SonexBuilders.net

Hi,

I appreciate all of the answers I received to my recent questions on oil consumption. Today I have additional information and a request for the collective wisdom.

After replacing the pushrod tubes (which I no longer think had any great affect on oil consumption) I kept hunting for issues. I had a lot of oil around the bottom oil filter plate (not sure if that's the right description...) and one of the nuts had oil dripping from it. I tried to tighten up all six nuts; 5 out of 6 torqued up nicely whilst the dripping nut turned & turned... it was stripped. The nut was tight to the stud; but the stud was stripped in the case. I ordered a helicoil kit to repair the case and decided to do an early oil change.

That's when the surprises started showing up. I am attaching two photos, which show:

1) the oil filter is filled with black hard rubbery particulates
2) the base of the plate is filled with similar
3) the mounting ring showed what appeared to be a runover gasket (or sludge)
4) that runover gasket or sludge compresses like rotten rubber

I've concluded that I've got plastic crap running through my engine, and I'm pretty discouraged about it, TBH. Could this have caused my oil pressure problem? Where did it come from?

What, Oh wise world of SonexBuilders, should I do? I never envisioned doing an overhaul myself. I'm not willing to fly with this engine until it is 'fixed', whatever that means. I would consider another engine, such as a rebuilt ULS Rotax. I want more power than what this engine has. I thought I might go the turbo route, but I'm feeling more skittish.

-- James

I'm not sure what the black rubbery stuff could be. If it was me I'd buy some new filters & oil, and run it to see what happens.

I’ve never seen sludge like that on my oil sump cover plate. It looks very thick. If I were you I’d would ask Sonex tech support. They’ll most likely need to know about the oil brand & type, any additives, past change schedule, and anything done during the engine build that wasn’t in the manual. Oh, also let them know how often the engine was run and OAT conditions.

Edit: that sludge looks a lot like Permatex aviation gasket maker. Possible?

XenosN42 wrote:Edit: that sludge looks a lot like Permatex aviation gasket maker. Possible?

That thought crossed my mind as well. If so, there will be a limited amount in there. Back to changing filters and oil to see what happens.

Edit: does not look like an engine wear symptom.

1) I thot the Oil changes had been regular, but I'm no longer sure. This would have been my first, and I was prepared to use the recommended oil with the zinc additive.

2) Engine rebuild was about 4.5 years ago. The log book sign off IAW with Sonex procedures FWIW.

3) No additives used. The prior owner emphasized the oil type.

4) Engine has been run for 15 hours this year; of that time, I put 9 hours in one week after I purchased it.

5) To my eye, it looks like a permatex like product that was inside the case and has fallen off. The gasket "ring" looks like a dissolved substance. But it could be sludge.

6) I was told the last oil change was at last annual (12-4-2022) but the logs don't show an oil change. Hmm. Just a signoff from an A&P for compression & condition.

7) The last recorded oil change is over 2 years ago. :-/ Don't know what to say about that.

Bryan Cotton wrote:

XenosN42 wrote:Edit: that sludge looks a lot like Permatex aviation gasket maker. Possible?

That thought crossed my mind as well. If so, there will be a limited amount in there. Back to changing filters and oil to see what happens.

Edit: does not look like an engine wear symptom.

I tend to agree with Bryan on this. I wonder if using an "engine flush" product from a reputable source would be helpful:

Amsoil - https://blog.amsoil.com/is-an-engine-flush-good-or-bad/

Admittedly I've never used any engine flush but I've never had to. Changed the oil in the Corvair today during condition inspection, checked the magnetic plug, cut open the filter, and took a sample for the lab guys. Everything looked wonderful. About 30 hours on the Rotella 15W40 T-4 conventional oil. Good stuff!
If I were flying a VW derivitive that's what I'd be using as that's what I use in my '74 VW bug.

I would familiarize yourself with the Aerovee assembly manual, especially the break-in periodic maintenance section. Then I'd look in the logbook for evidence they followed that guidance after rebuild. It's a lot of head torquing, valve adjusting, and oil changing. Once you are through the break-in period then you change oil every 25 hours, adjust the valves every 50, and torque the heads at annual.

During break-in it seemed like a pain sometimes, except for the excitement of a new airplane and ironing out the bugs. I got really good at all those tasks. Now I'm down to adjusting the valves 2-3 times a year as we have been flying a lot.

If it were me and I had a bunch of that black stuff floating around inside my engine I would pull the motor, split the case and clean everything out. The engine flush stuff isn’t going to do much of anything as you aren’t dealing with an oil sludge issue.. I would mostly be worried about the oil passage to the number 4 bearing right behind the prop getting clogged. It’s a small oil feed hole to that bearing and oil supply is critical there as that bearing is already doing more than it was designed originally designed for (it only supports the alternator/generator on a car application). Splitting the case is not that difficult of a job and only takes normal hand tools and maybe a breaker bar or impact gun to get the gland nut off. Reassembly is just following the steps in the aerovee manual. Since the motor isn’t worn out you aren’t doing a full overhaul. It’s just disassembly and reassembly. You shouldn’t even need to change out the crank or cylinder shims if they were done properly to start. I’m not sure where you are located but if you post it up there may be someone local that could help you with the motor.

Keith
#554

If you're going to split the case then why not just do the overhaul? If there is a chance that one of the passageways are compromised then what about the rest of the oil passageways through the crank, wrist pins, pushrods, etc.? Can we suppose that there may even be scoring on the main & rod bearings due to whatever has been floating around in the engine? Won't know until you look.

If you don't feel like you can trust it, pull it and take it apart for a rebuild. The parts to rebuild a VW engine are not that expensive. You'll fell better at 6500' on a cross country also ...

Dale
3.0 Corvair/Tailwheel

Hi,

More work on the problem today.... and a conclusion as to root cause.

At a prior oil change, someone used an incompatible rtv style sealant around the oil filter base plate. The black sludge is the excess internal material that has dissolved.

All of it (including the harder pieces) dissolves or smashes down in kerosene or acetone. The filter had a huge amount of it throughout.

I'm still deciding what to do... either an engine flush or a teardown / rebuild.

James