Van's Air Force
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Converting an O-360 to IO
- Thread starter Derek
- Start date
John Courte
Well Known Member
Well, you could do it the hardest way possible, like I did: Buy a used O-360 off eBay (with a backwards facing sump and front-mounted governor), throw a Superior cold-air horizontal intake sump on it, and finish it off with an Airflow Performance fuel injection system. You'll have to rework some of the baffles, get custom length fuel hoses and cables, make your own cable brackets, and if you use the Vetterman crossover exhaust, you'll have to get really clever with heat shields and cable routing. You might save a little money, but only if everything goes right and you get a stellar deal on the engine. Have an A&P look it over before you buy it, regardless.
I know the above sounds like whining, but it's not. This engine is going to rock the house when I'm done tinkering, and I have no regrets about doing it the way I did. Of course, knowing what I know now, I may have done it differently, but maybe not. But you should know what you're in for if you start ordering off-menu and a la carte.
The easiest way to do it is this: Buy a used O-360 that's as close as possible to the configuration that Van's sells, then get a Precision Silverhawk or a used or ovehauled Bendix FI system. With a stock Lycoming sump of either vertical or horizontal flavor, the bits in the appropriate FWF kit from Van's should just work with minimal hiccups.
I guess the short answer is 'yes, it's possible,' and 'but it depends.' This is experimental aviation, anything can be made to work, given enough resources, and assuming it doesn't violate principles of safety or the physical laws of the universe.
I know the above sounds like whining, but it's not. This engine is going to rock the house when I'm done tinkering, and I have no regrets about doing it the way I did. Of course, knowing what I know now, I may have done it differently, but maybe not. But you should know what you're in for if you start ordering off-menu and a la carte.
The easiest way to do it is this: Buy a used O-360 that's as close as possible to the configuration that Van's sells, then get a Precision Silverhawk or a used or ovehauled Bendix FI system. With a stock Lycoming sump of either vertical or horizontal flavor, the bits in the appropriate FWF kit from Van's should just work with minimal hiccups.
I guess the short answer is 'yes, it's possible,' and 'but it depends.' This is experimental aviation, anything can be made to work, given enough resources, and assuming it doesn't violate principles of safety or the physical laws of the universe.
Thanks John,
So assuming that my yet to be purchased O-360 has the correct sump, the part of the conversion that involves replacing the carb with the say a Bendix FI body should be pretty much straight forward ? Regarding the governer, I'm now real sure all that part works.
Regards
Derek
Walt
Well Known Member
I did the conversion on mine after flying for 2 years with a carb. Got the kit from AFP and dug in. Requires all new fuel lines/filter, relocate some firewall fittings, 2 new fuel pumps, new throttle/mixture cables/brackets etc. Not overly difficult but was quite a bit of work. Glad I did it.
G3i Ignition
Well Known Member
Fuel injection needs:
Check out Airflow Performance for your fuel injection needs. link: http://www.airflowperformance.com/html/kits.html
Check out Airflow Performance for your fuel injection needs. link: http://www.airflowperformance.com/html/kits.html
John Courte
Well Known Member
Not only will you need the throttle body, you'll need the fuel distributor, lines, and new inter-cylinder baffles to accommodate the fuel line from the TB to the fuel distributor, and as Walt mentioned, new pumps. Both Precision and AFP sell the components downstream from the engine fuel pump as a kit. AFP also has a high-pressure electric boost pump kit that Van's sells. I forgot to mention that you'll need to change out the engine-driven pump for the high-pressure version. Some of this stuff can be a little bit tricky, but Airflow Performance's documentation and support is legendary and that counted for a lot in influencing my decision to use their system.
The way it works is this (Correct me if I'm wrong): the throttle body feeds fuel to the distributor, commonly called a spider, which allows a metered amount of fuel into ports in the cylinder heads during the intake part of the cycle.
This is different from electronic fuel injection where solenoid-operated injectors squirt fuel into the cylinders when a computer tells them to. An example of that would be Simple Digital Systems or EFII (flyefii.com). With either, you have to weld injector bosses on your intake pipes, but EFII does it for you if you send them your pipes. A conventional Bendix-type system has ports already drilled into the cylinder heads to accommodate the injector nozzles.
The other option available is something like an Ellison Throttle Body Injection system or the Rotec TBI, where the fuel is injected into the throttle body instead of the cylinders. Ellison systems have been known to ice up, so you'll still have to do the duct work for carb heat.
Also look at the cylinder heads - it will be easier if they are already tapped for injector nozzles. The sump is not a deal breaker - Airflow offer an elbow that can be used to turn the injector through 90??. Yes, if you're building this up it will not be difficult. Make sure you order the correct fuel pump, etc.
