Hi guys, I have a crack in the head on my 06 ZD30. I service every 5000ks it has never been hot and I am not happy.I rang around and found out alot of the zd30 heads just crack when they feel like it.I talked to a bloke in Brisbane and he advises me to put an after market A.M.C head on and I will never touch it again.He said that the original head is just rubbish and A.M.C head has a lower silica content in the alloy and in general a better built head. If any one has used an A.M.C head on there zd30 some feed back would be great.It is a Spanish built head and he is the only bloke that has offered me something other than chinese crap.A.M.C stands for American Motor Corporation.
Cracked Head at 70000ks
- Thread starter barna
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i have to disagree a bit here. i've rarely heard of any ZD30 just cracking heads that didn't have other problems. typically pistons are cracked as well. all this is typical of excessive egt's which is quite possible with a chipped engine.
afaik these engines are japan built and i certainly prefer japan made to spanish made.
afaik these engines are japan built and i certainly prefer japan made to spanish made.
AMC - Cylinder HEADS for diesel and petrol engines its not american motor corp.
tukangbaso
Member
i've heard mostly is with patrol ZD30s as the maf gets dirty and send wrong signal and runs rich etc.. have not heard one on the navaras but i suppose there's always one. mine's done 180 000kms+ and it's still good
Sorry guys I forgot to note that the chip has only been on for about a month and the symtoms of loosing water have been going for about 3 months. At first I just thought it was a bit of evaporation and then tried a new radiator cap and then got it pressure tested and bingo cracked head.Correct me if i am wrong but if i were getting high egts would'nt the water temp guage move of normal position. The most i have ever towed is a 4.6m tinny around and my inlaws car on a trailer once for an hour.So in my eyes that should'nt crack a head.Yes i have heard the patrols mainly do this but they still have the same head as the nav 3.0lt.
i've heard mostly is with patrol ZD30s as the maf gets dirty and send wrong signal and runs rich etc.. have not heard one on the navaras but i suppose there's always one. mine's done 180 000kms+ and it's still good
Just thought i would ask the question mate do you load it up and tow any thing with it.
exactly.i've heard mostly is with patrol ZD30s as the maf gets dirty and send wrong signal and runs rich etc.. have not heard one on the navaras but i suppose there's always one. mine's done 180 000kms+ and it's still good
be interesting to see where the cracks are once head is removed.
could be just bad luck and got a bad head. but i don't think its a common problem.
having said that it may be caused by other common problems. eg the fouling up of the intake by the EGR, egt spikes from burning engine oil, poor running due to bad diesel, worn injectors, blocked up cat caused by all of the above.
high EGT's does not show on the water temp gauge. most factory gauges are dumb and it would have to be a massive increase in egt's over a long time before water temp would go up. engine will be history before water temp ever changes.
D
Dave
Guest
Pretty much what Tweake said.
The engine will destroy itself before the temp gauge goes up.
Its only measuring coolent temp.
EGT gauge is the way to go.
Cant comment on those heads as I have never had anything to do with them.
The engine will destroy itself before the temp gauge goes up.
Its only measuring coolent temp.
EGT gauge is the way to go.
Cant comment on those heads as I have never had anything to do with them.
The crack is between the glow plug and exhaust valve on number 4. I read some where on the net the glow plugs on these engines time for 5 minutes and the heat from them on a cold head could be the cause. I told a couple of mechanics that have sold heaps of the ZD30 heads and they laughed and said what a load of rubbish. Does any one no what EGT's these engines can go to before doing damage, Because there is no point having an EGT guage if you dont no the highest running temp.
the cracks are not caused by the glows.
the spot between glows and valve seams to be a weak point. its just had high egt's in that cylinder. egt gauge may not have even picked it up as it measures mixed temp from all cylinders.
the patrols tend to fail on the rear cylinders. not sure if its due to the manifold clogging up or those cylinders receiving higher amounts of egr. also it could have simply been a valve out of adjustment.
the spot between glows and valve seams to be a weak point. its just had high egt's in that cylinder. egt gauge may not have even picked it up as it measures mixed temp from all cylinders.
the patrols tend to fail on the rear cylinders. not sure if its due to the manifold clogging up or those cylinders receiving higher amounts of egr. also it could have simply been a valve out of adjustment.
D
Dave
Guest
The rear cylinders always run hotter.
TB42 heads crack in the rear cylinders and Falcon 4L SOHC engines always blow the head gasket in the No 6 cylinder.
TB42 heads crack in the rear cylinders and Falcon 4L SOHC engines always blow the head gasket in the No 6 cylinder.
Well I have sent the head of today and I will keep you posted on what the AMC head looks like and how it performs. Cant wait to get it so I can put it all back together. It puts a tear in my eye seeing my beast in a thousand pieces in my shed.
i hope you have cleaned the pistons up and had a really good look. i would be inclined to pull them and get them checked.
I am going to on the weekend. the machanic said to spray some carby cleaner on the pistons and have a realy good look. I have looked with a torch so far so good but will soon tell once there cleaned. Taking pistons out that makes me sick, I hope not .
EGT should NEVER go over 740 Degrees C for any more than 1 - 2 minutes duration infrequently. Maximum sustained exhaust temp I'll ever allow my other fourby to get to is 620 and even then I get antsee if its there for any longer than about 5 minutes.
Thanks for the info Stepho, But I have to ask, where did you get those temps from. I am not trying to be a smart ass, I would like to no for sure what these motors can run at?.
i don't know if anyone has actually tested these motors to destruction to find out.
generally its a max of 800c pre turbo. some people will use lower temp, especially if the motor has a known problem with blowing heads etc.
i think some of the D40 owners found they run about 800c with stock fueling !
generally its a max of 800c pre turbo. some people will use lower temp, especially if the motor has a known problem with blowing heads etc.
i think some of the D40 owners found they run about 800c with stock fueling !
Max Combustion/EGT temps
As Bama says below "no one has ever tested these engines to destruction" My temp range guide comes from experience driving trucks. Im not a professional truck driver but during the late 80 and early 90s I did a fair bit of float work driving Volvo's and Macks. The Mack hand book had some guidelines in it and I drove with a bloke who had years of experience on various different engines. These temps are exhaust temps post turbo, obviously the combustion temp is significantly higher. The further down the exhaust the Pyro thermocouple is the lower the read is going to be and hence more removed from reality with the combustion chamber temp.
Without getting into details I feel comfortable that these are "safe" temps and if stuck to will ensure engine longevity. I'm also a fitter/toolmaker by trade and I learnt a lot about metallurgy when doing my trade.
As Bama says below "no one has ever tested these engines to destruction" My temp range guide comes from experience driving trucks. Im not a professional truck driver but during the late 80 and early 90s I did a fair bit of float work driving Volvo's and Macks. The Mack hand book had some guidelines in it and I drove with a bloke who had years of experience on various different engines. These temps are exhaust temps post turbo, obviously the combustion temp is significantly higher. The further down the exhaust the Pyro thermocouple is the lower the read is going to be and hence more removed from reality with the combustion chamber temp.
Without getting into details I feel comfortable that these are "safe" temps and if stuck to will ensure engine longevity. I'm also a fitter/toolmaker by trade and I learnt a lot about metallurgy when doing my trade.
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