I finally got my hands on (ok it was pretty much placed in my hands, thanks Sucker King!) a genuine Subaru Service Manual for the 1977 Model Year.

(handy thing)

I was pretty much just going to swap the motor out on my 77 wagon,  (IF I ever freaking FIND ONE cheap enough I'm poor out here, happy, but poor)

 

But with Manual in hand I decided to try and see just what was up with the one I pulled.

 

SO...

I determined that the camshaft was not turning. But everything else seemed okay with the little EA71,

then I pulled the trans housing on the back of the engine and found this...

 

 

 

I figured that the camshaft was seized...But NO! (?!?) it is free to turn and opens and closes the valves.

looking in through the spark plug holes shows nothing unusual (broken, holed through, etc.)

 

So what am I looking at here, weak casting for the gear? Sudden uptake in power surging through the crankshaft leading to over torque, and subsequent failure of the cam gear?

I mean, what in the heck?

It was in front of an automatic transmission, and driven by an 80+ year old guy out of the foothills of Victor, Montana...so I ask again, scratching my head...

Whaaa?!?!

 

there are no marks on either gear to indicate that there was a drag or foreign bits that came between these two.

as I mentioned, the camshaft turns freely (well, with the drag from operating the valves.)

 

so why the failure?

 

any Ideas?

 

Puzzledly,

Timothy

I'm no metallurgist, but my first thought was a flaw in the casting. Pretty wild! I'll bet that was busy for a few seconds!

 

John

Flywheel bolt that was too long for the flange hitting the cam gear?

 

Crank thrust bearing is shot allowing the flange to hit the cam gear?

Push & pull on the crank flange to see how much play there is.

Wow

I'm sorry you had to find that, but on the bright side, you know what the problem is..

 

And that is rather amazing to see. Never seen that on these motors before.  Good luck with sourcing some replacements.