On a 302 with 10:1 compression (or so the P.O. told me), in the Bay Area of California. Temperatures in the 55° to 75° range. Any help here please? Brand & weight?
Thanks!!
not to hijack the thread but i have a 289 with 10 to 1 compression also, but i live in florida, i have been using 10 w 30 but i am not sure if it is correct
Best way to choose your oil weight is to use a mechanical gauge and guage your oil pressure from there. The rule of thumb is 10 lbs of pressure per 1,000 RPM. So, if you have a 6000 RPM redline a max warm oil pressure of 60 lbs is ideal.
A combination of that and what the ambient temp is.
Temps of 60-80 with stock clearances will allow a 10w-30, 10w-40, or 15w-40. You can also base it off the oil pressure as 2bav8 said. I use 10w-40 or 15w-40, but it gets into the low 100-110 range here in the desert. Usually Chevron brand.