oil weight question

Why 20w50? That is awefuly thick oil for an engine designed for 10w30. Thick oil may protect better, but unless the clearances are large enough it won't flow very well, and will actually protect less. Unless the engine has been rebuilt for this, I wouldn't run it. It will also cause more drag on the oil pump that will rob the engine of power, and could even break the oil pump shaft. So if you are going to run it, make sure you have an upgraded oil pump shaft. Thin oil may "protect less" but it will flow better, which will result in better protection, and will free up more HP. Oil starvation is more of a concern than anything else. Also, consider the worse time for wear is on start up, where the oil has drained down, it's going to take a lot longer for that oil to reach moving parts especially when cold. Unless your engine is built for 20w50, I would go a little thinner.

I run 0W40 Mobil 1. Super thin when cold, just a bit thicker when hot. I ran different oils before between 10w40 and 5w30 as well as 10w30. I read a lot of reviews on the 0w40M1 from different sourses. With the 10w40, the engine seemed to run well once warm and I had little noise, but it was loud on start up. The 5 and 10w30's were better at low RPM and cold start but I could always hear valve noise in upper RPM's. Now with 0W40 I am very impressed. Almost NO noise on start up, instant oil pressure, and it stays up there, and no high RPM noise at all, engine runs the best on this stuff.

Also, for protection, look into the zinc content of the oils.

I always use what the factory recommends. 10w30 is what I would use

Try a polymers in motor oil search. It turns out that the wider viscosity oils like 10w-40, 20w-50, 0w-40 have more man made polymers in the oil, which supposedly means less lubricating quality of the oil. 10w-30 oil has the least amount of polymers in it and the owners manual recommends 10w-30 so thats what i use and synthetic amsoil.

4rdnut said:

Try a polymers in motor oil search. It turns out that the wider viscosity oils like 10w-40, 20w-50, 0w-40 have more man made polymers in the oil, which supposedly means less lubricating quality of the oil. 10w-30 oil has the least amount of polymers in it and the owners manual recommends 10w-30 so thats what i use and synthetic amsoil.

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Very true of conventional oil but synthetic is another story.

93lxSaleenclone said:

I have no clye why he used 20w50. Thats why i was going switch to something else. Whats normal for oil pressure? Id have to double check but i think im running about 50 to 60.

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normal is about 20psi hot idle and 40-60 psi @ 2,000 rpms is good.

10W-30 here.
Try to run the thinnest you can.
I notice a difference if I use 10W-40.

5W30 or 10W30, nothing else on that motor. 20W50 is senseless, and hopefully he hasn't caused any damage by doing that.

I prefer 5W30, as it is better for the motor on cold startup and during the first few minutes of operation. That said, 10W30 is what they had when these cars were first made, it's what is called out in the owners manual, and people have gone well over 100K miles on it, so 10W30 is just fine, too.