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Darren S

Well Known Member
Hi all,

Is it possible to convert an O-320 E3D Fixed pitch 150 HP to a 160 HP, Constant Speed prop ?

Is the cost worth it or better to sell and buy a proper motor to start with ?

Thanks,

Darren
 
#1 Yes #2 Maybe

Darren S said:
Hi all,

Is it possible to convert an O-320 E3D Fixed pitch 150 HP to a 160 HP, Constant Speed prop ?

Is the cost worth it or better to sell and buy a proper motor to start with ?

Thanks,

Darren
Click to expand...

Darren,
Checking Lycoming SSP 108 shows that the E3D has:

3/8" prop flange bushings (older, but upgradable)
Slick Magnetos
0-235 Front Main Bearing (bad)
Dynafocal 1 mounting system (good)
Straight Riser Oil Sump
-32 Carburetor
Fixed Pitch Propeller

You will need to totally disassemble the engine to upgrade the front main bearing and replace the 7 to 1 pistons with 8.5 to 1 CR to raise the horsepower from 150 to 160.

Using a constant speed prop may or may not be an option. It depends on if the engine is fitted with a "solid nose" or "hollow nose" crankshaft. Look on the front of the crankshaft. There is a raised ring on the front of the prop flange area. If the area inside this ring is solid steel, you can not run a hydraulically controlled constant speed prop. (Aftermarket suppliers offer some electrically controllable C/S props to get around this)
If there is a soft plug (similar to the cooling system plugs found on automotive engine cylinder heads and blocks) inside the ring, you have a "hollow nose" crankshaft installed and can convert the crankshaft for C/S use. Use the search feature to find threads here on VAF which describe how this is done.
Determining whether to repair or replace the engine depends a lot of factors, including the crankshaft design, how important having a C/S prop is to you and the overall condition of the engine you have. How much do you have invested in the engine now?
I hope this helps.
Charlie Kuss
 
Darren S said:
Hi all,

Is it possible to convert an O-320 E3D Fixed pitch 150 HP to a 160 HP, Constant Speed prop ?

Is the cost worth it or better to sell and buy a proper motor to start with ?

Thanks,

Darren
Click to expand...

Darren,

It possible to do just about anything with a Lyc, the question is always is it worth it? Converting to 160hp is straight forward, buy high compression pistons ($55 each last time I looked), possibly with new rings - alternatively buy new cylinder assemblies ($800 each). Although Lyc says the front bearing should be changed most people don't.

Converting to CS is more difficult. I believe an E3D has a governor pad that has not been machined and a boss at the front of the crank case that also hasn't been machined (to take the angle fitting that sends oil into the crank). So you will have to split the engine to get boss drilled out and will have to have your accessory case machined, then fit the internal drive gears and a governor adapter. Then go buy a prop and governor.

The other way is to fit an electric MT c/s prop - no engine mods required. They are more expensive than a hydraulic prop, but with all the machining and parts (plus the costs of splitting the motor) it will almost certainly be a cheaper way forward.

Pete
 
Thanks all, you've given me some good information and things to go research. Much Appreciated :)

Darren
 
The Parts Manual...

chaskuss said:
Darren,
.......

Using a constant speed prop may or may not be an option. It depends on if the engine is fitted with a "solid nose" or "hollow nose" crankshaft. Look on the front of the crankshaft. There is a raised ring on the front of the prop flange area. If the area inside this ring is solid steel, you can not run a hydraulically controlled constant speed prop. (Aftermarket suppliers offer some electrically controllable C/S props to get around this)
If there is a soft plug (similar to the cooling system plugs found on automotive engine cylinder heads and blocks) inside the ring, you have a "hollow nose" crankshaft installed and can convert the crankshaft for C/S use. Use the search feature to find threads here on VAF which describe how this is done.
......
Click to expand...

...shows that a O-320-E3D does have the rear plug installed making the crankshaft (the really expen$ive bit) a candidate for CS operation.

It appears to be only on the -E1A, -E1F, -E2F and -E3D models of the "E series" of O-320s.

Of course this assumes no modifications during later rebuilds...
 
Last edited:
$800 new cylinders ?

Pete,

Where are you finding new cylinders for $800? I need 4 from my overhaul.
 
O-320-E3D does not have the nose bearing setup used for constant speed operation.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

Darren S said:
Hi all,

Is it possible to convert an O-320 E3D Fixed pitch 150 HP to a 160 HP, Constant Speed prop ?

Is the cost worth it or better to sell and buy a proper motor to start with ?

Thanks,

Darren
Click to expand...
 
how big a difference in speed, climb rate, fuel economy and sound

how big a difference in speed, climb rate, fuel economy and sound (i know i loved my 210 cruising at 2,200 rpm) between a fixed pitch and constant speed prop? with such a large difference between landing and cruise speed seems like it would be quite a bit.
 
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