chrismcdaniel

iTrader: (14)

Ok, i tried reading a bunch of links i found useing the search option... like this one.. https://ls1tech.com/forums/generation-iii-internal-engine/425641-oil-comparisons.html

But No BULLSHIT what type and weight of oil is best for a iron block 11.5:1 408? Ill be breaking it in in a couple weeks and want to start out with the oil im going to allways use in it.. i have allready purchased Mobile1 5w 40 truck/suv oil because i was told that was the best.. also remember i live in hawaii where the temps stay pretty much the same ALL YEAR LONG 60-90 degrees with cool days in the 50's nad hot days in the lower 90's.. help me out, im tired of researching this to get no where..

chrismcdaniel

iTrader: (14)

aslo, what about break in oil, should i use thinner oil for the break in period then swith to a little thicker synthetic oil? that kinda what i have been getting from the posts im reading.

Viper

iTrader: (6)

My engine builder said to use dino oil to seal the rings, then switch to synthetic. On my new motor I used GTX 10w40 for 2500 miles. FWIW.

chrismcdaniel

iTrader: (14)

cool, i know im not going to be able to find the german castol here on island in hawaii, we dont even have an auto zone.. si im thinking that after the break in with the Dino oil, ill be using the mobil 1 5w40 truck and SUV oil..

JL ws-6

iTrader: (50)

Alot of it has to do with the clearnaces in the motor, dependign on what they went with, will dictate what you should be running for oil. If it was built "loose" like a typical race or high Hp setup would be built to spec wise, you will proably find yourself running 20/50, but if it was built "tight" like a factory motor, something that's not gonna see boost, nitrous, or alot of abuse, the 10/40 is probably more like what you will end up running.

What was teh motor built to handle, what did you tell the builder your plans were? If he told you that in a couple years you will need to rering and bearing the motor, then you're gonna be running heavy oil, if it's supposed to be good for 100+K, then you have a light oil motor.

xaon

iTrader: (12)

I use 10w40 in my 408... It has worked excellently for the last 3,000 miles.

PREDATOR-Z

I broke my iron 370 with 5W30 for 500 miles and then 0W40 Mobil 1.

The 5W30 was a bit thin, with the Mobil I'm up by 10 psi across.

Darkness

iTrader: (4)

I use 10-40 on my 408, no issues.