Differences in O-540 models

[Charles Talleyrand]

I read that the O-540-A1A5 weighs 396 pounds, but that a IO-540-A1A5
weighs 437 pounds. Can the difference between a carb and fuel
injection really be 39 pounds?

Also, as I wrote an IO-540-A1A5 weighs 437 pounds. But an IO-540-c4b5
weighs 402 pounds, but produces 50 horsepower less. What did they
change about the engine that costs 50 horsepower but saves 35 pounds?

-Very Curious
-Charles Talleyrand

[Steven P. McNicoll[_2_]]

Charles Talleyrand wrote:
>
> I read that the O-540-A1A5 weighs 396 pounds, but that a IO-540-A1A5
> weighs 437 pounds. Can the difference between a carb and fuel
> injection really be 39 pounds?
>

Or 41 pounds?

[Mike[_22_]]

"Charles Talleyrand" > wrote in message
...
>I read that the O-540-A1A5 weighs 396 pounds, but that a IO-540-A1A5
> weighs 437 pounds. Can the difference between a carb and fuel
> injection really be 39 pounds?
>
> Also, as I wrote an IO-540-A1A5 weighs 437 pounds. But an IO-540-c4b5
> weighs 402 pounds, but produces 50 horsepower less. What did they
> change about the engine that costs 50 horsepower but saves 35 pounds?

I'm not familiar with the exact models in question, but some installations
require things like starter adapters, which add weight. Some engines are
also derated based on the application. The IO-540-AB1A5 used in the new
182s is a 230 BHP engine because it's limited to 2400 RPM. Other 540s put
out as much as 315 BHP.

[Charles Talleyrand]

On Aug 3, 6:34 pm, "Mike" > wrote:
> "Charles Talleyrand" > wrote in message
>
> ...
>
> >I read that the O-540-A1A5 weighs 396 pounds, but that a IO-540-A1A5
> > weighs 437 pounds. Can the difference between a carb and fuel
> > injection really be 39 pounds?
>
> > Also, as I wrote an IO-540-A1A5 weighs 437 pounds. But an IO-540-c4b5
> > weighs 402 pounds, but produces 50 horsepower less. What did they
> > change about the engine that costs 50 horsepower but saves 35 pounds?
>
> I'm not familiar with the exact models in question, but some installations
> require things like starter adapters, which add weight. Some engines are
> also derated based on the application. The IO-540-AB1A5 used in the new
> 182s is a 230 BHP engine because it's limited to 2400 RPM. Other 540s put
> out as much as 315 BHP.

I actually knew all that. But why would the engine weigh more?
Lowering the RPM does not add weight.

[Mike[_22_]]

"Charles Talleyrand" > wrote in message
...
> On Aug 3, 6:34 pm, "Mike" > wrote:
>> "Charles Talleyrand" > wrote in message
>>
>> ...
>>
>> >I read that the O-540-A1A5 weighs 396 pounds, but that a IO-540-A1A5
>> > weighs 437 pounds. Can the difference between a carb and fuel
>> > injection really be 39 pounds?
>>
>> > Also, as I wrote an IO-540-A1A5 weighs 437 pounds. But an IO-540-c4b5
>> > weighs 402 pounds, but produces 50 horsepower less. What did they
>> > change about the engine that costs 50 horsepower but saves 35 pounds?
>>
>> I'm not familiar with the exact models in question, but some
>> installations
>> require things like starter adapters, which add weight. Some engines are
>> also derated based on the application. The IO-540-AB1A5 used in the new
>> 182s is a 230 BHP engine because it's limited to 2400 RPM. Other 540s
>> put
>> out as much as 315 BHP.
>
> I actually knew all that. But why would the engine weigh more?
> Lowering the RPM does not add weight.

As I said, some applications require extra parts like a starter adapter.
That alone weighs 40 lbs or so if I were to guess. I'm not sure if Lycoming
engines need a starter adapter, but it could be some other accessory or
necessary part needed or desired in one application but not another.