My old Perkins 4108 was blowing about a cup of oil out of the air filter every few hours. There was a short rubber hose coming out of the rocker cover directly to the side of the air filter.
This was not a big deal, and I was told that it is quite common, but it was a pain to clean up the drip pan sump every morning. I equated it to changing the engines diaper every day.
A mechanic suggested getting a longer hose and running it into a bottle, instead of into the air filter. He stressed that it is important to leave the top of the bottle open so that it could breath.
I bought a 1 meter length of hose for this purpose, but then came up with a great idea. Instead of running the hose into a bottle, I ran the 1 meter length of hose up, in a loop, and back to the air filter. This 1 foot loop still provides perfect breathing for the oil system, but the rise in the hose is just enough to stop the oil from spitting out of the air filter.
Of course I still have other, normal oil leaks, like any Perkins 4108, but this has been greatly reduced by this simple modification.Howard [ Just Imagine ] 24-Jan-2008