0-540 engine dynafocal Type I or II

[Tim Anderson]

I'm planning on a new Lycoming Y0-540. The two dynafocal types (I or II) has multiple confusing posts all over the web. Type I (single engine 30 degree) or type II (twin engine 18 degree).

Any pro/ con suggestions?

[alaskabearhawk]

What engine mount do you have?

From another site:

"In this design the larger rubber isolators are positioned at an angle of 30°. The intent was to “focus” the mounts just ahead of the center of gravity of the engine/propeller combination. This mount proved to be very successful since it afforded a smoother ride. This Dynafocal mounting system is the most commonly used system."

"When Piper introduced the Twin Comanche, the aircraft had long extensions to the propeller hubs. This gave an exceptionally clean cowling, but the center of gravity of the engine/propeller was moved ahead of the focal point of the Type 1 Dynafocal mounts, so the angle was changed to 18° to compensate. This is known as the Type 2 Dynafocal and is used on the IO-320-B1A engines. At the same time, larger “three inch” Lord isolators were developed."

So, more muddy water.

Also: https://bearhawkforums.com/forum/bea...unts-for-order

FWIW, I have the Type II. My engine came off of a 1967 Piper Aztec and I went with the mounts it came with. Type I have a 1 3/8" opening in the mount adapters for the rubber isolators.
Type II have a 2' opening in the mount adapters for the rubber isolators. The Type II mount is larger, so I would think the more isolation material the better. I'm just glad it fits and hanging on the front of my fuselage.