Why would I use straight weight oil for break in???
12-26-2016, 07:58 PM
#12
1st Gear Member
Thread Starter
Join Date: Jun 2011
Location: Michigan
Posts: 115
After a very long discussion on bobistheoilguy, I finally have some answers. Here are some quotes from the final page of our discussion.
BrocLuno:
"The reason for SAE 30 HD is because it's all oil. There are no VII's to uncurl as the oil heats up, etc. VII's are not oil and they do not lubricate. They may carry oil molecules in their curled state. But they are not oil. They are plastics. You do not want them in a fresh metal motor scenario where there are no AW surfaces built up yet. ZDDP needs heat, pressure and time to bond and coat metal surfaces. With a fresh start you have zero in place. So you are relying 100% on the oil. At least have 100% oil to start out."
"The deal is how you get to multi-grades. Cheap ones have mineral oil base solvent refined and a ton of VII's. Expensive ones have synthetic base and can pass the viscosity tests with very little VII's. It's you choice. This is where research and thinking come in.
I am a proponent of straight grades where they are appropriate. But the upper mid-west is not one of those places. Phoenix, yes.
So just use a good narrow range multi from a well known refiner and you'll be fine"
(the actual forum post can be seen here: https://bobistheoilguy.com/forums/ub...pics/4254633/1
My own thoughts:
If you think about it, using a straight grade conventional makes even more sense. If you try and use a cheap multi grade oil (like bottom shelf 5w30 conventional), you don't know how much they had to pack the cheap base oil with the VII (viscosity index improvers) in order to make it thicken at higher temperatures. We know the VII's are not lubricators themselves, and we know that they will break down and cause the oil to head back to it's original thin base oil (multi grade oils start as thin oil). It's best to use a quality conventional SAE 30 oil because you know it does not have any VII's and you know the conventional will help break in the rings.
On the other hand, it does not sound like it would be particularly bad to use a quality multigrade oil. In the end it comes down to how finicky you want to be.
And if anyone is curious as to how my car turned out
BrocLuno:
"The reason for SAE 30 HD is because it's all oil. There are no VII's to uncurl as the oil heats up, etc. VII's are not oil and they do not lubricate. They may carry oil molecules in their curled state. But they are not oil. They are plastics. You do not want them in a fresh metal motor scenario where there are no AW surfaces built up yet. ZDDP needs heat, pressure and time to bond and coat metal surfaces. With a fresh start you have zero in place. So you are relying 100% on the oil. At least have 100% oil to start out."
"The deal is how you get to multi-grades. Cheap ones have mineral oil base solvent refined and a ton of VII's. Expensive ones have synthetic base and can pass the viscosity tests with very little VII's. It's you choice. This is where research and thinking come in.
I am a proponent of straight grades where they are appropriate. But the upper mid-west is not one of those places. Phoenix, yes.
So just use a good narrow range multi from a well known refiner and you'll be fine"
(the actual forum post can be seen here: https://bobistheoilguy.com/forums/ub...pics/4254633/1
My own thoughts:
If you think about it, using a straight grade conventional makes even more sense. If you try and use a cheap multi grade oil (like bottom shelf 5w30 conventional), you don't know how much they had to pack the cheap base oil with the VII (viscosity index improvers) in order to make it thicken at higher temperatures. We know the VII's are not lubricators themselves, and we know that they will break down and cause the oil to head back to it's original thin base oil (multi grade oils start as thin oil). It's best to use a quality conventional SAE 30 oil because you know it does not have any VII's and you know the conventional will help break in the rings.
On the other hand, it does not sound like it would be particularly bad to use a quality multigrade oil. In the end it comes down to how finicky you want to be.
And if anyone is curious as to how my car turned out
