Some Subaru History Facts

[Ron Mummert]

Opposed piston engines have two crankshafts and no cylinder head. Instead, two pistons share a cylinder and move towards and away from each other. As far as I know, this design has only been used on two-stroke diesels.


Voila! My mental invention has done already been patented, I guess.
Long ago I conceived of an engine whose pistons "bumped heads" to create a combustion chamber fired by one plug. Thus, it had to have two crankshafts. I thought this would be "cool" for watercraft where the "twin screw" is provided by one engine with gearing to control the driveshaft output. Do you know when this design was developed, & what the application was.

Ron (Gotta' patent the rubber band concept soon).

[Matthewmongan]

Originally Posted by Ron Mummert

Opposed piston engines have two crankshafts and no cylinder head. Instead, two pistons share a cylinder and move towards and away from each other. As far as I know, this design has only been used on two-stroke diesels.


Voila! My mental invention has done already been patented, I guess.
Long ago I conceived of an engine whose pistons "bumped heads" to create a combustion chamber fired by one plug. Thus, it had to have two crankshafts. I thought this would be "cool" for watercraft where the "twin screw" is provided by one engine with gearing to control the driveshaft output. Do you know when this design was developed, & what the application was.

Ron (Gotta' patent the rubber band concept soon).

no i dont but i may know someone who does. he is the master of machine trivia, gail mongan. ill ask him tomarrow.

[CigarJohnny]

Originally Posted by Ron Mummert

Opposed piston engines have two crankshafts and no cylinder head. Instead, two pistons share a cylinder and move towards and away from each other. As far as I know, this design has only been used on two-stroke diesels.


Voila! My mental invention has done already been patented, I guess.
Long ago I conceived of an engine whose pistons "bumped heads" to create a combustion chamber fired by one plug. Thus, it had to have two crankshafts. I thought this would be "cool" for watercraft where the "twin screw" is provided by one engine with gearing to control the driveshaft output. Do you know when this design was developed, & what the application was.

Ron (Gotta' patent the rubber band concept soon).

I believe you will find this link interesting, Ron. It seems Professor Hugo Junker first developed this type of engine in around 1929. In 1939 the Jumo 223 made 2200HP @ 4400rpm:

THE JUMO 223
The most extraordinary diesel built by Junkers – and perhaps the most extraordinary diesel ever built – was the Jumo 223. This engine grouped four banks of 6 cylinders laid out at 90° on the faces of an equilateral rhombus whose apices were formed by 4 crankshafts. Being the logical development of the 2 crankshaft engines, it comprised 24 cylinders and 48 pistons. The number of cylinders was quadrupled while multiplying by only two the number of crankshafts. In 1939, in attempting to win the war, one didn't retreat in the face of tremendous technical difficulties and exorbitant development costs.

Johnny

[Bobb]

Hi John, "Junkers" made planes at least during WWII. Since the engine you mention was a Diesel it might have been Junkers that tried to put a Diesel engine in an airplane. Boy, was it heavy. Take care, BOBB

[Royal Tiger]

Junkers made numerous planes during WWII. They also used diesel engines in some applications, including seaplanes where diesel's are preferable to gasoline. The Junkers Ju-88 medium bomber was Germany's second most used bomber behind the Heinkle He-111.

[Matthewmongan]

my grandfather (used to work as an engineer for fairchild) said the engine your talking about is a 'junker'. they were used in some water landing planes, apparently they had issues with timing and piston wear. he said he used to have one in his shop but he sold it to a friend who wanted to put it in his boat (not sure if he did the two screw shaft or not) that was almost 30 years ago. he used his to power a genorator and air copressor for his work shop (which is biger than his house). he did say they only have one output shaft so it would be diffocult to use it in the application you wanted, but they take up little space and produce insane amounts of hp.

[oab_au]

Yes Ron the Junker, was one of the German engine designs that were pilfered by the Allies after the War. It reappeared as the British Commer Knocker. A Three cylinder opposed piston two-stroke diesel. It used a single crank shaft, under the cylinders, with a set of rockers at the end of the cylinders to transfer the con rods movement to another set of rods connected to the crank underneath. Blowen by a Roots blower, it produced good torque, but burnt too many pistons.

I have no doubt that Subaru studed the early VW engine, and baised there design on it. So many German designs turned up in other Allied countrys. The BMW appeared as the Bristol engine that Cooper used in the Cooper Bristol. The DKW 125cc Two-stroke, appeared in the BSA Bantam, and also, mirror reversed as the 125 Harley Davidson.

GMTA. I also though of building a opposed piston engine, using two 500cc Triumps bolted barrel to barrel, inlet ports at one end ,exhausts at the other, blowen. The cranks rebolted 180 degs apart and chained together.

Harvey.

[Royal Tiger]

But how many of you know that the first pre-production Spitfire used a BMW liquid cooled V-12? Production versions used the Rolls Royce engine.

[Ron Mummert]

Originally Posted by CigarJohnny

I believe you will find this link interesting, Ron. It seems Professor Hugo Junker first developed this type of engine in around 1929. In 1939 the Jumo 223 made 2200HP @ 4400rpm:

Johnny

Well, I'll be dipped.

Thanks, Johnny.

Some of your info is a little off

Originally Posted by Tofu

2200 EJ22 - Adding the EJ22. Bored version of the EJ18. Same stroke. The EJ22E switched from dual port exhaust to single port, got roller rockers as the EJ22EZ, and switched from hydraulic to mechanical lifters and got dual rocker shafts as the EJ221/2.

