97 Legacy Outback N/A DOHC build.

[Crowboy]

I should be working. Or studying for my Fundamentals of Engineering exam in two weeks. I'm thinking about my engine.

My Legacy came to me with the stock 2.5L DOHC EJ25D engine in rough (read: completely not running) shape. The geared timing belt idler bearings had exploded, causing the timing belt to give up on life in general. All 16 valves were bent. The plan previously had been to build every back to complete stock. Now I'm having second thoughts.

Now, I know it's foolish to chase power with a N/A engine. Turbos are always the best bang for the buck. I've read the threads on built N/A engines here, on NASIOC, SubaruOutback.org, and Legacy central. (It's interesting, the varied flavors and recommendations on each, by the way.) Here are the plans:

Heads rebuilt with original parts with the exception of nitrided valves. (already done, waiting to be picked up.)
- Valve seats re-cut
- Valve clearances brought back to spec
- New valve stem seals
- New valve guides where needed.
- Head re-surfaced

No porting, polishing, or new cams... yet.

The question is the block. There are 220k miles on the one I have. I know on these it's usually not a problem, new stock rings and bearings, maybe a crank polish, and it's good to go at least another 100k. The next task is to tear it down and start measuring to see how good or bad it really is.

Or... should I just save myself some time and find an EJ251, EJ253 shortblock with low miles, clean that up, and benefit from the bump in CR from 9.7:1 to 10.4:1 as well as improved design of the internals? I suppose I could replace rings and bearings as well, though there is no time savings and no money savings there over rebuilding the stock block. I have no problem running midgrade if I need to, though folks with this hybrid have said they've been fine with regular. I'm planning on a PLX devices DM-100 or DM-200 OBDII multigauge which would also allow me to keep an eye on timing, or other relevant engine parameters.

Other pros:
- One of the gurus of this swap is up near Denver, about as close as anything to me.
- No engine management changes required.
- Flywheel and clutch same as stock

Other cons:
- The standard hybrid engine problems: keeping track of what is needed as far as replacement parts go.
- More cost with minimal performance improvement

Anybody got anything else? Any leads on a EJ251 short block close to Gunnison, CO? (Denver is a 5 hour drive one way, it'll be a few weeks before I have time for that.)

[chuckthefuk]

Have you considered a Japanese imported long block?

These can be purchased and shipped for around $800..

You have the piece of mind that the motor only has 60,000 km on it however you can only use the short block since the heads will be different. (I say this because they usually send 98+ motors which are sourced from BE/BH)

Always an option.. I usually do this when someone pops a H/G with more then 250,000km... No point to rebuild if its going to push past $1000...

What is the overall goal for your Lego? Do you plan on going with forced induction down the line? Making it a hi-reving non turbo? Or just a peppy motor for spirited driving?

-Chuck

[Crowboy]

Not really thinking of FI, though the idea of a supercharger is interesting. Probably not a good idea with this engine.

I plan on using another set of heads I have for DIY port match, polish, and casting cleanup. I am very seriously considering some Delta street cams.

I'd like to do this with no extra engine management. EJ25D cars don't have many tuning options and if I'm going to sign up for Piggyback ECU's I might as well find a WRX drivetrain to swap in to make it worth the wiring work.

I'm hoping to find a shortblock locally with under 200k and ideally under $400. If it's over 100k and/or has a questionable origin, I'm signing myself up for a full set of bearings at the least.

There is a "running when pulled" 95k 2002 forester engine near me for $1300, any ideas on the resale value of the SOHC heads, intake, etc? Am I dreaming to think I'll find a 100k short block for under $400?

[chuckthefuk]

Just to clarify that JDM motors are pulled and shipped at 60,000 kilometers not miles. If you want a babied motor this the way to go.

SOHC heads if in good condition can get you $300.. intake and accessories maybe $100..

$1300 for a used running motor is pretty high considering you can find a complete SF (98-02) Fozzy's for under $2000 running..

...

