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  #1  
Old 11-13-2017, 03:45 PM
dwranda dwranda is offline
 
Join Date: Jan 2015
Location: Jamestown,NY
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Default Need help understanding 9A engine choices

I'm an engine buying novice trying to learn all I can. I'm on Barnstormers everyday looking at engines and the more I look the more I am getting confused. I am building a 9A. I suppose the easy route is order new from Vans, but I'm trying to be as frugal as possible yet safe and hopefully reliable. Here are a few of many questions I have.
1. To burn mogas do you need lower compression pistons(7 vs 8.5) or is it more of an ignition issue? Is electronic ignition better in this regard than mags? Burning mogas intrigues me if it is available. I guess to boil it down would a 160 HP 320 with pmags be able to burn mogas? Does FI or carb matter?
2. HP? Obviously most everyone wants more. I've read the discussions of too much HP on a 9 but a 360 with 7.0 compression pistons to come in about 170 HP also intrigues me. Who out there has done that?
3. wide deck/narrow deck? From what I can tell from my research the narrow decks are older right? Does it matter or should I not be worried at looking at the older ones if they are in an overhauled engine? Does a high total engine time matter with an overhaul?
I've got to stop now so I'm not writing a novel.
Thanks for any input from the braintrust!!!
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  #2  
Old 11-13-2017, 03:53 PM
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Carl Froehlich Carl Froehlich is offline
 
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End your pain and get a show special 320 engine and CS Hartzell prop from Vanís. It will run on non-ethanol premium fuel. Do yourself another favor and get the new deal from Vanís for the engine to come with one pMag. I ordered my IO-360 with one pMag and nothing in the other hole for my installation of a second pMag.

While there are cheaper ways to go, I offer this is not better value out there than a Vanís engine/prop combo show special.

Carl
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  #3  
Old 11-13-2017, 04:45 PM
Rock Rock is offline
 
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Default Great write-up by Mahlon on this subject!

[quote=dwranda;1218651]I'm an engine buying novice trying to learn all I can. I'm on Barnstormers everyday looking at engines and the more I look the more I am getting confused. I am building a 9A. I suppose the easy route is order new from Vans, but I'm trying to be as frugal as possible yet safe and hopefully reliable. Here are a few of many questions I have.
1. To burn mogas do you need lower compression pistons(7 vs 8.5) or is it more of an ignition issue? Is electronic ignition better in this regard than mags? Burning mogas intrigues me if it is available. I guess to boil it down would a 160 HP 320 with pmags be able to burn mogas? Does FI or carb matter?
2. HP? Obviously most everyone wants more. I've read the discussions of too much HP on a 9 but a 360 with 7.0 compression pistons to come in about 170 HP also intrigues me. Who out there has done that?



This something I wrote a long time ago when I was in the engine business. Thought you might find it interesting reading.
Good Luck,
Mahlon

