Here is the #1 source for information to convert a Subaru engine for aircraft use:
Air Soob Forum, News list : https://groups.yahoo.com/group/airsoob/
Forum for Subaru Car Engines, Very good. ( People use these in cars? what a waste..) https://forums.nasioc.com/forums/
Various Engine Resources: https://www.ch601.org/engines.htm
Loud Valve Noise? It might be a bad HLA! I had one go bad in my EJ-22. It is quick and easy to fix. Complete instructions with photos here:
You can right-click on THIS LINK for a short video of a EJ-22 running with a failed HLA.
If you use AVGAS 100LL in your Subaru engine converted for aircraft use please take note:
Lead particles can and will over time damage your valves. To avoid this do two things:
1. Use mineral engine oil or synthetic mix. Pure synthetic oil does not suspend lead.
2. Use a lead arresting additive, TCP is a common way to do this but is highly toxic. Here is a new alternative:
Decalin Chemicals manufactures products for the experimental aircraft aviation community.
Decalin Fuel Additive in a 16 ounce bottle, treats up to 320 gallons of fuel.
Scavenges Lead in aviation fuel after combustion to prevent lead oxide buildup on valves but still allows the lead to perform the anti-knock function prior to combustion.
It is an excellent additive for auto conversions, where it reduces buildup on oxygen sensors and plugs. If you have to use 100LL, then this stuff is for you.
Prevents valve seat erosion from valve seat micro welding. It is equivalent to TCP.
Does not contain volatile solvents so it is safe to ship and safe in the cockpit. You can carry it with you for out-of-town airports.
Easy to use graduated measuring and dispensing resevoir built into the bottle. No messy syringes!
Tested and stable down to 0 degrees F.
Decalin TCP is not approved for use in the engines of certified aircraft.
Description Part No. Price Buy
Decalin Fuel Additive - 16 oz. bottle
Decalin Fuel Additive - Quart
Please note: I spoke with customer service for this product when I found excessive white powder on my spark plugs. I was told this is normal, it is Lead Oxide (shows it's working) and that EJ-22 users should use 1/2oz per 20 gallons NOT 1/2oz per 10 gallons as the label indicates.
See DOWNLOADS page for lots of soob downloadable info.
Subaru Engine / Car Data
Web pages for Subaru EA-81, EA-71 and EJ-22 engine users
https://www.lsecorp.com/Products/CrankSensor.htm Crank sensor system
https://www.carburetorfactory.com/expvw18.html Exploded View of a Holley model 2300 Carburetor
https://www.sdsefi.com/ The affordable engine management system that YOU can program!
Web pages for Subaru EJ-25 users:
Manuals! Here: https://22.214.171.124/STi_Stuff/STi_Manual/index.htm
Crossflow EJ-22 Redrive Info (PSRU)
Turn Key, Ready to go Subaru Aircraft Engines
If you are using a carb in your Subaru 2.2 engine conversion you MUST install EGT sensors for each exhaust port. Carbs that run fine on the ground can run very lean during flying conditions and cause sudden and serious engine damage/failure.
Converting a Holley 2300 Carb for Aircraft use:
1. Add larger jets.
2. Replace brass float with plastic one from Holley.
Two things: recommend Holley 2300 conversion for aviation. Bolt heads
Credit: dfwsfug ( soob news group )
Some people call the Holleys 'Ice Makers' so be sure to have carb heat or at least a carb temp gauge.
Ford Escort Ignition (2400) used in Subaru EJ-22 Conversion.
This conversion uses a 1982 Ford Escort Distributor with external module.
You have to grind down the slots on the bottom of the distributor slightly to get a good fit.
Also, you need to remove the vacuum advance and replace it with a mechanical advance of your own design.
I will be testing a 1983 distributor later this year. If it works it would be better because it has no points and it has a built in advance.
Mount the coil with rubber so it does not take vibration damage.
Note: This photo shows an improper coil. You should use a stock coil or a coil with at least 1ohm resistance that is matched to the Ford Ignition.
Soob Engine Cooling
EJ-22s are famous for having cooling problems especially if you take them out of the car.
The problems tend to be:
1. Air bubbles accumulate in the system. Even very very small amounts of air in the cooling system will cause heating problems. Make sure you have a filler tube that is tall enough to act as an air catch to remove air from the system.
2. Use the STOCK subaru EJ-22 thermostat. Do NOT use 3-rd party replacements that say they are for the EJ-22
3. Drill a small hole in the side of the thermostat. This will allow trapped air to past the thermostat.
4. EJ-22 water pumps will fail or degrade when stored for more than a few months in the engine. Loosen the timing belt and spray the inside of the pump above the thermostat with a good lubricant.
Custom EJ-22 and EA-81 Filler tubes that catch air:
EJ-22 Oil Leaks
EJ-22s sometimes develop minor leaks around some oil seals. By far the most common are:
1. Valve Covers. Simply replace the seals and don't forget the seals around the mounting bolts.
2. Front Cam and Crank Seals. These are a common issue. Typically, they fail when someone puts too much oil in the engine or has a habit of going to full RPM before the engine as come to operating temperature. Some people purposely run 1/2 quart low on oil just to avoid this problem. The seals are cheap and widely available but you have to remove the timing belt to replace them.
RAF Carb Heat Air filter for EJ-22 Engines with Hollys..
Above: Photos of Chris Spadafora Side by Side Air Command Elite
Note: be sure to use a Carb Temp gauge and EGT gauges with your setup!
Pictures of Converted Auto Engines
"Rotors... The only way to fly"