I do need an old IO-540. Get down there and find me a cherry!

Zzz wrote:

whee wrote:I felt that the 180hp lyc O360 was sufficient for me in a Bearhawk and I don't want the extra weight of a 540.

I struggle with the same question. The 540 is pretty popular on the Bearhawk, but definitely some extra pounds there. The reality though, is, you have 2 kids Your performance is going to dwindle year after year as they grow. The fuel savings isn't much, especially with injected, but the empty weight when solo (and doing fun things) won;t be as favorable.

I fly an O-360 172 right now, 2 of them actually. 1450 lbs vs 1520 lbs. I need more power. I used to fly a Hawk XP occasionally, too. That was a great motor, the IO-360 Continental, at least for the few hours I flew it. Definitely a little snappier, but I think the magic starts to happen around 220hp. The IO-390 is tempting, or rather, the XP-400.

I also enjoy riding 15-20 hours each year in a Hawk XP (II), and share it's hanger. The IO-360 seems to be a very happy engine - this one is almost 2000 hrs past TBO on condition. Same cylinders. It's always been run like a bigger 6, gently gently. It cruises everywhere at 50*F ROP, but that's a different story, it has GAMI and can run very nicely LOP. The owner says the GAMI is the best thing he's done for it. The engine itself has been very reliable, but it's chewed up more than it's share of accessories. Mags, alternators, starters, etc. It also leaks oil profusely, but I suppose that's just old engines. With the Cessna at gross (as it almost always is) it's not "overflowing" with power, but it's still got more than enough. At the same weight, the -540 BH definitely gets into the sky with noticeably more enthusiasm.

mtv wrote:I haven't flown a Bearhawk, but judging from the all up weight, you're going to want some horsepower. Again, you can get some power out of an IO 390 at 210 hp or so, but at that hp, a 540 will cost half as much or less and be loafing along.

MTV

IF you can load them to gross at all, (2700 T/O, 2500 landing). We run out of space in the plane (and then CG) every time before it gets past 2500lbs. I am contemplating a fibreglass pod.
I guess if you were hauling big rocks... in the back seat... but with 4 people and gear - you need HEAVY gear and it needs to be loaded forward.

This is 2700, the tanks are full of water. There are bags of steel offcuts, lead dive belts, and boxes full of rocks. The dive tanks are full.


When it's loaded with just full fuel tanks, 4 people, and gear for the day - there's not really a meaningful loss of performance with the IO-540. I think you would notice that load with a Lyc 360, probably much less so with the TCM 360

Zzz wrote:I do need an old IO-540. Get down there and find me a cherry!

I will go down there tomorrow and snap some pictures and try to find who owns them now. Many are just left for dead. It really hurts to see the waste! But, nobody here cares.

Moist tropical environment + neglect = corroded to all hell most likely....

Zzz wrote:Moist tropical environment + neglect = corroded to all hell most likely....

Yep. But, I know guys that have started them after five years with no preservation and flown them to the mainland! Frick'n nuts. They are tough engines!

Everybody has their idea of what "enough" power is for a plane. Some guys like having a O-320 in a Luscombe, I'm completely happy with a C85. Some guys want 260hp for the Bearhawk, I thought 180hp was totally fine. Aside from load testing the heaviest I flew it was ~2400lbs on a family trip to Chamberlain basin. I was totally happy. I'm not saying that I won't install a 540 in a bearhawk but as of now I don't have any plans to.

iceman wrote:just a word about mo gas since it gets discussed here for the IO 360.... not approved for the IO 360..if it was I would have gotten the stc long ago... and if you go to the back country. make sure you have a fairly new battery... I don't go to the back country without a fairly new battery...no problems... starts every time....hot starts have never been a problem anywhere at any altitude...I also have a lightweight starter that spins it over quite well, better in fact than the original... so make your own decisions on the IO 360 but I love mine....one other suggestion for an upgrade might be Gami Injectors... but then that's another discussion....

I don't really care that it isn't certified for mogas. The compression is low enough that mogas would be fine. The issue is the FI system and from what I've read it isn't a difficult problem to solve. As stated, I'll call Peterson and talk to them about what they found when they looked into it.

Made some calls yesterday and talked to Petersen Aviation.Great guy that spent some time talking about engines and mogas with me. He said they had all kinds of vapor lock issues on Lyc fuel injected (bendix) engines running mogas but the TCM fuel injected engines didn't have any vapor lock issues at all. The FAA wanted a boost pump on the TCM engine just to be safe so they installed a electric pump that provides ~4psi of extra pressure at the fuel tank. This was on the IO-520 and IO-470 engines.

They guy I spoke with at Fly Inpulse said they have seen some ticking of the fuel pressure gauge on their Cessna 180 (can't remember if it is a IO-550 or 520) when they turn the boost pump off at high altitudes on a hot day. He said that indicates vapor in the lines and it goes away right after they turn the boost pump back on.

I looked at the schematics of the FI systems for the IO-360 and the IO-470 in the overhaul manuals. They look very similar if not the same; even the description is the same. The IO-470 that is approved on the Fly Inpulse STC is the 8.6:1 compression version.

So with all this info it seems to me that a home builder should be able to successfully run a TCM IO-360 on mogas if they wanted to. I'm not sure that the water/methanol injection system would even be required.

