KZR750R1 2006 OBXT Head Gasket/Motor Refresh

Well I've been here for a little while. Have not offered much in entertainment so here is my stab at a build worthy of dorkumenting.

 

Little back history. Bought the OBXT new in 06.

Was a replacement for my single cab 2500 ram. Should have never dropped that truck from the fleet but that's another story. I was on the fence for a long time what Subaru was a good fit for my family. In the end the OBXT Limited fit the bill.

 

For years I just ran it stock. No mods just maintenance. Then came 90K and a weird issue. In the end it was a seized waste gate. My thinking the dealership would find the culprit while doing the 105K service and I'd be rolling down the road... Nope. Service was done but problem not solved. Only suggestion was a new Boost solenoid. Ended up at Garage One for further diagnosis and a fix by replacing the hot side of my VF40. a little over 600 bucks and it was good to go for quite a while.

 

FF to 120K and I started noticing oil seeping from the IC and really start getting my head wrapped around what is going on with this motor. Was having issues with stalling for quite a while. Picked up a Cobb AP and began throwing off the shelf maps at it.

 

Long story short here I have collected some nice hop up parts that aren't even on the car any more. Have gone back to stock on IC, intake, Up Pipe and what I really should have done was replace the AVCS. Wrapping all the vac lines was also a huge step forward. Lesson learned here.

 

So around 140K my turbo began squealing until it really warmed up. So it was time for a replacement. I decided to go with the 16G in the VF40 housing. Plus pull the perrin up and went to gutted stock. Main reasoning was visual inspection can be hit and miss fail with smog stations. I chose to look as stock as possible.

 

160K now and I'm for sure in head gasket failure land. Crappy looking coolant bubbles after warm up in the overflow. It's time to pull it.

 

Funny cause I have never heard of someone pulling the motor for a valve adjustment... Now I know why. It needs gaskets replace more that valve adjustment.

 

So I'm compiling a good size cart at Infamous now. Will add some items I'll get from Subaru. Hoping some of you experts can pipe in on some advice.

 

1) Should I just plan on replacing pistons and rings?

2) Better to just short block and rebuild this old one for future swaps?

 

Have discussed this a little else ware on the forum and really grateful local members are offering to help! This is huge!

I have not rebuilt a car motor before and going forward with it is going to be a learning and satisfying experience!

In cart now at Infamous:

Manley 99.75mm pistons

Standard size bearings for Rods and Crank

Group N Motor Mount's

Group N Pitch Stop Mount

Gates Racing Subaru Timing Kit - With Kevlar Racing Timing Belt

(Spare) Venair Silicone Throttle Body Hose - dropped mine is fine

Subaru Downpipe To Intermediate Pipe Hardware - dropped cause I don't need them

GrimmSpeed 02-10+ WRX/STi/LGT Header Collectors to Crossover Gasket Pair 7-layer 20% thicker then

GrimmSpeed 02-10+ WRX/STi/LGT Manifold to Uppipe Gasket 7-layer 22% thicker then OEM

Subaru 05-06 Legacy GT Full Engine Gasket and Seal Kit

*DELETE*Subaru EJ25 11mm Oil Pump - Brian3676

ARP Subaru EJ20 & EJ25 Head Stud Kit

Will upgrade the passenger ACVS hose the rest of the filter kit to make it a complete replacement.

 

From Subaru:

Thermostat

Water pump - PN: 21111AA026 based on Covert Russian suggestion.

Oil Pump

Turbo intake (possible) - F1inspiredLGT[/color

Heater core hoses to the case - Has to be Subaru as the silicon kit will not have these in it.

Oil cooler hose to the case

Coolant

Coolant conditioner

Crank Position Sensor

Half Moons

 

On the shelf already:

Killer B Oil Pickup

RalliTEK Trans mount bushing

Several gaskets for the exhaust

New coil connector kits

Free Range Racing hose kit

 

Need to buy:

Bulk fuel hose

Fuji bond -What I have is probably old.

Load of smooth bore hose clamps

Will upgrade the passenger ACVS line like the rest of the filter kit to make it a complete replacement.

