On a quest for the elusive "Dry AeroVee"

[pappas]

As Peter noted, if Garret states the recommended max psi on our turbo is 45 psi or bearing failure may occur, all of these bearings should fail. We see O/P up to 100 psi on a cold weather start-up for a few minutes and 60-70 psi on warm day start-ups. Even at cruise, Sonex wants 40-50 psi. Maybe Sonex should weigh in on it?

[Hap Hazard]

Why did you remove your oil filter?

Bill,
I'm not ready to dive into drilling and tapping the case for full flow. I am planning a couple of XC trips in a couple of months where I won't have the luxury of preheat overnight. I don't want the potential liability a few hundred miles from home of the oil filter popping on startup. Per Sonex the filter is only required if you have the turbo. So I'm taking it off for now. I think we can add pressure relief to our original pump and cover, which is what I'd like to do. That's a project for another day.

Hi Bryan,
Post-war, Micro-filtered oil systems was one of the biggest steps forward in modern engine longevity that we take for granted today and gives marked improvement in engine reliability. It’s an issue that Revmaster fully appreciate and obviously catered for in their engines. Changing the oil every 25 hour helps, but it doesn’t stop foreign particles being transported around the system and doing main-bearing damage. (Remember, your crank is like your spine in your body, look after it!).
FYI I am looking to fit a certain product (they are terrified of litigation in aircraft use, so I won’t name them) for the oil pump with the spin-on oil filter. Hopefully this will fit/work with the current Sonex exhaust system/cowl, baffles, etc, but I will know soon enough as I am putting the engine back together now with the cases bolted to my engine stand as I type.
What I did was to bored out the castings oil ways slightly larger (but have left the hole size standard where it bolts up to pump itself), flowed the 90 deg bends where the oil changes direction out of the pump and into to casting galleries and taken 45 g (1.6 Oz) out of the casting weight by taking as much excess aluminium off as I dare, to reduce weight a bit more (to put that into context, about the equivalent weight of around 6x 5/16th bolts 1-1/4 long!
Will let you know how it goes, but personally I wouldn’t be too quick to get rid of a micro-filtration system. On leaving the subject, although the aircraft came with the brand-new Sonex supplied mini-sump kit (not fitted) with paper filter, I do not trust a “suction” filtered system at all with any of my engines, hence why I don’t intend bolting it on to my motor….
Again, I refer readers back to what Revmaster does as a standard feature of their engine…..
HH

[BRS]

I'm a fan of the Revmaster oil-filter/oil-pump setup. Looks to me that it would bolt onto a Aerovee, is that not the case? I don't know if they would sell just their oil filter/pump assy.

[Area 51%]

I had the spin-on oil filter/pump assembly on my Aerovee. You do need to fit a short filter to clear the exhaust and a relief needs to be cut into the cowl. but other than that, there were no other fitment issues.

The mini-sump I installed had a washable filter and a relief valve if the oil was too thick to make it through the screen. I added it for the extra oil capacity and not necessarily for it's filtering ability.

I will definitely be installing the same on the upcoming engine. .

[Bryan Cotton]

Changing the oil every 25 hour helps, but it doesn’t stop foreign particles being transported around the system and doing main-bearing damage.
HH

HH,
All good points, thanks. I do realize the tradeoff is more frequent overhauls and I am flying enough that this will become reality. But the other tradeoff is I saved about 2.5 lbs, which is huge for me. Also I have had a couple of cold start oil filter blowouts. With the oil filter gone, this issue is also gone.