Welcome to the North American Subaru Impreza Owners Club Saturday August 27, 2016
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC General > Member's Car Gallery

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 10-20-2015, 10:35 PM   #1
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default Mike's 2007 WRX Engine Rebuild

On October 8, 2013 my engine failed while cruising down the highway, of all places. I live near Boston, MA and for those that know the area, I was on Tobin Bridge traveling on Rt 1S into the city. I could hear tiny bits of metal making their way through the exhaust and the engine was seized. I instantly shifted into neutral and coasted to the emergency lane. Below is a pic from that sad day.

This car is one of 3 Subarus I have owned (others were 01 Legacy GT, 02 Impreza wagon). I knew this day was coming. I was running a Blouch Dom 1.5 xt-r turbo at about 19-20 psi on a stock engine. It measured at 320whp at 18 psi on the dyno. After tearing down the engine, I found I had a #4 cylinder piston ringland failure (shocker, right?). I had always wanted to build an engine, and I've been itching to get more power safely on this car, so this was my chance.

I have already completed and installed the engine to this day and I have currently have about 400 miles on the engine, still in break-in. I'll treat this thread as a log of my build for my own documentation and to share with others. I have also created some special tools and some over-kill inspections which hopefully could help others in the future. Feel free to comment. This is my first build and I have learned a lot, especially about how complex these engines are. Thank god for these forums and fellow engine builders in my area that were always willing to give advice.

* Registered users of the site do not see these ads.

Last edited by mhWRX; 10-20-2015 at 10:50 PM.
mhWRX is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 10-20-2015, 11:08 PM   #2
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

I began teardown of the engine soon after the failure.



I first drained the oil and had a bunch of small metal particles, only some attached to the magnetic drain plug. The largest piece was a a fragment of a smooth curved piece of metal, see photo below. I have no idea what this is from. Any ideas?



The turbo, which was still relatively new, looked to be in good shape. I was worried about damage to the turbine since I know some particles made it through the exhaust. No visible damage on the turbine vanes. I was also worried about small particles in the oil blocking the small oil feed lines in the centerbody and bearing area. I sent the turbo back to Blouch for an inspection.

mhWRX is offline   Reply With Quote
Old 10-20-2015, 11:19 PM   #3
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

I pulled out all the spark plugs and the #4 had a the ground electrode crushed into the center electrode indicating there had been some impact.

I finally pulled the cylinder heads to reveal the failure. The #4 cylinder (driver side rear cylinder) has a large visible missing chunk. You can clearly see the top piston ring in the missing ringland area. The fracture surface was smeared over quite a bit, but it looks as though the failure started at the edge of the valve clearance groove closest to the ringland.

Majority of the fragments were still in the cylinder and the piston had wedged the fragments against the cylinder head and prevented any further rotation (piston just short of TDC). Once I pulled the heads off and removed the fragments, the engine rotated freely and was surprisingly smooth. I had some light scoring to the cylinder wall.



The cylinder head showed some damage as well. You can clearly see some denting from all the fragments bouncing around before the engine stopped rotating. Picture below shows the #4 cylinder cavity on the right. It almost looks like it's been bead blasted. I eventually had the valves inspected and sure enough I had bent two valves. My plan was to clean up and re-use the cylinder heads and re-machine as needed.

mhWRX is offline   Reply With Quote
Old 10-20-2015, 11:44 PM   #4
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

Now that I know what the failure was, I thought about potential root causes and ways to prevent or minimize the risk to similar failures on the new engine build. I also took time to research other common Subaru engine failures to do my best to build an engine I could use on the track but also drive daily.

Potential causes / contributions of failure, theory:
1. Excessive boost causing high combustion pressure & temperature, more prone to detonation which could surpass material capabilities of the pistons.
2. Excessive oil vapors in the intake: I had no air-oil separator system. Layer of oil coated the intake track. The higher boost also worsens blow-by. The oil vapors can reduce the effective octane rating, making the system more prone to detonation
3. Tune: Not blaming it on the tune, but maybe running it a bit more rich on WOT would be a good idea in the future.
4. Stock cast aluminum with thin ring lands unable to handle multiple detonations: stock pistons are made from a cast hypereutectic aluminum alloy. This alloy has low thermal expansion to better match the growth of the engine blow. This is nice and allows for a tighter piston to wall clearance (quiet operation, minimal oil consumption), but is more brittle and less capable than forged aluminum pistons.

