There's been a reasonable amount of discussion within the hallow corridors of BCP on engine upgrades and I've been pondering the same as well. So its set me to wondering which engine has proven over the years to be these gold standard in loyalty, reliability, TBO success, least AD's. I get that there are many variables which impact on the conversation so maybe its not an "answerable" question. It's not so much a brand loyalty question but more an overall "track record" question and I suspect given the collective wisdom that exist with the BCP community this could be an intriguing question, have at gang.

For the big engines, I think it depends a lot more on the operator (the pilots who actually fly the engine/s), the quality of the maintenance shop, and the operating environment than the engine design itself. This would include whether the plane is used for parachute ops, long distance cross-country, or pipeline patrols.

Most of the main-stream big engines from the big names (360, 470, 520, 540) seem pretty reliable.

Small engines, boutique engines, and auto conversions are a different story.

... and Lycoming is clearly better than TCM in terms of not cracking cylinders.

Agreed there are many variables which impact so let’s with GA operations, commercial ops are a huge variable to the discussion. Are the Conti jugs more susceptible to cracking, is this a cool issue or pilot handling issue?

Lighter cylinders in Continentals cracked according to all the mechanics I had. 182 jump planes had issue all the time because they tried to get up too fast and then down too fast. Also Lycomings would eat a valve and still get you home. That is from experience. Among the smaller engines I flew behind, Lycomings were 245 red line where Continentals were 220. A slow turning 135 hp 0-540 on a Pawnee or CallAir would run 245 in 80 degree weather and do fine. The small Continentals in two place trainers would run 220, but had to have ground effect or thermal or orographic relief to keep from overheating in 80 degree weather. Cooler air up high helped but engine climb to get there would overheat the engine. Ground effect in the desert worked the best for me, especially in a headwind.

I've paid to overhaul two Continentals now, along with some smaller repairs. First was a turbo, and made it to 1280 hours on a 1400 hr. TBO.

Second had 600 hours. It suffered a sudden stoppage and was submerged seconds later.

This didn’t sour me. I like the smoothness and performance of the big bore Continentals, and their ability to run lean of peak. I do think they last better in the hands of a gear head with an engine monitor.

The Lycoming 540s are not all created equal. The O-540 in a Cherokee 235 doesn’t have the same movable counterweights as the TIO-540 in a Comanche turbo 260. I didn’t like the 540 in the three Cherokees I flew and rode in. I was stunned by the smoothness of the TIO-540 in the Comanche. I think you can be less concerned about the mixture settings in the Lycoming and not have the cylinder troubles that a Continental will suffer.

I don’t like the predatory business practices of Continental, and they’ve turned out some really bad parts and engines and never publicly confessed. Bad lifters, valve seats not ground concentric with the guides, egg shaped and tapered cylinders, etc. They’re no better than their competition, but they ignore the fact that their excrement sometimes has a bad odour.

Lycoming parts and engines seem to have a better reputation but appear to be much more expensive. Still have a few major failures in their past.

For your application, owner maintenance? An O-360 Lycoming or an O-360 Continental are roughly the choices. I’d go with whatever combination of engine mount and engine and exhaust you can cobble together easiest and at lowest cost. They’ll weigh the same. They’ll have the same horsepower. The Connie will run smoother. The Lycoming will have fewer cylinders to cause you grief, and fewer spark plugs to buy. The Lycoming will be harder to find used, but there are options in the experimental arena you might be able to pull from. Lots of used Continentals around. Skymasters seem to be a prolific source.

Will any of the STC owners sell you undocumented parts at a discounted rate? That’s where I’d start. You need to buy a custom mount, build a custom mount, or find out which mount works to adapt the engines you’re picking from to the airframe. Once that’s done, then you have to do the same with exhaust. And then how does the cowl fit?

Any examples of 172 or 170 conversions in your area that you can use as patterns? Any 175 parts laying around that might help? Hawk XP parts? How does the entire firewall forward off a Skymaster line up?

I sit behind a Conti now, its smooth but getting long in the tooth. I could invest in it or put the funds into a full on heart transplant. While I have one particular loyalty and less cylinders to deal with has a distinct appeal the 0-300 has been both reliable and smooth.

Cracked cylinders on Continentals: Definitely an issue, much more so than Lycoming cylinders. When our maintenance gurus quit using rebuilt cylinders...only new Continental cylinders, that issue almost went away. Re-using cylinders creates chrystalization and other physical changes in cylinder head metal. At the Lycoming factory, NO cylinders are ever re-used, even on overhauls. As in never, that should be a clue.

Lycoming engines have the camshaft and associated parts mounted in the top of the engine. Park one of them for a year without use, and the next owner will likely be buying a cam and lifters. Buying one? Better get an honest answer how long it’s been sitting and whether it was properly pickled prior. Simple answer: fly the damn thing!

