which is prefered for high performance, heavy or light weight oil?

does oil get thicker or thinner as it warms up?

what happenes if you mix two different weight oils together?

what exactly do those numbers on the bottle mean?

thanks guys

 

http://www.atis.net/oil_faq.html more than you could ever want to know about oil...

1) Depends on the build of the motor. Newer tighter spec'd engines need 5-30 or 10-40
2) oil gets thinner as it heats up
3) As long as they are the same service grade (API rating - i.e. SJ, SG, SD, etc) it's fine but why mix? Just buy the appropriate weight to begin with
4) read the link above...

 

Heavy weight oil is typically for warmer climates & heavy duty applications. As the oil heats up, technically is become thinner. So to answer your question, would you rather trudge through thick mud knee deep or a puddle the same depth? You engine has to work harder with heavier oil. On the other hand, what sort of driving are you doing that you think a lighter weight oil will help. Personally, I don't think you would notice a difference. What I can say from experience (I have seen the dyno numbers to prove it) Mobil 1 Synthetic showed increased HP & gas mileage immediately. Now we're not talkin 5 horses or anything close, but everything helps. LAstly, whatever you choose, make sure the heart of your beloved pony is pumping with whatever will protect it best. Good luck!

 

For high performance, a heavy weight is best for the engine, however, a light weight oil will yield more hp due to the decrease in pumping loss. I know Ford now recommends 5W-20 for some vehicles. I personally wouldn't use it.

Oil gets thinner as it warms but the viscosity improvers increase the viscosity. The numbes are simple. 10W-30 means 10 (winter) when the oil is cold and 30 viscosity when it warms.

Mixing the two isn't a big deal, you just don't know what the true viscosity is.

 

i was mostly wondering about when you have roller rockers if there is an ideal oil. i guess 5w-30 would be the way to go right?

i use mobile 1 synthetic.

would one oil make the engine quieter if it was making noise?
also, i put new heads on about 2k miles ago, should i change the oil to make sure there are no metal shavings that were left in the head now flowing in my oil? if yes, with summer coming should i go with a higher weight oil? it gets pretty hot in so. cal.

 

I don't think the roler rockers would be effected by the oil weight. Generally, a heavier weight oil will quiet down an old, noisy engine but we all know that is not a cure (akin to turning up the radio).

What did you have done to your heads that you are concerned about metal in your oil? Are they iron or aluminum heads? If they are aluminum, there is less of a chance of damage with the softer aluminum. Cast iron head would be a different story (not sure where you'd get a pair of cast iron heads for a modern ride these days...or why you'd want to). Is there a reason to believe there might be debris from the head work? Was the shop dirty or did the mechs seem to not be concerned about your stuff? I guess I am just trying to see why you think you may have an issue. TO be on the safe side, change the oil. It won't hurt anything & is a prudent measure that will give you piece of mind. As for the oil weight, go with the heavier weight oil. It won't hurt your performance & you will have added protection if it gets hot.

 

Thx for the new sig.

 

i have alluminum. they said to spray them with compressed air to get all the sh*t out before intall but they said nothing about break in and oil changing.

so you think i should go with 15w-50? i run 5w-30 now......is there a medium with mobil 1 synthetic or would i have to get a different brand?


mike..enjoy i guess

 

Yeah...every one has their moments.