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newrider3 Reader
10/9/20 4:24 p.m.

Right now I'm tearing down the TDI to get all the parts cleaned up, and get ready for new gaskets and seals everywhere. Purple power and some brushie is working out well.
The intake manifold is soaking in a bin of water and dish soap in hopes of loosening the chunks of EGR carbon deposits.


This accessory drive bracket is a nice piece. One casting that holds the injection pump, alternator, power steering pump, and AC compressor.


The ALH is quite a compact engine. 470mm or 18.5in from the bellhousing surface to the front of the damper. This is going to help it fit in place of a relatively short boxer 4 cyl.


I've also been working on cleaning up the Forester interior. It's pretty filthy. Certainly not the worst, it's at least not residue from cigarette smoking or oily grease from a mechanic, but everywhere the previous owner touched is a gray stain. Not sure if he was big on lotion, or just not big on hand washing/showering.

After some degreaser and stiff brush action:



bgkast (Forum Supporter)
bgkast (Forum Supporter) PowerDork
10/9/20 5:09 p.m.

Can't wait to see where this goes!

docwyte UberDork
10/10/20 10:58 a.m.

That interior, ewww!!

brad131a4 (Forum Supporter)
brad131a4 (Forum Supporter) Reader
10/10/20 12:11 p.m.

Look for a vanagon diesel pan and pickup. Already set up for the 50 degree angle. They show up on cl every so often. Plus the Samba has a few every now and then.

newrider3 Reader
10/10/20 3:53 p.m.

In reply to brad131a4 (Forum Supporter) :

From what I see they don't fit the ALH without an adapter. It will be easy enough to fab up my own, I haven't gotten any TIG welder time in lately anyway. Plus, Vanagon parts are sought after and expensive around here too.

Nitroracer (Forum Supporter)
Nitroracer (Forum Supporter) UltraDork
10/10/20 9:09 p.m.

First off, this is a fun project to watch and the house has been a good one too!


Second, the ALH engine you picked, I noticed the cylinder head isn't one of the crossflow variety where intake and exhaust manifolds are mounted on opposite sides of the head.  Is that an old design, maybe in the last few years of its use?  Very few gas engines of that era had the manifolds on the same side, but I don't know much about TDIs.

orthoxstice New Reader
10/11/20 9:08 a.m.

In reply to Nitroracer (Forum Supporter) :

The ALH was sort of the last of its kind and traces its lineage back to the 1.5l diesel that VW made in the 1970's. They stopped making them (in the US) in 2003. 

newrider3 Reader
10/11/20 9:08 a.m.

It's definitely a carryover from VWs first watercooled 4 cylinder designs. The ALH was done by 2003, but I'm pretty sure the next couple generations of TDI carried on with a non-crossflow head. I don't think they modernized the design to DOHC/crossflow until the newer common rail injected diesels.

It's certainly an antiquated design, but in my case it helps with packaging, and I don't think I'll be wanting for more power or efficiency if I can achieve something like 230 wheel torques and 30+ mpg as advertised with a tune. 

newrider3 Reader
10/11/20 4:00 p.m.

Gave the Beetle carcass a shove and rode it downhill like a soapbox derby car, it can relax by my scrap pile and acclimate to the altitude while I decide what to do with it.



brad131a4 (Forum Supporter)
brad131a4 (Forum Supporter) Reader
10/12/20 12:38 a.m.

Ok kind of what I thought just couldn't remember if it was a straight bolt on or not. Still not as bad as the 911 prices or B.A.T Alfa Romeo prices or just about anything on B.A.T now a days sheesh.

newrider3 Reader
10/16/20 7:36 p.m.

Small progress with wiring, trimming excess engine harness out of the Forester and getting all of the donor engine harness out of the VW. 
This is most of what I need from the Beetle, just a few more pigtails and connectors to cut out of the main car harness as I need them.


Trying to depin as much as I can from the Subaru and cut as little as possible.


Pulled apart the Subaru 2.5na ECU to salvage the connector. Also should be able to use the bottom part of the ECU case to mount the TDI ECU with some velcro or PSA tape or something.


