Is there a difference in two near identical Lycoming/Clone in regards to weight? In other words, is one lighter than the other with the only difference being the mount style.

Which mount is preferred in a TW backcountry type aircraft?

Is there a deference in the weights of the two types?

The actual engine in my search is the O-340 Titan.

Conical is lighter but I don't recall how much so.

TCDS gives you that info.

https://ohio.shortwingpiperclub.org/Mai ... /E-274.pdf

Note 9 has the weights of the various models.

Are you talking about just the engine or are you considering the mount also. As usual several factors come into play. Plane/engine/lowered or stock mount/mags vs electronic ignition/exhaust/cowling fit. For example if you do a lowered Javron conical or Dynafocal mount you can have issues with mag clearance unless custom built for Bendix electronic mags are usually not a issue. Dynafocal will be heavier but allows for more engine movement and cowl contact something most don't notice unless things are built tight. How short of backcountry strips are you talking about?
DENNY

As usual, Denny has it right the engines weigh is the same, but the mount is heavier on the dynafocal . I think by about 6 lbs

Thanks everyone! I was looking at both the engine and mounts total weight. Full disclosure, I have a couple of Murphy Rebels and one has the conical and the other has the dynafocal. I got a quote for a new O-340 from Continental and since I plan on selling one of the Rebels when the other is finished, I was trying to get ahead of the game deciding which one I will keep. Sounds like I will keep the one that with the conical mount, which is the way I was leaning already. I'm thinking the lower compression for the ability to run lower octane fuel when needed, electronic ignition, and fuel injection. With 100LL prices and availability in the future in question, every little bit of fuel savings in helpful.

Since my long term plans are to install the TK1 gear also, which adds a little weight, removing it elsewhere will keep things in check.

DENNY, About the shortest strips that I currently visit are in the +/- 1,000' range, nothing drastically short. The Rebel is a great performer, no Super Cub, but it definitely is no slouch. I do want the ability to use much shorter strips. Heck, I might even get to fly up to Alaska one day, if...big if.....the Canadians ever allow BM to fly in/through their airspace.

WWhunter wrote:..... Sounds like I will keep the one that with the conical mount, which is the way I was leaning already. ......

One of the (theoretical?) advantages to a dynafocal is it's smoother.
Is that your experience with these two- conical vs dynafocal?
Lighter is nice, but smooth is pretty nice too.

I run a dynafocal on our PA-18A with an O-360, much smoother than a conical. The O-360 has some pretty good pulses at startup and shutdown. This is where the dynafocal mount shines. On the O-360, I prefer the dynafocal mount, additionally, I will claim that my dynafocal is stronger than the stock conical mount, based on the size of the tubing and the geometry of the 4 engine to mount attach points. My mount was made under contract by Airframes out of Big Lake for Penn Yan a bit over 20 years ago. Kind of funny as I was living in AK when I did this conversion and figured I could pick the mount up in Big Lake. Nope, it had to go all the way to Penn Yan NY for QA then shipped back to me in Alaska. Yep, it’s heavier than the stock conical, I’ll take stronger and smoother every time. Our Cub still tweaked in just under 1200 pounds with O-360, 2K upgross, 31’s and belly tank.

TR
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If you are working bigger strips I don't think the 6-7 lbs weight would matter that much. I would look at all the other factors espically availability of parts and how the engine fits with the cowling/exhaust/intake to make a decision.
DENNY