then it must be ok.

mike, about the motorcycle oil - i believe the difference is in the fact of having a wet clutch setup. supposes to be that using regular oil will make the clutches slip - so im guessing the cycle oil has some sort of friction modifier like rear end lube. i use whatever they carry at autozone, i believe it is valvoline dino.

 

I have run Amsoil in my 6.0PS truck for years. I think it is a great product. As for extended change intervals, a oil rep once told me that there are two reasons to change your oil. The first is due to vescosity breakdown. I know the PS engines sheer the oil badly and you should not run them longer than about 7500miles because the oil literally looses its thickness. The second reason is to remove the metal and other materials out of the oil. Filters do this up to a certain point, but most factory style filters do not remove material smaller than 40micron. 60% of engine wear is due to particles between 6-20micron. External filters can remove material this small, so most people who run synthetic and want extended run external filters. If you do not run external filters, then your are running oil with these harmful perticles suspended in it for long periods of time.

Synthetic oil is great. It is capable of running much longer than convential oils without suffereing from vescosity breakdown. The MAJOR issue with running oil longer are the particles suspended in it. Changing your oil often helps eliminate the affects of these particles, so if you are going to run 7500+miles, you should really use an external filter capable of filtering smaller particles.

I love Amsoil and the idea of synthetic oils. I run it in my diesel because I feel it is a supieror product. You cannot cost justify it. If you do everthing you should inorder to run the oil 10K+miles, you will not break even. The oil and the filter systems just cost too much compared to the $30 oil change. It is still cheaper to run traditional oil and change it every 3-4K. If you are like me and feel it is a better product, then use it, but do not think it is a good return on your money.

Edit: I hear Royal Purple and Redline are also great products. I just have not used them.

 

hell even with the full syn in the new stang im changing the oil and filter at 5k - i dont care if its premature or not.

(i can always use the used oil in the crappy mower or any other random projects