oil coming out exhaust, no compression

[kyledude351]

so after pulling off my turbos I found out they were fine, and the oil was coming from inside the motor.
The farthest cylinder from the front of the car is leaking oil out the exhaust, and only has 30 psi of compression.
Car was making a whine/grinding noise from that area right before I lost half my boost. Originally thought it was the rear turbo, but now I have no idea. Anybody have a problem similar to this?

[caliber676]

Leak down test will tell you what component is leaking compression. Usually piston rings or valve seals will leak oil, head gaskets as well. Either way you will have to pull the engine most likely

[Dragon Humper]

You fried #6 piston....very common. The rear of the motor is hotter than everywhere else so ring butting under a leanout is very common. Pull the motor and get to work. You can put another good used piston in there for a nice cheap fix that will last a very long time as long as the cyl wall isnt scored all to hell. If the cyl wall is all scored up then your only option is new pistons and a bore job.

When you do rebuild make sure that the rings on #6 are gapped .001" bigger than the rest to compensate for the extra heat at the back of the motor.




Jon.

[Bruizer]

Hope you got a good deal! welcome to GTR ownership (unless you're dragon humper with bullet proof gtr)

haha

[Skym]

You fried #6 piston....very common. The rear of the motor is hotter than everywhere else so ring butting under a leanout is very common. Pull the motor and get to work. You can put another good used piston in there for a nice cheap fix that will last a very long time as long as the cyl wall isnt scored all to hell. If the cyl wall is all scored up then your only option is new pistons and a bore job.

When you do rebuild make sure that the rings on #6 are gapped .001" bigger than the rest to compensate for the extra heat at the back of the motor.




Jon.

Can fit a slim sleeve to that cylinder (engine builder can do it) if it's too badly scored and want to reuse piston. But might as well fit forged pistons while it's apart.

Combination of stock intake plenum not flowing properly into 5th, 6th, bad ECU tune (lack of fuel) doesn't help. Also if get a leaking exhaust manifold from swinging exhaust (no flexi in front pipe), it can cause the exhaust studs to snap (replace exhaust manifold studs every 10 years or so).

Another trick is fitting the highest flowing injectors into 5th, 6th cylinders. But if have the money, buy a Link ECU or Vipec ECU with individual cylinder fuel, ignition trim feature (must have feature for front mounted intake plenums that don't flow evenly into each runner). That way you can run the last 2x cylinders richer to keep cylinder temps down.

[kyledude351]

right on. Well I guess i might aswell forge the bottom end while i have the chance, what should i do for pistons and rods?
Good intake plenum brand?

[Skym]

Cheap build is Tomei or similar (Cosworth, CP, ACL, JE, etc) forged pistons, stock Forged I beam conrods (as long as you keep stock or close to rev limiters), ARP conrod bolts, ACL race bearings or Nismo bearings, longer oil pump drive collar (forgot to mention this in another thread) for front of crank, good oil pump (adjustable Tomei to be safe with higher boost levels, rpm, etc), stock or N1 block, good to 700hp on dyno (high boost), around 460-480hp (low boost) for continuous racetrack use. Above 700hp, think about fitting H beam conrods.

Intake plenum, JUN style or genuine JUN.