Rebuilding EJ255 - does my plan make sense?

[BipBoby]

Hi, I got free, stock 170k miles Subaru Outback 2005 XT 2.5 from a friend. The motor had been overheating many times since years ago. It was also allegedly losing coolant and previous owners put stop leak in it. I pulled the motor already and took heads off, here are the pictures:

https://imgur.com/a/2Y0qymj

My goals are:
- first get the car running, on the road, reliable
- then try to tune it up to approx 400 HP

My restrictions are:
- I'm in California, will have to do SMOG in 2 years. I want to keep the car on the street and I will want to pass SMOG when needed
- I'm thinking approx $2700 budget for now, could go higher if justified

My current plan:

• get heads to the machine shop, approx $250
• get six star head gasket kit, approx $250 https://awdautoparts.com/product/subaru-dohc-head-gasket-kit-turbo-2005-forester/
• get OEM timing belt kit, includes OEM water pump, approx $280 https://www.summitracing.com/parts/asn-tkf-004/make/subaru/model/outback/submodel/xt/year/2005
• get ARP head bolts, approx $300 https://arp-bolts.com/kits/arpkit-detail.php?RecordID=1752
• get Mishimoto radiator, approx $400
• get any miscellaneous items that come up when putting motor together, perhaps hoses, or bolts approx $150
• get COBB 20G turbo, approx $1000 (used)
• oil, oil filter, spark plugs, approx $200
• thermostat, approx $15
• do all the labor myself

Let me know if that makes sense. Also, I'm not sure if I should open short block or not. I'm not planning on pulling that motor ever again so because it's already out of the car, it's relatively easy to open short block.
If I did open short block, I would consider replacing pistons / bearings / rods / crankshaft if makes sense. Let me know what you think.

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[amfedor12]

Originally Posted by BipBoby

- then try to tune it up to approx 400 HP

I am also rebuilding an EJ255 WRX, from what I've read anything over like 350hp is going to put a strain on the stock transmission. Otherwise that plan makes sense to me.

I've got mine down to the long block now, and will be replacing all hoses and bolts when it goes back together so if you have a place to get those or a list of all the part numbers let me know!

[SuperPete]

I would deck the engine too, cleaned, bore it , new manly pistons and rods, ARP studs and new kind bearings. Tell you what, after all these miles, rolling on old bearings its matter of time, add another 1K to your budget and you'll have yourself 500WHP capable motor that will last you a while

[benflynn]

+2mm rods 400$
Stroker pistons 600$
Acl race/king bearing 240$
full oem gasket set 300$
Oil pump 150$
Updated oil pick up 150$
50/50 intake avcs gears 150ish
Clutch disc what ever u run ??
Bc1600 valve springs 100$
Timing set (I used six star) 150$

So close deck or not? U need a real shop to bore or hone, I make good strong power on open deck and oem gasket, but I will eventually send one of these blocks out for sleeves prob since it’s 100mm already, or close deck if it was 99.5

[benflynn]

Also, I think the vf39/52 clone g25-550 upgrade and great option to a 20g. 320$ and it makes one hell of a diff, on E85 it’s night and day and prebalanced.

At 1k I would want ball bearings

[BipBoby]

I'm afraid boring will change my emissions and I will never be able to pass SMOG in California. Remember, that's one of my restrictions.

Planning on running 91 gas from regular pump.

[benflynn]

Hone then, how does Cali kno u bored it .25-.5 mm?

I wouldn’t do this with oem piston or u def will be in there again.

I won’t piston and rod another one without going +2mm on the rods, flatiron has the rods 400$

[BipBoby]

Originally Posted by benflynn

Hone then, how does Cali kno u bored it .25-.5 mm?

I wouldn't do this with oem piston or u def will be in there again.

I won't piston and rod another one without going +2mm on the rods, flatiron has the rods 400$

My understanding is that in order to pass SMOG I have to have stock ECU tune. If I hone or bore, will the motor still have the same emissions on stock ECU tune? I think the answer is nope.