Only engine that’s ever let me down: big Continental. No idea why, and NTSB had the engine for a year....no idea why it cratered. Would I fly another? Actually have...a lot.

Years ago when Continental had crankshaft failures on brand new engines, turned out that the problem was in the way the blanks were forged. I visited with Paul McBride, Lycomings Chief Tech Rep not long after that determination was public. I said to him, “Good job for Lycoming, using better cranks.” Paul responded: “Actually, there’s only one foundry in the world that makes crankshaft blanks for aircraft engines. We just caught all our bad cranks from that foundry in a recall before the new aircraft were sold.”

Point being, aircraft engine parts manufacture is a small world.

If I could choose an engine for my airplane, the choice between engine makes would depend on the airframe and engines available.

But for a 170, it’d be a four cylinder Lycoming.

MTV

After looking at airplane ads every day forever, it seems like a lot more Continentals have had top overhauls than Lycomings. Super un-scientifically speaking.

If you’re satisfied with your O-300, then your easiest and least expensive option is to have it overhauled. You’re not much above sea level, and that will be one of the reasons you don’t lust for more power.

Are you burning 100LL or premium car gas? As accorded by the owner maintenance category: If you’re using 100LL, find an engine rebuilder who knows his stuff and see if you can get some more power by increasing the compression ratio and/or increasing the redline.

Custom pistons are pretty easy to have made these days.

I tend to agree with pinecone. If yoy are happy with it I would put some high compression pistons in it and advance your timing a bit more. As long as your temps stay good then you are golden and get some extra ponies.
If we are talking strictly engines and not for your purpose specifically, then I tend to lean to the conti side. I think they sit better without use as the cam is down low. Still best to fly them often. But I do like them, and they are cheaper to buy brand new (last I priced them out) which is also nice. I also put myself and my family behind one every time we fly, so maybe my mind just tricks me into believing they are better...

mtv wrote:Cracked cylinders on Continentals: Definitely an issue, much more so than Lycoming cylinders. When our maintenance gurus quit using rebuilt cylinders...only new Continental cylinders, that issue almost went away. Re-using cylinders creates chrystalization and other physical changes in cylinder head metal. At the Lycoming factory, NO cylinders are ever re-used, even on overhauls. As in never, that should be a clue.

Funny we should all be talking about this...

My father in law was flying home IFR in his XP Hawk (TCM IO-360) and cracked a cylinder 50NM out over water in IMC....

The engine ran rough but kept on pulling hard, it took him all the way home and could probably have kept running a lot longer.

This is a brand new engine, only a few hundred hours out of the TCM factory. Manufactured in 2019...

I understand the crack was in a location down the side of the barrel, where the barrel meets the head, and could never have been found by inspection without removing the cylinder.

He runs the engine 50* ROP (despite my best advice) and takes care of it, however it didn't make it more than a few hundred hours from brand new.

His last engine came with the plane, and made it to 3,800hrs (2,000 TBO + 1,800). Now that's economy.

Lots of great BCP intel, thanks to all in the community.

A full transplant would be fun however given the latitude that is afforded too Canadian owner/operators thru the OM C of A I'm leaning hard towards an top overhaul. A full new jugs; not re-build's, higher compression pistons and a timing adjustment for a small HP bump and keep the 0-300 run a while yet.

Mapleflt wrote:Lots of great BCP intel, thanks to all in the community.

A full transplant would be fun however given the latitude that is afforded too Canadian owner/operators thru the OM C of A I'm leaning hard towards an top overhaul. A full new jugs; not re-build's, higher compression pistons and a timing adjustment for a small HP bump and keep the 0-300 run a while yet.

If you’re overhauling, new pistons are a no brainer. As engine parts go, they are “relatively” reasonably priced. I’d also consider new cylinders, particularly if going higher compression, higher pressures, UNLESS your cylinders are first run.

MTV

Yes new jugs as well, I did mention that in my previous comments. Actually this "thought process" started when I was forced to replace a jug last summer for an unrelated issue so I only have 5 more to go now.

Mapleflt wrote:.... I'm leaning hard towards an top overhaul. A full new jugs; not re-build's, higher compression pistons and a timing adjustment for a small HP bump and keep the 0-300 run a while yet.

A not uncommon mod for the C90/O200/O300series is to install C85 pistons.
Generally not legal on a certified engine, but some Swifters have done it.
It's not a straight drop-in though, the pistons have to be modified.
Some good information here, but you have to scroll down through everything to find it:

http://www.bowersflybaby.com/tech/fenton.html

I also believe that Light Speed Engineering offers high compression pistons that would fit the O300.