02-05 wrx drivetrains wont hold up to the abuse that most people throw at them.. Your stock Lego drivetrain will suffice..

...

Tuning with a piggyback like SAFC/PP6 will only benefit you if you have cams and full breathing mods..
...

[Crowboy]

Yeah, I though $1300 was high. I'm not opposed to a parts car, especially as I'm unsure of the current state of my transmission.

I'm not really considering the WRX swap. Just sayin' I'd want a lot more HP than stock if I'm going to rewire the car.

Re: Piggyback and programming, what I've culled from these interwebs is that the subaru ECUs generally learn really well. For the mild build I have in mind, the ECU should do a good job of sensing increased airflow (the real overall effect of the planned mods) and throw more fuel in naturally. There are plenty of cases of the ECUs learning around the piggyback programming anyway. Maybe if I get serious about tweaking down the road, but I suspect then I'll swap in a SOHC w/ harness that supports open source programming.

Seems like the big driving factor for the stock EJ25D vs EJ251,EJ253 swap is the state of my current block. If I gotta buy new pistons for the stocker, a good condition EJ251 looks a lot better. Guess I better dig in to the stock block ASAP. I don't think I have the budget for a complete, low-mile short block of any kind.

[chuckthefuk]

Pre-2000 ECU's are not EEPROM so no flashing capabilities..

Your ECU as you said is capable of re-learning the new modifications.. It just takes a bit of time and a proper test drive during the ECU reset.

I guess you just have to see how bad your block is.. from there as you said you can make a final decision.

Let us know whats the end result is.
-Chuck

[Crowboy]

Got the block, crank, pistons and rods apart and in to my machinist this morning. He noticed the installed rings were chrome which he said are much harder to get to seat unless the piston bore walls are perfect.

He's measuring everything up to see what is needed, but my hunch is that I will be rebuilding this block rather than trying to source an EJ251. Everything looked very good on disassembly with the exception of one of the #3 thrust bearings which was missing a very large chunk off the radial (not the thrust) face. Didn't seem to be any corresponding crank damage.

Does anyone know the material of the stock Subaru rings? Are there any other ring options for stock pistons other than custom? I've seen NRC rings, which seem to also be chromed steel. Google, NASIOC, SL-I search aren't coming up with much. I have the A pistons, btw.

Was planning to do Subaru or ALC bearing sets, whichever I could find a better deal on. My digital scale is on the way for checking the balance on the stock rods and pistons (and to modify if necessary).

Zack

[Crowboy]

The word from my machinist was not great. I could rebuild the block and have an ok bottom end. However, the crank needs turned, not just polished. The bores are .003 out of round. To get it right, he's telling me they should be bored, not just honed. I'm thinking I'm now better off finding that EJ251/EJ253 shortblock. I will have some time in a couple weeks to drive up towards Denver if I can put my hands on one there.

Thoughts?

[chuckthefuk]

Well its all about cost and timeframe.

Its not that hard to find a EJ25D used block or a used crank.. EJ251 bottom ends are pretty common..

Local subaru forums are the best since most members swap to turbo setups and have old EJ251/2/3/D just sitting around.

[Crowboy]

Well, searched all the forums, put out feelers for EJ251, EJ253 blocks. Found an EJ251 in one of the local scrap piles but all I was able to salvage was the aluminum block off plate. I need this car running sooner than later, so:

Ordered up 0.020" over pistons and rings for an EJ251 which will fit fine in the EJ25D block and will bump the compression to 10.4:1
Ordered up 0.25mm (yes I'm mixing units, think the car will explode?) crank and rod bearings
Got the rest of the Subaru OEM parts from Heuberger Subaru online.
My machine shop is going to turn and polish the crank and bore the block. I'm gonna talk to him about torque plates, but I doubt we'll be able to use them.

And in related news, I'm trying to get my hands on a different '97 in much better condition to put all these parts on instead. The price is right since it supposedly needs a new trans and it's somewhat local. We'll see how that goes, but I do prefer the black over grey, and I could make some money back on selling the blue one to a broke college student.

