Angle Trans Question

[Patrick McAndrew]

Will coupling alignment be affected as an engine is loaded and rpms increased when a 7 degree down angle transmission (Yanmar setup) is used with a dripless bearing, instead of a stuffing box? As the engine moves in the mounts due to torque, will it through out engine alignment? Seems that if a straight output trans is used the engine will want to rotate on the same centerline. Are special considerations needed with a down angle transmission?Thanks for your input,Patrick

 

[Don Alexander]

Good Question

Dunno the answer but it sure is a good question. I am advised that the engine can flex its mounts up to 0.2" and this will throw out all alignments whether straight or 7° down - so I fitted a flexible coupling

 

[Brad Forsythe]

Engine movement

Interesting. My Yanmar vibrate severely at low rpms and I know the engine physically moves 1/2" on the mounts causing a earth shaking shutter. Are we saying that the engine shouldn't move/torque/rotate?

 

[Patrick McAndrew]

engine movement reply

Brad,I think the engine is designed to move somewhat in the mounts when torque and thrust loads are applied. Thrust load should not alter the plane where you measure alignment at the coupling. I don't think a torque load will either if you're using a parallel output drive transmission. I can't seem to resolve how using an angle trans doesn't throw out the alignment when the engine torques/rotates. I am experience vibrations at higher rpms and after thoroughly checking the entire system, can't find the cause. Hopefully, the guys at PYI will shed some light on the subject soon.

 

[Alexander D Psychoyos]

Engine shudder shifting to neutral

My Yanmar 27 on my 2001 Beneteau 331 "shudders" when shifting to neutral, even under most controlled shifting. Engine mounts are OK and engine has less than 50 hours on it. Is this normal? What could be causing shuder? How can I remedy it?