1HZ Engines

Brett,
From 1990 to 1995 there was the 4.2 indirect injection diesel and the 4.2 direct injection turbo engine. After '95 the Multi Valve direct injection turbo diesel engine was on offer. The latter engine with the Multi Valve did have a different fuel pump and was a quicker vehicle but lacked low down toqure.

Wayne

Hi Brett,
The only difference that i know about is that the standard versions had one type of fuel pump(no tacho connection) and all the rest GXL etc had a different fuel pump which incorparated the tacho connection. The rest of the engine is the same as far as i know. Regards
.Bob

From what I understand, after late 1992, the 1HZ had a different crank and bearings to eliminate the earlier problems with spinning bearings.
When it came out in the 100 series it had a different inlet manifold that gave it another couple of KW.
Don't know of pump changes although it is possible as on the 2H engine there were 3 different pumps and 3 different injectors.
Regards
Tour boy

Brett,

Don't get confused with the turbo engines for cruisers which had a different engine designation as per wayne and tourboy's response.
The 1hz is still basically the same engine with very little changes. Head changed in 98 but really just a casting change everything else remained pretty much the same.

Thanks for the info guys. I did stumble over some info on the 'net........ I probably should have stumbled over this before I posted the question...duh!!
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IMPROVED DIESEL FOR LANDCRUISER 78 SERIES
It is the second improvement to workhorse LandCruiser's class-leading 4.2 litre naturally aspirated single-overhead camshaft 1HZ diesel engine in 18 months.

On-highway fuel economy has been improved by five percent.

The new LandCruiser diesel engine has a high-altitude compensator to reduce rich running in the high country.

The HAC therefore lowers engine emissions and minimises engine oil contamination.

Toyota has improved engine cooling by increasing fan blade diameter from 450 to 470mm. Fuel efficiency has been increased and noise has been decreased by adopting a three-stage viscous fan coupling in lieu of the two-stage on the superseded LandCruiser 75 Series.

In addition, the improved LandCruiser 78 Series diesel has a 10 percent increase in alternator capacity (to 110 Amps) and an aluminium radiator.

LandCruiser's 1HZ engine was upgraded in May 1998 to meet European emissions standards.

Improvements at that time included a new piston and combustion chamber design, large injector nozzle holes, new injection timing, a new glow-plug system, increased oil pan capacity and the adoption of an hydraulic cam chain tensioner.

The improvements increased maximum torque, increased engine service intervals, reduced exhaust emissions, reduced noise, improved piston wear resistance and improved reliability and durability.

Emissions of HC and NOx are 35 percent of those mandated by the Federal Government.

LandCruiser's diesel engine delivers 96kW of power at 4000rpm and 285Nm of torque at 2200rpm.

Yep that last article is on the right track...the 100 series and 78 got a altitude compensator, and the 100 got something along the lines of anti theift fuel cut solenoids or similar (dont know about the 78) power was close to if not thesame as b4 but cleaner running longer service intervals.
Andrew

cant give you any facts or figures but the 1hz in the 78s definitely go quite abit faster than the 75s

100 series 1hz have completely different injector pumps to early ones,injectors are different as well as some changes were made to the head.I have a 75 series with a 1hz and a 100 series with the same both standard and the 100 goes a hell of a lot better then the 75.