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Old 03-16-2014, 06:59 PM   #1
8thWonder
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it's motor buildin' time!

Default 05 STi rebuild coming together - any suggestions?

After indications of a leaky head gasket and questionable compression in cylinder #4, I decided to tear down my motor and build it out. Practically everything outside of the engine internals has already been modified, so I'm not new to working on it. I already spend a lot of time reading in the Built Motor section and wanted to share my plans directly with you guys, in hopes of getting some feedback.

My build thread is here with a lot more background and full list of mods: 8thWonder's build thread - 2005 STi

Long story short, I'm building the motor alongside my landlord, who is a master mechanic, former Navy aircraft mechanic, and rebuilds engines for a living. He has about 5 of every tool required on-hand, with a few exceptions (i.e. a local machine shop will be doing the valve-job on my heads & balancing the rotating assembly, and a clutch shop is resurfacing the flywheel). The goal is reliable power and oil-tightness. Here's what's going into it:

Wossner pistons 9.0:1
Manley Turbo-Tuff I-beam rods
ACL Race main & rod bearings
GSC Power Division valves (stainless intake, super alloy exhaust)
GSC single valve springs, titanium retainers, viton stem seals, valve guides
Killer B oil pickup & windage tray
OEM 11mm oil pump
Gates Racing timing belt & water pump kit
ARP head studs
Siruda head gaskets

other pertinent info:
Blouch Dom2.5XT-R 10cm
ID1300cc
DW300 pump, hard-wired
All supporting mods (intake mani, FMIC, full exhaust, fuel system, EBCS, etc... detailed in my build thread)
Not looking for higher-than-stock revs
Will be running E85 most of the time, with a 93oct map as backup
Tuned by Phatron

I'm currently waiting on a few of the above parts to arrive, as well as a torque plate for honing. Measurements being made with accurate internal mics.

Questions:
-There seem to be mixed reviews about ACL bearings. I'm going to measure them tonight to see how the clearances compare to the stock allowances. Anything I should know about or pay particular attention to?
-The 11mm oil pump will be an upgrade from my stock 10mm. Will this be an issue? Will it need any modifying (shims, etc)?
-I also have OEM head gaskets on hand, in case the Siruda aren't what they claim to be. Anyone have experience with Siruda on a build?
-As mentioned above, my #4 cylinder on the stock block had low compression compared to the other three. This is obviously nothing new for the EJ25. Has anyone modified their coolant flow or successfully found a way to reduce the amount of heat retained by this cylinder? I've read a lot of theories and lot of bickering, and searching "coolant mods" does not provide much helpful info for this specific purpose.
-Is there anything I'm forgetting or overlooking?

Thanks for any feedback!
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Old 03-16-2014, 07:43 PM   #2
KillerBMotorsport
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No point in going with an 11mm pump unless you are SIGNIFICANTLY opening up clearances and performing oiling modification to the block, passages and more. Even at that you'd need to add shims to the 11mm pump as it pushes ~10psi less pressure than the 10mm. Then they have issues revving past ~7,500RPMs and would need additional porting.
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Old 03-16-2014, 07:48 PM   #3
8thWonder
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Good to know, thank you. I do not want to open up clearances unless absolutely necessary, and like you said, I think the stock rev range points to "not necessary." Sounds like the motor will be happy with the 10mm.

Quote:
Originally Posted by KillerBMotorsport View Post
No point in going with an 11mm pump unless you are SIGNIFICANTLY opening up clearances and performing oiling modification to the block, passages and more. Even at that you'd need to add shims to the 11mm pump as it pushes ~10psi less pressure than the 10mm. Then they have issues revving past ~7,500RPMs and would need additional porting.
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Old 03-16-2014, 07:50 PM   #4
Paul
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^+2

Not really mixed reviews with ACL anymore.....Within the past few years everyone says they measure all over the place and no point to go with them since King's are great and cheap. Unless you like buying a couple sets and having a bunch of odd balls left over
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Old 03-16-2014, 08:23 PM   #5
8thWonder
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Default

I seem to be hearing this same thing everywhere. I was even considering OEM mains, but they're just so damn expensive. Perhaps King is the best bang for the buck.