I could put Manley pistons that are of the same dimensions as OEM ones.

[BipBoby]

Originally Posted by benflynn

Acl race/king bearing 240$

How did you get that price? I see bearings for $35 - $90. E.g. that set:
https://www.flatironstuning.com/king-xpg-main-bearings-ej20-ej25

[benflynn]

20g turbo kills the stock tune idea. Over ore is not enough to kick the tune, but it’s always best to not bore if u can help it.

Price might be project habits sneaking in, I always est high and add 20% on my projects at work.

[whozatguy]

$2700 budget will not get you close to 400 crank or wheel - at least not reliably. I would budget that amount just to get it back on the road. If your friend let the motor repeatedly overheat, then you will almost certainly find other things that were abused and ignored.

Being in CA and needing to pass smog puts you in a tough spot. I would recommend focusing on getting the car running right and then do some research and talk to a trusted shop about what it would take to realistically get to your power goals.

I'm not familiar with SMOG and the stock tune, but with just about anything engine related except a catback will require a re-tune.

[BipBoby]

Originally Posted by whozatguy

$2700 budget will not get you close to 400 crank or wheel - at least not reliably. I would budget that amount just to get it back on the road. If your friend let the motor repeatedly overheat, then you will almost certainly find other things that were abused and ignored.

Being in CA and needing to pass smog puts you in a tough spot. I would recommend focusing on getting the car running right and then do some research and talk to a trusted shop about what it would take to realistically get to your power goals.

I'm not familiar with SMOG and the stock tune, but with just about anything engine related except a catback will require a re-tune.

This is good advice. I just called Subaru machine shop in my area and they charge $400 for basic inspection + resurfacing heads. Based on the inspection and what they find - there may be more. Machine shop said that if I want to rebuild the short block, he recommends boring. He also mentioned that boring/honing would not affect California SMOG.
I did further research and came with updated game plan for now.

My updated plan:

• get heads + case to the machine shop, approx $400 + budget extra $200 for whatever may come up
• Manley Platinum pistons, approx $650 https://www.flatironstuning.com/manley-8-5-1-platinum-series-pistons-ej25
• Manley or Eagle rods, approx $500 https://www.maperformance.com/products/eagle-forged-h-beam-connecting-rods-multiple-subaru-ej20-ej25-crs5137s3d
• King XPG Main bearings, approx $70 https://www.flatironstuning.com/king-xpg-main-bearings-ej20-ej25
• King Rod bearings, approx $75 https://www.flatironstuning.com/king-xpgc-pmaxkote-rod-bearings-ej20-ej25
• Piston rings (what brand/model?), approx $70
• Six star head gasket kit, approx $250 https://awdautoparts.com/product/subaru-dohc-head-gasket-kit-turbo-2005-forester/
• OEM timing belt kit, includes OEM water pump, approx $280 https://www.summitracing.com/parts/asn-tkf-004/make/subaru/model/outback/submodel/xt/year/2005
• no ARP head bolts - reuse old head bolts
• Mishimoto radiator, approx $400
• Mishimoto automatic transmission radiator, approx $100
• Any miscellaneous items that come up when putting motor together, perhaps hoses, or bolts approx $150
• use stock turbo for now
• oil, oil filter, spark plugs, approx $200
• thermostat, approx $15
• oil pump - currently thinking of reusing existing one, potentially get a new OEM one for $250
• do all the labor myself / consider having machine shop assemble short block - that would be extra $600

That puts me at $3360 or almost $4000 if I decided to have machine shop rebuild the short block.

I'm thinking I could handle rebuilding the short block if parts were stock. If we talk about boring/honing and potentially machining crankshaft - that would put all of the components in non-standard sizes and would be so much more difficult to get bearings and tolerances right. Need to think it through.