Pete
rleffler
Well Known Member
Pick up the phone and give Don Rivera a call at Airflow Performance. Ask him the same question. At the end of the call, you'll be giving Don your credit card number. He provides great support and is always willing to assist.
He's helped me several times this past week or so with an issue that he didn't create. Although he did help resolve it!
We need more vendors like Don.....
bob
He's helped me several times this past week or so with an issue that he didn't create. Although he did help resolve it!
We need more vendors like Don.....
bob
Please help overcome my ignorance - what would be the benefits to this conversion? Why would I want to consider this?
Carl Froehlich
Well Known Member
Depends on what you want the plane to do. A weekly hop for a $100 hamburger, or high efficiency cross country? The later tends to require balanced fuel injection to properly run LOP.
My neighbor has a 20 year old RV-6A. I gave him the Precision injection system off my new IO-360-M1B as I installed the very nice AFP FM-150C. He back fitted it on his O-360. On his first trip he got the same speed but with a 1.5GPH fuel reduction. On many trips that is enough range boost to save a gas stop.
And you never again have to worry about carb heat….
Carl
Compared to a carb, generally a smaller GAMI spread...when leaned, each cylinder reaches peak EGT at about same fuel flow.
Allows inverted flight, assuming you also add the companion items (flop tube, oil system, second belt mount, etc).
Less prone to intake icing.
Often a bit more power.
Allows inverted flight, assuming you also add the companion items (flop tube, oil system, second belt mount, etc).
Less prone to intake icing.
Often a bit more power.
One more recommendation for AirFlow Performance for the fuel injection parts.
You can convert your O-360 to an IO-360-M1B and improve your engine with a "tuned" intake system. Obtain a sump from an IO-360-Axx model [angle valve]. [Lycoming P/N 74384] The angle valve sump fits right onto the parallel valve engines. The IO-360-Axx intake tubes can be adapted, however, you might have issues fitting the standard IO-360-M1B exhaust made by Vetterman. The correct -M1B intake tubes are big money. However, you can buy brand new ones direct from Clint at
Vetterman [along with the -M1B exhaust] very reasonably.
You can convert your O-360 to an IO-360-M1B and improve your engine with a "tuned" intake system. Obtain a sump from an IO-360-Axx model [angle valve]. [Lycoming P/N 74384] The angle valve sump fits right onto the parallel valve engines. The IO-360-Axx intake tubes can be adapted, however, you might have issues fitting the standard IO-360-M1B exhaust made by Vetterman. The correct -M1B intake tubes are big money. However, you can buy brand new ones direct from Clint at
Vetterman [along with the -M1B exhaust] very reasonably.
Slight error. The EFI systems inject fuel in the same general location as the legacy injection systems, that is, upstream of the intake valve. The don't inject directly into the cylinder.
Agreed on this - great parts/kit, and great support. I upgraded from carb to FI on my O-360 with AFP components several years ago.
Can you educate me on why the AV sump is an improvement on the PV sump?
BoydBirchler
Well Known Member
I converted my O-360 to an IO. I reused the original vertical induction sump. The servo body bolts right up to where the carb was. You will need a spacer (available from Airflow Performance) to make up for the servo's shorter length/height than the carb, allowing you to retain the original FAB air box. The mechanical fuel pump gets changed to a higher pressure pump and the electric aux/boost pump gets changed to a higher pressure version (airflow has a very good electric pump and filter for this purpose).
I was able, with one electronic ignition, to run LOP with a when the engine was equipped with a carb , but had a big spread between the front and rear cylinders of as much as 50 degrees EGT and .4 GPH between peak of the front cylinders versus rear. With Bendix style FI I can run LOP with all cylinders peaking within .1 GPH ( and no worry with ever needing carb heat).
I was able, with one electronic ignition, to run LOP with a when the engine was equipped with a carb , but had a big spread between the front and rear cylinders of as much as 50 degrees EGT and .4 GPH between peak of the front cylinders versus rear. With Bendix style FI I can run LOP with all cylinders peaking within .1 GPH ( and no worry with ever needing carb heat).
Very curious as I’m about to embark upon this transition over to FI myself with AFP components on my RV-8… What did you have to change out in regards to throttle cables, cable brackets? Was it relatively straight forward?
- Gabriel
BoydBirchler
Well Known Member
Throttle cable had to be replaced with a few inches longer version... I do not recall if I had to change the bracket...
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blaplante
Well Known Member
I converted my o-320-h2ad to Bendix FI (RSA5). I didn't need a new (#1/#3 side) inter-cylinder baffle because I just modified the one I had.
An another vote for Don who overhauled my used servo and spider.
FŸI, the angle valve sump is also used on the IO-360-M1B ( which is a parallel valve engine).
