so the shop that did my motor work callled me today......my block is finally done.....again[&:]
the guy said that he called JE tech support and they said that with forged pistons, i can no longer use 5w30 oil, aparently im supposed to use 10w40.......the guy at the shop said that he has never heard about this before.......has anyone on here??????

 

Im not going to disagree or agree, keep in mind, every mechanic differs slighty, and it shows hows your mechanic here and the mechanic as JE have different opinions.

What about at colder temperatures, if I ran that recommended 10w40 here in Manitoba during winter, it would never start without a plug in, and thats not always an option to plug in.

Maybe its a high performance thing

 

I've been using 10W40 forever in mine, probably why its stood the test of my beatings! I'd want to use the thicker oils such as 10w30 10w40 in a performance engine, the only time you shouldnt use anything but 5w30 is on the Chrysler Equiped MDS system for Cylinder deactivation, it will fk with that but otherwise you'll be allright.

 

10w40 is fine to run. I've used straight SAE 50 in the Texas summer before.

 

Oil weight has to do with clearences. A group of engineers at Buick ran their dirt track car with tight bearing and piston to wall clearences and light weight oil as an experiment and it lived. Since forged pistons expand more as they heat up cold clearence needs to be increased. The thicker oil acts as a cushion. Same with bearing clearences thicker oil is needed because it flows slower from the oil hole in the crank to the edges of the bearing insert. My Diplomat has over 200k and I run 20W-50 because it has clearenced itself out from wear.

 

on my old green Neon and in my dads red Neon we run/ran 20w50 in it. but thats mostly cause they began to either leak some various places or burn it. and since the cars reached the point that we didn't want to put any more money into it we just switched to 20w-50. both cars ran/run good still....its been this way for several years.

 

I use sae 50 in my race car plus a can of lucas or stp. Mostly summer