Immediate changes to address above theories:
1. Excessive Boost: I wont be running lower boost, but instead will be smarter and more aware of the system health. I added a Defi EGT sensor to measure exhaust temperatures near cylinder 4. I also upgraded to the v3 accessport to monitor feedback knock, knock learning, and DAM real-time at once.
2. Excessive oil vapor: I installed a Moroso twin catch can air-oil separator system. I liked this product because I could maintain the PCV and I wasn't sending back a nasty oil-water mixture back into the engine as some of the other air-oil separators produce in the colder New England conditions. I also liked how the crankcase and valve breathers are on separate catch cans.
3. Tune: Again, just being more aware.
4. Stock pistons: Went to forged on the new build. Even forged pistons can fail due to detonation, but the added resilience will strengthen the system.
mhWRX is offline   Reply With Quote
Old 10-21-2015, 12:00 AM   #5
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

Other common EJ25 issues and proactive planning:
I won't dive into these subjects, as there is a ton of material in this forum, but here's a few of the big hitters:

1. Spun bearings / poor oiling: I wanted to raise my redline rpm capability to over 8000 rpm to ensure I get all the top end from the new cams and larger turbo. I knew I had to address oil pressure and volume. I increased the target clearances on the rod and main bearings over stock and moved up to a 2008 11mm oil pump. Again, reducing/eliminating knocks will also reduce the risk of spinning a bearing. I also used King bearings as I saw reviews of more consistent clearances vs ACL bearings.
2. Oil pickup tube failure: The stock oil pick-up tube is a brazed assembly that is known to crack, causing air to be pulled instead of oil, starving the rotating assembly. I went to a Killer B oil pick-up and paired it with their oil baffle and oil pan. Their pan holds more volume and has a deeper well that is narrower in width to ensure the oil pickup is submerged, providing more protection during sustained higher-g turns.
3. By-pass valve (BPV) leaks: I was running around the known threshold of the stock BPV. I may have been starting to leak in the days before the failure. I wanted a recirculating BPV that could handle at least 24 psi of boost and I went with the Turbosmart plumb back.
4. Valve float at higher rpm: Not as common as the above, but to be same I went with BC springs that could handle the increased rpm. The stiffer springs do rob a bit more horsepower from the engine and are louder, but worth it for my build.
mhWRX is offline   Reply With Quote
Old 10-21-2015, 12:18 AM   #6
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

I spent the next year or so doing a ton of reading and researching. I also bought most of the parts and performed all my inspections / measurements during that time period.

The goal is a weekend warrior / daily driver capable of 400-450 whp on E85 and 350+ on pump 93 octane. I will be tracking a several times per year. I wanted the rotating assembly capable of 600 hp and 8,000+ rpm for margin. I decided the stock block was sufficient at these power levels and did not want to get a closed deck or have sleeves installed. Extra headaches and $$.

Here's the list on the engine internals:
Block case ---------- new OEM, 2007 EJ257, bored to match pistons
Pistons --------------- Manley, 8.5 CR Platinum Series, 99.75mm
Rods ------------------ Manley, Turbo Tuff I-beams
Crankshaft --------- Stock OEM, 2007 EJ257
Rod Bearings ------ King XPG, STD (~.002" clearance)
Main Bearings ----- King XPG, STD (~.0015" clearance)
Oil Pump ------------ 2008 11mm OEM
Oil Pickup ----------- Killer B Motorsport
Oil Baffle ------------ Killer B Motorsport
Oil Pan --------------- Killer B Motorsport
Head Studs -------- ARP 2000
Head Gasket ------ Cosworth, 0.78mm
Camshaft ----------- GSC Stage 1, 268/266
Intake Valves ----- Brian Crower, 36mm
Exhaust Valves -- Brian Crower, 32mm
Valve Springs ----- Brian Crower, cylindrical
Cylinder Head ---- Used 2007 WRX D25, re-machined
AVCS ---------------- Used, rebuilt 2007 WRX (intake only)