[chuckthefuk]

"Ordered up 0.25mm (yes I'm mixing units, think the car will explode?) crank and rod bearings'

:-|

ummm..

[anothernord]

The EJ25D ECU is very adaptable and shouldn't complain much to a higher compression engine. One can pretty readily run a variety of displacements without too much trouble. An N/A build such as this would not benefit greatly with a piggyback anyway, once the hassle is taken into account.

Good luck with the build!

[Crowboy]

25.4mm = 1.000 in. Don't worry, I figured out the conversion that the Mars Rover crew missed. I'm also not relying on published dimensions, I've told my machinist to wait until the parts are in hand. Measure twice, cut once.

The rings and pistons are from the same company, so they should be happy together. I'm using DNJ con-rod bearings and MAHLE/Clevite/Perfect Circle crank bearings, hence the different systems of units.

Having trouble sourcing the small end con-rod bearings, but we haven't actually determined that replacement is necessary. Any ideas there?

Zack

[Crowboy]

I'm a little confused on my information and may have ordered the wrong headgaskets for the CR that I am after.

So the chart in this link (http://www.sl-i.net/FORUM/viewtopic.php?f=31&t=22854) indicates for an EJ251 block with EJ25D heads that I'll have 10.4:1 with the 0.56mm head gasket, but only 9.6:1 with the 1.37mm gasket which is stock on the EJ25D.

But, I'm using my EJ25D block and swapping in EJ251 pistons. Stroke is the same, rod length is the same, so the pistons alone should make my block equivalent at least as far as CR goes. However, Matt Monson over on NASIOC and awdpirates.net has done the EJ251 block w/ EJ25D heads and calc'd a 10.8:1 CR with the 1.37mm headgasket. He's got my vote for one of the more knowledgeable builders of all things Subaru...

I had in my notes that I should get the headgasket to match the heads, so I ordered the thicker one. I guess I'll have to measure volumes when I get it assembled and possibly swap headgaskets at that point to get the CR I want. Anyone got better info?

Zack

[LGTtoBE]

If you're still using the EJ25D heads... you may want to consider that they came in 2 flavors:
The HLA (96 and some 97s) and the shimmed bucket lifter style (97-99)
HLA heads have larger combustion chambers and lower compression (and down about 10hp from the non-HLA).
HLA's are easily [externally] identifiable by the valve covers. They should read: 4CAM16VALVE
The Non-HLA's are blank
don't know if that helps but it's just a little more info...

[Crowboy]

Heads are from a late '97MY legacy outback. They match the '98 heads I rebuilt a few months ago, shim over buckets so for sure they're not HLA. Also, clean valve covers, but that's a good way to spot one or the other in the boneyard.

What I realized trying to predict my CR is that there are a thousand factors that will affect it (ok, maybe 6). I actually think I'm fine with the 1.37mm head gaskets, but I'll measure everything to be sure.

Anybody done the cloverleaf grinding to the combustion chamber that Costa Mesa R&D has been talking about to improve flow? What does that do to the quench area? Opinions, good, bad, indifferent?

Zack

[mike-tracy]

Lord Flashheart knows about that

[Crowboy]

Parts!
http://www.at0m9labs.com/Subaru/pics/piston.jpg
DNJ pistons. Cast OEM replacements. Pretty good build quality. I wasn't expecting to see coated skirts.

http://www.at0m9labs.com/Subaru/pics/rings.jpg

http://www.at0m9labs.com/Subaru/pics/scale.jpg
0.1g accuracy for teh smoothness

http://www.at0m9labs.com/Subaru/pics/crankbearings.jpg
Mahle/Clevite mains .25mm undersize crank

http://www.at0m9labs.com/Subaru/pics/oilsensor.jpg
For the price, I want a new one.

http://www.at0m9labs.com/Subaru/pics/blockoring.jpg
Subaru lists 3 different part numbers for the same part on the diagram. This isn't a true o-ring as it's got a lip on the inside. I don't expect a problem, should work fine.

