Cruising RPM - Engine welfare

[sloPoke]

We ran our O200 's on the racers up to 4200 rpms but they did break a connecting rod now and then. Of course they were balanced up real good. Did wear out kind of fast at that rpm though. 2600 to 2700 shouldn't put much strain on one.
charlie

[W.J.Langholz]

Hey All

I haven't been on this site but 2 weeks and I really like it. I have tried to read thru most of the threads and I have learned more than I care to admit.

If all of you are still around this thread....George knows becuase he answered earlier to one of my questions, however I'm a first cousin, I have a 1957 C-172 with a O-300. Love my plane, bought it this last April. My son (18) just pasted his knowledge test this last friday getting ready for his check ride. Will be nice to have a 2nd pilot in the family.

My question following this thread is.....I have a STC for auto gas and have access to 87 octane which I have been burning, but I too have been keeping at 2400 rpm. After ready thru this thread maybe I should be up there @ 2600 full rich, what say you all????

Thanks Willie

[170C]

Willie, welcome to our forum. As you know there is a lot of good, solid information (and a wee bit of opinions ) on about any subject dealing with our various aircraft. I, too, fly a C-172 ('56 w/ an O-300B engine). These guys let me mix with them because mine is what some call a C-170C model (it has a Bolen STC for a convential gear) I have an autogas stc and have had on at least one other aircraft and have been well pleased with the engine performance on autogas, but with the "stuff" they began putting in the auto fuel around the DFW area years ago and now the alcohol, I have stopped using autogas except when I happen to be out in the hinderlands and can get the better grade of autofuel. I am not an engineer so this is just my OPINION , but I have operated my engine on autofuel and 100LL and regularly run it at 2500 rpms at all altitudes and so far (hope this doesn't jinx me ) I have not had any detrimental effects that I am aware of. When flying with some of our 170 folks I even run up to 2600 rpm just to try to stay in sight of them (thus the moniker--Ole PokeY). I have a personal opinion that these engines were manufactured & certified to operate at 2700 rpm's all the time if we choose to do so. Of course the fuel consumption will go up quite a bit at the higher power settings. George and/or others may not agree with my opinion, but that makes for interesting discussion and an opportunity to learn more about the Continental operating limitations, etc.

[Bruce Fenstermacher]

Welcome cousin Willie

Operate your 0-300 anyway you want within the limitations. More RPM means go faster, burn more fuel. Lean it the same whether using 100 or autofuel.

BTW Frank is always pleased to hear of another guy flying a goofy tail airplane sneaking around here.

[W.J.Langholz]

Thanks Guys

I really do like this site....atleast you guys talk my kind of language. I like my 57, it's a little younger than I am but it's a nice bird and fun to fly. Most of the people here seem to like their 170's just the way they are which is nice to read about, make you feel at home.

If someday I make this 57 into a Texas Taildragger would I be closer than a first cousin?????

Anyway I glad I found this site, will be reading everyday, always something new to learn and I try to keep my mouth shut as to not getting in trouble

Willie

[GAHorn]

... George and/or others may not agree with my opinion,....

What is going on around here??? I DO agree! RPM is not going to hurt this engine, and neither is autofuel if it meets the STC specs and has no alcohol in it, as long as it is Fresh. I have less confidence it won't hurt that expensive carb and fuel system, especially if it is not completely consumed or if the airplane is stored with autofuel.