Last edited by mhWRX; 10-24-2015 at 01:11 AM.
mhWRX is offline   Reply With Quote
Old 10-21-2015, 12:37 AM   #7
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

Here's a list of some of the supporting modifications:
(have additional modifications to mounts, bushings, etc)

Intake ----------------- Cobb SF Intake w/ Box, already on car
Turbo Inlet ----------- Perrin 2.4" inlet, already on car
Intercooler ----------- Process West TMIC, already on car
Intake Manifold ---- Grimmspeed Port n Polish, p'n'p new to build
TGV ------------------- Custom delete, already on car
Turbocharger ------- Blouch Dom 1.5 XT-R, already on car, switched to new housings (10 cm^2 hot side, 2.4" inlet cold side), internal wastegate
Boost Controller -- Grimmspeed 3 port EBCS, already on car
Bypass Valve ----- Turbosmart Recirculating BOV, Plumb Back, new to build
Exhaust Header -- Stock reducers, port & polished, Grimmspeed Hi-flow Crosspipe, new to build
Up-pipe -------------- TurboXS, catless, already on car
Down-pipe ---------- Cobb, catted, already on car
Cat-back ------------ Borla, S-Type, already on car
Fuel Pump --------- Walbro 255Lph, already on car
Injectors ------------ ID 1000 cc, already on car
Oil Separation ---- Moroso twin catch can, new to build
Transmission ----- Stock 5 speed
Clutch --------------- SPEC Stage 2+, already on car
Flywheel ------------ Stock OEM
Crank Pulley ------ Fluidampr, new to car

Gauge details:
Boost ------------ Defi, connected to intake manifold forward port, steering column
AFR, ------------ AEM UEGO, connected to Cobb downpipe bung, steering column
Oil Temp ------- Defi, connected to KBM oil pan, center dash cluster
Oil Pressure -- Defi, connected to port on block (top, back, under turbo), center dash cluster
EGT ------------- Defi, connected to tap in 3-4 header reducer, center dash cluster

Last edited by mhWRX; 10-23-2015 at 08:05 AM.
mhWRX is offline   Reply With Quote
Old 10-22-2015, 12:13 PM   #8
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

I found a good deal on a brand new stock assembled EJ257 short block. I disassembled the block and kept the case halves and the crankshaft. I put aside the pistons, connecting rods, and bearings to either sell or rebuild a stock block in the future.

I gave the Manley pistons over to a machine shop along with the case halves to bore and hone the cylinders to match the pistons and achieve the desired piston to wall gap. Before giving over to the machined shop I measured the bores of the stock block:

Stock, measured at ~1.5" from the deck:
Cylinder -- Avg Dia -- Out of Round
1 --------- 3.9172 ----- .0003
2 --------- 3.9171 ----- .0002
3 --------- 3.9171 ----- .0002
4 --------- 3.9171 ----- .0002
These are all "B" sized cylinders, matching the "BBBB" marking on the block

Many of the drop in pistons are better suited to the slightly larger "A" sized cylinders (.0005" difference in nominal diameter), so I still went down the path of machining to match 99.75 pistons.

The Manley 99.75 pistons I received were all within .0001" in diameter, which is excellent. They measured on average 3.9241". So in order to target .0035" PTW clearance, I needed the block machined to 3.9276", which is .0105" removal.

I dropped off the block 1/19/2014 and received it on 1/31/2014.
I remeasured all the bores and I was very pleased with the results.