Zack

[mlitz]

sweet! keep us updated can't wait to see how this turns out

[mike-tracy]

Hadn't heard of DNJ before. The piston pic I saw didn't have the coating either, score! Sad that they don't offer pistons for the ej22T, even though they offer everything else for it...

[Crowboy]

DNJ = Domestic N Japanese. You can get them a few places, but mine came from Rock Auto. The box for the pistons says Rock Pistons. However, the DNJ logo on the top is just laser etched, so doubt they are actually manufactured by DNJ.

Unfortunately, my machinist is slammed with work right now, so it may be a while before I get everything back for reassembly. I'll post how everything goes back together eventually. I also have to find a garage space to rent for a while, since I will essentially be rebuilding most of the car. I took the engine out in my gravel driveway, but I'm not so enthusiastic about putting it back in there.

[Crowboy]

All my parts are back from the machine shop. Crank was turned 0.010" under (mains and rods.) Block was bored and honed 0.020" over (matched to pistons to hit factory clearance. Everything was hot tanked. Oh, and heads were completely rebuilt with new coated valves and valve seals. The valve springs were shimmed to bring the uncompressed spring height back to spec. I'm thinking about replacing those, but the budget is getting a bit tight. Machine shop work (which included new head parts) came to about $1080.

http://www.at0m9labs.com/Subaru/pics/DSCN1104.JPG
The rebuild is happening in my kitchen. That's my kitchen table. I might need more space.

http://www.at0m9labs.com/Subaru/pics/DSCN1106.JPG
The crank turned, cat-eyed, all polished and purdy.

http://www.at0m9labs.com/Subaru/pics/DSCN1112.JPG
Time to check ring gaps. Turns out all of them needed a little tweaking.

http://www.at0m9labs.com/Subaru/pics/DSCN1116.JPG
I set up this jig to help me lap the end gap as square as possible. It worked pretty well, the coarse diamond stone does well with the chrome rings, but it doesn't take that much off. It's a little tedious.

http://www.at0m9labs.com/Subaru/pics/DSCN1120.JPG

I'm matching the rings to the cylinders. Probably not necessary, but easy enough to do. Rings are measured in their respective cylinder, then kept with the other parts for that cylinder.

I need to build a jig for balancing connecting rods. The pistons are easy enough to weigh, so they'll get the balance treatment first, then the rods.

Time to get a few hours sleep before work tomorrow.

Zack

[mike-tracy]

Now thats how you build a motor! Lol I used a 2x4 with a couple of nails in it to hold my rings for filing. I think keeping the rings with individual cylinders is a good idea. Even though my machine shop bored my block out to .020, they labeled the brand new pistons by cylinder, so I followed their numbering system for both pistons and rings.

[Crowboy]

Well....

I checked main bearing clearances tonight. The factory service manual lists oil clearance between 0.0001" and 0.0012" with the service limit at 0.0016" for #1,3,5 and 0.0018" for #2,4. This is a freshly turned crank and new bearings undersized 0.0098" (.25mm). Block bolts cranked down, though I had to estimate 34 ftlbs since my torque wrench is 30 miles away. All my clearances are 0.0030"

I know of a company that builds EJ25 engines for experimental aircraft, and they blueprint their engines on the high side of factory tolerance up to 0.0020 for better oil flow at higher rpms. And, the standard rule of thumb for many engines of 0.001" for every 1" of journal diameter +0.0005 would suggest a clearance of 0.0025 for this engine.

Ug, I'll check the rod bearing clearances tomorrow, then I suppose I should measure bearing thicknesses and take the crank back to the machine shop to see if it is within Subaru's clearances. If not, we'll have to start a discussion with the "very reputable" crank shop that didn't even want to hear about the bearings I had already chosen.

Thoughts? Anybody run a crank with clearances this large?

