Hi, Dave! I'm really not knocking the Lyc as much as it might appear....it certainly has a large following. But the fact is that Cessna only used it in the 172 after they'd bought 5,000 of them for the Cardinal in 1967 and found it too underpowered for the airplane and had to put 'em in something. They decided the now-reputation-damaged Cardinal would not replace the 172 so they stayed in production with it and used all those Lycs in it. But the problem then was vibration so they used special, soft Lord mounts to absorbe the shocks. (If you put those type mounts on a TCM C145/O300 you'd swear you were driving a turbine! So comparing the Lyc in smoothness to a TCM isn't apples to apples unless you also let the TCM have big Lord-mounts as well.)Dave Clark wrote:George you should really lighten up on the Lycoming a bit. Mine is smoother at cruise than a C-145 with a low but legal cylinder and only shakes noticeably starting and stopping. There are thousands of these O-360's on many types of aircraft and it is noted as being one of the best and most durable engines on the market. I love it.
That said the 180 Lyc doesn't make the C170 into a C180 by any means but I think it's a great choice for the airframe. I really like the idea of the Cont IO-360 also, especially if you think you'll use the extra ponies. If I were to decide to do a conversion I'd be looking for a good deal on either engine and go from there.
One thing to consider is that if you go with the DelAir conversion Lyc you can get a 200lb. gross weight increase. With my Lyc the last 100 lbs or so still makes it feel heavy. Or is that the first 100 overgross? Still it climbs at gross as well as a stocker does light.
The Lycoming has a nasty history of poor valve lubrication, galled cams, failed oil pumps, broken cranks, and vibration problems. While it's not my favorite engine, it's also not a slouch either, tho'.
I've found that asking a pilot how he feels about his equipment is like asking him if he likes his wife when she's standing next to him....the answer's always the same.
"Bulletproof" is what most Lyc owners like to say about their engines, and they point to high recommended TBO's as proof. But most of them conveniently forget 1) most of 'em will not own an engine from new-to-TBO or 2)that their engine was "topped" at about 1100 hours (sometimes by a previous owner) while they brag about it getting to TBO. Theres at least as many TCMs that have gone beyond TBO just as well as the Lycs, but the difference is that the TCMs will be able to reuse their valve trains....the Lycs won't. (And that's part of the problem.....TCMs reputations subsequently suffer because their parts were not replaced at TBO but were re-used because they looked so good after a full run the owner tried to save money by reinstalling them. Its important to examine maintenance records when purchasing an airplane and see exactly WHICH parts were replaced with new!)
If anyone thinks a C145/O300 has a problem with sticking valves,....it's because they've never experienced a totally swallowed valve with a Lycoming. (The two Lyc failures due to swallowed valves I've had were both at night. One of 'em took out the adjacent cylinder with it.)
Your mileage may vary. (There may be some personal opinion expressed in the previous msg.)