I am a engine guy not a RV 9 guy, so you have to bear with me if I am
missing something here, but I can't see any disadvantage to using a O-
360 on a 9 other than approximately 14 pounds loss of useful load.
First off any engine using a fixed pitch prop never sees rated
horsepower during normal operation. An O-360 is rated at 180 Hp at
sea level at full throttle and 2700 RPM. The only way you will get to
those numbers, with a properly pitched propeller, is at full
throttle, at full speed, at sea level. The engine will most likely
never see more than 2500RPM during climb or at takeoff power, unless
you climb the aircraft very flat with a climb prop on it. The 180HP O-
360 is alternately rated at 160 HP at 2400 rpm, so a 180 HP 360 with
a cruise prop on it, will likely only turn 2400 RPM during take off
and climb at sea level. Guess what, a true 160HP from the 360 just
like the fixed pitch guys get with the constant speed equipped 320
(160HP + 2700RPM and full throttle). All you have done by turning
2400 is de-rated the engine to 160 HP! Now if the climb is flat or
the speed builds up, pull the throttle back and keep it below 2400
RPM for a true 160 HP. Imagine what this will do at altitude, you
have a cruise prop installed and 20 extra horsepower at your disposal
to use, as you climb to higher altitude. Wow! This is a great way to
go for those operating out of higher altitude fields all the time or
just fly high all the time.
Some say, it is too tempting and you will break the 160 HP rule or
you do most of your flying at low altitude and you don't want to have
to manage the throttle so much, so lets have some insurance. We put
low compression pistons in the 360 and you now have a 167 HP, O-360.
rated 2700 RPM. Guess what! With climb prop we now get 2500 RPM
during sea level take off and climb..... That's right, a true 160HP
at 2500 RPM. And to boot you still have the extra 7 horsepower at
your disposal as you go up.
The key to all this is you have to regulate engine power with the
throttle. This is done everyday, all the time, with a fixed pitch
prop and engine combination.
If you have a slightly under pitched prop (or as some would call a
super climb prop) on a 320 like Clay seems to have, you have to pull
the throttle back to prevent exceeding RPM limitations and thus true
horsepower output. No different with the 360 with fixed pitch prop at
180 hp or 167 HP.
The 2400 RPM 160HP 360 is a certified, Lycoming engine, not something
I am making up..IO-360-L2A used on the more modern C172 RG's is a 160
HP 2400 RPM 360.. fuel injected no less! So is the O-360 J2A. The 167
HP O-360 is a certified engine as well; it's the O-360 D series of
engines.
You can use the same logic with a constant speed prop, use a prop and
gov limited to 2400RPM at take off, like the 172RG, and get a true
160HP at 2400 and full mp just like the 320 constant speed guys at
2700 RPM..The down side is no more oomph at altitude. Same with the
167 HP versions, prop gov set to 2500 RPM and you have a 160 hp
engine, again with no extra power at altitude.
To me the fixed pitch version of this scenario is the way to go with
very little throttle management (no more than an under pitched 320)
you get a full 160 HP with plenty of power to keep things going well
at altitude. The 360 engine is less expensive if you are purchasing a
non vans supplied one, and so is the fixed pitch prop but the
performance is the same as the more expensive 320 with a constant
speed prop!
I know you have to think "Out of the bun" here, because nobody told
you about this before and the support from Vans using an O-360 isn't
really there. But other than about 14 pounds (heavier) fixed pitch to
fixed pitch,( one muest understand that the fixed pitch 360 has a solid flange crankshaft that weighs more, If you compare the weights iof the hollow shaft 360which is the cinsatnt speed version and the hollow shaft 320 constant speed version the weight difference is only o or a little taller (about 2 inches) and a little wider (1
inch) and the carb air box mounting flange being a different size the
rest of the engine is the same as a 320 on the outside. From what I
am told, the 360 will fit on the airplane with the -7 360 cowl and
you get the performance of a constant speed 320 for a lot less money
with about the same weight up front, if you consider the weight
difference of the cs prop on the 320 and FP on the 360. Even fixed
pith to fixed pitch the weight difference is 15 lbs total prop and
engine to prop and engine.
I hope the operators of lots of the 360 powered RV9's reply to Clay's
post, as I can't see what is undesirable with the 360... but I would
sure like to find out if there is a down side.
Please shoot holes in this explanation, if I am wrong or if I am
missing something, you won't hurt my feelings and I will learn
something!!
Good Luck,
Mahlon
These are actual weights of the engine as shipped from us.
The superior O-360 weighs more then the O-360 listed due to the fact the sump weighs more then the one Eci or Lycoming uses. Superior lists the weight of there O-360 with a hollow shaft as 287 lbs which is 6 lbs heavier then the same exact engine with a Lycoming or Eci vertical sump installed.

TMX O-360 Fixed Pitch (Solid Shaft 180HP):
25"x 33"x 29" 286 Lbs.

TMX O-360 Constant Speed (180 HP) :
25"x 33"x 29" 281 Lbs.

TMX O-320 Constant Speed (150/160 HP) :
22"x 32.2"x 29" 274 Lbs.
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  #4  
Old 11-13-2017, 06:37 PM
Jrskygod Jrskygod is offline
 
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Yesterday as I was climbing up to altitude through some weather to be on top at 15K I was wishing I had a 360 with a constant speed and not the 320. You can always pull the throttle back if your true airspeed gets up too high but the 320 just puts out so much and a few extra ponies would make those long climbs much easier. Don't get me wrong I really like my 9, and its no slouch, but when I travel its always above 10000 where the 9 really shines and is so efficient. With the 360 you would be able to get up there quicker and get into cruise throttled back with the same fuel burn as the 320, or if you wanted higher the power is there to get you further up quicker.

If I was to build another 9 there is no question that I would do a I0-360 with a constant speed lightweight prop and extended fuel.
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  #5  
Old 11-13-2017, 09:00 PM
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RVbySDI RVbySDI is offline
 
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Ok, I am going to post just a brief comment since I agree 100% with Mahlon. I cannot add anything to what he has said about the 360. It is dead on . . . But, too many of the engine guys and even the RV guys are not paying attention to the Titan O/IO340! I will not post a bunch of numbers here since I do not know all of them by heart but if you take a few minutes to explore this engine you will see an awful lot of what Mahlon was saying about the 360 in the performance of the 340. And the kicker. . . It gives you that 180 hp engine with aproximately 20 lbs less weight than the 360 while fitting in the plane just like a 320. Mahlon, give it a look and then let us know if what I am saying aint so!

