While fuel injected engines are indeed typically smoother than carbureted engines, perhaps the more significant issue is that fuel injected engines, run and leaned properly, will consume less fuel for a given horsepower output than a carbureted engine. Look at Jeremy's numbers, and in my experience, those differences might be on the low side.

The fuel injection systems, assuming they have well tuned injectors, provide a nearly equal charge of fuel to each cylinder.....something that a carbureted engine can't do. One consequence of that is smoothness, but it also levels out differences in exhaust gas temps. Since we lean using EGT, having all the EGTs equal means we can lean more aggressively than with a carburetor, where one cylinder peaks WELL before the others, and thus, a bunch of the fuel you push into those cooler cylinders is just run out the exhaust, and wasted.

With FI, you can use the fuel flowing to each cylinder equally....if you lean to 100 ROP, the cylinders ALL run 100 ROP, and you're throwing an equal amount of gas out the exhaust of each cylinder. But, if you lean "properly" (whatever that is ), with FI, you can save a LOT of fuel vs a carburetor.

The 200 hp Husky is fuel injected, whereas the 180 hp Husky is carbureted. In my experience, you can run the 200 hp airplane about 1 to 1.5 GPH lower fuel flows at comparable power settings (just because it's rated at higher power doesn't mean you can't run it at lower power.). With six or seven (or more) hours endurance, that's a huge fuel savings on a cross country trip.

So, consider again Jeremy's numbers: 1 gallon per hour difference.....over a 2000 hour life of the engine. Tell me that saving 2000 gallons of gas won't be welcome when you're facing an overhaul down the road.

As to used or new, I think your checkbook probably has more influence than anything there. I wouldn't be afraid to go either way......BUT, based on my experience, I'd try to find a "run out" engine of the flavor you want. Pickle it till you're about to need it, and in the meantime, search around for a small engine shop that does really good work. You'll have some time to research....they're out there. Find the right guy and have him field overhaul the engine, replacing that which needs it, reusing that which is good. You'll save money in the end, and have a great "almost new" engine to hang on your brand new airframe.

Me, I like fuel injection. Install a primer for flat battery starts. If you go with electronic ignition, you definitely need a small backup battery anyway.

FWIW

MTV

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ What MTV said ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Thanks MTV.

Here's are some more questions:

Is the fuel injection on the IO models something that is inherent in the case design? Does the case have to be designed to accommodate the fuel pump? Can a carburetor be mated to an IO? That might be a silly endeavor, but I am curious nonetheless.

Before I start a WTB thread or go searching I need to figure out the exact submodel(s) I'm after that will give me a good platform to build on. I noticed that the J model Jeremy noted for being lightweight was also a -D model, which denotes dual magneto. This is something I want to avoid since I'll likely be putting electronic ignition on, and need 2 separate magneto fixtures to do so. Although, I was reading on the Fly EFII website that their products can be used to replace the dual magneto. I have no information on whether the case of these models is actually different.

It seems as though the low end of 540 weights is around 356 lbs, with the upper end tipping the scales at around 396 lbs. Where is the weight coming from? And a serious tangent: An XP-400 based on the IO-390 platform is about 310 lbs. What's more important? 30+ more horsepower? Or saving 70-80 lbs of empty weight?

Speaking of electronic ignition, for those experimenters out there, have you had success in running 91 octane in a +8.50:1 engine by taking advantage of variable timing/advance? "Why would you want to run auto gas in a $30,000+ engine?" I guess it's all about keeping your options open.

In regard to the stated RPMs from that list by Maules.com, where the value is, I assume, redline? 2400 vs 2575 vs 2700. Are these actually a function of the engine itself? Or simply the props that are mated to them? Which is more desirable for what we do?

Thanks everyone.

With the J model engines that use a single mag mount it is basically the accessory case that's different on the back of the engine, this can be changed it you have or find the parts. I believe electroair, light speed, and efii electronic ignition systems can all be used with the single mag mount like on the J engines.

