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9 Posts
Discussion Starter #1
Bought a 03 350z with a vq35de that somebody already invested the money so I didn't have to.

But as we all know, when you buy someone's project, it turns into your headache from day 1.

The car was purchased with AAMs twin turbo borg warner 71/63 kit and a "built motor" already in place. (Full parts list at bottom) and previous owner stated 620hp on 17psi and 800 at 27. Never saw a dyno slip for either though. So, who knows.

When I went to look at the car, it was hard to start, and wouldnt rev or drive, I brought new parts and tools with me and the previous owner and i got to work on getting it to run a bit smoother. We replaced the fuel pump and the fuel pressure regulator, fired it up and drove it down the road a bit. Pressure was still low and you couldn't build any boost before running out of fuel. Good enough for me!

Loaded the car on a trailer and headed home.

Once home I noticed the fuel pressures weren't up to par and instantaneously died off from 25psi to 0 as soon as it went through a priming cycle. I replaced the pump with a new walbro 400 fuel pump and also replaced the pump basket with a new one and reinstalled the return fuel system into the new basket.

Pressure came up to 70psi and held. Success!
I turned the pressure down

Drained all the fuel and replaced with new fuel and added some VP110 just incase, because I did not know if the tuning was anywhere close to stoich.

Car ran great! AFR reading extremely rich. The old AEM gauge taps out at 10:1 and that's where she sat at wide open throttle.

I drove the car a bit more and noticed smoke from exhaust a decel. A cold compression test showed 110 in all cylinders (should have warmed it up, I know). Leakdown showed atleast 70% loss through exhaust on 5 cylinders.

I pulled the motor and transmission and that's where we are today. This thread will just be a basic breakdown on what I'm looking for while tearing the motor down, what problems I've run into, and what changes I make throughout the process.

Hoping to take as many pictures along the way as possible. Being new to 350z's and this all being a learning process for myself, I expect we'll end up covering alot of things newbies may experience and help cover some common issues.


*built by AAM
*Bored to 3.7
*Balanced and blue printed
*Manley H beam rods.
*Manley 8.3:1 pistons
*ARP L19 head studs
*revup oil pump
*AAM oil feed and return kit.
*AAM oil pan spacer
*HKS head gaskets
*Admin tuning catch can

-Forced induction-
*AAM twin turbo kit. Borg warner EFR71/63's.
*AAM big MAF
*grimmspeed manual boost controller.
*Throttle body spacer
*AAM plenum spacer
*AAM full 3 inch exhaust single exit.
*AAM test pipes

*AAM stage1 fuel return kit with billet fuel rails.
*Walbro 450 in tank pump
*Modified fuel basket with return, enlarged jet pump.
*deatschwerks 1000cc injectors
*Aeromotive fuel pressure regulator

*Spec super twin disc clutch

-Suspension, wheels, tires-
*Akebono big brake kit.
*rear camber kit
*drilled and slotted rotors
*Vossen VFS-2 wheels. 19x9.5 front, 19x11 rear.
*rear tires are 325/30x19

9 Posts
Discussion Starter #3

After pulling heads and valves I dont see anything major or even minor for that matter. Valve mating surfaces look good. Found 1 cylinder with excessive buildup of oil/ carbon compared to the others.


Intake valve on that cylinder has light pitting and after measuring valve seals, the seals are a little worn out .0012 compared to new seals. Nothing major IMO.

All were properly seated. And guides are in great shape.


All in all, the motor looks great. Going to cut valve seats clean some things up and start the reassemble.

Wire/vaccum tuck and fuel system simplification coming in once parts for the rebuild come in.

Anyone have suggestions on other things I should be checking or replacing while I've got it apart?

1,197 Posts
Was the crank mag'd and checked for straightness? Might be the time to check it while the shortblock is apart.
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