The First EJ22 was an EJ22E

2200 EJ22T - Turbo version of the EJ22. Distinguished by it's closed-deck block. Powered the 92-94 Legacy Sport Sedan and 93-94 Legacy Touring Wagon.

The Sport sedan was from 91-94 and the Touring wagon was from 92-94

2500 ej25 - EJ25D and EJ25DZ are DOHC 16 valve. Bored version of the EJ18/22, same stroke. Powered automatic and then later manual versions of the Legacy Outback, Legacy GT and other variations, the Forester, and the Impreza 2.5RS. Later became the EJ251/2/3, with a switch to SOHC dual rocker shaft 16 valve heads, a different crank, and a different block. Some 98/99 Impreza 2.5RS and Outback models were built with the new block, but the old crank and heads. Currently powers all non-WRX/STi Imprezas and most Legacys and Foresters.

All EJ25's are bored AND stroked. In order for an EJ25 to have the noted 2457cc of displacement with the same 75mm stroke the bore would have to be 102.1mm. They're not though. All EJ25's are 79mm stroke with 99.5mm bore. The difference between the EJ25D and newer EJ25's (1/3/etc) is the location of the thrust bearing. Also note that all subaru engines changed at one point or another to the different thrust bearing. In the US the changed happened in 99 for imprezas and foresters, and in 98 for legacys.

Originally Posted by THAWA

Some of your info is a little off



The First EJ22 was an EJ22E

I know, that's what I typed. The EJ22E started life with solid rockers, dual port exhausts, and a single rocker shaft that holds both the intake and exhaust rockers. The block material was changed slightly in 1995, the heads became single port in 1996. In 1997, the EJ22E became the EJ22EZ, technically due to the evaporative emissions controls. The rockers were changed from solid rockers to roller rockers. In 1999, the EJ22EZ was supplanted by the EJ221/EJ222, with a change to the head design, adopting dual rocker shafts per head, switching to mechanical lifters, and a handful of other minor design details.

The Sport sedan was from 91-94 and the Touring wagon was from 92-94

Probably true.

All EJ25's are bored AND stroked. In order for an EJ25 to have the noted 2457cc of displacement with the same 75mm stroke the bore would have to be 102.1mm. They're not though. All EJ25's are 79mm stroke with 99.5mm bore.

That's what I get for looking in the piston catalog and not checking the math.

The difference between the EJ25D and newer EJ25's (1/3/etc) is the location of the thrust bearing. Also note that all subaru engines changed at one point or another to the different thrust bearing. In the US the changed happened in 99 for imprezas and foresters, and in 98 for legacys.

You're just right enough to be wrong about this part though.

The biggest difference between an EJ25D and an EJ25# obviously is not the location of the thrust bearing, but the head design. EJ25Ds are DOHC, and EJ25# are SOHC, with a head design nearly the same as the EJ22#, ie, SOHC, dual rocker shafts, roller rockers, mechanical adjustment. The case design was changed as well - the bellhousing now has eight bolts where there used to be four, the internal machining is slightly different to accomodate the aforementioned change in thrust location. Officially the EJ25# supplanted the EJ25D in 1999 for the Impreza 2.5RS and Forester, and 2000 in the Legacy, although, read below, that wasn't strictly true. Further changes included the location of the PCV valve changed in early 2001, while the crank and cam gears changed somewhat randomly to accomodate changes to the crank and cam sensor programs - some Legacies share their crank and cam gears with the CA emissions Impreza version of the EJ22#, and some don't. And somewhere around 2003, the rear of the LH head was drilled to accomodate a big hard pipe for the EGR system.

The curiosity about the change from the EJ25D to the EJ25# is that sometime in the middle of that changeover Subaru found themselves with a lot of EJ25# blocks and a lot of DOHC heads. So an unknown number of blocks were machined to accept the EJ25D crank, pistons, and DOHC heads, and were subsequently installed in a handful of '98 Impreza 2.5RS and '99 Legacy Outback models without telling anyone. To this day, Subaru does not officially recognize or admit that these half and half engines exist, but a lot of people have seen them - we've seen at least three at my work. The changeover happened gradually and possibly randomly - we've told people the only way to know for sure is to count the bellhousing bolts. DOHC + 4 would be an EJ25D, DOHC + 8 would be the nondocumented mix-n-match engine, and SOHC + 8 would be an EJ25#.

Originally Posted by Tofu

I know, that's what I typed. The EJ22E started life with solid rockers, dual port exhausts, and a single rocker shaft that holds both the intake and exhaust rockers. The block material was changed slightly in 1995, the heads became single port in 1996. In 1997, the EJ22E became the EJ22EZ, technically due to the evaporative emissions controls. The rockers were changed from solid rockers to roller rockers. In 1999, the EJ22EZ was supplanted by the EJ221/EJ222, with a change to the head design, adopting dual rocker shafts per head, switching to mechanical lifters, and a handful of other minor design details.

ah okay, I thought you were saying the firs 2.2 was an "EJ22" and that it became and "EJ22E" with dual ports.

[SVX-FF]

Originally Posted by PA_SVX

But how many of you know that the first pre-production Spitfire used a BMW liquid cooled V-12? Production versions used the Rolls Royce engine.

Did you also know that the BMW logo was inspired by the propeller back in 1917.

http://www.bmwworld.com/bmw/history/10s.htm

Steve

[SVX-FF]

I wrote to SOA to see if they could help me in determining the origin of the Subaru boxer motors and more on the EG33. I hope they give me somthing good. For all of us.

Steve

[Royal Tiger]

I did know the BMW symbol is a spinning propeller. But here's one for you. Why is it blue and white? I know.