The fuel pump can be removed and you just put a cover over the pad where it used to be, this is what I have done and I believe most guys with carburated bearhawks have done. (gravity flow)

I kind of wish I went to electronic ignition for lower fuel flow and easier starting in the winter. Electronic ignition is lighter than mags until you add in the weight of a back up battery, solenoid, and wires. If you are going to build up an engine it will cost about the same for electronic ignition versus buying mags or sending yours out to get rebuilt and then buying all new sparkplugs, I have personally proved this point.

If you are going to use aftermarket fuel injection and ignition it really doesn't matter what model of 540 you get. Just shop around and you can find plenty of good deals on used 540's. I believe there's a couple on the alaskalist for a reasonable price right now. Barnstormers is also good place to find one.

One other thing about weights. I think this has been mentioned before but typically with the bearhawk and 4 cylinder engines you'll run out of cg before you use up the usefull load and with the 6 cylinder engines you'll run out of usefull load before you reach the aft cg. I don't know if you have all the "Beartracks" newsletters but if you do look at the empty cg on some of the completed planes and run some numbers on how you would load the plane, this helped me when I was deciding which engine to go with.

Bhawk wrote:With the J model engines that use a single mag mount it is basically the accessory case that's different on the back of the engine, this can be changed it you have or find the parts. I believe electroair, light speed, and efii electronic ignition systems can all be used with the single mag mount like on the J engines.

So the dual magnetos don't use a different/special hole on the case, right? They just cover up one of the magneto holes on the case and put the dual mag on the other hole?

It is a different housing, there is only one spot for a mag on the j models

The -540 is "affordable" power.
The -390 is going to be hard to find and expensive to buy.

The BH needs a little weight on the nose if you want to load to MTOW. My empty CG is at the front, load 4 people, 50gal of gas, and 120lbs of gear I'm out of aft CG (but can still take more weight) and even then the performance remains outstanding, ~500ft is ample. When it's empty, 260hp will drag you off the ground in 105ft - that's 5 lengths of the aircraft.

Like others have said, most-any model of -540 can be retrofitted with mechanical injection. I suppose the more heavily built engines are going to be stronger and last better. But if you really want to know ALL about them, call Bob Barrows and talk to him. He's like some kind of Lycoming dictionary, they don't make a part he doesn't know the number of .

Zzz wrote:Thanks MTV.

Here's are some more questions:

Is the fuel injection on the IO models something that is inherent in the case design? Does the case have to be designed to accommodate the fuel pump? Can a carburetor be mated to an IO? That might be a silly endeavor, but I am curious nonetheless.

Before I start a WTB thread or go searching I need to figure out the exact submodel(s) I'm after that will give me a good platform to build on. I noticed that the J model Jeremy noted for being lightweight was also a -D model, which denotes dual magneto. This is something I want to avoid since I'll likely be putting electronic ignition on, and need 2 separate magneto fixtures to do so. Although, I was reading on the Fly EFII website that their products can be used to replace the dual magneto. I have no information on whether the case of these models is actually different.

It seems as though the low end of 540 weights is around 356 lbs, with the upper end tipping the scales at around 396 lbs. Where is the weight coming from? And a serious tangent: An XP-400 based on the IO-390 platform is about 310 lbs. What's more important? 30+ more horsepower? Or saving 70-80 lbs of empty weight?

Speaking of electronic ignition, for those experimenters out there, have you had success in running 91 octane in a +8.50:1 engine by taking advantage of variable timing/advance? "Why would you want to run auto gas in a $30,000+ engine?" I guess it's all about keeping your options open.

In regard to the stated RPMs from that list by Maules.com, where the value is, I assume, redline? 2400 vs 2575 vs 2700. Are these actually a function of the engine itself? Or simply the props that are mated to them? Which is more desirable for what we do?

Thanks everyone.

