So i have a stock block and the previous owner was running 20w50 VR1 in it. One of my DSM buddies (built quite a few cars in his days) saw that is way to thick, especially for winter time with temps in the 40s.

should i be running the 10w30 in winter? and then back to 20w50 in summer. or is the 20w50 still to over kill and i should run the 10w30 all year around?

 

10W30, for the winter at least. I run 20W50 ZROD in the summer but I don't have a stock motor.

 

i run 20w50 but its not a stock motor either. when i was stock i ran w.e. the oil cap said lol

 

5 30 mobil 1 synthetic.

 

huh. i wonder why the guy before me was using VR1 instead of standard synthetic? Is there really any reason to run the VR1 on a stock bottom end? maybe he was just doing it because its cheaper then regular synthetic.

should i run 10w30 synthetic or race on this stock block?

 

it's cheaper but has to be replaced more often

 

VR1 comes in conventional and synthetic. Not sure what you have, but the both versions are fortified with high ZDDP contents for anti-wear protection. I don't advise 20w50 for stock bearing clearance either.

 

well i guess the combination of tick oil, probably not being changed like it should and different type of oil was probably not good for it. lol still seems to run fine (besides the bad HG) but i will switch over to 10w30 syn tonight.

 

oops double post some how

 

Exactly what the cap says, Mobil 1 10w-30 Synthetic

 

if the car had an FP Red or Black Journal bearing on it previously, it perhaps was for the zinc additives as someone already mentioned.

 

10w-30... I use 5W-30 in the winter.. but I live in AK I think in the service manual there is a list of different oil weights for temp ranges and how hard you drive... I think

 

Yeah, the manual recommends 20W-40 for summer which you can't find.

 

Stay away from standard synthetic mobile 1. I had a factory MR turbo fail at 90k miles because of that crap. Good oil is Amsoil or royal purple in 10w30 if temp does not go below 35-40 degrees. If running higher boost levels or moderate mods, you can bump to 20w50, but I say stick with 10w30. Forced performance has a great article on their website discussing recommended oil

 

I've been using Mobil 1 10W-30, and no issues whatsoever