SonexBuilders.net

So I read a lot of pages back in the search results but couldn't find a discussion on this so....

In the new to me plane - the builder has fitted a Peterson 400 series Oil Filter. Has a bypass in the event of serious blockage, is solidly built like an aviation oil filter - rather than an automotive filter - which never seem as robust. Changing the oil yesterday - and I'm wading in to get at the oil screen too. Why?

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Let's look at my certificated engine experience. Fitting the F&H Filter adapter STC to a Continental-O200. The fitting of a Tempest or Champion aviation style filter raises the permitted oil change interval from 25 hours to 50 hours. It is a REQUIREMENT of fitting the STC filter kit that the oil screen is permanently removed.

While it is not explicitly stated as to why - most reason that if people are changing the filters and NOT looking at the oil screen too - then the screen will clog up with the all important large flakes with serial numbers on them and the oil flow will stop. And the point of the filter (apart from the increased time between changes) is to stop having to open the screen up.

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So - If I'm using decent filtration - why AM I leaving the oil screen in place on the AeroVee? It's just a pile of work to get at it - and the constant disturbing of things just adds to risk of maintenance induced failures.

When I asked the builder - they did say they had thought of leaving the screen out too. Just hadn't done it.

I am NOT planning on raising the oil change interval. Stick with 25 hours as I'll be in there doing the tappets anyway and oil changes are cheap insurance. Just thinking of getting rid of the screen

So - thoughts?

Graeme,

The screen protects the oil pickup tube in ways that the oil filter can't, like if something large and strange fell into the sump. Although this is unlikely, a piece of errant case sealant, or a foil top from an oil bottle, or the torn-off corner of a shop towel could find it's way inside and then lodged in the pickup tube. The screen prevents these chunky items from reaching the pickup. You could probably get by without a screen, or without an oil filter, but using both provides additional protection in a belt and suspenders sort of way.

One thing you might consider doing is removing and cleaning the screen during every other oil change. This will give you an idea of how "dirty" the screen is getting in between oil changes, and help you develop a sense of the right timing in servicing it.

Jeff