Scudrunners

Looks like I have a couple oil changes in my near future. Before I just go dumping the used oil from the sump to a bucket does anyone have any clever rigs for this?

If the drain has a clear drop underneath it …. Just a large funnel on top of a 5 gallon plastic pail on top of a milk crate. Close the hangar door to kill the wind.

If the drain has stuff underneath it, cut and bend a piece of aluminum to make an angled channel to the bucket.

Most important thing is to change it after a flight so the oil is thin. Speeds things up, better drain. If you can’t fly it, preheat it to at least 100F

If it’s a taildragger you may need to jack the tail to get a more complete drain if the fitting is not mounted at the back of the sump.

Some people put a clear hose on the drain fitting if you can snake it in there.

Sometimes it seems, all I do is oil changes. Before I had to leave Canada in 2015, I think I was up to 24 aircraft I was maintaining.

I’d rather fly them than fix them, but sometimes you don’t have a choice.

And remember if possible use straight grade (no plus) with enough Camguard that you can smell it on final.

Free advice: if you’re not flying it much, change the oil every 10 hours. It sounds stupid but …

Colonel wrote: ↑

Sun Apr 09, 2023 2:54 pm

if you’re not flying it much, change the oil every 10 hours. It sounds stupid but …

Tragically I’d be surprised if 3/4 of the fleet I’m overseeing had put on ten hours over the last year. Sub optimal but I’m working on getting them exercised more.

Maybe it’s just me but I think you need minimum 2 oil changes a year regardless of hours flown - ideally once in the spring and once before winter. In Canada you might want to change to straight grade for summer, and multi-grade for winter? If you're not going to fly in the winter, maybe stick with straight-grade. It's a better preservative oil w/Camguard.

PS If you've got a lot of blowby, 50 hours isn't going to work for oil changes regardless of filter. It's going to contaminate the oil regardless. Back to 10 hour oil changes IMHO.

We just run straight grade mineral year-round and don’t fly in the winter. Snow removal is pretty lacklustre anyways. Ostensibly winter is for building and maintaining but for various reasons that’s sort of fallen by the wayside. Getting back on track starting this year though.

I think I’m going to feed some Cam Guard to a Cub or two and see how I like the stuff, then maybe do them all later this year or starting next.

You gotta do what works for you but ashless dispersant might keep your engine cleaner inside.

Camguard is just a better additives package than that “plus” stuff from Aeroshell.

I’ve run Camguard in opposed Lycomings and Continentals for decades now. Fantastic stuff. W100 or W120 (over 100F on the ground) with Camguard is the best oil I can find.

At this point I think the mineral oil slime is probably integral to sealing the engine, if not structural. The plan there is to leave well enough alone, save some money, put some parts aside, and if I want to switch oils it’s going to be major rebuilds for the whole fleet over one winter so that we only need to stock a single grade.

Sounds good. Note that many people have moved away from the idea that you must use mineral oil for engine break-in.

Ashless dispersant doesn't stop the rings from seating. Just don't run any additive packages like the Aeroshell "plus" or Camguard, which advertise improved metal-to-metal protection at extreme temp/pres - that's exactly what you don't want between the ring and the cylinder wall during the first 5 hours.

You can do a lot worse than running straight grade AD oil - 80/100/120 your choice - during break-in, then changing it and running the same oil with Camguard added, after the rings seat.

The downside to straight grade is poor performance at low temperatures in two aspects

1) initial flowing at start to reduce cold metal-to-metal
2) avoiding congealing in oil cooler at low temps because multi-vis has lower pour point

If you preheat and don't fly below -20C (pour point of W100) AD W100 is a very good choice - with no expensive "plus".

W100 is a good all-round oil and is ok in moderate temperatures, but once the temp on the ground gets over 100F and the oil temp gets over 200F, it starts to show it's weakness in terms of controlling prop RPM. You can see that in the engine data. That's why I use W120 as a summer weight oil - far better RPM control. Note that your vernatherm forces oil through the cooler above 170F oil temp or so (YMMV). If your oil temp is climbing higher than that, you need to think about why.

Multi-vis oil is a train wreck when it comes to oil pressure loss at high oil temps. Many people report poor RPM control in the summer with it as a result. You have to wonder if that cat piss is foaming up? I do not know why people run multi-vis oil in the summer. To me, it is a winter-weight oil only - literally the lesser of two evils, when you are flying below -20C and you do not wish your oil cooler to congeal.

Note that data-logging engine monitors are good, because you now know exactly what's going on, and they're bad, because you now know exactly what's going on :^) Three samples a second is very informative - you can catch all sorts of stuff that before, was simply a complete mystery.

Colonel wrote: ↑

Mon Apr 10, 2023 2:28 pm

Note that many people have moved away from the idea that you must use mineral oil for engine break-in.

I try not to outsmart the old tech, a lot of the time I find some funny decisions were made with purpose and through experience and who am I to think I’m somehow better?

The history of the A40 engine is fascinating for that sort of thing. For example, there are ‘better’ materials than stock to make a head gasket out of but they shed a lot of heat through their cylinder heads and using the factory metal sandwich gaskets can actually prevent magneto failures. Yep, the heads affect the mags. Who knew?

Another one is the rod bearings in my Model T. When it came time to replace them (they’re poured integral to the rod and machined out) I did some searching for the right shop to do it. Plenty will do the work but there are some newer mods that have become popular over the years. “Send them to so-and-so,” they all say, “He cuts in oil grooves and drills the caps for dippers. I switched to that and they lasted a full ten years before needing to do them again!” Meanwhile mine made it ninety five years without the grooves and dippers. Makes you wonder. I figure Ford made over twelve million of the things before they got to mine so if there was a significant problem they’d have sorted it already.

Anyways something about airplane oil? For now I’m going to leave well enough alone and any changes will come after very careful study.

Just change it more frequently than once a year.

How often you change it might be more important than the exact oil that you use.

I say twice a year. The short bald guy that invented Camguard says 4 times a year. He knows more about this stuff than I do.

I suspect engines and their maintenance requirements differ which is not accounted for. An engine in Key West with alll that heat, humidity and salt in the air, with worn rings and a lot of blowby, is going to need frequent oil changes.