Oil weight question

[Yellow75]

I have a fairly stock 302 that has about 40? thousand on it (crate motor from ATC by previous owner). Anyways, i've been running 10w30 but when it gets hot and I come to a stop it only puts out about 5-7 psi of oil pressure. Sooo, I changed the oil today and put in some Valvoline 20W50 Synthetic oil and the oil pressure drops to about 20-25 now at a stop but when I first fire it up cold it hits almost 60, also when hitting high rpms's. Am I going to hurt anything? Will my oil pump be able to keep up?

 

[astark]

If you have a stock guage like mine, it may not be right. But you should have no problem with the 20W50, it's good stuff.

 

[EricLar80]

South Dakota gets pretty cold I'm sure, so you may want to run a thin oil (10w30) in the winter, but not during the summer. Personally I run 30w all year round in California, but I live where the weather is extremely constant. Your oil pump will be able to keep up, but I know that you run the risk of breaking your oil pump shaft and/or ruining your bearings if the oil pressure is too high. When you first start up 60lbs is fine, but you don't want a constant pressure like that, only when you are on (full throttle) the go pedal. Rule of thumb is 10lbs for every 1000 rpm, so 5-7 lbs at idle is pushing it. I had over 60 thou on my old engine, and it would still run 20lbs at idle on a warm day, and 38-40lbs on the freeway. Good luck!<br>-Eric

 

[74bronc]

20W50 will not hurt anything in your motor, especially if it is synthetic. The reason why you have higher oil pressure is because the oil is thicker at all temperatures across the board and it takes up the extra space in the engine clearances. Won't hurt anything.

 

[t2jeff]

yep, mine drops from about 15 down to about 5 or 10 while driving, kinda scary, but this info is from the stock gauge...........think I will try a thicker weight also, thanks!<br><br>jeff

 

[Broncobowsher]

I run 15W50 in mine year round. But, I live in Phoenix. I don't even have to winterize my boat. I don't like that heavy of an oil except that I built my engine a bit loose and I need the thickness to build some pressure when sitting in traffic.<br><br>I see that you are in South Dakota. Use a lighter oil in the winter. That heavy oil will have a hard time pumping when cold. Just take a quart of oil and put it in the freezer for a day and see how thick it gets. You can place enough stress on the oil pump drive shaft to twist and break them. It also makes for a hard starting engine. <br><br>As far as high RPM with the thick oil, I would recomend driving around a little and getting the oil up to temp (not the water temp) before winding it to the sky. or use a lighter oil.<br><br>The heavy oil also hurts gas mileage a little. You have to put more work into spinning the oil pump that isn't productive. The actual difference you probably will never notice.