I was wondering what oil i should use

guy who did my pistons (ctr high Compression) said i should use regular oil rather than Syntec i mean the part of my motor with the high milage is the valve train and the crank do you think it would hurt if i now switch to syntec or should i just wait till i do the valve train and everything else and then start with syntec

 

whats high mileage, need a number.

 

crank and valvetrain-145,000
everything else-say 20,000

 

i'd say just stick with 5w30 or you could go to 10w30.

 

Maybe he meant to say use regular oil during the piston break in period so the rings set properly. But since you've been on regular oil for about 20k miles and there are no excessive leaks than I'd say switching to synthetic is fine. And when you change your valvetrain, synthetic should still be fine as they don't need a break in period to set like rings on pistons do.

But like I said, if you do have leaks than synthetic oil is not the best choice because it is thinner and it will leak out faster. Thus wasting extra $$ to top off the oil more often.

Good luck!

 

yes, use regulr. They say, after 75K miles, its better because the synt is thick. For older motors, the regular will burn better and more easily......Ive heard this from many people....or u can use the high millage oil too