0320 up grade
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Steve Pierce
BENEFACTOR
Graham, TX
Engine converted to O-320-B2Bconfiguration and data plate stamped with “C” IAW LycomingService Instruction 1304J
dan d, I have to disagree after uping the compression on a few 150 hp O-320s to 160 hp.
dan d, I have to disagree after uping the compression on a few 150 hp O-320s to 160 hp.
flynlow
FRIEND
Fowler, Ks
I rebuilt a Narrowdeck 150hp. I considered using the 8.5 pistons
I live at 2500 msl and even in cold days rarely see density altitudes below 1000 msl.
Thinking even with the 160 hp piston , this engine will rarely see 150 horses much less 160
Any history of the bootlegged 160 horse engines popping cylinders without banana plates??
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+6.6 % is noticeable on take off and definitely when loaded up.
I think the conversion is worthwhile. But something to consider is Most 150’s are converted at end of tbo/life when they are likely putting out less than 150 hp. I know when I converted it was very noticeable. I think the real test would be to compare a freshly overhauled 150 and 160. I sent lycon are narrow deck 150 and got back a wide deck 160. I would use them again.
Steve Pierce
BENEFACTOR
Graham, TX
Just did one with less than 100 hours, big difference.
Not to pile on but something that is objective is prop pitch. More than one guy on here has had to repitch props after installing an 8.5 to 1 top. Even Catto will recommend a different prop pitch depending on if you’re running a 150 or 160hp.
When’s the last time you saw a competitive stol comp. won with a 150 hp O-320? They are usually high compression + +
When’s the last time you saw a competitive stol comp. won with a 150 hp O-320? They are usually high compression + +
The engine guys I've talked to say increasing compression by one adds approx 4% HP. That's what Lycoming used to rate my 390 going from 8.9-1 to 10-1. Continental estimates are more conservative. How a 320 goes from 150 to 160 has never made sense to me.
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I scratched myself bald-headed long ago, your turn...
Steve Pierce
BENEFACTOR
Graham, TX
I put some 11 to 1 cylinder/piston sets on an RV8 recently. The engine builder told me it won't make a huge difference until he goes up to altitude. It has electronic ignition, constant speed prop etc.
skywagon8a
MEMBER
SE Mass MA6
Part of it is the requirement to use 100 octane rather than 80.
You believe higher octane produces more power?
A standard 320 uses 7-1 so upping compression to 8.5-1 may add 6%. My error was in thinking 320s used 7.5-1. Oops. What's more interesting is the bore is the same for 320s and 360s. 360s add 1/2" of stroke and get 20 hp. Add fuel injection and add another 20. That's a pretty big jump. Some guys say using 10-1 in a 320 makes 180+ hp but stock 360s typically perform better from what I've seen and heard. Displacement in action. Then there's the 390. Standard compression at 8.7-1 with bigger pistons and the same stroke as a 360. Rated at 210 hp. Up mine to 10-1 and Lycoming rates it at 220 hp, although some believe it's higher. The IO-400 had a longer stroke than the 390 and was rated at 215 hp but mine made 220 on a dyno on a very hot Dallas day. How these engines are rated for power output is a head scratcher. Piston size, stroke, compression, and fuel delivery all matter and the ratio doesn't appear to be linear. A good friend more familiar with high performance airplanes than anyone I know convinced me to increase the compression in my 390. He says high compression works better with bigger bores and in the 390/580 cylinders it's really impressive. Time will tell. Interesting topic. To me, anyway.
A standard 320 uses 7-1 so upping compression to 8.5-1 may add 6%. My error was in thinking 320s used 7.5-1. Oops. What's more interesting is the bore is the same for 320s and 360s. 360s add 1/2" of stroke and get 20 hp. Add fuel injection and add another 20. That's a pretty big jump. Some guys say using 10-1 in a 320 makes 180+ hp but stock 360s typically perform better from what I've seen and heard. Displacement in action. Then there's the 390. Standard compression at 8.7-1 with bigger pistons and the same stroke as a 360. Rated at 210 hp. Up mine to 10-1 and Lycoming rates it at 220 hp, although some believe it's higher. The IO-400 had a longer stroke than the 390 and was rated at 215 hp but mine made 220 on a dyno on a very hot Dallas day. How these engines are rated for power output is a head scratcher. Piston size, stroke, compression, and fuel delivery all matter and the ratio doesn't appear to be linear. A good friend more familiar with high performance airplanes than anyone I know convinced me to increase the compression in my 390. He says high compression works better with bigger bores and in the 390/580 cylinders it's really impressive. Time will tell. Interesting topic. To me, anyway.
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DJ
MEMBER
Bolivia
There are diminished returns for each compression point the higher you go.
StewartB you are forgetting to take Angle valve versus Parallel valve differences into account. Fuel injection doesn't add 20 hp to a 360 cubic inch Lycoming. More airflow through a tuned induction and angle valve heads makes the difference.
StewartB you are forgetting to take Angle valve versus Parallel valve differences into account. Fuel injection doesn't add 20 hp to a 360 cubic inch Lycoming. More airflow through a tuned induction and angle valve heads makes the difference.
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john schwamm
SPONSOR
Anchorage, Alaska Carefree, AZ
Port and polish with cylinders flowed may give one better HP than stock setup. My guess is more than 10HP on an 0320.
John
John
Steve Pierce
BENEFACTOR
Graham, TX
Sure does make it run smooth, no idea on horse power but I'm happy.
skywagon8a
MEMBER
SE Mass MA6
I did not say that the higher octane produces more power. The higher octane is used to assist the rest of the upgrades to produce the power without damaging the engine.
DJ is correct, fuel injection doesn't add 20 hp to a 360 cubic inch Lycoming. The engine in my Cub is a IO360-BiD. It produces 180 hp and is identical to a carburetor O-360 except for the fuel/air delivery method.
PerryB
FRIEND
Chico, CA
It must. I can't tell you how many Barnstormer ads I've seen with parallel valve 360's that have been converted to injection and claiming to be 200 hp. I've actually called a couple pretending to be a potential buyer and asked how they got 200 hp. The answer was "By converting it to injection". Caveat emptor...
txpacer
SPONSOR
Iowa Park, TX
That's called "California horsepower"
scottsville
Registered User
I have a narrow deck 0320 a2b and I have heard you can not put high compression pistons on that motor legally. I do not think its a B model. Is there away to do this?
Thank you for any advice. I bought a prop for a 160 so I am kind of in a pickle!
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
I think some narrow deck cylinders are spot-faced for the hold-down nuts, which makes them incompatible with banana plates and not usable for 160 HP.
We’ve all heard of bootleg 8.5 pistons in a ND 320 with no banana plates, and I’ve always wondered, say a guy is running a 82x42 or 41 borer, are his cylinder pressures any higher with the 8.5’s than they would be with the 7.0’s and a 74x56 or 58 cruise prop? I’ve always wanted a transducer to measure it... maybe some of the engineers/mathmeticiams here can give us a rough idea
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