NorthWet

"Ignition amplifier" aka Ignitor, aka the transistor that switches the coil to ground. On a stock setup, it is mounted to the coil bracket. If you have spark, and supplemental fuel causes a response, then the ignitor/ignition is not the major problem. I don't recall regulators being much of an issue, though I imagine a couple members have replaced bad ones. I do recall a few posts asking for replacement injectors, though I can recall only 1 that said whether it helped (yes) or not. Distributor electronics/signals seem to be a more common cause. No rotational/positional data, no injection. The MAF and/or it's wiring could also affect things.

Dumb question, can't remember if you stated it clearly before, too lazy/tired/time-constrained to look back, so apologies in advance: Are you using the EA81 distributor or the SPFI one? Second question: Is it possible that you swapped the fuel feed and fuel return lines? It is easy to do (guess how I know?), and will cause all manner of confusion.

Cut my be difficult. Temporarily spacing would probably be acceptable.

The implication, and thus assumption, is that only the rear segment of the driveshaft was removed, leaving the front section to plug the rear of the tailshaft and the center carrier bearing to support the front section of the driveshaft. This, however, may be an incorrect assumption. I am still puzzled how a front bearing could cause so much drag, and not have MAJOR observable issues (eg - wheels the wobble easily by hand when off of the ground), and how both (assumption) could be so bad at the same time.

I'm still betting that the buddy set the parking brake and jacked up the front of the car... not realizing the parking brake works on the front. Or, maybe, brake pads were improperly replaced recently.

Any possibility that the parking brake was on when your buddy tried to spin the wheels that the parking brake acts on?

I think that 3 should be dismissed out of hand. Having a hardened steel jumping-jack bouncing around inside the diff sounds like no fun. I think either options 1 or 2 would be acceptable. I would probably opt for 1, as the radius from center is small (70 or 80 mms??), the mass around it is great and it is not "unsprung mass", subject to harmonics from a sprung mount. Option 2 is probably fine, since you don't strike me as someone likely to try to do an AWD burn out. The R160s were used in Datsun 240Zs back when BRE was racing them, so they probably have a lot of margin of safety in the strength department.

Ivan: The roller-follower EJ18's were interference? I don't recall hearing this, but it would be useful to know. (I have a couple in storage.)

It should be the same shaft, but if the splines got chewed off deep in the tranny, there is probably something very wrong back there... along with a ton of metal debris.

If you are close enough to Portland to make it worth it, there are/were several pull-it-yourself junk yards where you could grab a used one for cheap. Otherwise, there is an inline pump for a Ford F150 that you can get new for around $40 that is supposed to work well. I should have suggested that you take a battery and some wire and directly apply power and ground to the pump to insure that it is dead. The connector is right there at the pump, and polarity won't matter for testing for life.

Did you have the heads re-surfaced at the HG replacement? If not, this may be part of the issue. Your mechanics experience is arrayed against a broader experience from long-time USMB members. Exhaust divider cracks are the only common head crack, and those only in MPFI heads and those (to my questionable-knowledge) exclusively in turbo heads that have been seriously overheated. These cracks dump coolant into the exhaust more than directly cause overheating. The slightly-raised roof is probably what is referred to as a "Touring Wagon" in the US.

Where did the shaft snap? (As in, were you able to retrieve all the pieces?)

93 Impreza would be a non-interference engine: No damage will occur from a belt break. If I had to guess, you probably have a bad tensioner/idler/water-pump (pick one or more). Best to replace all of the rotating components that the t-belt rides against. Lots of places sell complete kits for reasonable prices.

Cool response from SOA. The belt take up mechanism is really a mechanism (sorry for the tautology): It has components to lock the belt when the car decelerates quickly... like in a crash. It probably has debris and general crud in it. Far better to either properly clean it or replace it. If SOA will do it for free, and possibly get brand new belts out of the deal, this sounds like the best route.

is you belt twisted where it heads into the take-up reel? The belt itself might be causing the jam. Do all of the other windows roll down with their own switches? If so, yes, dirty switch: replace, or clean if you are adventurous. If not, the window lock switch may be on.

+1

Probably won't help much after a blown radiator hose and overheat.

Yes, the "flat washer" should be slightly dished. It is designed to be put on convex-outwards, so that the nut first makes contact on the center, while the outer rim contacts the bearing outer-race first. This helps insure proper transfer of force from the nut to the stationary outer race. Installing the dished washer incorrectly, or using a regular flat washer, prevents proper fastening of the axle.

+1. I did not mention that it is not economically practical to get the engine professionally rebuilt as you said that it was already sent off. There is little point on most of them to split the cases to do bearings and rings. wear and failure rates are very low, and it is cheaper to just find a used block. I75eya: OP typed that the WATER pump was on one side (which it is), and it feeds the right-side case through a small passage at the very top of the engine.

It is a "Rite of Passage" for all Subaru owners.

Again, the "Gen 3" reference is ONLY for dual-intake-port MPFI heads.

+1 on everything grossgary typed. In the USA, we are conditioned to think of things as good or bad, with nothing in between. The EA82 engine is good at what it does, but not good at what it doesn't do... so, many just say it is bad. Yes, they require maintenance. Yes, their cooling design was not upgraded and can't handle power increase, regardless of how big of a radiator you put on it. Yes, they are 20+ years old, and that is a long time for a headgasket to survive, especially one whose fire-ring tends to wear a groove in the head surface. But, yes, if well maintained and used as intended and not abused, they can run seemingly forever. People like to complain that they are underpowered, but I think that is just people wingeing: I am quite happy with mine. I also have a couple SVXs, and both types have pleasurable qualities. As long as your expectations are reasonable, the Ea82 can be a pleasurable, economical and reliable engine.

It is EXTREMELY unlikely that the head has cracked (unless it is a turbo version, EA-series don't crack heads). They do have headgasket failures, though. Saying that the head is cracked will get few inquiries; saying that it needs headgaskets will be more successful for you. Cheers!

Most of the "emissions control" are part-and-parcel of the engine management. There are no "power robbing" components on the car. As far as the exhaust system being restrictive, it pretty much complements the rest of the air-handling on the engine. Any changes to "open up" the exhaust will mostly just make it louder.

There is no real issue with the heads on the non-turbo cars. HG issues are probably due to the gasket dying from old-age or from overheating. Many of the cars in the wrecking yards probably have a broken timing belt, or a rotor screw that backed out, ot one of any number of minor things that people don't want to futz with,