Q: Given Lycoming’s propensity for cam lobe spalling, are O-320s available with roller cams?
John Caulkins
A: Before I respond to your question John, I’d like to make a statement regarding your comment about Lycoming’s propensity for cam lobe spalling.
I will agree that over the years we’ve all heard the “hangar talk” about Lycoming cam and tappet problems. While many of these cases caused serious and costly repairs, I can tell you that the majority of the problems were caused by extended periods of inactivity, infrequent oil and filter changes, high RPM starts in cold climates without proper preheating, etc.
You may be rolling on the floor laughing, but if you stop and think about it, it really does make sense.
I could go on for hours about what causes cam and tappet problems, but I think you know where I’m coming from.
I admit that there were one or two specific models of Lycoming engines several years ago that did suffer more problems, but through engineering improvements, those models today are as reliable as any.
That being said, I can tell you that Lycoming has done the industry a great service by implementing the roller tappets on almost all of its engine models.
My suggestion for you would be to contact the Lycoming distributor of your choice to inquire about your specific engine model or contact the factory directly with any questions you may have.
I worked for a Cessna dealer in Baltimore in the decade of the ’70’s, and things went downhill when 80/87 avgas was phased out. Then came along the 172 with the -H2AD. We had them in our rental and flight school fleet, and they rarely sat idle for more than a few days. But once the tappet spalling issue surfaced, I was checking all tappets on all the -H2AD engines every 50 hours. Glad I did, too, as I caught them going bad before there was any camshaft damage. Between tapper inspections, valve train inspections and D2000 mag checks, I spent more maintenance time on one -H2AD than on three engines of any other type. Then there was the 0-235-L2C in our 152 aircraft. Carbon and lead build-up like never before. Rust inside all the rocker box covers. No accelerator pump, a single cylinder priming system and only one impulse mag has students killing the battery trying to start it on a chilly day. I illegally added a second impulse mag and cobbled up a 3-cylinder priming system, and starting improved, but the lead and carbon troubles kept on keeping on. Next to the trouble-free 0-320-E2D, these two engines were pariahs.
And NOW — Henry — you’ve described why I kept the original O320-E2D from my ’75 C172M. Unfortunately, IT only had a single cylinder priming system and one impulse mag. The 160hp -D3G (cum D2G) also has one primer and impulse mag. As soon as the Lycoming electronic mags come along legally … one will be on that engine.
I’ve found a judicial squirt of starting fluid into the Brackett foam air filter (don’t let students do that) works wonders for the first start of the day.
OH … and you forgot 12 volt electrical systems, too 🙂
I forgot to mention that with the L2C, I rerouted the plug wires so the original impulse mag sparked all the top plugs. When the lower plugs choked with lead, students couldn’t get the engines started……not a good thing when they’d be on a cross country!
I bought a 65 Cherokee that sat 2 years not knowing anything about the engine but it had 1200 tt so l thought this will.go 2000 hr easy
Not only did it go 2000 it went 3467 when l sent it in for overhaul it was 1400 over recommended time .
I had to replace the cam and lifters just about 900 dollars everything else was going ok l put another 200 hrs then sold it to someone from Idaho that came out and flew it back to Idaho and put another 3000 hrs on it at a flight school 0320 is a tough tough motor but the h2ad version stay away from unless it’s got low time on it talk about bad cam lifters
I owned a ’67 PA28-140 w/ O320-E2A bought in 2002 when it had 2,000 hours on its original engine. It had never been apart for 35 years. The parts got “married” and were happy together since 1967. It still is.
The airplane had sat in a hangar in western MA during the 1980’s when its owner passed away. I put 200 hours on that engine over the next 16 years with no issues whatever including keeping it in a hangar in FL for four years. During my 16 years with it, it was hangared. I kept a rubber ball in the exhaust tube w/ silica gel packets above it. When I moved the airplane to WI west of Oshkosh, I additionally kept the engine covered, sealed as best as possible and a gun cabinet dehumidifying heater in the lower engine bay. That 25 watt heater’s job was to dehumidify — not heat — the engine bay. (I had a second dehumidifier in the cockpit area, too). It sat in my hangar in WI for six months of every year for 12 years with no issues. The guy I sold it to in 2018 was all nervous about the engine but has now put 200 more hours on it trouble free still in WI. That original O320 engine is now 53 years old and happy as a clam !!
I’ve owned a C172M for 35 years and flew its original engine to 2405 hours when I finally replaced it for time with a new engine. I’ve used the same method for storage in WI as I did the PA28. Both airplanes sat side by side in my hangar from 2014 to 2018. I’d fly its old 80 octane low compression 150hp engine (which I still have) again, if necessary. My point is that the low compression O320 is about as “Iron Duke” an airplane engine as there is followed by the high compression 160hp version.
I use Mike Busch’s idea of removing plugs and rotating it by hand then by starter until I see oil pressure after a period of inactivity. How they’re treated and stored and then brought back up to active status is the key. SO far, it’s worked for me on three different O320’s plus an O235. Borescoping the engines shows no signs of corrosion despite long periods of inactivity in winter time.
Fly the engines, store them IN a hangar properly, re-activate them gingerly and don’t do a lot of touch and goes. OH … one other thing. If your engine has a screen, replace it with a regular oil filter. Oil is cheap insurance. That’s the secret. And stop worrying about the cam. It’ll “talk” to you when it’s time. That’s why you cut open your oil filter media.
Even if you fly 100 hours per year your engine is setting the other 99% of the 8760 hours in a year. I use my Hangar refrigerator’s freezer section and an aquarium pump to blow in desert dry air into my crankcase while it is in the hangar.
Curious that by paying attention to how cars are driven vs. how the manufacturer wishes them to be driven, car engine reliability has gotten tremendously better since the 1960’s. Now, 40 years after camshaft spalling issues were well known* and 20 years after experimental markets found rollers mitigated the issue, Lycoming does a “great service” by offering a this fix. Progress – I guess.
* I have a couple of destroyed camshafts from a big box of them my IA was offering for the taking. They make nifty industrial-style lamp stands.