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Auto Engines

Welcome!Gyroplanes are fun, exciting and safe. Take an introductory lesson this weekend !




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
05-01406 $19.95
Decalin Fuel Additive - Quart
05-01413 $31.50


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 EJ-22 Engine Manual 1/2

Subaru EJ-22 Engine Manual 2/2

Subaru EJ-22 Parts Catalog / Manual / Diagrams

Subaru Engine Chart

EJ-22 Overhaul Procedures

Timing Belt Removal (EJ-22)

HLA notice (EJ-22)

Engine Repair Info (EJ-22)


Subaru Engine / Car Data

Years Engine
Subaru 2WD models 1.1 - 1.6 Auto Parts 70-79 1.1-1.6
Subaru 2WD models 1.6 & 1.8 Auto Parts 80-84 EA71,81
Subaru 4WD models exc. Brat Auto Parts 80-84 EA71,81
Subaru 4WD models exc. Brat Auto Parts 75-79 EA63,71
Subaru 4WD Turbo exc. Brat Auto Parts 83-84 EA81T
Subaru Baja 2.5 Pickup Auto Parts 2003 EJ25
Subaru Brat 1.6/1.8 Pickup Auto Parts 77-81 EA71,81
Subaru Brat 1.8 Pickup Auto Parts 82-88 EA81
Subaru Brat 1.8 Turbo P/up Auto Parts 83-84 EA81T
Subaru Forester 2.5 Auto Parts 2003 EJ25
Subaru Forester 2.5 Auto Parts 98-02 EJ25
Subaru Hatchback OHV 2WD Auto Parts 85-89 EA71,81
Subaru Hatchback OHV 4WD Auto Parts 85-89 EA81
Subaru Impreza 1.8 2WD Auto Parts 93-96 EJ18
Subaru Impreza 1.8 4WD Auto Parts 93-97 EJ18
Subaru Impreza 2.0 TurboWRX Auto Parts 02-03 EJ20
Subaru Impreza 2.2 4WD Auto Parts 95-01 EJ22
Subaru Impreza 2.5 4WD Auto Parts 02-03 EJ25
Subaru Impreza 2.5 RS 4WD Auto Parts 98-01 EJ25
Subaru Impreza2.5TurbWRXSTI Auto Parts 2004 EJ25
Subaru Justy 1.2 2WD Auto Parts 87-94 EF12
Subaru Justy 1.2 4WD Auto Parts 88-94 EF12
Subaru Legacy 2.2 2WD Auto Parts 95-98 EJ22
Subaru Legacy 2.2 2WD Auto Parts 90-94 EJ22
Subaru Legacy 2.2 4WD Auto Parts 90-94 EJ22
Subaru Legacy 2.2 SOHC 4WD Auto Parts 95-99 EJ22
Subaru Legacy 2.2 Turbo 2WD Auto Parts 91 EJ22T
Subaru Legacy 2.2 Turbo 4WD Auto Parts 91-94 EJ22T
Subaru Legacy 2.5 4WD Auto Parts 00-03 EJ25
Subaru Legacy 2.5 DOHC 4WD Auto Parts 96-99 EJ25
Subaru Leone/Loyale OHC 2WD Auto Parts 85-93 EA82
Subaru Leone/Loyale OHC 4WD Auto Parts 85-94 EA82
Subaru Leone/LoyaleTurbo2WD Auto Parts 86-90 EA82T
Subaru Leone/LoyaleTurbo4WD Auto Parts 85-90 EA82T
Subaru Outback 2.2 SOHC Auto Parts 96 EJ22
Subaru Outback 2.5 4-Cyl. Auto Parts 00-03 EJ25
Subaru Outback 2.5 DOHC Auto Parts 96-99 EJ25
Subaru Outback 3.0 6-Cyl. Auto Parts 01-03 EZ30
Subaru Outback Sport 2.2 Auto Parts 96-01 EJ22
Subaru Outback Sport 2.5 Auto Parts 02-03 EJ25
Subaru SVX 3.3 2WD Auto Parts 94-95 EG33
Subaru SVX 3.3 4WD Auto Parts 92-97 EG33
Subaru XT 1.8 2WD Auto Parts 85-91 EA82
Subaru XT 1.8 4WD Auto Parts 87-91 EA82
Subaru XT 1.8 Turbo 2WD Auto Parts 85-87 EA82T
Subaru XT 1.8 Turbo 4WD Auto Parts 85-87 EA82T
Subaru XT6 2.7 2WD Auto Parts 88-91 ER27
Subaru XT6 2.7 4WD Auto Parts 88-91 ER27

