Hi everyone,

I just rebuilt my S4 NA 13B with news bearings -- it's running premix now, and I have a couple of questions regarding the break-in process

- What type of oil should I use?
- When should I change the oil?
- RPM limits?
- Any other specific recommendations?

I've searched and found a lot of different answers/opinions on this, but nothing specific on premix'd engines...


Thanks in advance!
-Dan

 

I just use regular 10w-30 oil, I change mines at 50 miles, then 200, then again at 800 miles.
I never boost until 100 miles are done, and rpm are kept under 4k.
I always try to drive in stop and go situation never highway, to get the engine load up and down, though I will never put extreme load on it where it would boost first in the first 100 miles. I also tend to engine brake a lot on a fully rebuilt engine with new bearings, and apex seals.

This is just my method, Ive done this to two engine and nothing went wrong so far, though I rarely exceed 2000 miles a year between them engines. I premix half ounce to a gallon.
Breaking in an engine with new bearings, many people have different opinions on it, but the one constant seems to be changing you oil, and never boost until a certain amount of miles.

 

With those fresh bearing definitely take it easy for the first few hundred miles. The kind of oil doesn't matter. Premixing doesn't matter for break-in either(hence why you didn't find anything...it doesn't change anything)


On my motor (reused bearings) I was boosting to redline after around 30 miles. That was over 3 years ago and the motor is doing great.

 

I have a stupid question to ask because I am new to premixing. Do I have to run motor oil in the engine? Or do I just use the premix oil in the gas tank alone?

 

you still run oil. some people premix to be able to use synthetic oil in the engine because its not recommended to burn it.

 

Premix only lubricates the rotor seals. You still need to run oil in the sump because that is what is pumped around the engine to lubricate all the bearings, machined surfaces and cool the rotors.

The FSM and Haynes has a great diagram of the oiling system.

 

Gotcha! Thanks for the info.

 

Ah! Thanks a ton arroncake!