I started playing around with engine paint to get an idea of the look. Detroit Diesel Alpine Green. It looks super teal in bright sunlight but more subdued in the shade.

Professor_Brap (Forum Supporter)
Professor_Brap (Forum Supporter) UltraDork
10/16/20 7:54 p.m.

If you need any tdi help get ahold of me. 

newrider3 Reader
10/20/20 4:05 p.m.

Subarus are required to have gold wheels, right?


The color was supposed to be hammered finish but the orange peel effect never actually wrinkled up. These are off the Beetle, they have just a hair less positive offset so will give me more tire to strut clearance. I think they look mildly better than the Subaru wheels.



I reached the end of my patience for letting the VW wiring harness tell me what to do, so I got drastic with the wire cutters.


I decided I didn't want to deal with the extra VW connectors and chasing stuff everywhere, so I clipped the harness at the two ECU connectors, then clipped the engine side at the various redundant junctions and connectors, leaving me with two engine umbilicals. There should be a third engine harness umbilical for the glow plugs, not pictured. I'm going to connect the wires that need to get directly from the ECU to the engine through the passenger side footwell using two Deutsch bulkhead connectors. Anything that needs to interface from the VW ECU to the Subaru car harness (like power/ground, CEL, OBD2, glow plug light, cruise/brake/clutch switches) will connect via the Subaru ECU harness and salvaged connector. 


I did manage to butcher the glow plug relay harness while trimming because I didn't recognize the connector. Not too bad, there's still a couple inches of wire left to splice to, but I would have rather left more.



While I was playing with wiring, I took a look at the drive-by-wire throttle pedal.


It's not terribly different in size than the Subaru pedal. The bend is shaped a little differently, which would make it hit the firewall before WOT if I mounted it in the same plane as the stock pedal. Time to make a spacer adaptor.


First, I had to remove some locating nubs on the back of the VW pedal to allow it to sit flat. Easy with a flap wheel on the angle grinder and a delicate touch.


Started with some wood for a mockup.


Position feels fine to me, but it still does hit the floor before full WOT. The spacer probably needs to end up a full inch thick.


solfly Dork
10/20/20 4:57 p.m.


metty New Reader
10/21/20 9:39 a.m.
newrider3 said:

Position feels fine to me, but it still does hit the floor before full WOT. The spacer probably needs to end up a full inch thick.



if you are going into the ECU anyway, you can probably re-map the pedal input so that whatever your physically available WOT is corresponds to max throttle in the ECU. The pedal is putting out a 0-5V signal so you just need to tell the ECU "hey, 3.5V is now maximum throttle".

it should interpolate from there or at least most ECUs i have seen do. 

californiamilleghia SuperDork
10/21/20 11:28 a.m.

did Subaru ever sell this model with a diesel  in another market ?

I know they did not make a boxer diesel but maybe bought them from another company ???

newrider3 Reader
10/21/20 12:20 p.m.

In reply to metty :

The throttle pedal isn't just a potentiometer, there are also switches inside corresponding to WOT/kickdown and closed throttle. Besides, making a thick spacer is far far easier, since a spacer/adapter needs to be made in any case. I don't plan to do the ECU fiddling myself, it has to be mailed out to delete the immobilizer so it will get a canned tune uploaded while it's there.


In reply to californiamilleghia :

I touched on this earlier in the thread; Subaru sold the EE20 diesel in Japan and Europe between 2007 and 2020, but they're prohibitively expensive to import, and the only option to run it that people in the US have found is an expensive Bosch Motorsport ECU.

I saw this EE20 diesel swapped Impreza running at Pikes Peak years ago:


2002maniac Dork
10/22/20 9:19 a.m.

Excellent build! My current daily is an ALH golf and I've owned a half dozen subies. I noticed that adapter plate a while back and have daydreamed about this swap. I have only gone as far as parking the golf next to my gambler 500 Outback and taking some basic measurements. 

Keep us updated!


BoostedBrandon SuperDork
10/22/20 10:44 a.m.

I'm BoostedBrandon, and I approve this thread.

newrider3 Reader
4/7/21 3:19 p.m.