Edit: Bearing thicknesses are dead on. I'll pick up my torque wrench and some more plastigauge tomorrow and check again.

Zack

[Crowboy]

Ahhh, well I feel a bit better now. I learned the following:
1. Torque the block bolts to spec with a TORQUE WRENCH not by feel.
2. Get the range of plastigauge with the correct resolution for the range you are trying to measure. For EJ25 mains and rods this is GREEN.

http://www.at0m9labs.com/Subaru/pics/DSCN1127.JPG

My clearance are still on the high side:
http://www.at0m9labs.com/Subaru/pics/DSCN1128.JPG
http://www.at0m9labs.com/Subaru/pics/DSCN1129.JPG

#1 = 0.0017
#2 = 0.0020
#3 = 0.0030
#4 = 0.0017
#5 = 0.0020

#3 is out of spec but I think I'm OK with it. I don't intend high revs for this engine, so a little more oil to the center bearing shouldn't starve the rest and if I was going to over-oil any of them, it would be the center thrust bearing. The down side of too much clearance is more potential for crank chatter potentially throwing the misfire code. I intend to keep the stock damper pully, but I will be running a 13lb flywheel. I guess we'll see. I'm worried less since it's only one bearing outside of spec and not all 5 as I previously though.

Journal clearances were good too, 0.0015 for all 4. Time to balance the reciprocating parts so I can put the block back together.

Zack

[mike-tracy]

It's said that "these things run poorly longer than most cars run at all" so I think you'll be totally fine, even at the 6500k redline. These ecu's aren't as sensitive to LW flywheels as the later ones. But it's not totally unheard of to have an infrequent CEL as you mentioned.

[Crowboy]

I can't recommend the DNJ pistons. I had an 8.5 gram difference between the heaviest and the lightest pistons in the set. I'm not sure I can even get that much weight out of one piston. That's almost 3 cubic centimeters of material to remove. Now the bores have been sized to the pistons, I'm not sure what the best plan is. Calling Rock Auto/DNJ today.

Edit:
So, I'm thinking I have the following options:
1. Buy another set of the exact same pistons, measure to confirm they are identical bore to the set I have, then mix and match to get weights closer to a match. Tweak to balance. Cost about $180 for a new set.
2. Swap the ones I have around so the two heavy ones are opposite and the two light ones are opposite, tweak a bit and roll with it.

Thoughts?

[Crowboy]

Strike 2 for DNJ. I left voicemail and email for their tech department last week. Haven't heard anything. Sent my question through Rock Auto who I bought the pistons from. Nothing yet.

Anyone have any thoughts on my options in the previous post? I guess another option is to take a micrometer and a scale to the dealership and get a full brand new set from them. :smt021

[mike-tracy]

My opinion is that I would take the rods, crank and piston to a machine shop that specializes in balancing. A competent place will take care of you for sure. And you'll be able to say your build is balanced and blueprinted, lol.

There's a speedshop near me that does that but I suspect they outsource the work.

[Thomistopheles]

I'd go down to Subaru and pick your own. I wouldn't get another set of DNJ pistons, sounds like they have terrible QC if your set is that far apart in weight.

That sucks, looks like the build was going rather well until this.

[mike-tracy]

I'd go down to Subaru and pick your own. I wouldn't get another set of DNJ pistons, sounds like they have terrible QC if your set is that far apart in weight.

He had his block bored to the size of the new pistons so that won't work. This is one of those "I should have double checked xx before I did yy kind of things, that we all do sometimes unfortunately. Like me putting the HG on backwards, lol. All but one passage lined up perfectly. That damn oil galley, lol. I blame the alcohol.

[Crowboy]

The cylinders were all bored and honed to the same dimensions. My machinist said the pistons were within 0.0001" of each other as far as diameter. The diameter spec on the pistons is published and it falls within Subaru's specifications, so 0.50mm over Subaru pistons should match up. I'd still take a micrometer, and probably the block halves, with me to verify. That is quickly becoming my preferred plan.