Upper and Lower Silicon hoses black

 

 

What else?

Oil Pressure send unit - F1inspiredLGT

TiC FU Cam Bolt Kit - Single AVCS - MrTris - Received

 

Tools to purchase:

Ring compressor

Oil squirt can

Edited October 7, 2014 by kzr750r1

Reserved for the start pics.

Subscribed and offering up an extra set of hands for help with the work. I'm about 35 or 40 miles down the road from you. Look forward to meeting you for the engine pull.

Few things to add here.

 

Intake to turbo - check the rubber around the turbo (intake side), if this hasn't been replaced before, it maybe a good time to replace it. The rubber at the turbo will break down over time.

 

Bulk fuel hoses - ??? - is this used to replace venting hoses?

 

Pistons/rings - You can drop new pistons in as long as the rings are measured correctly, this is one of the defaults from Subaru. Are you seperating the block?

 

Oil pressure gauge - If you don't have one, it would be good to check oil pressures on start up.

I could get another intake if this one is perished. Probably 25K on it. Also have a perrin on the shelf.

In addition I have a Perrin TMIC that may go on if I'm inclined for a Stage 2 tune after this build is over with. Been pining for a DP for a long time. I have some conflicting goals so stage two my not be in the cards right now.

 

The hoses I'm thinking of are ones Max has suggested using safety wire to stop the vapor smell. Should have done it last time I had the intake off but was not having an issue then with it so moved on.

 

Will look into a oil pressure send unit.

 

I was not intending to separate the block. I'm looking for some sage advice here.

Am I high thinking this block can last another 100K after this work? If so I may pass till go boom. If not I'd like to avoid doing this again for the next three or so years.

On the fence about this part.

Mechanic friend thinks I'm not doing it right unless the rings at minimum are replaced. Now granted he's not a Subaru mechanic.

Also coworker and Subaru fanatic has a Subaru certified mechanic as a house mate... Will be bending his ear on this subject as well.

So this may turn into a full rebuild. Well see.

 

Just added a few more hoses by general description I'll be picking up. Just replaced a bunch with the radiator a couple months back.

Edited July 23, 2014 by kzr750r1

It's not going to hurt any by dropping in new pistons/rings. But the main question is, how is you're oil consumption currently?

 

If you're loosing a quart of oil every 1000 miles, then it would be wise to rebuild the shortblock. This was my problem, I was going through a quart almost every month. To find out that I had a cracked ringland and scoring on the cylinder wall, causing a lot of oil loss. Once your heads are off you can check the cylinder walls for any scoring.

Skip the 11mm oil pump, if yours is bad just replace it with a stock 10mm one. Lots of write ups why, look for some on nasioc by KillerB

^^ True.

 

11mm is overkill for a DD. If you plan on racing, then it would be a good idea.

McPerfect... I was thinking as such about the oil pump. Thanks Brian!

 

Not having issues with oil consumption. I'm thinking just as you are. Inspect, if McHosed walls then decide bore/new pistons or short block. Stay stage one unless I really just build another long block.

 

My friends argument is the boost is hell on rings and by his account I drive hard. But then again he's half blind and drives trucks most of the time.

Oh yeah... I did bullet proof the stock TMIC that's in service now so covered x2, since perrin.

You can put the tmic on and still stay stage 1 boost levels but hold it longer. It will just breathe better.

Just added Crank Position Sensor to the Subaru list.

 

Getting a little nervous thinking I can rebuild this block.

 

I'll be out of state next week and probably not very active here.

Just watched Subaru Mikes STI block rebuild again. Shifting my thinking a little. It's not all that complicated rebuilding... What has me thinking more to split this case is the internal seals. Mainly the washer seals on the case bolts but also the orings. A refresh on these would surely be helpful with longevity of all the work pulling the motor.

 

Main thing I like about Mikes videos is he's explaining in normal english the important things to be concerned about. Using lube on the bolts for a proper torque is a good tip.

 

Will need to get a ring compressor, Oil can.

 

What do you guys think about his use of Ultra grey silicone for case seal?

