[grsouthern]

Two engines in 172,149 Km.

My question is. What more could I have done to prevent the second engine from failing again?

This is my "second" motor in 172,149Kms.
The first was covered by extended warranty and replaced by Nissan at 132,000.
After that I installed everything on the list (NADS) thinking I would miss the grenade effect with the "new" motor.

Developed an oil leak from the cylinder head and took to my diesel mechanic not Nissan.
Just got the old girl back and she had cracks thru all cylinders, bent rods on the valves, and cracked glow plug seats.
A month ago I was stuck in Perth with a dying fuel pump and a $4,500 account to fix.

I tow a 2.8Kg caravan about 10 times a year shortest distance is 1500 km
A LOT of 4X4 driven with care as we photograph native orchids and stop a lot.
EGT temps never go above 500
Boost up to 18 psi
Slow wind up for turbo with screw on VNT just above the seat.
Automatic
Serviced professionally by a diesel mech every 5,000Km

I love the 4x4 ability of the Patrol and its very comfortable on long distances, and would rather keep if possible as there isn't a vehicle out there that I would prefer.
What can I do to preserve the vehicle ?

Thanks in advance,
Tanya

 

[skegbudley]

That's a couple of problems.
The head cracking part is easily preventable with a glow plug timer and steel tip glow plugs.
Any idea what caused the bent valves?

 

[skegbudley]

Glow plug timer mod. Costs under $50. Value = priceless.

Stops this.

Go have a look in the ZD30 section for several threads on the subject.

 

[geeyoutoo]

Mate, a grenade holes pistons 3 & 4 (usually), maybe crack the head, it doesn't bend valves, that is another scenario. My grenaded ZD30 was rebuilt in late 2006 and never another issue since then, so I'm not sure what else you could have done, bent valves is a timing issue.

 

[patrol97]

if you bend the valve could be related to the timing chain - or timing chain guide?

 

[DieselTuner]

The engine would not have run AT ALL if any of the valves were bent.

Interested to hear you have made the turbo spool up slowly? That definitely can cause problems with the head cracking if there isnt enough boost to burn the fuel properly.

Also, what does he mean by cracked glow plug seats?

 

[grsouthern]

My understanding from the mechanic. He was checking and testing everything while rebuilding the engine.
When checking the valves he found they were bent.
I changed the spool rate yesterday after getting the car back, as I had a lag and then a sudden surge when putting my foot down from standing still, that is remedied now. I am finding this is a very fine line. It is now a smooth acceleration.
I believe the area around the glow plugs were cracked as well as the head.

The photo from skegbudley is exactly what I had on all four cylinders.

 

[geeyoutoo]

WTF! slow down and explain each step step so we can all understand what is happening here.

 

[motomuzz]

The first motor exited then replaced..but the head exited on second motor 50k later? Is this another example of reusing the original head on a rebuild? Which weve seen before with bad results.
Its hard to fathem whats going on here.

 

[grsouthern]

P { margin-bottom: 0.21cm; } Replacement First engine @ 132,000km
An indicator that I had a problem was the Patrol consumed 1 litre of coolant on an 8 hour 4x4 outing.
Next day I returned to Nissan and they found that number 4 had cracked.
After 13 weeks I got it back (haggle about extended warranty).
I had the injectors replaced at this point.
I was informed by the service manager that it was a new engine, but have since found that it was a reconditioned short motor from a Sydney company.

Installed NADS.

(Nothing but problems with oil leaking from dip stick, ( an O ring problem. Remedied. Coolant leak from front, remedied. Finally a sudden huge oil leak left hand side of the cylinder head at 172,000km (garage floor indicated problem) .

Took to Diesel Mechanic (Nev) thought it may be another sealng issue.
When he dismantled the engine he found cracks .
Replacement Second Cylinder Head @ 172,000Km
The invoice contains;
Mill exhaust manifold.
Test injectors.
Cylinder head kit incl GSV2318SSXND, GSS2318SS2D, HBK4964D, NSI cylinder head
Pressure test
Consumables.. etc.

During the Check and test, (injectors etc) this is where he found the valve rods bent - he tested them on "the machine". When telling me he was amazed and could only shake his head. When I asked what caused this, he didn't answer but something like fear ran across his eyes.
He was meticulous in checking everything. He is like that ;-))

Got the Patrol back on Thursday and there was a dead spot (lag?) from moving from standstill. It was like it had asthma, then at 1500rpm would shoot forward (surge?).
So I changed the spool control back to factory by turning the needle valve off, and returned to the factory setting with the screw on the VNT. That appears to have remedied the slow asthmatic start and the sudden surge forward at 1500rpm. It is now a smooth acceleration.
Dawes valve with heavy spring is set at max 18 psi.
I'm up in Perth in May and will book into a tuning specialist especially in regard to this model Patrol with experience re Dawes and needle valve.
In the meantime I'll get the glow plug timer installed, and steel tip glow plugs.

Thank you all for your help it has been very constructive.
Cheers,
Tanya

 

[ACMPatrol]

Can someone explain why using a glow plug timer helps to stop the glow plug tips from burning/breaking/causing head cracks.

I always thought that the glow plug tips got red hot anyway from the compression and subsequent fuel ignition.

Can't see how a bit of supplementary electric heating after cold start would cause problems.

 

[tweak'e]

Can someone explain why using a glow plug timer helps to stop the glow plug tips from burning/breaking/causing head cracks.

I always thought that the glow plug tips got red hot anyway from the compression and subsequent fuel ignition.

Can't see how a bit of supplementary electric heating after cold start would cause problems.

they don't have supplementary heating, ie low voltage. they run full voltage until engine is up to temp. so they run extremely hot.
some of the toyotas have the same issue. the glow plugs are meant to be replaced every 100,000 km's regardless, otherwise they break and damage the engine.

 

[skegbudley]

Can someone explain why using a glow plug timer helps to stop the glow plug tips from burning/breaking/causing head cracks.

I always thought that the glow plug tips got red hot anyway from the compression and subsequent fuel ignition.

Can't see how a bit of supplementary electric heating after cold start would cause problems.

The light on the dash is just a "idiot" light.
The ECU in the Di keeps the glow plugs on for 5 minutes unless the engine is already at operating temperature. The ceramic tips get white hot and can easily melt through the top of a piston. The heads crack between the glow plugs and the valves due to the constant heat.
Having the timer set to 30sec with steel glow plugs should resolve this.
Piece of mind for less than $50. I can live with that.

 

[Bekah]

The light on the dash is just a "idiot" light.
The ECU in the Di keeps the glow plugs on for 5 minutes unless the engine is already at operating temperature. The ceramic tips get white hot and can easily melt through the top of a piston. The heads crack between the glow plugs and the valves due to the constant heat.
Having the timer set to 30sec with steel glow plugs should resolve this.
Piece of mind for less than $50. I can live with that.

Think i need to do this one

 

[ACMPatrol]

So does that mean that while the engine is running with the glow plugs unpowered, they still get hot from compression but not as hot as when powered?

 

[skegbudley]

Yes