Oily Engine

By: Wayne Mandeville

There is nothing more frustrating than trying to keep a clean engine compartment. All of us have experienced the drudgery of cleaning up the oil and grime on our Model A engines. One major contributor is easily fixed, and that is the age old issue of presumed “blow by” coming out of the oil fill tube. Often the true cause of oil coming out is not blow by, but is merely oil being slung out by the crankshaft.

The oil fill tube is in direct alignment with the web or throw on the crankshaft. As the crankshaft spins while running, it centrifugally throws oil outward. As the crankshaft passes the oil fill tube the oil can be slung out through the tube if not properly contained. Ole Henry knew what to do. He placed baffles in the tube to deflect the oil back into the engine oil pan. This works if the baffles have not been modified or altered. A lot of people have straightened out the baffles to make it faster to add oil to the engine. That is all well and good as long as the engine isn’t running but works against you while running. The baffles must fit tight against the outside of the oil fill tube and leave a staggered or baffled route in the center of the tube.

Excessive crank case pressure can make the oil come out of the oil tube easily. If excessive blow by does exist due to worn engine conditions, several simple but cost effective solutions are available. The first and easiest is to put coarse steel wool in the oil fill cap and this helps to contain the oil in the engine. The steel wool acts as another baffle. Secondly, you can add an extension or make a longer oil tube. This causes the oil to loose speed as it is thrown upward and results in the oil draining back down instead of out. Thirdly, there are several after market oil fill tubes with hoses that vent down below the engine and let the oil out there. Another solution is to install a PCV (positive crankcase ventilation) valve system on your engine. This allows the engine vacuum at the intake manifold to pull the oil back into the engine. All have their advantages and comes to be somewhat of a personal choice. The most expensive solution is to overhaul your engine.

You can pick and choose a solution to meet your budget, but do something and just don’t loaf around and do nothing. When you stop tracking oil in your house and making nasty spots on the driveway everyone will be happier.

Wayne