Quote:
Originally Posted by Paul View Post
^+2 Not really mixed reviews with ACL anymore.....Within the past few years everyone says they measure all over the place and no point to go with them since King's are great and cheap. Unless you like buying a couple sets and having a bunch of odd balls left over
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Old 03-16-2014, 09:49 PM   #6
BeastianSTI
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Quote:
Originally Posted by 8thWonder View Post
After indications of a leaky head gasket and questionable compression in cylinder #4, I decided to tear down my motor and build it out. Practically everything outside of the engine internals has already been modified, so I'm not new to working on it. I already spend a lot of time reading in the Built Motor section and wanted to share my plans directly with you guys, in hopes of getting some feedback. My build thread is here with a lot more background and full list of mods: 8thWonder's build thread - 2005 STi Long story short, I'm building the motor alongside my landlord, who is a master mechanic, former Navy aircraft mechanic, and rebuilds engines for a living. He has about 5 of every tool required on-hand, with a few exceptions (i.e. a local machine shop will be doing the valve-job on my heads & balancing the rotating assembly, and a clutch shop is resurfacing the flywheel). The goal is reliable power and oil-tightness. Here's what's going into it: Wossner pistons 9.0:1 Manley Turbo-Tuff I-beam rods ACL Race main & rod bearings GSC Power Division valves (stainless intake, super alloy exhaust) GSC single valve springs, titanium retainers, viton stem seals, valve guides Killer B oil pickup & windage tray OEM 11mm oil pump Gates Racing timing belt & water pump kit ARP head studs Siruda head gaskets other pertinent info: Blouch Dom2.5XT-R 10cm ID1300cc DW300 pump, hard-wired All supporting mods (intake mani, FMIC, full exhaust, fuel system, EBCS, etc... detailed in my build thread) Not looking for higher-than-stock revs Will be running E85 most of the time, with a 93oct map as backup Tuned by Phatron I'm currently waiting on a few of the above parts to arrive, as well as a torque plate for honing. Measurements being made with accurate internal mics. Questions: -There seem to be mixed reviews about ACL bearings. I'm going to measure them tonight to see how the clearances compare to the stock allowances. Anything I should know about or pay particular attention to? -The 11mm oil pump will be an upgrade from my stock 10mm. Will this be an issue? Will it need any modifying (shims, etc)? -I also have OEM head gaskets on hand, in case the Siruda aren't what they claim to be. Anyone have experience with Siruda on a build? -As mentioned above, my #4 cylinder on the stock block had low compression compared to the other three. This is obviously nothing new for the EJ25. Has anyone modified their coolant flow or successfully found a way to reduce the amount of heat retained by this cylinder? I've read a lot of theories and lot of bickering, and searching "coolant mods" does not provide much helpful info for this specific purpose. -Is there anything I'm forgetting or overlooking? Thanks for any feedback!
I don't reAlly know why they put the coolant return right in the back of that head, but oh well...

I guess your best bet would be to wrap your turbo and up pipe at the very least. Any reason why you're upping the compression with those pistons ? Stock is 8.2:1. Not much reason to increase it unless you're making a straight on race car
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Old 03-16-2014, 10:17 PM   #7
Paul
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00 RSTI Coupe
Twin Scroll 2.5XTR EJ207

Default

Quote:
Originally Posted by 8thWonder View Post
I seem to be hearing this same thing everywhere. I was even considering OEM mains, but they're just so damn expensive. Perhaps King is the best bang for the buck.
Not really best bang for buck.....just the best
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Old 03-17-2014, 12:26 AM   #8
8thWonder
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it's motor buildin' time!

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9.0 compression wasn't really on my wish list, but a variety of factors made it reality:
-I wanted Wossner pistons due to the 4032 alloy allowing tighter oil clearances.
-Wossner only makes 8.0 and 9.0 pistons for the EJ.
-Wossner and all of their US distributors are back-ordered on the 8.0, and I couldn't get an answer as to when the next shipment was arriving.
-This is my daily driver, and the engine is already torn down, so I can't afford to wait for an unknown arrival date.
-Tuner said 9.0 would behave well with E85.