Machined, measured at ~1.5" from the deck:
Cylinder -- Avg Dia -- Out of Round
1 --------- 3.9275 ----- .0005
2 --------- 3.9277 ----- .0011
3 --------- 3.9276 ----- .0011
4 --------- 3.9275 ----- .0008

I also measured diameter taper in the cylinder from 1.5 to 2.5" from the deck:
Cylinder -- Taper
1 -------- .0005
2 -------- .0003
3 ---------.0005
4 -------- .0005

I was not worried about the out-of-round because I knew the block was machined with a torque plate which simulates the cylinder head being installed. These aluminum blocks are known to deflect a bit with the heads installed and the cylinders do go out of round. Machining with the torque plate attempts to achieve as round a cylinder as possible in the assembled state and it is honed in this state. My measurements above were in the free state, where the average diameter is more informative. These values of out-of-round are in line with others reported when measuring in the free state after machining with a torque plate.
mhWRX is offline   Reply With Quote
Old 10-22-2015, 12:30 PM   #9
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

In the meantime, I continued with measurements of the crankshaft and connecting rods.

The crankshaft part number is 12200AA330, which I believe is the heat-treated version. You could clearly see the rainbow colors indicating the heat treat. I measured all the rod and main journals with outside 2-3" micrometers good to .0001". I labelled the main journals in order from fwd to aft.

Rod journal requirement: 2.0466 - 2.0472"
Main journal requirement: 2.3619 - 2.3625"

My measurement results:
Rod Journal -- Avg Dia -- Out of Round
1 ------------ 2.0467 ---- .0002
2 ------------ 2.0467 ---- .0001
3 ------------ 2.0467 ---- .0000
4 ------------ 2.0467 ---- .0000
(Excellent, all the same and meeting spec, minimal out-of-round, and .0002" smaller than nominal which can help with a tad bit more clearance)

Main Journal - Avg Dia -- Out of Round
1 ------------ 2.3619 ---- .0001
2 ------------ 2.3620 ---- .0001
3 ------------ 2.3619 ---- .0001
4 ------------ 2.3619 ---- .0001
5 ------------ 2.3619 ---- .0000
(Excellent, all within .0001 and meeting spec, minimal out-of-round, and .0003" smaller than nominal which can help with a tad bit more clearance)




Last edited by mhWRX; 10-22-2015 at 12:57 PM.
mhWRX is offline   Reply With Quote
Old 10-22-2015, 12:55 PM   #10
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

Next I measured the Manley Turbo Tuff I Beam rods. The rods come in individual boxes with the weights labeled on them, along with a spec sheet. They report the Pin End and Big End weights. I double checked the total weights (pin + big) using the average of three measurements each with both a triple beam balance (method A) and a kitchen food scale (method B). All values are in grams.

Rod -- Pin End -- Big End -- Total --- "A" ----- "B" ---- "A"-Manley
1 ----- 170.0 --- 420.8 --- 590.8 -- 590.5 -- 590.3 ---- -0.30
2 ----- 170.1 --- 421.0 --- 591.1 -- 590.4 -- 590.5 ---- -0.70
1 ----- 170.6 --- 422.3 --- 592.9 -- 592.2 -- 592.3 ---- -0.67
1 ----- 170.7 --- 422.4 --- 593.1 -- 592.5 -- 592.2 ---- -0.57
Range -- 0.7 ----- 1.6 ----- 2.3 ---- 2.1 ----- 2.0

My measurements do not match as closely as I would have hoped, but they are all within 1 gram (0.1% error) and as good as I can get given my tools. I trust the manufacturer's values are best, and I did match their trends. The 2 grams variation in mass between the total rod mass is good, that's a variation of 0.3%, but still enough to consider when balancing the rotating assembly.

I next measured the crankshaft interface bore (big end) with a telescoping ID gage and outside micrometers. Of course I had the rod bolts tightened down.

Big End - Crankshaft Interface:
Rod --- Avg Dia -- Out of Round
1 ------ 2.1650 ----- .0001
2 ------ 2.1651 ----- .0002
3 ------ 2.1651 ----- .0003
4 ------ 2.1651 ----- .0003
The target is 2.1650, so again, I am pleased with these results.