First the angle valve sump has equal intake runner tube length. This means it's a tuned intake which gives you a little horsepower boost and a smoother idle. The intake tube lengths on the other parallel valve engines have unequal length runners. Think of the angle valve intake tubes as being similar to tuned exhaust headers. The other advantage is that the intake passageways inside the sump aren't bathed in hot oil as is done on the other parallel valves sumps. The hot oil heats the air inside the intake passageways on the parallel valve system which makes the air thinner and therefore slightly reduces the potential horsepower.
It's certainly possible. I'm doing an updraft conversion right now. Airflow Performance can fix you up with most of the parts.
LW 13864 for both...unless the angle valve happens to be a -119, or C, or D IO-390, all of which add another sump to the collection.
I've not had a set of M1B intake tubes in hand, and the parts book isn't real clear. That said, the M1B tubes may not be tuned length, despite sharing the 13864 sump with most angle valve engines. Different part numbers for sure.
I made intake port pressure measurements a few years back. It appears the common tuned tubes for 360 and 390A (#'s 78741-2-3-4) were designed for best cruise torque. At 2400 there was a nice positive wave arriving at the intake valve just as it was closing. I suspect the additional peak HP has more to do with better ports.
They have different part numbers because the bends are different. It's the overall length of the induction from the throttle body to the intake valve that has to be equal. If you need IO-360- M1B intake tubes you can save quite a bit of money by ordering a set from Clint at Vetterman Exhaust Systems. He makes them from scratch.
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blaplante
Well Known Member
The most expensive part is the servo (FM-150 at Airflow performance) - around $3200 new.
I bought an RSA-5 off eBay and had Don rebuild and re-curve it. Multiple used ones on eBay for under $1000. Don doesn't list his rebuild price but I'm guessing based on my ~2015 experience that it's under $1000.
For the flow divider (spider), new is $600, eBay has some around $250. Very inexpensive rebuild as there's one spring and one diaphragm in it.
Add fuel pump, lines to the injectors, and injectors.
Assuming this will bolt up to your sump...
Control cables ... nothing extra as I did this at build time.
Sure, equal is good, but are the M1B tubes the same length as the tubes for an angle valve with the same sump? Length and diameter set the RPM for which they are tuned. Parts books illustrations suggest the angle valve tubes are longer.
BTW, I'm not saying they must be the same or they are somehow inferior. I am curious if they are tuned for a higher RPM.
Dan, the angle valve IO-360-Axx intake tubes can be used on a parallel valve engine. However due to the differences in the parallel valve and angle valve cylinders you need to fabricate a spacer to go between the intake port and the intake tube. This will of course require using two gaskets at this joint. Due to differences in the bends of the tubes for the angle valve engines when used on a parallel valve engine there can be contact between the intake tubes and a standard veteran exhaust system. Would necessitate a custom exhaust system which would be prohibitively expensive. I do not know what RPM the IO-360-M1B intake system is tuned for.
Dan 57
Well Known Member
as well as probably some other VAFers, I'm on the fence regarding a change from carb to FI on my soon to start engine replacement...
Some of the arguments in favour of FI are known and valid, but might not be as consequent as might appear. A carb in an RV still offers simplicity, lower fuel pressure requirements, lower power requirements, reliability, uncomplicated starting, easier self servicing ability, lighter weight, cheaper overall, and maybe more.
For me the biggest downside in the carb being more prone to vapor lock. Which can be greatly reduced by the use of Avgas, or/and a careful installation of the whole fuel system. I'm primarily burning Mogas and my ship sports a dual fuel selector valve, dual Facet e-pumps, no 90° bends, firesleeved lines, etc.
My actual motor is a 1977 vintage, has now run in excess of 2K hours SMOH without missing a beat since 2005.
Dual LSE EI and iridium plugs permit leaning well LOP, with the engine loosing power at the same time as experiencing the onset of roughness... operating well into LOP regime.
Despite having flown more than one time in conditions very conductive to carb ice, I've never encountered the issue. I've had the cowl inlet completely closed by ice a couple of times (along with a cm or 2 of ice build-up on the wings, windshield iced up for a while)... engine started rapidly to run very rough, no drop in MP, pulled the Mickey-Mouse carb heat, which immediately restored smoothness.
Anyway, slightly bored above a closed cloud cover over the sea on a 6+h flight last week, I took a couple of screenshots off my MFD 3GX. Those are my slightly too fast (Carson speed would be 112KIAS on my bird) LRC settings, and looking at the EGT values I'm not sure an FI would offer a substantial increase in economy (it also seems that the resolution of the system is 5°F minimum).
One thing I sure observed is that those tight values are best at these settings, higher will lead to wider gaps.