So, long time since last update; as per usual with my projects and build threads :( After we finally moved into our new house last fall I was having a super hard time with any project and motivation in general. 2020 was such an assdisaster in general and I wasn't at all happy the way I thought I would be when I moved into the house I built, so I finally sought out counseling and psychiatric help. Came away with an ADHD diagnosis, which I think may have been a long time coming and a big factor in my high school laziness followed by college straight-D grades. Anyway, away from too much personal information and back to Subaru diesel swapping. 


I finally realized I was letting "good" and "pretty" get in the way of progress and "good enough". I wanted to have the ALH cylinder head tanked and decked, I wanted to fully clean and paint the engine block, some of the accessories were still too dirty for my liking, etc. I have given up on having a spotless pretty engine in favor of getting it running, started painting over dirty aluminum parts instead of fussing with baked-on grime. 

Plugged the original turbo drain port, since the return will go to the new oil pan with the 50-degree engine mounting. 


Started reinstalling accessories, including the steel-bottomed oil pan I was able to find for a ridiculously low price by searching amazon for 1.8T oil pans. 


Gave the head a clean-up with sandpaper and a granite surface plate I scored from my previous employer's landlord. Glad I didn't bother taking it to a machine shop, it was already as flat as it really could be.


Gave the head gasket a spritz with the copper coat that diesel guys all seem to love so much, and threw the cylinder head on with new TTY bolts.


Got the engine timed, hopefully correctly. I used a cheap TDI timing tool set so it should be OK as long as the #1 cylinder was as close to TDC as I thought I got it. Still nerve-wracking with absolutely no keys holding the pulley on and no timing marks on the belt. 


Slippery UberDork
4/7/21 8:55 p.m.

I was wondering what happened to this project. Glad its on again. 

newrider3 Reader
4/8/21 9:52 a.m.

At the end of March I finally gave in and let myself order the four-post lift I've been eyeing for months. Had to send it to a freight terminal, but even with driving to pick it up myself it was practically faster shipping than I get from amazon these days... But it freed up a garage space for the Forester. It's so much easier to get out and tinker when the car isn't buried in the side yard under snow or dirt. 



I've also been piddling around with the Subaru 5mt transmission at the same time as I started working on the engine again. I searched for a little bit for a WRX trans and rear diff to get a better overdrive and final drive ratio for the diesel, but realized I could live with the existing 4.11s if I swapped in the WRX 5th gearset. Ended up cheaper to order the gears from a dealer than I would have been able to get a different used trans. 
Also opened my existing rear diff out of curiosity and found I already have a functional limited slip, score.

Rear housing pops off the trans easily, removing the center diff viscous coupling and rear drive transfer gears. I fought with the trans propped up on an old wheel for a while before I realized I could just screw it down to some 2x4s.



WRX 0.738 fifth gearset, to replace the stock Forester terrible 0.871 :


Had to buy a 35mm socket as well as a giant 50mm socket (which was almost not deep enough) to get the 5th gearset off. The drive gear and corresponding nut came off the mainshaft with no fuss, but the huge 50mm nut and driven gear took a distressing amount of force to remove from the pinion shaft. Hopefully I didn't mangle anything too terribly.


Just need to press on the new gear, reassemble, and add all the new output and shift seals that I ordered from the dealer. Got a cheap urethane shift linkage bushing set to throw in before I reinstall too. 

clutchsmoke UltraDork
4/11/21 1:13 p.m.

Great progress! This is a great project. 

newrider3 Reader
7/6/21 10:03 p.m.

Yet another long delay between updates; but the engine is now mocked up in the car with the SubaruGears adapter plate.

Plenty of room for activities to the rear and either side; the radiator is about 1/4" from the crank pulley; but the adapter is hitting the crossmember and the engine is hitting the hood. Turns out when I initially mocked up I measured 50deg layover from horizontal rather than vertical, so it's not as short as I expected. Notched the crossmember and cut some crossbraces out of the hood and it's still pretty far from closing. Probably going to solve this with some front subframe spacers.



Professor_Brap (Forum Supporter)
Professor_Brap (Forum Supporter) UltraDork
7/7/21 6:37 a.m.

This is going beyond good. 

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