Have you ever been completely baffled as to where that pesky oil leak is coming from? Often times it can come from a place you’d not normally expect, your rocker covers. Finding oil seeping from your cowling or finding oil on your cylinders is a major sign of a leaky rocker cover gasket.
This type of leak has a few different causes we will discuss in this article as well as numerous solutions, all of which are quick and easy fixes.
A quick tip: One, surprisingly easy, way to check to see if oil is leaking from your gasket cover is to simply use your finger as shown below.
Rocker Cover Gasket
Rocker cover gaskets come in three different materials: paper, cork, and silicone. Each has its own advantages and disadvantages, but we suggest silicone as the best of all worlds.
Cork is an option as well. Cork has an advantage over paper due to the fact that is requires no seal. Cork seals better by absorbing oil and swelling, causing a tighter seal between the rocker cover and the cylinder surface.
Lastly, the ideal option is using a silicone rocker cover gasket. This gasket is the preferred method due to a few different reasons.
First, it is much thicker than paper and cork, as shown in the picture below.
Second, the thickness of the silicone cover gasket creates a tighter seal, filling in the defects, between the cylinder head and the cover.
Third, by changing the gaskets to silicone you will save more money simply because they are reusable and you won’t have to replace them. It is suggested that you re-torque every 100 hours, but if you utilize a product such as this one coupled with a silicone gasket, you can extend that estimate much longer.
Prop Governor Gasket
A prop governor gasket resides between the prop governor and the crank case. This gasket is typically made of paper which is a material that is a bit outdated due to silicone and coated gaskets being available now.
A simple upgrade you can make to protect your governor is purchasing and installing a prop governor gasket that is equipped with a filter screen, which stops any debris from entering the governor and causing damage.
But, these are not perfect gaskets by any means…
An Issue You May Overlook
Following directions and procedures is always a good idea, but sometimes alternatives arise that may be more beneficial. So, you’ve bought your silicone rocker cover gasket, you’ve got all the right screws, you added Loctite 515™, and properly torqued the screws.
Then it happens… An oil drip!
Often times the suggested torque is simply too much for a silicone gasket. Picture toothpaste squishing out of the tube, this is what is happening to your silicone gasket when you torque it to the suggested numbers.
Continental ¼”-20” screws are recommended to be torqued at 55-65 lbs. for a paper gasket.
Lycoming ¼”-20” screws are recommended to be torqued at 50 lbs. for a cork gasket.
We suggest lightening up on this torque for the APS® silicone gaskets to:
Cold engine: 25” lbs. of torque.
Warm engine: 20” lbs. of torque.
These tips can help you achieve a better seal for your gaskets, and keep your engine dry. When the time comes to change your gaskets it is a very good idea to change your hardware as well. Little tips such as the ones detailed in this article can truly save you time and money in the long run.