Lycoming charges a lot for roller tappets, yet the presumably lower camshaft wear & tear does not result in higher TBO nor does performance or fuel consumption noticeably improve, according to Lycoming. So why would one get roller tappets?
Roller Tappets for IO-540 worth the extra cost?
- Thread starter lucius
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- io-540 lycoming roller tappets
455 Bravo Uniform
Final Approach
In automotive applications, roller valve train allows more aggressive camshaft profiles (for higher performance, efficiency, less lope, etc) which require higher valvespring pressures. Rollers allow that with less wear and less incidence of cam and lifter failure. Automotive oils have also been formulated differently due to environmental regulations which tended to cause additional wear to older conventional flat tappet (lifter) cam designs. So rollers became commonplace, where they only used to be used in racing applications.
Now how that translates into aviation engines, I don’t know for sure, but what I’ve read about tells me folks worry about internal engine corrosion from disuse and subsequent cam failures from spalling. Roller lifters and cams could possibly reduce the incidence of disuse related corrosion based cam failures. But this is an educated guess.
Now how that translates into aviation engines, I don’t know for sure, but what I’ve read about tells me folks worry about internal engine corrosion from disuse and subsequent cam failures from spalling. Roller lifters and cams could possibly reduce the incidence of disuse related corrosion based cam failures. But this is an educated guess.
unsafervguy
En-Route
i was told by one of the better know engine shops not to bother when I asked about the cost of converting when I overhaul my 360. he said it was not worth the extra cost.
bob
bob
Stewartb
Final Approach
Rollers in car engines allow higher spring pressure for high revving engines. I never thought much about it for an airplane engine until I bought a Superior XIO-400 for my exp. Superior uses roller lifters as standard. Theirs are unique since they can be removed from the top. Better? I don’t know about the rollers being better but top removable is definitely better.
Roller Lifters
Our roller lifters were developed to provide a smoother running engine and to help reduce wear between the camshaft lobe and the roller face, minimizing the occurrences of cam-lifter spalling.
Superior Exclusive!
A unique feature of our roller lifter design is that they can be removed without opening the engine case, which reduces costly maintenance and repairs.
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Ted
The pilot formerly known as Twin Engine Ted
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The purpose of Lycoming going to the roller tappets was to reduce wear during cold start conditions, which they do pretty well. Personally I wouldn't spend extra money for them. However if you send a flat tappet engine in for a factory reman or overhaul (which can make sense in a lot of cases), you will get a roller tappet engine back out.