I would still run the DNJ pistons if they or Rock Auto should decide to make the situation right. I'm looking at a minimum of $200 for a full set of Subaru pistons, I don't know what my local (an hour away) stealership is going to want if I want to cherry pick.

[mlitz]

Call them and tell them your situation and ask them if they don't mind if you cherry pick the ones you want. I wouldn't dive an hour to find out they won't let you.

[Crowboy]

And, according to the Subaru dealer near me, the nearest 0.50mm OS Subaru pistons are in California, so no trying on for size. And they want $102 each. I could order them blind from 1st Subaru for $64 each.

Rock Auto was very helpful and suggested if I wanted to order a second set of pistons to mix and match that I could do that, then send a full set back for refund as long as I don't send the one that I machined already. I'm going for that. Even if I don't send a set back, I'll still be out less than the cost of a full set of Subaru pistons.

I wish cost wasn't an issue, but I'm running out of budget for this build. $600+ for forged pistons would be ideal, but they would be custom for N/A as near as I can tell

[Thomistopheles]

Well, good luck. Hopefully the second set will give you what you need for a matched set.

[Crowboy]

Second set of pistons arrived today. Via the mail scale here at work, they are a lot closer to each other in weight than the set at home. I'm not sure if I'll be able to piece together a set of unmolested pistons to send back for a refund, but even if I don't I'll have a more solid set that require less tweaking to get balanced. Vamos!

[Crowboy]

Got motivated yesterday after work (wasn't hard) and built up the shortblock. The balance is within 0.1g for each reciprocating assembly. The second set of DNJ pistons wasn't much better in terms of weight spread, but two sets of pistons and two sets of wrist pins makes it easier to play the mix and match game. I did not end up using the piston I had already tried to lighten, so I won't be able to send back a set for refund. The oil pump and various galley plugs are soaking in parts cleaner. Long block is next!

Zack

[Thomistopheles]

Sweeeeet! I've been following the thread pretty closely since I may be going down the same road soon. Glad you're making progress!

[Crowboy]

Next steps:
1. Assemble shortblock. There are plenty of write-ups for this with much better pictures than I am apparently capable of taking. Mostly, I referenced: This thread (http://www.rs25.com/forums/f105/t71639-diy-engine-building-ej251-sti-rods-pistons-head-work.html) from RS25.com.

2. Attach heads. Use ARP studs. These were kind of a pain. Their tolerances are so good, they were actually difficult to thread into my block even after thorough cleaning the block threads with brake cleaner and chasing with the old (cleaned) block bolts. Got it done, but the final torque will be tomorrow. (ARP and others recommend letting it sit at torque for 24 hours then re-torque.) My machinist dialed in the valve clearances with a combination of grinding the valve ends and his bin of Subaru bucket shims. He listed the final results in Sharpie for me. Of course, I checked them after the heads were bolted up to see if anything changed, but all was well.
http://www.at0m9labs.com/Subaru/pics/IMG_0484.jpg

3. Stare at this:
http://www.at0m9labs.com/Subaru/pics/IMG_0482.jpg
to make the list of all the parts I forgot to buy. I am dealing with a pilfered engine rebuild gasket kit, and I forgot a few. It turns out the oil pump o-ring is not an easy Subaru part number to find. It's 806919050 I think.

I used Opposed Forces (http://opposedforces.com/) for their online part lookup. Then built my order with a more-or-less local dealer: Heuberger Motors (http://parts.subaru.com/?siteid=215892) online parts store. It takes a little back-and-forth and a slight bit of guessing since Opposed Forces is missing a few key parts and Heuberger's online lookup is not that spiffy. The o-ring for the oil pick-up tube eluded me until I resorted to Teh Googles. Subaru part number 806917070 I think.

4. In a tribute to Beer Garage (http://beergarage.com/) whose writing style greatly amuses...

Then I finished my beer.
http://www.at0m9labs.com/Subaru/pics/IMG_0485.jpg

[Crowboy]

Oh, and I passed that Fundamentals of Engineering exam. The P.E. is in October. Hopefully I will be driving the Subie there.

