Subaru Frankenmotor for the Westy

[a914622]

The early 2.5s are way different short blocks! The 96 used a big cc heads and were the first with longer stroke and shorter rods with smaller dia rod end. (48mm vers 52mm on the 2.2s and 2.5 phase 2) The early 2.5 had failer do to the short rods and smaller bearings.
The phase 2 also got 9 and 10mm oil pumps.
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87 gl powerd buy 2.5subaru
75 914 getting 2.2t subaru scratch that SVX subaru

[D Clymer]

[goffoz]

[Farfrumwork]

I know people with the frankenmotors in their subarus.

There is a difference between the ph1 and ph2 EJ25's blocks, but to get a more freindly compression ratio, go for the Sti short block (EJ257). This will get you closer to 10.5:1 (vs. 11.x:1 with the NA blocks) and has stronger internals.

people spin bearings on Sti's by revving the crap out of them or loading them hard befroe the oil is up to temp. A EJ257 blcok will last forever in a vanagon if you treat it well


Search "Matt Monson" and frankenmotor on legacycentral.org
A local "Souixbe" has one in his '91 legacy wagon. He runs mid-grade here at altitude and has no issues. (Although I would run premium in this setup with my van).

And I would stay away from the delta cams in a van application. I have the "torque grinds" in my '93 turbo leg and have heard many reports of the same cams in the EJ22 which yielda a noticeable lope at idle (which I have in spades - had to increase my idle speed via a custom chipped ECU) <- and that custom chipped ECU is only available for the turbo motors (based of the EJ20 ECU).

I'm going to build a frankenmotor myself in the next few years. Just for the reasons mentioned (more torque and some more HP) - the big gain is in torque, which the small valves/ports on the EJ22 heads really work well to generate. No harness work - bolt in and go!! I'll buy a problem Sti block and have it refurb'd (new Sti blocks are ~$1900 , but it would be NEW! )


And just to clarify, when you run 2.5l block, you get 2.5l of displacement. It doesn't matter what heads you run (that only affects compression)
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sold -> '85 Wolfsburg Syncro / 'Built' DOHC EJ25 (a great machine!)
'07 Legacy spec.B, road tuned stgII
'17 4x4 Sprinter, stone grey, SMB pop-top, on 33"s

"Blood stains, speed kills - Fast cars, cheap thrills - Rich girls, fine wine - I've lost my sense, I've lost control, I've lost my mind"

[Franklinstower]

[Farfrumwork]

^^ I bet Delta would say that! They are good cams, but they DO add lope to the idle. I have the Torque grinds, same as the NA application, the 1000/1500/2000 are for the NA 2.5 SOHC heads.

Lucas of Wildwesty here in Boulder actually had several cam sets for sale due to customers not liking the change at idle (in there suby converted vanagons). I'm sure my turbo motor does react differently than the NA motors (worse) but all acounts from the 2.2 crowd say you will have a noticeble lope. Some may like that though... I kind of like it on my hot rod '93 turbo.


I need to look into it again - like you've found there is lots of information (and misinformation) out there - but I'm pretty sure both NA 2.5 blocks yield quite high compression ratios. The Sti block keeps it reasonable as the block is meant for lower compression in the end (but the 2.2 heads have low volume, raising it back up) - - - not stating anything you don't know already most likely.


I'll see if I can find some documented results...
_________________
sold -> '85 Wolfsburg Syncro / 'Built' DOHC EJ25 (a great machine!)
'07 Legacy spec.B, road tuned stgII
'17 4x4 Sprinter, stone grey, SMB pop-top, on 33"s

"Blood stains, speed kills - Fast cars, cheap thrills - Rich girls, fine wine - I've lost my sense, I've lost control, I've lost my mind"

[Farfrumwork]

more ramblings from various threads...


From Siouxbe (on legacycentral.org):

"I am already driving my 2.2l SOHC heads with the STi short block set-up and I love it!
Use the 4 layer steel OEM Subaru 2.5l headgaskets and you'll be able to run 87 oct. pump gas no problem!
My dyno test showed 125 ft./lbs. of torque at the wheels!"

"IIRC the C.R. is closer to 10.3
BTW the SOA part # for the H.G. I used is 11044AA610 4 layer multi-steel 2.5
I carefully drilled holes to match-up to the 2.2L heads.
End result is it works GREAT!"
Others use Cometic Head Gaskets - you can get any thickness you wish (but I'd go OEM if possible)



Some guy named elwood on nasioc:
"hey all,
I wanted to throw my $.02 into this thread. I just put one of these together, with great results so far.