My first goal is reliability and longevity. If I can only get up to 300 HP or 350 HP reliable, let it be. I can't do all that work now only to have to rebuild the engine again in 6 months. Anyway, does the updated game plan make more sense? Honestly, I thought I could fit in smaller budget. I can stretch it as long is it makes sense and has good value.

[benflynn]

Cost 0$ more to +2mm it

I like NPR rings, my last build I used Cosworth rings, but I’d swear they were NPR rings too.

[BipBoby]

Why are you so excited about +2mm? Explain please. Is benefit of +2mm so good that it's worth it?

I'm also considering keeping old rods as my HP target isn't excessive and that would mean saving $500. I think I should be fine on old rods, no?

[K3rm1tth3fr0g]

Originally Posted by BipBoby

Why are you so excited about +2mm? Explain please. Is benefit of +2mm so good that it's worth it?



I'm also considering keeping old rods as my HP target isn't excessive and that would mean saving $500. I think I should be fine on old rods, no?

Rod ratio

[benflynn]

As the rod ratio increases;
Mean piston speed comes down
Dwells more at the top of stoke
Dwells less at the bottom of stroke
Makes less rod angle

Better things are happening at the top of the stroke, combustion and cylinder filling are both happening at the top. So more time to fill the cyl, more time for pressure to act on piston.

I always figure rod ratio is why the Nissan 3.0 felt so good

[whozatguy]

Originally Posted by BipBoby

My first goal is reliability and longevity. If I can only get up to 300 HP or 350 HP reliable, let it be. I can't do all that work now only to have to rebuild the engine again in 6 months. Anyway, does the updated game plan make more sense? Honestly, I thought I could fit in smaller budget. I can stretch it as long is it makes sense and has good value.

It really depends how far down the rabbit hole you want to go. Costs can get into the ridiculous territory really quickly. I would bet there are also other areas that need addressed - brakes, bushings, suspension. From your part list, it looks like you have an auto trans, which probably needs a good service as well. If you plan to mod the motor down the road and don't want to tear it apart again, your best bet is to over build now, but even then its a roll of the dice.

[BipBoby]

Originally Posted by benflynn

As the rod ratio increases;
Mean piston speed comes down
Dwells more at the top of stoke
Dwells less at the bottom of stroke
Makes less rod angle

Better things are happening at the top of the stroke, combustion and cylinder filling are both happening at the top. So more time to fill the cyl, more time for pressure to act on piston.

I always figure rod ratio is why the Nissan 3.0 felt so good

What does it take to do +2mm rods? Is machine shop required for that? Any modifications to crankshaft or bearings required? Or I simply get new pistons and new rods to match +2mm and job done?

[benflynn]

Just +2mm rods and stroker 83mm pistons.

[BipBoby]

Can I mix pistons for D25 heads with B25 heads? What's the difference between those two types of heads?

My heads are B25.

[motorbykemike]

Originally Posted by BipBoby

I'm afraid boring will change my emissions and I will never be able to pass SMOG in California. Remember, that's one of my restrictions.

Planning on running 91 gas from regular pump.

and by that rationale a cobb 20g is ok ?

[motorbykemike]

Originally Posted by BipBoby

Can I mix pistons for D25 heads with B25 heads? What's the difference between those two types of heads?

My heads are B25.

as long as you use them as a set sure


just plan your c/r and tune & emission regs accordingly

i love a bit of c/r bump , but in cali you are screwed with regs and b/s gas

just get a new or "piston" short block

go from there

bring more money

it will need a proper tune

call your tuner

bring more money

"overheated many times" - cool story , buy all cooling system components or kill new motor

penny wise = dollar dumb

bring more money

again

[BipBoby]

Cobb 20G has CARB approved sticker, it is legal as a component to have under the hood in California. Cobb 20G that is on the default ECU will pass SMOG.

What people do is flash custom ECU during regular day to day operation and for SMOG time they reflash back to default ECU. That is how to pass SMOG in California. SMOG is every 2 years, so not too bad.