Pin End - Wrist Pin Interface:
Rod --- Avg Dia -- Out of Round
1 ------ 0.9051 ----- .0001
2 ------ 0.9056 ----- .0002
3 ------ 0.9056 ----- .0001
4 ------ 0.9056 ----- .0000
The target is 0.9055. 3 of the 4 are within .0001, but Rod 1 is slightly small. I made note to pair it with the smallest diameter wrist pin and to ensure it fit.

I then tried to estimate the center to center distance based on 1/2 pin bore diameter + 1/2 crank bore diameter + pin to crank bore edge to edge length. The target is 5.137"

Rod --- Avg Dia -- Dev from Target
1 ------ 5.1338 ----- -.0032
2 ------ 5.1349 ----- -.0021
3 ------ 5.1355 ----- -.0015
4 ------ 5.1345 ----- -.0025

Given the tolerances involved in my measurements (edge to edge length was measured with calipers) I believe my measurements are only good to +/- .0020" here, so I'd say my rod lengths are generally good.
mhWRX is offline   Reply With Quote
Old 10-22-2015, 02:33 PM   #11
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

For the pistons, I ordered Manley PN 612002C, the 99.75mm.

I mentioned the piston diameter in a previous post. I also weighted the pistons and wrist pins using a triple beam balance. The spec sheet gave weights of 396-397g.

Piston -- Mass
1 ------ 396.6
2 ------ 395.8
3 ------ 396.9
4 ------ 396.1
Avg ---- 396.4
Range -- 1.10

Pin ----- Mass --- Diameter
1 ------ 131.9 ---- .9054
2 ------ 131.6 ---- .9053
3 ------ 131.7 ---- .9053
4 ------ 131.8 ---- .9053
Avg ---- 131.8
Range -- 0.23

The wrist pins are essentially interchangeable based on diameter and mass. The pistons are interchangeable based on their diameters (all the same) but their masses are different enough that this was taken into account during assembly.
mhWRX is offline   Reply With Quote
Old 10-22-2015, 02:52 PM   #12
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

I then performed a hand calculation on the imbalance of the rotating assembly to select the best combination of piston, wrist pin, and connecting rod combinations.

I had given each piston, pin, and rod a label of A, B, C, or D. I initially paired piston A with wrist pin A and rod A, and so on. I calculated the mass moment of each cylinder pair (1-2, 3-4) when the pistons are at TDC. The mass-moment is the mass*length (gm-in) where the mass is the mass of the component and the length is the center of mass of that component from the engine centerline. Here are my assumptions on the Cg (center of gravity) positions which I got roughly by balancing each component on a knife-edge and measured from the knife-edge to an interfacing feature:

Piston Cg from pin hole = .45"
Rod Cg from Big End centerline = 1.3"
Wrist pin Cg is at its own centerline

Knowing the stroke and the rod length, I could then find all the Cg's from engine centerline and calculate the total Cg of the rod and piston in each cylinder.
Cg of each component from engine centerline at TDC:
Rod: 2.86
Pin: 6.69
Piston: 7.14

My goal is to cancel out the mass-moment of cylinder 1 and 2 (opposing cylinders) to get as close to zero as possible. Same for 3 and 4. I also cared about the forward to back imbalance (1-2 vs 3-4).

The initial combination was no good. I then selected to balance out the rods first (heavy rod across a heavy rod, light rod across a light rod) then try to null out the remainder with the right piston and pin combination.

On my final iteration, I got about -0.5 gm-in imbalance between cyl 1 & 2, and 0.6 gm-in between cyl 2 & 3. The net is nearly zero, 0.1 gm-in, between the 1-2 and 3-4 pair. To put this in perspective, each piston, pin, rod assembly has a mass moment of about 5400 gm-in. So a pair would be 10800 gm-in. An imbalance of 1 gm-in is pretty good and should provide me with smooth operation. This is all assuming the crank shaft is balanced. I've read that Subaru does a good job at balancing these components. The best thing is to actually build up the rotating assembly and have it professionally balanced, but I did not want to spend the money given the results above.

So now I have assigned each piston, wrist pin, and connecting rod to a cylinder. I could now move on to sizing piston rings and bearings.