Subaru Engine Specs and Designations

Last updated July 19, 1999

Posted by Witte; from Ultimate Subaru Message Board, additional info from GeoffreyR

year General Size Actual Size HP Torque Designation Notes all unlisted cr are 9
70-71 1100 1088 62@6000 63@3200 unknown FF1 Not SAE rated
71 1300 1267 80@6400 73@4000 un 1300G Not SAE rated
72 1300 1267 61@5600 65@4000 un 1300G
73-74 1400 1361 61@5600 69@3600 EA-63 1400
75 1400 1361 58@5200 68@2400 EA-63 1400 2wd
75 1400 1361 56@5200 67@2400 EA-63 1400 4wd
76 1400 1361 58@5200 68@2400 EA-63 1400 2wd cr 8.5
76 1400 1361 56@5200 67@2400 EA-63 1400 4wd cr 8.5
76-79 1600 1590 67@5200 81@2400 EA-71 1600 2wd cr 8.5
76-79 1600 1590 65@5200 80@2400 EA-71 1600 4wd cr 8.5
80-82 1600 1595 68@4800 84@2800 EA-81 1600 cr 8.5
80-82 1800 1781 72@4800 92@2400 EA-81 1800 2wd cr 8.7
80-82 1800 1781 71@4200 92@2800 EA-81 1800 4wd cr 8.7
83-87 1600 1595 68@4800 84@2800 EA-81 1600 cr 9
83-84 1800 1781 73@4800 94@2400 EA-81 1800 cr 8.7
83-84 1800 1781 95@4200 123@2800 EA-81T 1800 turbo cr 7.7
85-87 1800 1781 73@4800 94@2400 EA-81 Brat, 85 2dr GL
85-89 1500 1595 69@4800 86@2400 EA-81 2dr
85-86 1800 1781 82@4800 101@2800 EA-82 4dr
85-86 1800 1781 94@5200 101@2800 EA-82 GL-10 MPFI & XT
85-86 1800 1781 111@4800 134@2800 EA-82T turbo
86-94 1800 1781 90@5600 101@2800 EA-82 SPFI
86-89 1800 1781 84@5200 101@3200 EA-82 SPFI 4dr 2wd
87-88 1800 1781 84@5200 101@3200 EA-82 carbed
87-91 1800 1781 97@5200 103@3200 EA-82 XT MPFI
87-90 1800 1781 115@5200 134@2800 EA-82T turbo
87-93 1200 1189 66@5200 70@3600 EF-12 Justy carbed.
88-91 2700 2672 145@5200 156@4000 ER-27 XT6 (coolest of all 2 valve)
90-93 2200 2212 130@5600 137@2400 EJ-22 Legacy
90-94 1200 1189 73@5600 71@3600 EF-12 Justy MPFI
92-94 2200 2212 160@5600 181@2800 EJ-22T? Legacy Turbo
92-97 3300 3318 230@5400 228@4400 E?-33 SVX
93-96 1800 1820 110@5600 110@4400 EJ-18 Impreza
95-96 2200 2212 135@5400 140@4400 EJ-22 Legacy,Impreza
96 2500 2457 155@5600 155@2800 EJ-25 Legacy




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:



Redrive Info:

Crossflow EJ-22 Redrive Info (PSRU)

Turn Key, Ready to go Subaru Aircraft Engines




Important Note:

 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
#19 x4 should be drilled and lock wired. The float chamber parts #38
#21 if loose could dump fuel on hot engine :( Also use reverse return
spring on throttle butterfly arm. It your throttle linkage fails the
spring will give you full throttle and a quick trip home. Shutting off
ignition over the numbers much better place to get some glider time:)
CE in SS

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:

Tech Welding

4460 Shemwell Lane Paducah, KY 42003

(270) 898-3776 twelding@apex.net

 Interior H20 heaters, custom size, radiators, low profile intake, manifolds, custom water manifolds, low profile oil filter necks for Subaru engine Call for info and $$


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


AirCommand SxS Elite, EJ-22, RAF intake, RAF Exhaust, NewHorisons Redrive, Holley 300cfm, Escort Ignition

AirCommand SxS Elite, EJ-22, RAF intake, RAF Exhaust, NewHorisons Redrive, Holley 300cfm, Escort Ignition

AirCommand SxS Elite, EJ-22, RAF intake, RAF Exhaust, NewHorisons Redrive, Holley 300cfm, Escort Ignition

AirCommand SxS Elite, EJ-22, RAF intake, RAF Exhaust, NewHorisons Redrive, Holley 300cfm, Escort Ignition





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