The readout of the actual consumption at 20.7 LPH (liters/hour = 5.47 USG) is not, as usually on carb installs, very stable, but fluctuates by about +/-2 litres. Nevertheless this very value is quite precise in the end as calculations post refuelling showed.
Now I can't help but wonder how many flight hours I'd need fly in order to offset the 3-5K more expensive system, notwithstanding the many hours spent modifying the actual installation...
PS
Yep, I'll work on those baffles and cylinder fences (...CHTs) during the engine's installation
Some of the arguments in favour of FI are known and valid, but might not be as consequent as might appear. A carb in an RV still offers simplicity, lower fuel pressure requirements, lower power requirements, reliability, uncomplicated starting, easier self servicing ability, lighter weight, cheaper overall, and maybe more.
For me the biggest downside in the carb being more prone to vapor lock. Which can be greatly reduced by the use of Avgas, or/and a careful installation of the whole fuel system. I'm primarily burning Mogas and my ship sports a dual fuel selector valve, dual Facet e-pumps, no 90° bends, firesleeved lines, etc.
My actual motor is a 1977 vintage, has now run in excess of 2K hours SMOH without missing a beat since 2005.
Dual LSE EI and iridium plugs permit leaning well LOP, with the engine loosing power at the same time as experiencing the onset of roughness... operating well into LOP regime.
Despite having flown more than one time in conditions very conductive to carb ice, I've never encountered the issue. I've had the cowl inlet completely closed by ice a couple of times (along with a cm or 2 of ice build-up on the wings, windshield iced up for a while)... engine started rapidly to run very rough, no drop in MP, pulled the Mickey-Mouse carb heat, which immediately restored smoothness.
Anyway, slightly bored above a closed cloud cover over the sea on a 6+h flight last week, I took a couple of screenshots off my MFD 3GX. Those are my slightly too fast (Carson speed would be 112KIAS on my bird) LRC settings, and looking at the EGT values I'm not sure an FI would offer a substantial increase in economy (it also seems that the resolution of the system is 5°F minimum).
One thing I sure observed is that those tight values are best at these settings, higher will lead to wider gaps.
The readout of the actual consumption at 20.7 LPH (liters/hour = 5.47 USG) is not, as usually on carb installs, very stable, but fluctuates by about +/-2 litres. Nevertheless this very value is quite precise in the end as calculations post refuelling showed.
Now I can't help but wonder how many flight hours I'd need fly in order to offset the 3-5K more expensive system, notwithstanding the many hours spent modifying the actual installation...
PS
Yep, I'll work on those baffles and cylinder fences (...CHTs) during the engine's installation
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blaplante
Well Known Member
At the time I pulled the trigger on FI (about 10 years ago) the used RSA-5 with an overhaul was cheaper than the best deal I could find on a carb. Probably all parts together I spent more, but it wasn't much more at build time. It all depends on what you stumble into!
With FI you can certainly run LOP. Don't know if you've tried that w/Carb. Works for some, not for others, depending on cylinder balance.
With FI you can certainly run LOP. Don't know if you've tried that w/Carb. Works for some, not for others, depending on cylinder balance.
BoydBirchler
Well Known Member
My RV7 O-360 originally had a Jeff Rose EI and would run moderately well when running LOP with a carb. With a carb the CHT's and EGTS on the front 2 cylinders, ran 40 to 50 degrees cooler than the rear two. The front 2 cylinders would peak .4 GPH before the rear 2 cylinders.
When I majored the engine to go to a hollow crank, so that I could use a C/S prop, I also converted to a Bendix RSA5. With the Bendix RSA5 FI, all cylinders peak within less than .1 GPH and CHT's/ EGT's are very close together.
Now, as configured with one P-Mag and Bendix FI, at 8,000 feet I can run a WOT TAS of 155KTS on 7.2 to 7.7 GPH.
PS I usually run my plane on 90 octane non alcohol MoGas. To keep from getting vapor lock I have removed the Gascolator and have a filter adjacent to the Airflow Performance boost pump. Water ,if present, is removed at the tank fuel drains.
When I majored the engine to go to a hollow crank, so that I could use a C/S prop, I also converted to a Bendix RSA5. With the Bendix RSA5 FI, all cylinders peak within less than .1 GPH and CHT's/ EGT's are very close together.
Now, as configured with one P-Mag and Bendix FI, at 8,000 feet I can run a WOT TAS of 155KTS on 7.2 to 7.7 GPH.
PS I usually run my plane on 90 octane non alcohol MoGas. To keep from getting vapor lock I have removed the Gascolator and have a filter adjacent to the Airflow Performance boost pump. Water ,if present, is removed at the tank fuel drains.
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