Is the IO360 engine mount and the O-470 mount at all similar? Avipro makes a O470 mount for the bearhawk and I'm wondering if it would be of any use to buy that mount and modify it to work with the IO360.

This is all just curiosity as I have bought a BH kit or anything yet.

whee wrote:Is the IO360 engine mount and the O-470 mount at all similar? Avipro makes a O470 mount for the bearhawk and I'm wondering if it would be of any use to buy that mount and modify it to work with the IO360.

This is all just curiosity as I have bought a BH kit or anything yet.

You'll need to build a bed mount for the IO360. To bad there isn't a dynafocal mount for the IO360's. I bought one of Avipro's O470 mounts hoping it would fit my IO520. Came close but the bed mounts were at a different angle. There is a Bearhawk in Brazil flying with the IO360.

The "standard" engines for the bearhawk seem to be some version of the Lyc 360 or 540. Interesting to see the IO-360 Cont discussed as a possible alternative. Seems like the 220 Franklin might also be something to consider, esp if they go back into production. 220hp out of only 350 cubic inches. Everyone I've ever met who flies a 220-powered Maule Stinson or 170 raves about them.
I'm surprised to hear that Avipro offers a mount for the 470 Cont-- I've never heard that engine mentioned before with regards to installation on a Bearhawk but it sure makes a lot of sense. I don't know how it compares weight-wise with the 540 Lyc, but Cessna made over 6,000 470-powered Cessna 180's and it sure works well on that airplane.

Although I've never flown behind a 220 Franklin I really like the design and efficiency of the engine and would choose it but I want to be able to run mogas. Also I've always thought a pponk would be cool to try on the Bearhawk but the O470 is heavier than the O540 based on the numbers I've seen and a pponk would be even more so.

m_moyle wrote:You'll need to build a bed mount for the IO360. To bad there isn't a dynafocal mount for the IO360's. I bought one of Avipro's O470 mounts hoping it would fit my IO520. Came close but the bed mounts were at a different angle. There is a Bearhawk in Brazil flying with the IO360.

Hmm. Wouldn't it be easier to change the angle of the bed mounts rather than start from scratch? I've heard about the Bearhawk in Brazil but I've never been able to find any performance data on it.

There's a T-41 here in the flying club that has a TCM IO-360 in it. I wonder if it'd be too big of a pain to modify that mount?

Hmm. Wouldn't it be easier to change the angle of the bed mounts rather than start from scratch? I've heard about the Bearhawk in Brazil but I've never been able to find any performance data on it.[/quote]

I tried to modify the O470 mount to fit a permold TSIO520WB, converted to natural aspiration. Came close. I ended up cutting it apart, using the 4 engine mount pads with new lord mounts, adding tubing. Can post pics of the attempted fit and fabricating the new mount.

Asked Bob Barrows about the O470. He's flown a Bearhawk so equipped, says it performed well. The Avipro mount is for the R model O470. With accessories weight in at 425 lbs
My completed engine with all accessories, baffles and exhaust weighs 462.5 pounds. Using 1200 series bendix mags converted to shower of sparks.....haven't installed the light weight alternator or starter yet...maybe electronic ignition.... Should be able to get the weight down to 431-ish. Looks really cool under the Acclaim cowl!
Mark M.

Any thoughts about buying a TSIO360 and removing the turbo normalizing? That will leave me with essentially a IO360AF; TCMs alternative fuel engine which can run on mogas and is rated at 200hp. There doesn't seem to be many IO360s for sale but I've seen several TSIO engines available that had VAR cranks and heavy cases. I'm not going to be ready for an engine for a while but I'm keeping my eye out in case a deal comes along.

My two cents: instead of frankensteining an engine ( buying a TSIO and removing the TS, or buying an IO and removing the I), just decide what standard engine you want and buy one. It might be more money than buying something that's not quite what you want and morphoditing it, but I would guess you'll be happier in the long run. In the case of the Bearhawk, it seems like most everyone is running some version of the 360 or 540 Lycoming, so it'd be pretty hard to go wrong with one of those.

I hear what you are saying but guys take TSIO520s and turn them into Pponks and IO470 an turn them into 260hp O470s on certified planes...how much Frankensteining does it really take? I'm not going to remove the I on the IO360.

Texas Skyways is the outfit to call for information on the O520 and O470/520

I've heard that a cessna 337 rear engine mount bolts right up to a cessna 170, not a bearhawk I understand but it might be a good place to start. Hey it's experimental, get the saws all!

River rat wrote:I've heard that a cessna 337 rear engine mount bolts right up to a cessna 170, not a bearhawk I understand but it might be a good place to start. Hey it's experimental, get the saws all!

Another Bearhawk builder did just that. He got a rear 337 mount cheap and used it as a starting point. I've been watching for a donor mount but the going rate seem to be ~$800. I'm not doing that.

Seems to me,
If the compression ratio is right, and
You don't mind paying for / making a new exhaust and intake system, and
The fuel controller and injectors are still compatible once you're lost the turbo (Don Rivera at Airflow Performance could tell you, and sell you any new / refurb'd Exp parts you might need), and
You don't mind a slightly heavier overbuilt case / crank,

Then I can't see why it wouldn't work. Having given it a just a dangerous little though.
I bet Bob would be able to tell you for sure.