Some people will think I’m crazy for even considering such an engine as a viable replacement for the undependable 3L engine that originally took pride of place in the engine bay of my Patrol. However, it was one of the best (and worst) decisions I’ve made.
The trusty TD42 engine may have been originally designed by the engineers at Nissan to power forklifts, but someone made the silly (read: amazing) decision back in 1987 to shove it in the updated Patrol replacing the once reliable, now dinosaur, SD33 naturally aspirated diesel. It was one of the best things Nissan has done.
Little did they know, people two decades later would mount turbochargers to them in an attempt to extract more than three times the horsepower they were designed to produce. So, once the little ZD30 engine gave up trying to move 3.5 tonnes around on a daily basis some five years ago, the choice to drop the TD42 into its place was regrettably obvious.
"Big capacity diesels being fed big boost are as addictive as heroin (I assume)."
Before I explain, let me sing you the song of my people – the diesel torque-addicted, black soot-chugging people.
Big capacity diesels being fed big boost are as addictive as heroin (I assume). The resulting torque produced is astounding and unmatched by their petrol brothers due to much higher combustion pressures at low rpm. The problem with big power is whilst the tyres are trying to rotate the earth in the opposite direction, the engine is trying to tear itself apart.
Now, Nissan got it pretty bang on when it came to engineering the TD42, but not perfect. Commonly referred to as a kettle, they do suffer from overheating issues at the slightest sniff of a hill if the cooling system or tune is not up to scratch. Oh, and they snap cranks. Daily. Yeah, not ideal.
So why would a crank-snapping kettle find itself in the engine bay of my Patrol? Well, I never said I was smart. But with the potential of 1000Nm of torque at the rear wheels, great parts availability, economical and a (somewhat) reliable package. The devil on my shoulder took the reins and in she went.
Five years, 30psi of boost, most of Australia toured and a million smiles of fun later, the old TD was starting to get tired. It did a bloody good job to last that long. But, with our schedule at RDD looking like an interstate freight company’s log book, the decision was made to pull the engine out and send it to Performance 4x4 in Brisbane for a full rebuild with all the best bits available, as well as machining and balancing to suit.
As mentioned, the TD42 is a stout motor, even in standard form and can take some ridiculously high boost levels with relative ease. However, with my history of never being satisfied and the potential (inevitability) that I will turn up the wick at some point, I wanted the engine to take whatever I would throw at it.
A set of ceramic-coated pistons to keep the crowns from melting under “full send” hills
ARP Head studs to stop the head from lifting off the turbo-spec conrods with the larger 32mm gudgeon pins, ’cause race car
Turbo spec oil squirters to keep the piston temps down
Brand new assembled head with HD valve springs
Oversized liners to prevent bore expansions under extreme load
Alloy flywheel to reduce torsional vibration and keep the harmonics smoothed out
And all balanced and machined within tolerances that makes the inner machinist in me blush.
Whilst the engine was out, I also took the opportunity to replace a few things that are typically a pain to do with the engine in such as steering shaft coupling, unbreakable engine mounts, new clutch thrust bearing, and gave the chassis a birthday paint job.
This also gave me an excuse to tidy up some wiring, install some new Redarc EGT, boost, coolant temp and oil pressure gauges so I can keep my eye on everything whilst out on my adventures. It was time to run the engine in so that the piston rings could bed themselves in, all the bearings could settle and everything mechanical could find its home.
Once she was all run in, it was time to strap it to the dyno at Automotive Etcellence in Sydney and see what kind of numbers it would throw down. 214hp and 765Nm of torque on the 35in Toyos. Not bloody bad if you ask me! Enough torque to pull a dump truck I reckon and keep me giggling like the little girl I am. Hot damn am I excited to see how it goes in the bush!
Now, where’s the nearest muddy hill?