Ingredients:
94 Leggy Wagon, 5spd, 2.2L with spun rod bearing at 115k miles. ($cheap)
99 (phase 1) 2.5L shortblock, unknown mileage ($super cheap)
98 (phase 1) head gaskets ($23/ea at 1stsubaruparts.com)

The conversion was extremely straight forward. absolutely everything form the 2.2 bolted onto the 2.5. The only trick was on the head gaskets. the coolant passages at the tops of the cylinders didn't line up with the 2.2 head. I used a drill and a dremel to make some new holes in the gaskets to line up. It was kind of a pain to get the edges of the new holes cleaned up on the multi-layered steel gaskets, but it is doable.

The results so far have been pretty rewarding. Using the head volumes on the EJ calcs page, I figure about 11:1 CR with this combo. I've got over 1000 miles on it now. I've run a couple of tankfuls of shell 93 octane and one tank of speedway 92 octane... have not yet heard a bit of detonation.

Performance wise, it's a nice step up from the 2.2. It's not OMG fast, but man is it torquey. Between 2000 and 4000 rpms, it tugs like a V8 compared to the old 2.2. With the 5 speed and 4.11 final drive, it makes for a fun car to drive around town. I put an RS pressure plate in at the same time. I believe it's a little stiffer than the stock 2.2 plate, but I don't think it's quite enough for this motor. It'll slip all the way through 1st with a moderately agressive launch.

It does seem to fall flat at higher revs. It will certainly still out run a stock 2.2 all the way to the redline, but it doesn't seem as fast up high as the 2.5 cars I've been in.

I really don't have any idea what the long-term durability of the setup will be, but if it keeps performing this nicely, without detonation, I'll say it's a highly recommendable setup for someone looking to replace a dead 2.2 or just make a fun car on a budget."

followup:
"15k and counting on mine! and they haven't been exactly "easy" miles." he comes back later with 45+kmi and a-ok


there's more out there to read/sift through, but safe to say the combo works.
I'd probably still go Sti block for a more normal CR (low 10:1 range), or maybe the EJ255 block (2.5l wrx & legacygt) but I'd have to compare the piston volumes.
_________________
sold -> '85 Wolfsburg Syncro / 'Built' DOHC EJ25 (a great machine!)
'07 Legacy spec.B, road tuned stgII
'17 4x4 Sprinter, stone grey, SMB pop-top, on 33"s

"Blood stains, speed kills - Fast cars, cheap thrills - Rich girls, fine wine - I've lost my sense, I've lost control, I've lost my mind"

[Franklinstower]

good info, thanks.

Cometic I believe now makes a 'hybrid' gasket for the 2.5 block and 2.2 heads. just got to call the dude at cometic.

I would still like to see a chart of the different block and head configurations with the compression ratio's...

Paul
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'89 Westy - EJ25/22 Frank 4.44 5mt
'75 Miami Blue Sunroof FI Standard Bug
YITB

[Franklinstower]

i posted a question on the USMB regarding the frakenmotor for a Vanagon - GeneralDisorder - a very knowledgable subbie mechanic stated the following info:

EJ25D compression is about 10.5:1. It's actually the lowest of the frankenmotor combo's. There are quite a few people running a lot higher though without any problems - there's a guy on NASIOC running 12:1 on 89 octane and he says his monitoring software indicates no knock and his ECU isn't pulling his timing at all
It will still be a little lumpy with the torque cam - especially when cold. But it's not terrible. And the '92 harness/ECU is fine. Not as sophisticated as the later stuff but you don't need to rewire it just because of that. If you do rewire it I would go with Mega-Squirt.

The frankenmotor is big on torque - max NA HP on the EJ22 heads is around 185 to 190 - they just don't flow for beans up high. But the torque curve is INSANE - it hops up to about 200 ft/lbs of torque at 1200 - 1500 RPM, then climbs a bit more to around 220 and stays pretty much flat all the way to 5500.

you will have to "retune" your idle air control valve (IACV) by rotating the thermostatic air inlet valve inside it to give the engine more air at idle. The larger displacement and duration of the torque cams causes problems with the engine needing more idle air than the 2.2 valve was setup for.

