oil temp vs water temp

[madmaxx]

Excellent point, and I know nothing about big blocks. I know very little about stroked small blocks but I know they have very tight tolerances, .002" in main bearings, utilze needle bearings in hydraulic roller lifters, the size of the oil hole in the lifters is tiny not to mention the hole on the roller rocker arms to lube the valve tip etc. I would have serious reservations about using anything heavier than 10W30. I think you nailed it, whatever the builder indicates. I know Roush, KC and Ford recommend 10W30 in their stroked small blocks.

I have personnally seen the difference in 20W50 and 10W30 on rocker arms with an engine running. The 20W50 overflows the rocker arm cavity and it would appear there was a ton of oil as compared to the 10w30 that pentrates through the rocker arm bearings and valve tip hole. Obviously the 10W30 was doing a superior job of getting oil to the bearings while 50% of the 20W50 was just overflowing and draining back into the head.

Originally Posted by JBCOBRA

Hi Madd
I totally agree with everything you said. Especially if your builder recommends a certain weight of oil. Not all engines are designed for 10/30 however. So there is a yin and yang thing.
The goal would be to make enough pressure, close to 60, but not exceed the pump relief pressure valve.