Tire Shredder said:
what's the theory for using a constant weight oil? I'm assuming when you say 30w it is NOT multi viscosity oil? It was my understanding you want the car to be warmed up before you start the 3/4 throttle pulls to seat the rings. If so, then how could it hurt running a 5w-30 or 10w-30 for the initial startup? I'm unclear on the theory behind this, only hearing "use 30w" all over supramania.
to save me posting a second question, if you can convince me a monograde oil is the way to go, would something like the castrol HD30 do the trick?
Well, I'm not going to try and convince you of anything...I will tell you my opinion, and then you can do whatever you like
1) Straight 30W motor oil does not contain the amount of additives a multi-grade does, notability anti-wear and film thickness modifiers. This actually provides more base oil by volume in a bottle.
2) Everything I have read says to use a straight 30W on older era motors (like the 7M). It allows wear to take place to properly seat the rings. Newer (especially high performance) motors come from the factory with a syn oil fill...these engines have closer tolerances than those of the past. You have to decide what you want to go with.
3) Straight 30W is very good at dissolving assembly lube.
4) It's cheap...you're going to do a couple oil changes in the 1st 1,500 miles. Why use anything else. While your at it, grab a couple SuperTech filters at WalMart...pretty good filter, especially for as long as they will be on the car.
Castrol 30 HD is an API SM service oil...it well exceeds the oils originally spec'ed for the 7M. It will be fine.
BTW - I deleted the repeat post. This forum is moderated by me...all posts have to be approved before they will appear. I'm usually pretty quick about it, but sometimes my family, my "day job", and the dozen or so projects I have going on take precedence over me being able to answer.