RAF Journey from 2.2 to 2.5

[lanichol]

I had a RAF with a 2.2 engine, SDS ecu, delta cams, 3 blade warp drive prop.
It pulled 520# on a fairly cool day. (This engine is for sale)

My KennyJ Sparrowhawk with a 2.2, IVO medium in flight adjustable prop pulled a 485#
I live at nearly 4,000ft 230 miles east of Denver.

Anyone see a problem?

So the journey begins transitioning from 2.2 to 2.5

I had a Subaru EJ25 1998 sold to me from an airplane guy saying it only had 1000 miles on it.
I tore it down and had a friend review. The pistons were full of carbon.
Further review the pistons oil ring gaps were all aligned. It had been rebuilt and the piston rings
had not seated. In go new pistons & rings. The ecu I used was the microsquirt, inexpensive and self tunes.
This engine had a deep knock after about 5 hrs of tied down time. No way. New subaru block purchased.

On a 2.2 to 2.5 conversion there is only a couple things you need. A longer prerotator bracket. A few mods
to the intake maniford and water crossover pipe for sensors. The microsquirt requires a specific year crank
gear. So plan where you are putting your sensor, there are only a few changes there from the 2.2. Most
parts are available on Amazon. GM sensors were used as they are very linear and on the list of sensor when
you configure the microsquirt ecu. I do have the amazon sensor and other parts list

 

[lanichol]

Engines!
You could pull one out of a car.
Buy used on Ebay
Buy a JDM motor EJ251 on Ebay with less than 60K miles. (2000 Subaru outback works in searches.)
Buy a new factory block from Subaru.
PT070206 Short Block Engine Part Number: 10103AB390 is the newest version. Each improvement Subaru give a new number.
Subaru Dealer Pickup Wichita KS $2,194.81 or $2,000 if you know a mechanic.

Using the factory ECU is a thing of the past in so many ways. But it does work.
Microsquirt, RAF 2000 has an ECU, SDS Canada, Linked, Subaru racers use Haltech that can have a display.
And there are several others.

I talked to Duane Hund nearly daily (before he left this world) for 2 years. RAF factory suggest run the engine for their suggested time.
If it is a used Engine that has been running..Why? Well, dumb ass, so it does not quit on you and require an engine out landing. You will catch
all the minor problems if you are listening. Buy new injectors or have the old ones clean and flow tested.
I had the injectors clean here @ $21 per injector: https://www.advancedinjector.com/ I have been in his garage shop. Crazy equipment.

Solution is easy. Factory block, everything new. The ebay JDM engines I believe most are over 60K miles
and not a good value. Buy a new block, have the heads rebuilt and go from there. I did do some mods. Also the killerB oil pan and pickup tube.

The heads were rebuilt here: https://thecylinderheadshop.com/pro...ads-ej25-impreza-forester-outback-legacy-baja
I had a 1500 Delta cam grind here: https://deltacam.com/
Killer B Oil pan & pickup tube here: https://www.killerbmotorsport.net/shop/category/oiling-1
includes a port for engine oil temp.
Microsquirt ECU with harness & PC usb adapter here: https://www.diyautotune.com/product/ampd-microsquirt-with-8-harness/
Mechanical fuel gauge before injection rail (43.3#) should not bleed off
https://www.amazon.com/dp/B0C2YDP4C8?psc=1&ref_=cm_sw_r_cp_ud_ct_J5TF7G3SVWBWS5PZ7WP1
3/.8 barb fuel pressure gauge fitting adapter with 1/8 npt sensor gage port
https://www.amazon.com/dp/B0CQTDPTWQ?psc=1&ref_=cm_sw_r_cp_ud_ct_PJGA7ZN3BGCF1EJAE26Y
Breakin oil must not be synthetic or the rings will not seat
Dual Fuel Flow Meters: before rail & on fuel return line.
https://www.amazon.com/dp/B07QRZJD14?psc=1&ref_=cm_sw_r_cp_ud_ct_WWPMDH991JTDE474Z7D6
Michigan avionics FF-5 Fuel Computer
https://www.michiganavionics.com/product/ff-5/
Fuel flow, multi point calibrated fuel tank sensor, various alarms

 

[lindandavid]

Don’t remember the years but there were a few years where the 2.5 was prone to head gasket failure. And I had one of the bad ones. There is a FelPro gasket that was recommended, and the head surface and block surface had to be polished to a mirror finish. I also replaced the stretch bolts with ARP head bolts that required conventional torque methods. Fortunately my head gasket failed in the pattern. The terrain here in Ruidoso, NM would not have allowed for a pretty landing.

 

[Brent Drake]

On a Subaru, remember to secure the oil line.

 

[GyrOZprey]

Thanks for coming in here to post about your Subaru engine knowledge & journey, Larry!

 

[lanichol]

Don’t remember the years but there were a few years where the 2.5 was prone to head gasket failure. And I had one of the bad ones. There is a FelPro gasket that was recommended, and the head surface and block surface had to be polished to a mirror finish. I also replaced the stretch bolts with ARP head bolts that required conventional torque methods. Fortunately my head gasket failed in the pattern. The terrain here in Ruidoso, NM would not have allowed for a pretty landing.

Yes it was a problem. The new OEM gasket fixed this problem.
I did have the heads rebuilt, new valve guides, the surface checked or planed.

I still used a copper spray on both sides of the gasket as it seals better and transfer heat better. In HS during muscle car years we had
domed pistons with high compression 13:1. We used the copper spray to hold the head gaskets from blowing.

The factory methods for tightening the head bolts is rather unique. If you follow the direction, it is not difficult.

 

[lanichol]

Propeller: I have a 5 blade bolly pitched to 14 degrees.
Rotor Blades: Gyrotech tower on the RAF head and Gyrotech blades. Very easy to string.
Stabilator Aluminum wing and a left right trim via buttons on the stick. EK & SC Texas & BL Canada
ECU tune EK & SC tune Texas. It has a mild tune for breakin and burn 5 gal hour @ 65 using regular non ethanol fuel.
It does have a Larry Boyer drop keel and horizontal. For beginners the horizontal is good. Larry E also makes a horizontal.
When your skill level is good, take off the horizontal.
If you need the drop keel plates. I have them in a autocad drawing and can be laser cut. Larry Boyer has the original drawings.
The mast magic rubber bushing is from Todd CA on ebay.

Takeoff 5,000 RPM at elev 4300 ft. Cruise 65 4300 RPM with 2 adult males. 5 gal/hr

What have I learned: I have been on this forum since Norm.
I have seen all the RAF trash talk.
The 2.2L engine is good for one person.
The subaru ecu works. It is not the most efficient or produce the most power.
I owned the first 2.2l Sparrowhawk Conversion done by KennyJ. It was top heavy.
The sportcopter tower is too high and hubbar too heavy requiring crazing trim setups.
The gyrotech tower lower profile and blades are awesome, fly about 10 mph faster
The stabilator by Duane Hunn (Ill give him credit) was a good solution especially for trim as required on the RAF
You can buy the factory or build your own. It would be a great addition to other gyros such as AC.
The drop keel may not be required, but the drop keel may have better air flow and faster with less fuel consumption.
Horizontals Boyer, Parham, Ellerman make it easier and safer for new students.
Duane Hunn knew alot about the RAF. We talked up to when he got Covid in the Hospital and passed. And some very heated debates
on the changes I was making.
In the end the longer mast RAF with the Stabilator is probably all that is need.

I know of 12 sets of Gyrotech tower and blades on RAFs.

I just counted phone numbers. I have 43 RAF owners not on this forum that I have had discussions by phone.

Interesting numbers!