Thoughts on the 1HZ (1 Viewer)

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Joined
Jul 22, 2003
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Location
Perth Western Australia
The new motor is on its 2nd tank of fuel and has clocked up its 1st 1000klms
Im really impressed with the power of the 1HZ. I driven lots of new ones but for some reason never considered mine would equal or even surpass them.:D
Maybe the lower weight of the 73 series compared to the HZJ75 makes some difference.

Driving it up hills is a breeze and it can accellerate in 4th gear on the steep hills or at least hold that gear if its really steep. Certainly a big improvement over my tired old 3F.
Driving in traffic is ..well,a breeeze and I have never wished for something faster.
It has its own broad torque curve which pushes it along quite nicely if you can keep the rpms around 2000-2200
On the open road it has plenty left for overtaking and as its still new I havent exceeded 120 klms yet,but it still has a fair bit in reserve even in 5th gear.
The shop that rebuilt the pump told me that this is where I would get the most out of the rebuild and they were certainly accurate about that.

Starting in the morning is easy,count out 10 seconds ,hit the key and it fires up within 2 seconds.No smoke ,no rough idle ,just a steady diesel growl:D
I only have a simple glow plug button without timer,drawing its power from the old coil wire.
As the 1HZ is reknown for its easy starting in warmer climes I dont see a need to change it to something more complex(troublesome).

Fuel economy is also superb and I got 650 klms out the 90 litre tank.
That was in its 1st week with a tight motor ,so it may improve even more.
Ive had other engines rebuilt over the years and they all ran hot for the 1st week at least.
Not the 1HZ,it ran warmish for the 1st hour in traffic and slightly more on its 1st freeway trip but the gauge has now settled to about 1/4-1/3 and doesnt move at all when in 4x4
I still havent sorted out the oil pressure gauge. The 1HZ uses the same sender as the F motor but for some resason is not reading with the new motor.
When I tested the oil pressure mechanically when I first started it ,it was reading 75 psi at about 2500 rpm and 30 at idle.
Certainly flowing well as I can see it splashing around through the oil filler hole.
I will change the oil and filter soon and retest it. Oil is only slightly discolured

All in all the 1HZ motor is great for those who want a naturally aspirated diesel without holding the traffic up.
And who said diesels were smelly,noisy and slow?:cool:
 
Last edited:
Welcome to the club! they really are great engines.

Oil sender:
I had the same issue when I did my swap. The 1HZ sender would not register on the original guage in the truck. I swapped it out for the old 2H sender and still no dice. It is possible the 2H sender was bad (might explain how the PO ran it low on oil causing the thrown rod bearing in the 2H in the first place). I never got around to trying a new 2H oil pressure sender, i just ended up installing a mechanical gauge under the dash. Let me know if you discover anything.
 
VTCruiser said:
Welcome to the club! they really are great engines.

Oil sender:
I had the same issue when I did my swap. The 1HZ sender would not register on the original guage in the truck. I swapped it out for the old 2H sender and still no dice. It is possible the 2H sender was bad (might explain how the PO ran it low on oil causing the thrown rod bearing in the 2H in the first place). I never got around to trying a new 2H oil pressure sender, i just ended up installing a mechanical gauge under the dash. Let me know if you discover anything.

So far Ive tried a new sender and the old newish one off the 3F.
Im not 100% I have the right wire as the end got mangled during the ind=stall.

I think the wire was in a bunch of spaghetti that ran to the old starter or coil.
That spaghetti is mainly redundant so it may have something to do with that not doing anything but Im only guessing.
Il probably give it to my auto electrician who loves the jobs I give him:rolleyes:

The temp gauge works ok using the old wiring and sensor
 
Rosco:

Good to hear you got her going!

My fuel economy appears to be a bit better than what you are reporting - probably due to the fact that my engine is broken it.

Last tank at 110 to 120 km/hr speeds resulted in 8.5 km/liter - going uphill on the Coquihalla.


I'm going to post up more detail results in my HZJ73 thread.

Jim
 
Jim_Hbar said:
Rosco:

Good to hear you got her going!

My fuel economy appears to be a bit better than what you are reporting - probably due to the fact that my engine is broken it.

Last tank at 110 to 120 km/hr speeds resulted in 8.5 km/liter - going uphill on the Coquihalla.


I'm going to post up more detail results in my HZJ73 thread.

Jim

I dunno about that,650 divided by 90 liters comes to 7.2 klm/litre;)
Mine was nearly all city driving:D
 
slap on a turbo, intercooling and a fuel pump tweak...the fun jus started


I have a 1HZ turbo-intercooled coupled to a R151F straight from a 2001 HZJ79.


very torquey:cool:
 
Mine has the 1HZ and I know exactly what you are talking about: the growl, the power... it is an awesome engine. I get about 650km per tank too. Congrats on equipping your LC with a new "beast" :)

Sergio
 

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