Last edited by mhWRX; 10-24-2015 at 03:28 PM.
mhWRX is offline   Reply With Quote
Old 10-22-2015, 03:06 PM   #13
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

Once I got the block back, I sized the piston rings. I apologize for not having any images of this process. My phone was water-damaged and I lost many of my build photos.

I believe the rings that are supplied with the Manley pistons are Total Seal rings. The Manley recommendation for piston ring gap for a Blown Gas application is the following:
Top Ring: Bore x .0055
Second Ring: Bore x .0035
Oil Rail: Min .015"

Given my bore diameter (at 2" depth from the deck) is roughly 3.9277" I get the following:

Top ring = 3.9277 x .0055 = .0216" = .022" gap
2nd ring = 3.9277 x .0035 = .0137" = .014" gap
Oil ring = .015" min

I didn't feel good about the 2nd ring running that tight and in fact found many posts in forums and other engine building websites recommending that the 2nd ring have a slightly larger gap over the top ring, but .002". I also saw other examples of Total Seal rings sizing this way, so my final selected gaps were .022" on the top ring, and .024" on the 2nd ring.

I used a hand piston ring filer ($60 off amazon) to ensure the ends of the rings butt up perfectly (pure radial cut). I placed the ring into the cylinder, then used the piston flipped upside down to square up the ring in the cylinder and push it down to about 2" from the deck. I then used shims to measure the gap. I would install, measure, file, clean, install, measure, .. several times until I could just barely fit a .022" shim, but not a .023" shim on the top ring. Same process on the 2nd ring, but gapped to .024". With some light machining oil, this process is relatively quick. For the oil ring, I just placed and square up in the cylinder and made sure the gap was over .015. I was getting about .020 to .024 gap on the oil rail rings.

I now had my rings sized to the specific cylinders.
mhWRX is offline   Reply With Quote
Old 10-22-2015, 03:34 PM   #14
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

Over the next several months, I continued gathering parts and doing research.

I decided on King bearings for both the main and rod journals over ACL due to more recent inconsistencies reported with ACL bearings. People seemed to need 2-4 boxes to get a set they liked for clearances, whereas Kings needed 1-2. To be on the safe side, I got 2 boxes of each set.

King MB5382XPG STD for the mains
King CR4125XPG STD for the rods

I did not get significant time to work on the engine again until Dec 2014 due to graduate school classes & research.
mhWRX is offline   Reply With Quote
Old 10-22-2015, 06:19 PM   #15
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

Between 12/29/14 and 1/9/15 I installed the rod bearings for test fits and clearance checks.

Using the rod journal diameter of 2.0467 (see previous post) I was looking for a rod bearing ID of 2.0487 to achieve my target clearance of .002". I simply used the first 2 bearings in cyl #1 rod, the next two in cyl #2 rod, etc to start with. When I found a set in a rod that met my target (.0019 - .0021) I set that aside and kept iterating with the others. In total, I had to build up a rod 12 times among the 4 connecting rods to find a combination that gave me my target across the board. A bit of a pain and I knew this part of the build would be.



Every time I built up the rods, I torqued the rod bolts down to 50-55 ft-lbs to get .005 to .006' of bolt stretch. The Manley spec sheet calls for 45-50 ft-lbs and .0058-.0062 bolt stretch for the 3/8x1.6 ARP 2000 bolts. The ARP spec sheet says 55 ft-lb and .0055-.0060 with their lube. I verified bolt stretch with calipers before and after. Not perfect, and not as good as the ARP bolt stretch gauge, but good enough to within .001" to make sure I'm not completely out of line. I used a bench vise with some towels to hold the connecting rods to torque down the heads.





I made sure the tabs on the bearing fit into the grooves in the connecting rods, and that the tabs are not on the same seam but instead on opposite sides.

mhWRX is offline   Reply With Quote
Old 10-22-2015, 06:26 PM   #16
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

I used a telescoping gauge and an outside micrometer to measure the ID at multiple areas to capture the average diameter and runout. I used a very little amount of assembly lube to help minimize any scratching of the bearing surface.

