Opinions on oil...

[Shakin66]

I have my 347 Installed and wonder what the varied opinions are on weights and using synthetic on a brand new engine.

 

[2bav8]

I'd ask the engine builder what weight of oil to use. My engine builder was very specific to use 20-50W in my 347.

As for synthetic oil, wait until the motor is fully broken in before using.

 

[66HertzClone]

My Keith Craft stroker came with instructions that recommend using non-synthetic 10w40 oil. I have been using Pennzoil 10w40, but after I reach 3000 miles will switch to Mobil 1 10w30 synthetic oil.

Using a synthetic oil during the break-in period may not allow the piston rings to seat properly.

 

[bnickel]

i use 20w50 castrol in mine. my engine still isn't totally broken in yet as it only has driveway miles on it, i will eventually switch to a synthetic either mobil 1 or valvoline. i have used castrol syntec before and i wiped 2 lobes off the cam after i switched to it, but that is more likely because it was when it first came out and they only had 5w50 at that time.