location of propeller on crankshaft

N8366A · Post by **N8366A** » Sun Jul 09, 2006 6:56 pm

Does anyone have the propeller location of the propeller on the crankshaft with relation to the case split or some other known reference. I have a recently completed overhaul on a O300A engine, 8 bolt crankshaft and want to make certain we are installing the propeller properly. Seems to me I read somewhere in the past that the original information had been modified to provide less vibration.

cessna170bdriver · Post by **cessna170bdriver** » Sun Jul 09, 2006 11:11 pm

I think that there is an article in The 170 Book on this subject, but I don't have mine handy. From my memory of the article, I set my engine so that #1 piston is at top dead center, then mounted the prop at roughly the 10:30 - 4:30 position, facing the hub. I couldn't ask for a smoother running engine.

Miles

Post by **GAHorn** » Mon Jul 10, 2006 1:27 am

My copy of Cessna Service Information includes a Service News Letter dated 7/8/53, stating that beginning with serial number 26110, airplanes leaving the factory have their props advanced 45-degrees (one bolt-hole)forward/clockwise for improved vibration results. It is recommended that at next prop removal, all other 170's also advance their props one bolt-hole.
This SNL came out when the original position of the props had the #1 blade at 11 o'clock (when viewed from the cockpit) with #1 cyl at TDC. Therefore the props after advancement had their #1 blades at the 1 o'clock position when viewed from the cockpit. This also had the nice effect of having a blade at a convenient angle for hand-starting the airplane.

cessna170bdriver · Post by **cessna170bdriver** » Mon Jul 10, 2006 2:36 pm

The 1:00 position from the cockpit (10:30 to 11:00 from the position of installing the prop) is where I remember the 170 News article said was best. I have never been aware that there was a position documented by Cessna to be best; nice to know! I missed it by one hole (45 degrees) once and couldn't believe how rough the engine ran! Mine is as stated above, and I couldn't ask for smoother.

Miles