The results of the final configuration:
Cylinder ---- Avg Dia -- Out of Round -- Clearance, avg -- Clearance, min
1 ----------- 2.0488 ----- .0005 ---------- .0021 ---------- .0017
2 ----------- 2.0488 ----- .0006 ---------- .0021 ---------- .0018
3 ----------- 2.0487 ----- .0003 ---------- .0020 ---------- .0018
4 ----------- 2.0488 ----- .0008 ---------- .0020 ---------- .0015

This was good enough to me. Average clearance was right what I was targeting using the STD bearings and I did not need the STDX bearings. These clearance values are calculated clearances. Even the min clearance, using the out-of-round info, is good in my mind. For reference, the OEM clearances are suppose to be .00125 +/- .00055, with a limit of .002.






mhWRX is offline   Reply With Quote
Old 10-22-2015, 06:41 PM   #17
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

I had the rod caps match-marked to the rest of the rod, and numbered them with permanent marker. I also marked the backing of the bearings. This way I can repeat the assembly exactly.
I then cleaned the bearings, rod, rod bolts with a diluted concentration of simple green. Then I dried and bagged them up until they are ready on install.

mhWRX is offline   Reply With Quote
Old 10-22-2015, 07:46 PM   #18
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

On 1/17/2015 I worked on the main bearings. I started with assembling the bearing halves into the block. The #1 and #3 bearings are the same, as are the #2 & #4. #5 is the thrust bearing.



I placed the driver side block half on top of the passenger side half and got it on the dowel pins. I lightly tapped it them together with a rubber mallet. I bolted it up using just the 10 10mm case bolts to the factory service manual specs, and did not bother with the outer 8 and 6mm case bolts. This is sufficient to get the bearing area tight to get accurate measurements.



I then used the telescoping gauge with an outside micrometer to measure the bearing inner diameters, similar to the rod bearings.



mhWRX is offline   Reply With Quote
Old 10-22-2015, 09:08 PM   #19
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

In addition to the hand calculations of the clearance (bearing ID - crankshaft journal OD) I also measured the clearance using plastigage.

I took apart the block to drop in the crankshaft onto the passenger side block half with the bearings installed. I then placed a strip of .001 to .003 plastigage (green one) on each journal, as shown in the pics below.





As before I bolted down the driver side block half per the FSM. I was careful not to have the crankshaft rotate AT ALL, otherwise it would smear the plastigage and give inaccurate readings.



The plastigage is a wax wire and is suppose to compress and spread out due to the contact with the bearing. The width of the compressed plastigage is a function of the diametral clearance, with an interpretation scale provided with the plastigage. The tighter the clearance, the wider the plastigage. As you can see, I was measuring between .001 and .0015.







Last edited by mhWRX; 10-23-2015 at 07:54 AM.
mhWRX is offline   Reply With Quote
Old 10-22-2015, 09:21 PM   #20
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

I think I got lucky with the main bearings (and King did a good job with sizing) and I was able to keep my initial iteration - no swapping needed.

I was shooting for a clearance of .0015" on the mains. Here are the results of the measured and calculated clearances along with the plastigage readings.

Calculated Method (Bearing ID - Journal OD)
Journal ---- Avg Clearance -- Min Clearance
1 ------------- .0015 -----------.0013
2 ------------- .0019 -----------.0017
3 ------------- .0014 -----------.0013
4 ------------- .0018 -----------.0015
5 ------------- .0017 -----------.0015
Average --- .0017 ---------- .0013

Plastigage Method (estimated between .001 and .0015 visually)
(Added Avg Clearance from above for comparison)
Journal --- Plastigage -- Measured
1 ------------- .0012 -------- .0015
2 ------------- .0013 -------- .0019
3 ------------- .0013 -------- .0014
4 ------------- .0013 -------- .0018
5 ------------- .0012 -------- .0017
Average --- .0013 -------- .0017
Overall average of both methods = .0015

As you can see, the plastigage was giving consistently lower readings that the calculated values. The plastigage is really only reading in that specific direction, where as with the measurements I include the runout to get average and min clearances. Overall, the numbers are only a few tenths of a mil off and either .0013 or .0017 is fine with me. These numbers are hovering around my target of .0015 and I decided to continue with the build. I only needed 1 box of the King Bearings and 1 iteration, which was awesome.

