Went into my mate's workshop the other day to buy some oil that meets Nissans oddball requirement (will be Mobil 3000 synthetic when it comes in - Mobil tech gave me what sounds finally like a reason for Nissan wanting nothing more than CF-4, namely that they've told mobil that with their OHC diesels, soot dispersion wears out the valvetrain).
Anyway, he was bitter, as his Nissan Navara 3L direct Injection turbo had lost two pistons after a gear change towing a trailer up a hill (It's rated to tow 3,000Kg)...he's got another 2 waiting for engine rebuild after grenading also.
Looks like Nissan got a bit too carried away with this engine.
It's a 4 valve per cylinder direct injection turbodiesel, with EGR, and a crankcase ventilation system that discharges straight into the turbo inlet.
I've known that there's a lot of oil gets through, as the pressurised induction hoses all weep.
In order to get the EGR to work on an "unthrottled" diesel, they've modified the "normal" operation of the shutoff butterfly to partially close under EGR conditions, reducing the boost in the inlet, and driving the EGR into the manifold...this can be as frequently as every gear change this butterfly partially closes.
The evidence appears that the combination of soot and oil and junk can get this butterfly to stick, following a high load downshift up a hill, which under airs, and overfuels the engine. My mate reportd that he downshifted, felt a lack of power, then saw blue smoke everywhere.
There's also a "swirl" butterfly to close one intake port under light load conditions "to improve driveablility", where it really seems only to improve EGR mixing.
This morning I blocked the EGR.
Before I could mod the butterfly controls, boss needed the car.
She came back wildly happy that an intersection she normally kangaroos/snatches at was smooth as silk..."what did you do to the car"
Tried it myself, and very impressed at the responsiveness in the lower rev range.
So does a "Butt dyno" count if it's your spouse, and she doesn't know what on Earth you are doing in the shed ?
Anyway, he was bitter, as his Nissan Navara 3L direct Injection turbo had lost two pistons after a gear change towing a trailer up a hill (It's rated to tow 3,000Kg)...he's got another 2 waiting for engine rebuild after grenading also.
Looks like Nissan got a bit too carried away with this engine.
It's a 4 valve per cylinder direct injection turbodiesel, with EGR, and a crankcase ventilation system that discharges straight into the turbo inlet.
I've known that there's a lot of oil gets through, as the pressurised induction hoses all weep.
In order to get the EGR to work on an "unthrottled" diesel, they've modified the "normal" operation of the shutoff butterfly to partially close under EGR conditions, reducing the boost in the inlet, and driving the EGR into the manifold...this can be as frequently as every gear change this butterfly partially closes.
The evidence appears that the combination of soot and oil and junk can get this butterfly to stick, following a high load downshift up a hill, which under airs, and overfuels the engine. My mate reportd that he downshifted, felt a lack of power, then saw blue smoke everywhere.
There's also a "swirl" butterfly to close one intake port under light load conditions "to improve driveablility", where it really seems only to improve EGR mixing.
This morning I blocked the EGR.
Before I could mod the butterfly controls, boss needed the car.
She came back wildly happy that an intersection she normally kangaroos/snatches at was smooth as silk..."what did you do to the car"
Tried it myself, and very impressed at the responsiveness in the lower rev range.
So does a "Butt dyno" count if it's your spouse, and she doesn't know what on Earth you are doing in the shed ?
