Quote:
Originally Posted by BAN SUVS
Okay, yes or no question- Should I screw around with drilling/machining/otherwise altering my EJ25 crank to hit 8200 RPM safely?
If so, what specifically should I have done?
I apologize if that's made clear in another thread, but my searches here turn up either terrible signal-to-noise threads, or impossible tech geek-to-layman ratios.
I did do some searches, and to find many of the threads you would have to know a few keywords that might not be obvious. I have some suggestions I am going to pass by a few mods as to how we might make it eaiser to find the information you are looking for. As it is now, often the only way to learn is to spend some significant time ( 3 - 6 months ) watching and reading threads.
Quote:
Originally Posted by Homemade WRX
It is nothing more than a theory for now...it could be suspect however looking at the fact that the crank design being mentioned is used in the Spec C cars from the factory and are known to spend 9k rpm on a factory built bottom end.
So I'd say the cross drilling myth is busted as to cross-drilling being the cause of our failed rod bearings. Oil timing however may not...yes, I said timing.
Agreed, as the Spec C bottom end revs well to at least 8250 if not more. I ran a Spec C block with and AVO500 with good results many years ago, eventually having a problem with piston scoring not bearings.
Like many other areas of Subaru performance, cause is often well mixed up with many factors. Many people post up about having a spun bearing without any further disclosure. Did they know their oil pressure? What oil? What tune? Was it knocking? Do they know how to know if it was knocking?
Why did they choose the bearing clearances they did? Do they even know what bearing clearances are?
In the overall view, one would conclude that the EJ257 engines are not easy to rev about 7500 rpm, but that broad statement is a very oversimplified point of view.
You can be sure that if your oil pressure, when hot, drops to 35psi at 8000 rpm you will have a problem.
Indeed the oil timing is an interesting concept. Has someone looked at the oil timing for the newer WRX crank, and is it the same as the older Spec C cranks?
Jeff