I could now move on to prep the block and begin final assembly.

Last edited by mhWRX; 10-23-2015 at 07:54 AM.
mhWRX is offline   Reply With Quote
Old 10-23-2015, 01:33 PM   #21
03SubyWRX
Scooby Specialist
 
Member#: 200767
Join Date: Jan 2009
Chapter/Region: NESIC
Location: Waltham, MA
Vehicle:
2007 OBS 5MT
Lifted

Default

Great write up so far! Your attention to detail is impressive. Keep up the good work and good luck with your build.
03SubyWRX is offline   Reply With Quote
Old 10-23-2015, 11:54 PM   #22
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

^ Thank you!

Next I did some light clean-up on some sharp edges and casting flash on the block. Probably more of me being paranoid than anything else, but since I had it apart and access, I figured it wouldn't hurt. I based the work on these threads:
http://forums.nasioc.com/forums/show....php?t=2237089
http://forums.nasioc.com/forums/show...1176430&page=9

I used a dremel with HSS cutters and mini aluminum oxide grind wheels. The extension flex dremel attachment made this easier.



I marked areas I wanted to clean up in green marker. I also opened up one of the oil passages to better match the port on the other half.





After carefully grinding away what I wanted, I hosed down the block to wash away all the shavings. I then cleaned the block halves with simple green in my tub and water flushed several times. I made sure to dry off the bores immediately to prevent any rusting, then added a light coat of oil.


Last edited by mhWRX; 10-24-2015 at 12:03 AM.
mhWRX is offline   Reply With Quote
Old 10-24-2015, 12:02 AM   #23
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

on 1/27/2015, I cleaned up the pistons, wrist pins, rings, and crankshaft. I again used a diluted solution of simple green and a light bristle brush.




Last edited by mhWRX; 10-24-2015 at 12:07 AM.
mhWRX is offline   Reply With Quote
Old 10-24-2015, 12:23 AM   #24
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

I then assembled the piston rings to the pistons. I started from the bottom rings and worked my way up to the top ring. The oil rail ring is a 3 piece ring, a thin inner and outer thin ring that sandwich a corrugated ring. The Manley spec sheets provide the orientation of all the gaps. One of the thin rings has a bend end which fits into a oil cooling hole in the piston for anti-rotation. This ring goes onto the bottom. The top thin ring gap was aligned with the oil cooler hole on the other side of the same skirt. These rings went on easily by hand, but I was careful not to stretch them open too much to yield the rings.



For the top two rings, I used a ring spreading tool to spread the ring just enough to be able to slide it over the piston. This step can be done by hand, but I didn't want to over-expand the rings or scratch the pistons by not expanding enough. I won't dive into the ring orientation, gap placement, etc here. The spec sheet captures all of that information and additional info can be found in detail by searching the forums.



I then bagged up the pistons with the rings and the wrist pins to keep them clean for install on another day.

mhWRX is offline   Reply With Quote
Old 10-24-2015, 12:42 AM   #25
mhWRX
Scooby Newbie
 
Member#: 407939
Join Date: Dec 2014
Chapter/Region: NESIC
Location: Boston, MA
Vehicle:
2007 WRX Limited
White

Default

On 2/2/2015, I assembled the connecting rods to the crankshaft and installed into the block.

I started with installing the rod bearings into the connecting rods being mindful of the position markings to make sure I got repeated results for the clearance. I used red line assembly lube on all interfaces.



I lubed each journal one by one to avoid any dust contamination. I got the rod on first, then placed the rod cap onto the journal and torqued the rod bolt incrementally up to 55 to 60 ft-lbs to be able to achieve .006" in bolt stretch.







The assembly went smoothly. After each rod I installed, I rotated it to make sure the rod rotated freely.
mhWRX is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 03:44 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2016, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2016 Axivo Inc.
Copyright ©1999 - 2016, North American Subaru Impreza Owners Club, Inc.