I actually like where the thread is going. It's not often you hear much positive comments on the HZ series. I think the engine has been overshadowed by the HD series, just because they are so darn good. On the other hand the HZ has had some minor weakness's that have been exposed through lowsy turbo jobs, and hence they now have a (imho) a unfairly bad rep.
To answer IndroCruise and anyone else wondering why I have settled on the 1HZ build over a 1HD-FTE, let me explain. Cost is only part of it, but as you're about to see, my build won't be that much cheaper in the end, but it will be what I want. This may be a lengthy explanation, and will probably draw in a few jaded ex 1HZ owners too - not sorry.
I use the car as a daily driver around town, so I don't want a wild off-road beast at all. The 105's are superior off-road right out of the factory anyways. I will have 2inch lift, 285/75/16 tires, and some basic bolt on mods for touring. That's the main end goal- a car that tours well, and gives me really good drivability towing a camper or boat, and really good power and economy. All engineered to last at least 300,000kms without any major overhauls (that's 2xtiming belts if anyone cares). I used to have a HZJ105r with a 1HZ. Yes it was lowsy without the turbo, but it was smooth to drive with the manual, and with a safari turbo (mitsubishi? I think)
@12psi, fmic and 3inch ex with a big muffler, it gave me around 380nm and 140ish wheel HP (I think). It was completely transformed and performed faultlessly for me for the next three years, before it made way for a LC Prado that the misso could drive- and unlock the doors! The standard 105's didn't have central locking and she couldn't reach to the other side to unlock all the doors for the kids.
. Interestingly, before the turbo I got 13-14ltr/100 pretty consistently, unless you were towing, then the mileage suffered big time. But after the turbo & tune, I got consistent 13ltr/100 and on a 10,400km tour to Darwin and back, we averaged 14.5ltr/100 with the camper which was around 1500kg/3300lbs. UnclejakeNZ while 16ltr/100km is still considered OK, I suspect if you added a 3inch exhaust and fmic + tune, you would knock the fuel consumption down even more, and the egt's. Plus mine was part-time 4x4 so most of those kms were in 2wd on tarmac highway. I might also note that whilst many would like a 6th gear, or taller diff ratios, the HZ seems to really
sing at around 2400rpm- which is kinda noisy especially for 10400kms! I am a marine tech by trade, and we always found that any engine, petrol or diesel, and regardless of drive type, always had an rpm that it seemed to really
'sing' at, especially once it was prop'd correctly. Basically it felt just right for the engine itself. I never minded it, so long as the engine was happy- could just be part of the mechanics mental disposition, plus I always like to cruise at 110km/h if I can. Anyways I digress.
I was initially set on a 1hd-fte swap, and I have those here (in Perth) for $12k with a harness and pedal, but not much else. I want the finish product to feel, and look and perform as if it was the 1999 model 105 Toyota should have built, without restriction. As a mechanic, I didn't really like that I wasn't going to know how may km's were on my new motor, and I was still going to need to buy a bunch of add-ons (to improve overall engineering & efficiency) that would bump the whole cost right up. And those add-ons could give me potentially 1000nm/250rwkw which I didn't need or want. Actually I take that back- I just didn't want flow-on drive train problems, I wanted reliability. Who doesn't ever want more power?
The other thing was that I wanted to keep my trans, and fit a new valve body & tune it, potentially with a compushift. Then I would have a bulletproof & better performing A442f. But I needed to change the bellhousing, input shaft, and some other little bits to mate it to any of the diesel blocks which would basically require it to be fully stripped down and rebuilt, adding significant cost. Along the way, I always had the 1HZ
ground-up option in the back of my mind.
So I started looking around and very quickly (at the local wrecker) found a complete 1HZ from a HZJ80 which are apparently stronger than the 105 blocks wich they would sell super cheap, and without a warranty, it was not running, but it turned over and all the bits are there. And they also had a super rare A442f that started it's life behind a 1HZ. So for $3k I had all the basic ingredients to do a 1HZ build with the factory trans, and completely rebuild the engine + turbo to suit my needs - fix all the weakness's of the HZ and have a zero km engine that I knew inside and out.
Finally the question I'm sure everyone is dying to pose;
"But the 1hd-fte are quieter/smoother/produce more power/torque and are more economical, why would you go to so much effort on a 1HZ?"
The answer is that I just like the 1HZ. I like that's it a little agricultural, and sounds more like a 12HT and less like a 2ltr twin turbo Amarok. I like that I can tune and repair every single thing on the car without a laptop, and I like that it is pre everything that makes diesel engines snotty. I don't think there's any question the 1HD-FTE is pretty much the best engine Toyota ever made, (bar the 12HT) but it's just a little too silky for me.
So in the end, it will be a complete long-motor rebuild from the g-turbo lads, I have been following their R&D on the 1HZ for a few years now and the testing and reliability is now pretty extensive (they have extracted 500hp from a 4.5ltr stroked 1HZ on nos! why?... well why not?) Mine will have ADS 12mm pump, and upgraded injectors. G-turbo red wheel G350 @26psi. Probably (not sure yet) a PDI FMIC, and a Redback 3inch exhaust, again with 1 large muffler- these give good flow, a nice tone- but no drone at highway speeds. And some other minor machining mods to the block and head.
Oh and upgraded head studs, rods and pistons. Important note here- One of the most common failures of turbo 1HZ's is cracking pistons. I'm sure there would be numerous threads here on the subject, but the problem was/is caused by poor tuning, and turbo kits that are not well engineered or matched to the 1hz. Simply put too much diesel fuel & not enough air. Burning diesel = combustion heat, period. More diesel... more heat. The factory pistons could handle plenty boost and even the combustion pressures, in fact some are running 25+ psi without any issues for some time. But they can not handle the heat, so the correct tune needs plenty of boost, and a correctly matched turbo + proper tuning to clear out the cylinders after each power stroke and keep cool, fresh air circulating through the engine efficiently. I'd love anyone who has solid info, or real life experience on this to chime in, or correct me if I am wrong. And point me to any threads on the subject please. Anyways the stronger pistons are just extra insurance.
I will also fit a part time kit to the AWD system to help it drive a little better on the highway, I suspect the extra torque will probably give some more feedback, plus it will help with economy. And, I will also keep the two factory fuel tanks as they are- this has been an important factor for me, particularly since I want good range on the fuel I can carry. The old standard I had, with the barn doors sucked- the top/bottom rear tailgate on the GXL's is heaps better, and with 3 kids and the dog either on or off the road I like to be able to get into the rear of the car easily, even with the camper on. So I didn't want wheel carriers in the way, but to keep it as clean and clear as possible.
So the target, which has already been reliably proven a few times by the g-turbo guys, is 170kw/650nm at the wheels, and average fuel consumption as low (or lower) than 12ltr/100km, through the 4 speed A442f and the factory diff ratio's from the 1FZ, which should land me at 2200rpm @ 110km/h. All up the cost would be similar to a imported 1hdfte swap, but with zero km's, and similar end results. Plus there are some other random benefits like the factory cruise control still working as it should etc.
Happy questioning/input/advice please, just don't bash me with your keyboards yet. I'm a forum noob.
He reckons with the lockup it drives completely different, you can really use the engines low down torque now.
never going to be a rocket ship but hasn't let me down in all the years I've had it. I've heard great things about the gturbo kits they spool a lot earlier too. I've fitted the redback turbo back 3" exhaust and fits very well without interfering with anything. I've seen they do kits to suit different turbo set-ups or factory.