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Thread: O320 weight

  1. #1

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    O320 weight

    Whats the average running weight of a o320 straight mount. Engine and accessory's including stacks and muffler

  2. #2

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    Eci claims their 340 weighs the same as a 0320 with accessories 275 lbs
    Not sure what exhaust weighs.....15 lbs??
    Probably add oil etc. so 300?


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  3. #3

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    About 20-30 pounds lighter than the lightest optioned o360.

  4. #4
    Bill Rusk's Avatar
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    MoJo not necessarily.

    The 0-320 can weigh from about 270 to 310 pounds (not including muffler) depending on straight mount, dynafocal, angle valve, hollow crank or solid crank, narrow deck, wide deck, etc etc. A lot of folks assume the narrow deck is lighter than a wide deck but again there are other variables in play so a narrow deck is not necessarily lighter than a wide deck. And .....in fact, if you are just weighing the case, the mid 60's wide deck is the lightest case. (to make sure we are apples to apples this includes the thru bolts and banana plates)

    The 0-360 can run from about 280 to as much as 350 pounds, again depending on variant.

    Bottom line some folks blindly think they are saving weight by putting an 0-320 on but if you don't pay attention you may actually be heavier than a 0-360. If you go strictly lightest 0-320 to lightest 0-360 it is about 10 pounds.

    Bill
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  5. #5
    DJ's Avatar
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    And now there is a great, lightweight certified prop for the O-360 powered PA-18.

    Sent from my SM-G965U1 using SuperCub.Org mobile app
    The heavens declare the glory of God; the skies proclaim the work of His hands. Psalms 19:1

  6. #6

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    Quote Originally Posted by DJ View Post
    And now there is a great, lightweight certified prop for the O-360 powered PA-18.

    Sent from my SM-G965U1 using SuperCub.Org mobile app
    And has me finally thinking about an 0360 when the time comes.

  7. #7

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    Bill,

    Do you know how one would read the serial number or designation stamp on the case to tell the yr it was made?

  8. #8
    Bill Rusk's Avatar
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    Kevin

    Honestly....no. I had access to a large rebuilding shop at Poplar Grove. Went in and the manager of the engine rebuild shop (Dave Mitock) helped me weigh a bunch of cases. There is definite creep over the years. The older cases (1950's stuff) was pretty light and they got progressively heavier over the years with the newest ones being close to 7 pounds heavier than the older ones. Unfortunately I lost that notebook so I don't have all the specific weights. I do remember that the narrow deck with the thru bolts and banana plates, was heavier than the wide deck (with the appropriate case bolts). Also the mid 60's wide deck case was the lightest. There was no significant weight difference on cylinders that had the tapered fins. The hollow crank was quite a bit lighter than the solid, and also allows the flexibility to go Constant speed prop in the future if you so desire.
    Now.....if you add light weight Emags, Magnesium sump and flywheel, B&C case mounted alternator, light starter, (conical case obviously) no swing out mounts, built in thrust line, composite prop,............ you are way lighter with a 0-360 than the original 0-320 set up.

    The carb for the 0-360 Vs the 0-320 is about 2.5 pounds heavier. Big difference there and a good throttle body type set up (if there was one) could be a significant weight savings. But all my research so far has not really been so positive in that area. There seems to be some success with smaller Rotax, Jabariu, type engines but almost no one in the RV group is running throttle body carbs. Why? If they really worked everyone would be doing it, kinda like the Pmag is getting VERY common. Just my opinions and all that folks. Sorry I no longer have all the exact weights to share to document this. Perhaps I will go back sometime and spend a day reweighing everything to get those numbers. I know exactly when and where I lost that notebook. That sucked. I had a ton of info there.

    Hope this helps

    Bill
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  9. #9
    Bill Rusk's Avatar
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    So the point I am trying to make is you can add weight to the airplane for nothing. Two engines 0-320 both put out the same Hp but one weighs 20 pounds more. You added 20 pounds and got nothing for it. If I add 20 pounds to my airplane I want to get something in return. Increased performance, safety, comfort......something.
    I recently saw a post where someone made a carbon fiber storage box. It weighs close to 1 pound more than my CF box. Apples to apples. So even using CF or other technology does not guarantee weight savings. Light weight takes time and money but more than anything else it takes attention to detail. Why make your seats comfortable for 6 hour flights (that weigh 20 pounds) when you never fly more than one hour? Make a 5 pound seat that is comfortable for two hours. Constant evaluation and thought.....apply the 90% rule.........and don't ever think..."well,.... it will only add a little weight..."

    Bill
    Very Blessed.

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