[r3v_v3ng3]

Oh, and I passed that Fundamentals is Engineering exam. The P.E. is in October. Hopefully I will be driving the Subie there.


Congrats! Your build is coming along real nice

[Crowboy]

Engine is buttoned back up. You all know what these look like when they're together. I didn't paint or otherwise aesthetically treat anything, which was a big internal discussion for me. I like a lot of the tastefully done engine bays in member's cars and a part of me would like that in my car. But, I don't have a workshop, much less a paint booth, and spraypainting would not go well in my kitchen. There is also something about the patina of a used engine that I like, so parts got cleaned so I can track leaks, then put back together. It'll go in this week and I'll wrap this thread up with a performance report. More info on the rest of the rebuild will go into my Member's ride thread.

Cheers!
Zack

[Crowboy]

Engine swap, COMPLETE!

Yeah, I'm stoked. Nothing blew up.

I used the factory break in (2000 rpm for 20 minutes) to check for leaks and otherwise convince myself it was basically roadworthy. Then about 30 miles of varying throttle rates to higher and higher rpms and lots of engine braking. Then 100 miles of trying not to drive at a constant speed. It's had its first oil change and is purring pretty well. I'm running midgrade until I have a chance to pull the plugs and hook up my logging scanner to watch for the computer retarding the timing under load. Then I'll know if I'm fine to run regular (probably fine, but I want some data to be sure.)

I put some high performance mojo on the engine:

Titanium knock sensor bolt. (at least 5 hp...)
http://www.at0m9labs.com/Subaru/pics/IMG_0513.jpg

Bike chain links for washers on the heater core hose clamps.
http://www.at0m9labs.com/Subaru/pics/IMG_0515.jpg

Hard to tell from the butt dyno if the higher compression is making a difference in torque or horsepower since I was driving it on 3.5 cylinders before. I definitely like the lightened flywheel and bypassing the clutch damper also seems positive. Shifting is a lot more like my motorcycle and less like the jerky unpredictable subie I used to have.

[LGTtoBE]

I'm doing just about the same thing... The machine shop $ is keeping progress slow. I really want to put in the "stage 2" Delta cams but I worry a little about piston to valve clearance.

Have you verified your compression? If so, what did you end-up with?

I have my EJ251 block, new pistons, rings, con rods (the machine shop said they'd order bearings for me). I have my 25D heads, full gasket and seals (except HG), timing and H2O pump kit, oil pump etc.

But I'm down to the machining and the cams being the last of the major expenses.

I'm looking into a wideband sensor setup and some engine management from DIYAutoTune.com (megasquirt etc.).

Do you have any updates or advice you can offer?

[Crowboy]

To be honest, I'm not completely thrilled with the build. I've got significant piston slap and a flat spot between 4000k and 5000k that I haven't figured out yet. I ended up using the EJ25D head gasket at 1.37mm and so far have had no perceivable knocking or retarding of the timing even on 85 octane (keep in mind I'm at 8000 ft.) My viscous coupler is at the end of its life and I think the whole trans isn't far behind. When those come out I'm going to switch to the EJ251 head gasket (0.65mm) and hopefully have time to make an actual compression volume measurement. I had to get the car running under a tight deadline before and ran out of time to make compression measurements. My guess is that currently I am at slightly higher than stock CR for the EJ25D, maybe 9.9:1. I'd like to get the thinner gaskets in there and get into the 10.4:1 area. The car has pretty good power as it is, but I'm going to try to squeeze a bit more out.

Since you're pretty set on cams, I would start with the 1.37mm headgasket and maybe check piston clearance with the clay test. There's a good writeup on Ottawa Subaru: http://www.ottawasubaru.com/forum/viewtopic.php?f=6&t=22976. Let me know how the cams go, I think they might be in my future as well.

Good luck!