Boy do I like those torque numbers. Apparently the small valves with the higher compression is where the torque is developed. Reminds me of my old Chevy C-50 dump truck. It had the 350-I V8 - steel crank, 178 valves and a two barrell carb. it had all its torque coming right off idle but had no upper end oomph.
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'89 Westy - EJ25/22 Frank 4.44 5mt
'75 Miami Blue Sunroof FI Standard Bug
YITB

[JeffRobenolt]

What years are the EJ25D?
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For OEM Subaru and SixStar parts and harness modications
AVsubaruconversions.com

[Franklinstower]

[a914622]

The 96 ej25D had larger head chambers so the pistons have a smaller dish. Used with the ej2.2 heads you may end up with comprection over 11.5-1.

Hey Im going up to drill the jag calipers today.

jcl
_________________
87 gl powerd buy 2.5subaru
75 914 getting 2.2t subaru scratch that SVX subaru

[Franklinstower]

[Franklinstower]

i found further info that confirms what A914622 says - the '96 had much smaller dishes in the pistons - 8-10cc's so using the EJ22 heads on that would yield 11+:1 cr. 97-98 blocks are just standard ej25d blocks and the '99 is the best 25D block because it's actually a 253 with 25D pistons. 8 bolt bell-housing, 52mm rod journals, and #5 thrust bearing. It's the ultimate 25D. So building a frankenmotor with the 2.2 heads and intake is best done on the 97 to 99 blocks with the '99 being the strongest.
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'89 Westy - EJ25/22 Frank 4.44 5mt
'75 Miami Blue Sunroof FI Standard Bug
YITB

[Escorial Syncro]

Cool thread, great stuff. But a question from a guy not experienced at all in engine building:

If you do a swap like this, say a '99 EJ25D block and '94 EJ22 heads, do you then have an interference engine? Meaning if you snap the timing belt are you going to have piston/valve contact?

Thanks, Joel
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Joel Lane
1985 Vanagon converted to syncro, ALH TDI w/GTB2056 turbo, Reimo clone top with Westy interior
2002 Toyota Tundra 4x4

[oneburnedvan]

Hi,

I traded some email with pro subie / vanagon gentlemen several months ago. I think he's located in the Portland area. Here are some highlights with Ken's info. (Since he advertised on Craigslist, I figure he wouldn't mind me putting it out there.) I did not use his service so this is not a recommendation, just information. But should my 2.2 fail, I'd certainly consider this route. Thanks for a great post. -TG

EMAIL 2_____________________

Yes I ran one for a long time in my auto but now running a quad cam engine in it and putting a highbred in one of the Syncros I have, no interference issues, I use 2.5 head gaskets and I use 2.2 rods which are .050 shorter which lowers the deck hight and lowers the compression, I think this is the best engine for a Syncro as they put out brutal bottom end torque, the smaller valves give better lower end torque and the shorter rods give more rod angularity which gives better lower end torque, they flatten out after about 5500 rpm but under 4000 they will beat any other 2.5
Also you could put a 2.5 quad cam in with no mods to the van but some minor mods to the engine like pull off the EGR valve and switch the wire loom under the intake manifold to the 2.2 loom so as to match up to the loom in your van.
Also for a Syncro I think its a must to go to a 11mm or a 12mm oil pump as you need more oil pressure at low rpm when your lugging it around in low gear as that is torture on rod bearings.
Ken

EMAIL 1___________________
Yes done many conversions, I have two of my own an automatic and a Syncro.
Yes if its a strait forward replacement I would do it for $1800 but I don't do the whole conversions for costumers any more as I am to busy, no the overbore will not increase the power any but I can do a highbred with a 2.5 block and 2.2 heads and it drops in with no modifications.

Ken Welter
[email protected]
LL# 360-834-4089
cell# 360-253-0703

[Franklinstower]

I just came home with a 97 2.5 block. no idea of the condition of the block other than the guy i got it from said it needed a head gasket. I am going to start cleaning it up, pull the heads etc. Although My Honey Pie just gave me quite the to do list before I can start any more engine projects. The appeal of all that torque is what really intrigues me.

Paul
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'89 Westy - EJ25/22 Frank 4.44 5mt
'75 Miami Blue Sunroof FI Standard Bug
YITB

[Syncroincity]

[a914622]

[syncrodoka]