I inspected the short block water jacket and it looks surprisingly good. Regarding the rest - I will be replacing few hoses and radiator. Not sure yet if I should replace heater core too.

The car is 2005 Outback XT and is beat up. I'm not planning on putting crazy money into that car as I don't even know in what shape the transmission is, differentials and the rest of the car. I think I will just rebuild the heads and leave the short block back as is and keep the rest stock. That would put me at around $1200 - $1500 total budget to get the car back on the road, stock.

Short block has 170k miles and if I won't tune it, I think it's likely that it will live for few more years.

I realized that trying to push this build to 400 HP will eat up total of $5k+ and this is too much to put in a car where everything else is old & in bad shape. Who knows if I won't be rebuilding transmission in two months.

[BipBoby]

Status update:
I have heads back from machine shop, I paid $250 for decking the surfaces, valve seals change and vacuum test of the valves. Valve lapping was not done and valve guides were not replaced. The shop said they didn't have to do the extra things.

Now I measured the block with feeler gauge and machinist straight edge and it has 0.0015" warpage. I was hoping to reuse short block as is but it seems 0.0015" is above allowed tolerance.

So now the plan is to split the case, bring it to machine shop and have them bore and hone the cylinders and deck the surface. One machine shop quoted $400 total for that, another quoted $640. Both use the torque plate. I think I will go with the cheaper one.

• $400 for boring + honing the block and decking the surfaces, use the torque plate
• $730 for Wiseco 99.75 pistons https://www.rallysportdirect.com/par...t-99-75mm-bore
• $63 for main bearings (King XPG) https://www.flatironstuning.com/king...ings-ej20-ej25
• $61 for rod bearings (ACL) https://www.iagperformance.com/acl-r...standard-size/
• $0 for case bolts (planning on reusing existing ones)
• $0 for head bolts (planning on reusing existing ones)
• $0 for rods (planning on reusing existing ones)
• $0 for crankshaft (planning on reusing existing one)

I'm really lowering my expectations at this point - shooting for reliable daily driver with potential to go up to approx 350 HP one day.

[BipBoby]

I just got another block with spun bearing. The block is straight, it comes from 2013 WRX with 100k miles. I'm planning on using it as is. I've done measurements, please have a look. I'm thinking of buying two sets of king bearings, standard size and +0.002" oversized and mix and match to get OEM bearing clearances.

Pistons measured at the very top:

1. 3.8920"
2. 3.8919-3.8920" (small oval)
3. 3.8919"
4. 3.8920"

Piston skirts are all between 3.916" and 3.919". Is it normal that the skirts are so much wider?

Rods, big diameter:

• BGE 2.1660"
• BFN 2.1660 - 2.1655"
• BGH 2.1660"
• BFI 2.1665 - 2.1660"
• BLQ 2.1660"
• BLW 2.1660"
• BLS 2.1665 - 2.1660"

Crankshaft from 2005 180k miles overheated motor - all journals are perfect circles, no ovals:

1. 2.3624 - 2.2621" - first one has slight taper
2. 2.0466"
3. 2.3622"
4. 2.0466"
5. 2.3622"
6. 2.0467"
7. 2.3622"
8. 2.0467"
9. 2.3622"

Block with spun bearing on cylinder 1, cylinders:

1. 3.9170 - 3.9160" (slight oval, no taper)
2. 3.9160 - 3.9170" (slight oval, no taper)
3. 3.9160 - 3.9165" (slight oval, no taper)
4. 3.9165" circle, no taper

Block with spun bearing on cylinder 1, crankshaft housings:

1. 2.5215"
2. 2.5215"
3. 2.5205"
4. 2.5205"
5. 2.5210"

Edit - I think I measured the pistons incorrectly. I have empty case torqued with the case bolts and pistons fit but very tight. I cannot force 0.0015" feeler gauge in between cylinder wall and the piston skirt. They must have <0.0010" of clearance. Is such a tight clearance ok for stock build?