Those of you who have struggled with oil leaks will know that it only takes a small amount of oil leakage from around an engine to make a mess of an engine compartment; the air pressure and airflow does a great job of spreading the oil everywhere. In my case, I have been dealing with an oil leak from somewhere on the accessory case for over a year.
The oil leak was high up on the accessory case, from somewhere in the Vernatherm area of the ancillaries. However, I was not able to easily pinpoint the source of the leak. All I knew was that oil would appear at the bottom of the front of the engine, and would coat the ancillaries and pipes and also run into the P-51 scoop when the plane was at rest with a hot engine.
In the last 2-3 months the oil leak had worsened, to the point that I found 2-3 tablespoons of oil in the bottom of the P-51 scoop when I removed the lower cowling today as part of the prep for magneto replacement. That much oil in flight will slowly mess up an engine compartment.
With the Right magneto not in the plane due to a replacement process (see previous posting), I was able to determine that the source of the leak was not the Vernatherm switch (which was my initial suspicion), but it was the Vernatherm casing itself, which is bolted to the accessory case. I was able to gain access to the four bolts that hold the Vernatherm casing to the accessory case.
I found that the two bottom bolts on the Vernatherm casing were slightly loose, so I tightened then as far as I could. Only time will tell if this will stop the oil leak. If it does not, I may have to remove the casing and re-seal it. That will be a hassle since it will require the removal of the oil cooler, and possibly other engine ancillaries.