Quote:
Originally Posted by BeastianSTI View Post
I don't reAlly know why they put the coolant return right in the back of that head, but oh well... I guess your best bet would be to wrap your turbo and up pipe at the very least. Any reason why you're upping the compression with those pistons ? Stock is 8.2:1. Not much reason to increase it unless you're making a straight on race car
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Old 03-17-2014, 12:31 AM   #9
BeastianSTI
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Haha we have the same tuner. I believe he recommended not to go higher even with e85 for me cp 8.2:1 for me !
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Old 03-17-2014, 12:39 AM   #10
BeastianSTI
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Oh and why not go with a normal gates timing belt kit ? I've heard that the racing belt is intended to be changed more often than normal. If u don't mind doing it more often, no worries :-) glad to hear you're making good progress like me bud !
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Old 03-17-2014, 03:00 AM   #11
8thWonder
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Haha. I guess my somewhat unusual piston choice limited my options. Got Ron's approval before pulling the trigger on them though.

Quote:
Originally Posted by BeastianSTI View Post
Haha we have the same tuner. I believe he recommended not to go higher even with e85 for me cp 8.2:1 for me !
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Old 03-17-2014, 03:34 AM   #12
8thWonder
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I've never heard that (not to say it isn't true). I assumed the Kevlar reinforcement would make it last longer, or at least as long as the stocker.

Quote:
Originally Posted by BeastianSTI View Post
Oh and why not go with a normal gates timing belt kit ? I've heard that the racing belt is intended to be changed more often than normal. If u don't mind doing it more often, no worries :-) glad to hear you're making good progress like me bud !
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Old 03-17-2014, 10:41 PM   #13
8thWonder
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Bump for any more thoughts on my questions in the first post. Maybe I'm not overlooking anything, in which case silence is good!
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Old 03-18-2014, 06:19 PM   #14
8thWonder
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Since none of my bearings were spun & there were no solids present in the oil for any other reason, how crucial is it to purchase a new oil pump, being that I'm staying with the stock size (10mm)? The current pump has about 90k on it (same as the motor).
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Old 03-18-2014, 06:59 PM   #15
BeastianSTI
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Quote:
Originally Posted by 8thWonder View Post
Since none of my bearings were spun & there were no solids present in the oil for any other reason, how crucial is it to purchase a new oil pump, being that I'm staying with the stock size (10mm)? The current pump has about 90k on it (same as the motor).

Haha - I was actually going to say something about that... I would just stick with your stock 10mm oil pump. I'm going to re-use mine, and just clean it up before installing. Since you didn't spin a bearing, of course.
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Old 03-18-2014, 07:09 PM   #16
Paul
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To me its peace of mind...whats another 180$ after spending several grand on a motor. Also yours has 90k on it...its not like you just replaced it
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Old 03-18-2014, 07:17 PM   #17
8thWonder
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Quote:
Originally Posted by Paul View Post
To me its peace of mind...whats another 180$ after spending several grand on a motor. Also yours has 90k on it...its not like you just replaced it
That was pretty much my thought as well, but if these pumps are designed to last a few hundred thousand miles, then I could really use that $180 elsewhere. I don't know if they have a generally accepted/expected lifespan.
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Old 03-18-2014, 07:28 PM   #18
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Quote:
Originally Posted by 8thWonder View Post
That was pretty much my thought as well, but if these pumps are designed to last a few hundred thousand miles, then I could really use that $180 elsewhere. I don't know if they have a generally accepted/expected lifespan.
any time I've done timing belts and what not- oil pimps get replaced. Peace of mind
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Old 03-18-2014, 07:48 PM   #19
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Quote:
Originally Posted by 8thWonder View Post
Since none of my bearings were spun & there were no solids present in the oil for any other reason, how crucial is it to purchase a new oil pump, being that I'm staying with the stock size (10mm)? The current pump has about 90k on it (same as the motor).
Toss it. You might be near the service limits, you might be exceeding them you just don't know, but one thing is certain. It's not going to perform as well as a new pump.

