Except for dad’s Skylane, I’ve only flown behind Lycoming engines. Dad’s Skyhawk was a 172L that was built two years after Cessna switched from the Continental. AIUI, the Continental O-300 has a TBO of 1,800 hours, vs. the 2,000-hour TBO of the Lycoming O-320 – and there are two fewer cylinders to overhaul. The O-320 has five horses over the O-300 (comparing the 145 and 150 hp ones), and is more fuel-efficient to boot. It seems to me that the Lycoming wins.
I’ve flown behind Lycomings, Continentals, Rotaxes, a Rolls Royce, and a couple I don’t remember the names of (at least one rotary? Odd number of cylinders in a circle). I’ve had 1 Lycoming and 1 Continental quit on me - in both cases it had nothing to do with the engine itself but with something connected to the engine.
I’ve heard a number of people claim Lycoming is superior. Maybe it is, given the numbers you gave. But from the reliability standpoint they both seem about equal to me.
However, if the Continental O-300 is the 150 hp 6 cylinder one - MUCH less engine vibration while in flight, it is a notably smoother ride than a 4 cylinder.
I’ve flown a Continental 145 hp 6-banger in a very old C172 - VERY smooth ride.
I’ve flown the Lycoming 4 cylinder O-320 150 hp, too.
So, my statement regarding a smoother ride was based on experience. If it’s important to you that might be a deciding factor. If not, probably fuel efficiency.
I don’t know of any real differences in reliability between the two, other than the slightly shorter TBO on the continental (which doesn’t necessarily mean anything). However, the Continental will likely be more expensive to maintain - two more cylinders and the shorter TBO raise the cost of ownership.
As others have said, the six-cylinder engines are generally smoother (although there’s some engine-to-engine variance due to balance quality). I flew a Stinson 108-C with an old Franklin six banger in it, and it was the smoothest, most vibration-free airplane I’ve ever sold.
All that said, I’d go with the Lycoming, if for no other reason than that it’s a much more common engine, so mechanics will be more comfortable with it and parts are more available and all that.
The guys in my shop take a dim view of Continentals. They say they need top overhauls much more often than Lycomings. Sometimes in a startlingly short amount of time.
The Lycoming favors the left bank of cylinders because of the way the oil passages are set up to feed the top end through the pushrods. You can probably address this more but I believe it’s the O-320H model that does the best job of keeping things oiled/cooled.
The cost of the engine should not be the driving financial force. One of the reasons I upgraded from an O-235 to an O-320 is that the O-320 was cheaper to overhaul by a significant amount. It was cheaper to buy and overhaul the O-320 than it was to just overhaul the O-235. I believe that may have changed since I’ve done it but at the time it was ridiculous what things like pistons rings cost for an O-235. But since the engine was in demand for home-built airplanes it was a no-brainer to sell it and swap in a bigger one.
Things to understand about the O-320. If you want the 160 hp setup the engine has to spec out first (I think it’s the tolerances for the crank). It’s not a given that you can do the upgrade. And if you’re swapping between a Continental and a Lycoming there will certainly be different motor mounts, exhaust systems, propellers, spinners, and everything else that is specific to the motor.
I had to go with the 150 hp version but I raced a Cherokee 140 and won (I did have a weight advantage). The 108 version would take a long time to climb to 12,000 feet and then wallow when it got there. It’s basically a Tri-Pacer without flaps so 7-800 fpm climb is about right. It doesn’t have enough elevator to stall so the extra hp allows you to fly at a ridiculously steep angle which puts your weight on the seat back.
What is most notable is the larger prop. it acts like a speed brake when the engine is pulled to idle. You can push the nose over and really drop like a rock without hitting VNE.
Would love to fly a really old bipe like a Sopwith or a Jenny.
Unfortunately, I’m not at all current in anything, much less something from the dawn of aviation. Nevermind the unlikelihood of getting such an opportunity.
