ZD 30 Options.

[PMC]

[QUOTE=nissannewby;661796]I would still recommend to remove the head to perform the work you want to do.[

I agree 110% with nissannewby, all my engine rebuilds over the years i have always removed the the head/heads when horning and boring cylinders. It is crucial that the horning tool scores the entire bore and leaves no lip at the top of the bore.

Regards,

PMC

[mudnut]

Yeah, I was hoping that end of the bore could be got at.

[Rumcajs]

The pistons melting isn't the root cause. Heat is. Same with any engine.

Aaaaaaaaaaaaaaaand the heat is melting the pistons .

Seriously, the ZD30 woefully inadequate pistons design and materials they're made from can't really cope with the output asked for especially when combine with that fail prone high pressure fuel injection system and results are there. Basically on their limits during easy to moderate loads once introduced to serious workout in high ambient temperatures like in Australia it is just a matter of time.

Had Nissan used cast iron skirt less pistons (not really widely available at the time though but still could use steel forged crown and articulate skirt units)and designed cast iron head as well it would be non issue today and ZD30 would have the distinction of be the most reliable Nissan diesel engine with the power output to match and TD42 would be largely forgotten.

Lets not kid ourselves, ZD30 was born at times when Nissan faced bankruptcy (the world would be better off indeed in the hindsight) so it was only natural for the cost cutting exercise to use the cheapest design and materials available. I'm pretty sure everyone is pretty much well aware of Nissan business model by now ==> cheap and nasty and keep recycling old stuff as long as possible.

My guess, Nissan car engine division boffins went to a Sushi bar got drunk and knocked off petrol engine design together with balance shaft crap and penned the mongrel with diesel injectors....using petrol motor components. Honestly I'm yet to see decent Nissan car division modern diesel engine, not a nice record there, just look at the mongrels produced ==> RD28 (RB petrol based/copy mongrel), ZD30(QD based perhaps a bit of TD2x thrown in) vs Nissan UD truck engine department designed TD42 small truck/bus/forklift engine.

Anyway, back to OP,

Remove the head and do the job properly. You can source slightly stronger pistons as well from ACL rebuild kits if they're still available. Make sure to have injectors checked or replaced, those dual spring abominations are known to leak/dribble fuel....

Cheers

[mudnut]

There is the answer I am looking for. Better quality pistons can be fitted to eliminate the grenade factor. If I was getting a recoed ZD30 I would fit the better pistons in a heart beat.

[nissannewby]

Just changing the pistons will not eliminate the "grenading" that can happen with these engines. For any engine for that matter. The pistons are just part of the equation.

Then there is also rebuild practices as well. It needs to be done right. There are quite a few people around that have spent dollars on rebuilds only for them to fail again. This isnt limited to the zd30 either

[mudnut]

I re-read what I wrote, and should've written: eliminate one cause of the grenade factor.

From what I can understand, soot from the EGR combined with contamination from the turbo cake up the intake, result in reduced are flow and high tempuratures.

That is taken care of by blocking the EGR and installing a catch can. Also running proper oil levels a must with this engine. Control of the boost is taken care of with a needle and Dawes valve.

With all of this taken care of, I struggle to understand why roofy's unit still failed.

[nissannewby]

Many factors mate. And his isnt the first to fail with nads.

All parts of the equation ecu, fuel system, intake system, egr system etc etc. Sure you can fix one but the others still exist.

[mudski]

Many factors mate. And his isnt the first to fail with nads.

All parts of the equation ecu, fuel system, intake system, egr system etc etc. Sure you can fix one but the others still exist.

Yeah, we discovered from the 3ltr we pulled from my car that number 4 piston had a crack in it so it was only a matter of time for my motor. And I had done everything know to man to eliminate said issues. Well try to atleast.

[PMC]

G'day folks,

Two things i am going to look into while playing with my 3lt Patrol,

Firstly to purchase a second hand short motor with the aim of rebuilding it with ceramic crown coating forged piston from Diesel Performance Parts. My research has found that these pistons are the ducks nuts for performance diesel motors. The following is a spiel about these pistons

Diesel Performance Parts® is ENGINE Australia’s private label, range of aftermarket performance diesel engine parts. The range consists of pistons with ceramic coated crowns and MoS2/Teflon coated skirts, to suit the Nissan diesel engines. These pistons are pre-topped 0.15 mm to compensate for decking the block and were further pre-topped in the factory to allow for the added thickness of the ceramic crown coating. New pistons are being continually added to the range.

The non-porous ceramic crown coating can withstand temperatures of up to 1300°C and pressures of up to 69,000 kPa (10,000 psi). This helps to keep the piston cooler, which stops it from softening and failing prematurely from high combustion chamber temperatures. Reduced heat loss to the piston equates to better fuel burn rates, and increased power and fuel economy, depending on how the engine is operated.

The MoS2 skirt coating contains Teflon and is a dry film lubricant. It adds 0.025 mm (0.001”) to the skirt diameter and can withstand temperatures of up to 600°C. It will help prevent piston scuffing in the bores in most marginal lubrication conditions.

Product packaged under the Diesel Performance Parts® brand is manufactured exclusively for Engine Australia, to Engine Australia’s specifications. Customers using Diesel Performance Parts® products benefit from Engine Australia’s extensive engineering experience with, and knowledge of, diesel engines, their operations and components. With direct access to engine parts manufacturers around the Globe, Engine Australia is able to better service the aftermarket diesel engine parts industry with quality Diesel Performance Parts®.

Secondly is to resigned the inlet manifold so that the correct fuel air ratios are balanced to all ports. One of the main problems i can see why 3/4 pistons are letting go is due to over fueling in these cylinders, resulting in extremely high temps. Also the fact that the Nissan Pistons in the 3lt are a substandard material which does not help.

As Nissannewby rightly explains there are a multitude of problems that cause these motors to let go. It is being able to address all these problems together.

This is going to be my research and development hobby!!!!!!!!!!!!!!!

Regards,

PMC

[mudnut]

Thanks, mate. I wonder if anyone would object to getting a set installed on roofy's new engine?

Edit: reco mob use different pistons anyway, apparently.