 

Depending on condition of the cylinders and bearings I'm hoping to reuse all the bearings and just reseal after honing the bores. New stock rings go in and go onto the next step of putting the heads back on after a refresh.

If you go all the way to tearing the block down and honing the cylinders why skip on the $120 bearings?

Yeah... That's why I'm sounding off... Perfect come back...

 

So I'd need to add to the list rod and crank bearing kits.

 

I'm slightly concerned about the full motor gasket kit and wondering if anyone has used the kit Mike is selling at Infamous. I'm not all that concerned about the quality of the head gasket. I'm expecting to swap the head gaskets for a different set. Have the rest been up to par as well?

 

I'm assuming not using the head gaskets in the kit would be due to getting the right gasket thickness matching up the difference from how much material was removed decking the head (case if needed). Plus making sure I've installing the latest bad ass materials.

 

Already thinking I need to order the bolts MrTris is using for the cam gears.

Do it. For $40, it's so much easier. Then again, you'll also need the Company23 AVCS cam gear tools, though, unless you plan on borrowing some/taking it to a shop to have them set the timing.

 

Run a spreadsheet for what you'll spend on new rings, bearings, and machine shop work. It's really hard to beat the ease and realiability of an OEM shortblock and gasket kit for just over $2k when you price it out. Plus, 12k mi warranty!

Thanks. I hear you on the parts cost.

 

Warranty sounds good but is that covered without factory certified tech installing?

 

Why not the wrench that will hold both intake and exhaust?

Thanks. I hear you on the parts cost.

 

Warranty sounds good but is that covered without factory certified tech installing?

 

Why not the wrench that will hold both intake and exhaust?

 

I know of no such tool (Just one) that will hold both intake and exh cam gears while you torque the cam gear bolts without slipping a tooth. Link?

http://www.rallysportdirect.com/Company23-500-STD-Intake-Exhaust-Cam-Sprocket-Tool

Probably wrong as I looked again. This would be for Dual ACVS heads I'd guess.

Special note: Exh cams only.

 

I've researched this before -- To buy both of the right wrenches, it'll run you about $100.

Well put a fork in it, for sure done.

I have been driving it on a limited basis. Left it at the airport over the week while on this business trip. Needed to go pick up my daughter and found coolant puked on the driveway. So no go and told the future ex she needs to go get the girl.

 

Now I just need to figure out how to get up to pick up this loaner ride and I can begin the tear down.

 

Really don't need this right now but I have no choice.

Well put a fork in it, for sure done.

I have been driving it on a limited basis. Left it at the airport over the week while on this business trip. Needed to go pick up my daughter and found coolant puked on the driveway. So no go and told the future ex she needs to go get the girl.

 

Now I just need to figure out how to get up to pick up this loaner ride and I can begin the tear down.

 

Really don't need this right now but I have no choice.

 

You'd be surprised how many of us have LGTs as a result of a divorce/separation/life bullshit.

 

I've been there, dude.

 

Next week will be two years since I left her, and, in that amount of time, I've found love again, rebuilt my life, and I'm just on the other side of rebuilding the escape pod that I started out with - Things can get SO much better after a breakup, even if you can't see it right away.

 

Besides being expensive, rebuilding an LGT can be a theraputic, and even cathartic experience. It costs only slightly more than actual therapy, and I think, at the end of it all, having something tangible for your efforts is worth so much more. And if you're anything like me, your mind can wander while you're tearing things down and cleaning, painting, sorting, and then putting it all back together. It can drive you crazy. But just stay focused, and don't forget to reach out here - We're all brothers, and we're all in this together.

 

PM if you ever wanna talk.

Alcohol worked for me.

Ok found the machine shop I'll be using. Al Hubbard in Hayward will take the split block and heads from the tear down. Refresh both and hand back for rebuild with a rough estimate of 500 bones. This work will give me the measurements needed for the bearings, potential need for over bore pistons and will check the crank and such.

 

They have been in business for years and although don't do a lot of EJ motors have and will do it.

 

I spoke to GTS and their take on this was they will not do anything but a complete motor refresh... Rough estimate $7500... Yeah no thanks.