Mounting 618 and 670 to KF-IV

[Aker]

Good info video footage would be great if you can.

Thanks.

[Aker]

Any more updates?

[rdooley79]

It's been a while. Life happened but I've been working on the bird in general. There were other things that needed attention. Since I've bought this bird it's been a much bigger project than I anticipated. The plane had more issues than I thought. I had a failure that really made me pause and very closely look at the plane. Flew for a couple hours and the plane was working great. I was taxiing out after filling up at a close airport. As I was lining up on the center line the throttle cable snapped. Right where it attached to the bell crank it had abrated and the cable had failed right at the barrel end. Very good timing I wasn't even moving but could have been a very bad day if it failed a couple throttle adjustments later. PHEW!
This made me take a long harder look at the plane and decided to do a few things I knew needed some love.

I've ended up;
Rebuilt throttle assembly from carbs to dash.
Re-wired the rats nest behind the dash and labeled everything.
New Odyssey 625 battery and relocated to behind the passengers seat.
Ran 4ga wire and replaced the solenoid.
Zip-Tied and organized all connections.
Replaced the starter motor with a new one.
Removed the halogen landing/driving lights.
Flushed and cleaned the radiator.
New coolant lines with less connections and better routing.
Ran all new fuel line and fuel filter, cleaned the gascolator.
Rebuilt Mikuni fuel pump
Reinforced the seat pan with cables/turnbuckles, keep from rubbing control rods.
Added foam to the seat bottom and back.
New bolts for seat belts.
Rebuilt the flaperon handle friction plate with new leather
Fabricated new exhaust mount.





The day after Thanksgiving I'm planning on running it up and checking everything out.

[rdooley79]

Alright Guys,

I wanted to give you all some close up pics of a 670 installed on a Kitfox 4.

Just had the annual inspection done and she passed. I had no doubt especially after the work just done.

First pic is my favorite!


Second one is a good one too. This is the High compression head. No it's not a bluehead from a 582. It's the 670 head that's made for the 670! Then Rotax Rick has a shop put in the dual spark plugs. Notice that it has the recirculator hose just like a blue head. It's just as good as the blue head but it's made for the 670 AND has dual ignition. BONUS!

If you're wondering what's on the sparkplug, It's some rubber to make a solid positive contact with the cowl lip. Without the rubber it vibrates just barely touching. In this case it's better to contact it solidly. Works nicely actually. Simple solution.



In hindsight, I wish I would have put the exhaust probes coming in from the top. If you have any exhaust splatter, cut up some exhaust gasket for washers around the probe between the clamp and the y pipe. Or weld on some bungs, that would be the best.


The exhaust is wrapped with Titanium Exhaust Wrap! Yes I said TITANIUM EXHAUST WRAP!!!!! It's super light and helps your exhaust retain a uniform heat profile. It doesn't add any power but it does look nice and keep heat off of the components.

Also notice the simple yet strong bracket. That was a good buddies design and it turned out very nice!

This exhaust was made specifically for the 670. It's what makes the engine have a nice flat power curve and perform at 90h+hp. A key to this engine is the Exhaust.



The cowl did need to get trimmed quite a bit.


One of the modifications done when the battery was located behind the passengers seat was to install a charging connector. The connector has 8ga wire that goes directly to the Odyssey 625 battery. That battery then connects to the solenoid with 4ga wire. The connector sits just under the passengers seat frame crossmember. I've wired up a battery charger/maintainer to connect to this SB15 connector. I used all together 3 SB15 connectors to make a splice with the clamp cables that come with the charger and one for the plane. I can also use this for a booster battery connection as well. BTW, you can get all of these that you want at batteries plus. Their used in APC UPS units.


Stubby nose, needs a spinner. That'll come soon enough.

[t j]

Thanks for the update. I've got a 96 Ski Doo Summit with the 670. That thing pulls like a freight train

[LSaupe]

If I can ask what is your max power RPM and cruise RPM. Did you need to change the port timing at all? I had a 670 on an MXZ and was thinking max HP was up around 7800 RPM.

What gear box ratio are you running?

[rdooley79]

I cruise at 6000, redline is set at 6350. Cruise at 6000 is about 83mph indicated but that's at 7500msl so at sea level you'll get better performance.
You could get more power out of this engine but it's tuned for reliability and longevity.
Spinning the engine faster means the prop spins faster so that introduces gearing considerations. The RPM that the 670 likes to run is right at 5900-6000.
It just humms right along at that power setting. Fuel burn is averaging right around 4.5-5gph. That's about the same as a 582.

I didn't do any port timing changes but it did come freshly built with an hour on Rotax Rick's test stand, ready to go. The exhaust timing is done with the exhaust which is critical for these engines to make power with a nice flat power curve, consistent power throughout the rpm band. The exhaust Rick has available is the "breakthrough" for the 670 to be used on aircraft. Dual Ducati electronic ignition is a must to be even considered as a serious aircraft engine to me.

Mounting the exhaust is the trick with the 670. It's a larger exhaust and takes up more space.

The prop pitch tends to work best if you pitch it a little course. I'm running a 3 blade Warp Drive, 72" 3:1 gearbox. The 670 has more torque and can swing a loaded prop better than a 582 and provides good thrust as well.

Jetting needs to be watched, especially at a mile high field elevation. Rick likes to run these engines rich, 40:1 and big main jets. I've had to go down in jet sizes because of my altitude. I'm running 162's with both needles dropped to the top notch. This makes the plugs look nice rich brown without being too rich. Rick sets them up at sea level with 180's, needles set to the middle notch. This made my engine cough and stutter but once I jetted it like a rich 582, it ran GREAT! I might go down to 160's but I'm watching the plugs as the true indicator, NOT egt's. They're showing 900 at WOT, 1150 at 5700. It's weird but talking with Rick about it he says that's about right and is typical. Also he confirmed the prop pitch being a bit on the course side working better also. I can say that it's running great now.

Swapping out the 582 for the 670 is a fantastic upgrade. Made my plane fly so much better. If only I could fly as well as the plane! Working on that.

[Grogen]

This is the current configuration. Cooling is much better, gained 4 mph, and no radiator (speed break) handing under the fuselage.

[Grogen]

I used my original top cowl and made my own bottom cowl. The front cowl is a piper hose you can get for $120 from Aircraft Spruce. I built my own brackets for the radiators mounted up front in the cooling holes in the front cowl.

[Grogen]

This is the other side. A tuned exhaust is important to get the HP out of this engine.