As experimental you can make an injected Lycoming carbureted, but it depends if your going to run gravity feed fuel system or if you need a fuel pump. Some injected fuel pumps are rotary pumps and some are diaphragm pumps. You can make either work by switching out a idler gear on the accessory case if needed. You can also make a carbureted engine injected by adding throttle body, fuel pump, fuel servo, and 21psi boost pump. If at all possible stay away from the Dual mag AKA two mags made into one. There getting harder to find parts for and there a pain to put on and take off.

The redline should be determined by crank and counter-weights. I know you can turn a IO-540 250hp into a 260 hp by changing counter weights because a 250hp is rated at 2500rpm and a 260hp is rated at 2700rpm.

I just wanted to say that this was an extremely helpful thread. Thanks to all who chimed in.

Z

Don't let the hot start scare you away from the many benefits of FI as previously mentioned. Once you experiment and find out the proper technique to hot start your particular engine your are fine. I have found a technique for my IO-470F that has not failed me once in many years.

I'm curious if you (or any of the bearhawk builders here) have considered a Continental 470? Most Cessna 180 owners are happy with them, and those that aren't bump them up to a Ponk carburated 520. Lots of guys have upgraded to a K or R model engine, so you can often find 470-J's for a pretty good price, and I know lots of guys who've run their J's to TBO and beyond without much trouble along the way.
Regarding 540's, I've seen or heard of only a couple 180/185's that were fitted with various versions of it. If it was that much superior to a Continental, I think there's be more of them.

The 540 doesn't see much use in Skywagons simply because the Continental was the engine they shipped with. The Lycoming O-360 sees widespread use in upgraded 170s because it's the de facto 180hp engine on the market, and it's cheaper than the Continental 360. You could also ask why you rarely see Maules with O-470s. Tied by the manufacturer and/or lack of STC I'd imagine.

Given the choice, it's Fords and Chevys. And as open and flexible as the experimental world is, the Bearhawk was designed around the Lycomings and all the support for engine mounts and induction and stuff is Lycoming biased.

bcp2012 wrote:Don't let the hot start scare you away from the many benefits of FI as previously mentioned. Once you experiment and find out the proper technique to hot start your particular engine your are fine. I have found a technique for my IO-470F that has not failed me once in many years.

+1

Our Lycoming IO-540-L1C5 on the Bush Hawk is the smoothest-running and easiest-hot-starting recip I've ever flown.

Zzz wrote: The 540 doesn't see much use in Skywagons simply because the Continental was the engine they shipped with. The Lycoming O-360 sees widespread use in upgraded 170s because it's the de facto 180hp engine on the market, and it's cheaper than the Continental 360......

Not necessarily, I've seen 170's upgraded to
150hp or 160hp Lyc 320
170hp Lyc 340,
180hp Lyc 360
190hp Lyc 435
210p Cont IO-360
165hp Franklin
220hp Franklin
Ditto Swifts (originally Continental C-85)
125hp Continental (factory)
145hp Continental
150/160hp Lyc 320
180/200 hp O or IO360 Lyc
210hp Continental
I've even heard of one with a 250hp turbo'd Franklin
IMHO if the O/IO-540 Lyc was that much of an improvement over the big Continentals, you'd see a lot of 180/185 guys running them. Look at how many 180/182's have been upgraded to the Ponk 470+50-- probably not much cheaper (if any) than a 540 Lyc and mount so I'd say the cost is not much of an issue.
I don't know much about the Bearhawk, but I did glance at their website and it appeared to have some nformation re factory support for the 470.

I'm building a light IO-540 for my biplane. I started with an O-540-B2B5 (235 hp Pawnee engine). Added a Bendix RSA-5 fuel injection system. Using a B&C light weight starter and SD-8 alternator. Planning on changing Pistons to 8.7 or 9.5:1. Should make 260-280 (depending on Pistons) hp and be under 380 pounds.

8GCBC wrote:

my $0.02 (your milage may vary)

I remember when mogas was $0.17 (and the guy at the station was tweaked when I tried to buy four cents worth for a motoer scooter) . . . even back then you couldn't get much mileage for $0.02 though