Quote:
Originally Posted by Paul View Post
To me its peace of mind...whats another 180$ after spending several grand on a motor. Also yours has 90k on it...its not like you just replaced it
Same here. I've thrown them out with a few thousand miles on them. It's just not worth it. Like those that change their timing belt without changing the water pump because it sounds fine. Save yourself the cost of the pump and when it does fail you've paid twice that in labor. So what have you saved? With an oil pump it's more critical since it's failure to operate correctly can kill your engine.
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Old 03-18-2014, 08:05 PM   #20
8thWonder
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Pulled the trigger on the pump. From what I hear, after all these parts come in, my mind will be the most peaceful it's ever been.
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Old 03-18-2014, 08:42 PM   #21
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Hmmm true. I might pick up a new one as well. My current one does have 100k on it... Had might as well!
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Old 03-21-2014, 12:00 PM   #22
8thWonder
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Random thoughts as I stare at my block while waiting on parts to arrive... We know that cylinder 4 is disadvantaged. Subaru gives it more timing so that it will knock first, and it retains more heat, as evidenced by people who have monitored EGT on all 4 cylinders. I know that EGTs can be equalized a bit with some porting, EL exhaust manifold, etc., and I'm sure this info is out there somewhere, but I haven't come across any while searching... Do people ever attempt to modify or improve coolant circulation around this cylinder? And does the proximity to the bell housing/flywheel contribute to the heat issue with any significance? I don't want to mess with the water jacket or anything, just wondering if that cylinder is at a disadvantage from a coolant flow perspective, in addition to the timing.

Last edited by 8thWonder; 03-21-2014 at 12:43 PM.
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Old 03-21-2014, 02:54 PM   #23
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IMO the cooling shortfalls (which are highly arguable), have more to do with the general design; 1 inlet split flow to both halves, then back together. I don't think there's much you can do about that. Personally I've found running a 80/20 mix with a splash of Water Wetter and the OEM thermostat is about as good as it will get... Unless you're going to take it to another level and perform some serious block modifications and independently cool each side.

Running high RPMs and it wouldn't hurt to use our high flow inlet housing to further reduce bubble formation.
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Old 03-21-2014, 04:49 PM   #24
8thWonder
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What about using an auxiliary water pump, like the old Mercedes 190 had? Not necessarily to cool each side individually, but to help move some hot coolant away from #4 and into the heater core or radiator? There's a conveniently-placed casting plug that might lend itself to something like this.
just a stock image I found: _
Quote:
Originally Posted by KillerBMotorsport View Post
IMO the cooling shortfalls (which are highly arguable), have more to do with the general design; 1 inlet split flow to both halves, then back together. I don't think there's much you can do about that. Personally I've found running a 80/20 mix with a splash of Water Wetter and the OEM thermostat is about as good as it will get... Unless you're going to take it to another level and perform some serious block modifications and independently cool each side. Running high RPMs and it wouldn't hurt to use our high flow inlet housing to further reduce bubble formation.

Last edited by 8thWonder; 03-23-2014 at 02:24 AM.
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Old 04-19-2014, 11:58 AM   #25
8thWonder
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I need some feedback about potentially boring to 100mm. My plan was to just go with stock 99.5mm pistons, which I've already purchased from Wossner. After an initial hone with the torque plate, it's clear that the slap/scuff mark in my #4 cylinder is a bit deeper than I had anticipated, so for the sake of oil-tightness and uniform clearances, I'd feel better about starting with a fresh bore, and I don't have an extra $1k at this point for new case halves. Wossner unfortunately does not make a 99.75mm piston, so 100mm is the first oversize option.
I've read numerous threads about when sleeving/pinning is necessary, and it kind of seems like a crapshoot. I really have no desire to sleeve my daily driver. What do the gurus have to say about cylinder wall strength at 100mm? Is it a death sentence without sleeves? Should I ditch Wossner and go with a 99.75mm option instead?

Reminder: this will be a stock location Dom2.5XTR with full mods running E85 the majority of the time, planning for ballpark 450WHP/500WTQ.
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