For some good reading check this out:
http://www.continentalmotors.aero/ti...ines/x340.aspx
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Last edited by RVbySDI : 11-14-2017 at 10:08 AM.
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  #6  
Old 11-14-2017, 04:22 AM
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KRviator KRviator is offline
 
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Quote:
Originally Posted by RVbySDI View Post
Ok, I am going to post just a brief comment since I agree 100% with Mahlon. I cannot add anything to what he has said about the 360. It is dead on . . . But, too many in the engine guys and even the RV guys are not paying attention to the Titan O/IO340! I will not post a bunch of numbers here since I do not know all of them by heart but if you take a few minutes to explore this engine you will see an awful lot of what Mahlon was saying about the 360 in the performance of the 340. And the kicker. . . It gives you that 180 hp engine with aproximately 20 lbs less weight than the 360 while fitting in the plane just like a 320. Mahlon, give it a look and then let us know if what I am saying aint so!

For some good reading check this out:
http://www.continentalmotors.aero/ti...ines/x340.aspx
I have one of the original ECI OX-340S' in my -9A and I love it. Derated to 165HP using 7.2:1 pistons to ensure Mogas compatibility though it would probably have been fine with a bit more power even with the standard pistons, easily 'upgradeable' to ~175+HP using nothing more than higher compression pistons, and perhaps a little more if I want EFI.

Lighter than the O-360, and $1000 cheaper than Vans' show pricing too, even equipped with 2 P-Mags. I regularly cruise at 145KTAS burning 24.2LPH/6.4USGPH at 8,500-9,500 and can sustain an initial climb rate of 1700FPM at 1320Lbs gross until I hit my CHT limits using a Sensenich ground adjustable prop.

EDIT: Had an epiphany that perhaps my 2013 prices aren't current, but as a data point:
An OX-340S with:
  • 7.2:1 Pistons
  • Dynafocal 1 mount
  • 14mm plug bosses & automotive plugs all round
  • Dual P-Mags
  • Low-pressure, engine-driven fuel pump
  • 2 hours break-in on their test cell
  • But without a carb
cost me $25,604, including crating but excluding shipping in May 2013.
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Last edited by KRviator : 11-14-2017 at 04:26 AM.
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  #7  
Old 11-14-2017, 06:02 AM
dwranda dwranda is offline
 
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Thanks everyone. Mahlon's article is pretty much what I was talking about. Thanks! The 340 sounds good too. I will definitely look into that if I go the new engine route.
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Old 11-14-2017, 08:28 AM
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I'm running an IO360 and constant speed in my 9A, and I have never once had occasion to wish I had installed the smaller engine - and lots of times I was glad I had the extra cubic inches. Throttle is one of the controls in the airplane that is used by the pilot as needed to achieve the flight conditions desired.

As for fuel, I'm running 8.7:1 compression and built the entire fuel system with no natural rubber seals or components anywhere, and I'm running 91E10 autofuel for about 135 hours now with no problems other than cranky hotstarts in the summer - and the AFP purge valve has pretty much solved that one too.
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Built an off-plan 9A with too much fuel and too much HP. Should drop dead any minute now.
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Old 11-14-2017, 09:12 AM
Rock Rock is offline
 
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Default Youíre Welcome!

Quote:
Originally Posted by dwranda View Post
Thanks everyone. Mahlon's article is pretty much what I was talking about. Thanks! The 340 sounds good too. I will definitely look into that if I go the new engine route.

I observed in your initial post that you were attempting to keep Engine purchase costs down and have been searching for deals online. Iím sure youíve found several 360s at reasonable prices. Going that route and adding Electronic Ignition and possibly Electronic Fuel Injection could give you a very nice performing engine, economically. Iíve been doing similar research for a future project Iím considering.
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Old 11-14-2017, 09:21 AM
dwranda dwranda is offline
 
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Quote:
Originally Posted by Rock View Post
I observed in your initial post that you were attempting to keep Engine purchase costs down and have been searching for deals online. Iím sure youíve found several 360s at reasonable prices. Going that route and adding Electronic Ignition and possibly Electronic Fuel Injection could give you a very nice performing engine, economically. Iíve been doing similar research for a future project Iím considering.
There's part of me that really likes the electronic FI and ignition choices that have been debated lately on VAF. The other part of me says you're a newbie so keep it simple stupid. The building of the electrical system of the plane is probably my weak link of the whole project and I honestly don't trust myself in putting together an all electric system. A man's gotta know his limitations and I believe that's mine. I don't have a lot of builders around here to pop in and critique or help with it so trying to keep it simple as possible. Pmags will help in that respect I believe.
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