LD20T-II valve settings

Discuss (and cuss) the Nissan LD-series OHC Six diesel engine, popularly available in the US in 1981-83 Datsun/Nissan Maxima Sedans & Wagons.

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inniss
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LD20T-II valve settings

#1

Post by inniss » 12 years ago

Hi folks

An new to diesel engines and just trying to keep an old vehicle functioning.

can anyone tell me what is the vlave clearance for the LD20T-II preferablly cold?

Samuel
LD20T-II in old ISUZU VAN

davehoos
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Location:Karuah Valley,NSW Australia
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#2

Post by davehoos » 12 years ago

engine warm.lock nut 36-43f/lb
IN
0.010 [0.25mm]
Ex
0.012[0.30mm]
WCJR31 Skyline.3.0 manual.wagon
R31 SKYLINE/Passage GT/PINTARA
LPG Ford Falcon 99-06 93 Disco
Local Shire Southern Zone Mechanic.

inniss
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Joined:12 years ago

#3

Post by inniss » 12 years ago

Thanks.

I found it difficult to move these nuts, any suggestions? They appear to be 12 and 14 mm nuts, is this correct.

My other problem is that the engine is smoking too much when under pressure like going up hill and just after moving off. Any suggestions?

The person who set it up for me did not connect andy of the wires on the fuel injector. Could this be the reason for the smoking?

any idea where these wires should be connected?

Samuel
LD20T-II in old ISUZU VAN

davehoos
Posts:525
Joined:14 years ago
Location:Karuah Valley,NSW Australia
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#4

Post by davehoos » 12 years ago

there are no wires conected to injectors.

4 glow plugs--screw into the head near the injectors to preheat before starting.these are looped together and run 12 volt for a few seconds.
these will run 7 volt for a longer time.

Injector Pump.
you only need the single wire on the rear of the pump that turns on the fuel.throttle position is not used.

there is a cold start solinoid on the fuel return pipe on cold climate cars.
from memory putting power to this shuts off the fuel return causing rich mixture.
WCJR31 Skyline.3.0 manual.wagon
R31 SKYLINE/Passage GT/PINTARA
LPG Ford Falcon 99-06 93 Disco
Local Shire Southern Zone Mechanic.

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asavage
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#5

Post by asavage » 12 years ago

davehoos wrote:there is a cold start solinoid on the fuel return pipe on cold climate cars.

from memory putting power to this shuts off the fuel return causing rich mixture.
Surely not. Perhaps you meant "advanced timing"? This is the way the EGR/throttle position sensor/intake butterfly system works on the LD28: when the EGR system is active in Stage II or Stage III, the IP timing is advanced during EGR operation to improve driveability.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

inniss
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#6

Post by inniss » 12 years ago

Thanks guys but I still have the problem of black smoke at times.

How can I remedy this?
LD20T-II in old ISUZU VAN

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asavage
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#7

Post by asavage » 12 years ago

I don't know. My LD28 has been a heavy smoker all its life. Cleaning the intake didn't really help. B100 improves, but does not eliminate the problem.

On the LD28s that smoke, I've come to believe that the internal advancer no longer functions on most of them, the timing remains more or less static, and that's the cause of the smoke on the ones I've had through my hands. Just a guess, but an educated guess.

Fix: rebuild the IP.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

davehoos
Posts:525
Joined:14 years ago
Location:Karuah Valley,NSW Australia
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#8

Post by davehoos » 12 years ago

LD20 have the timing lever on the side-water or ischoke cable operated.
same as USA LD28 this also contacts the fast idle.
some other brands of engines have a mechanical mechanism refered to as retarder.
retarded timing can often asist with starting and quick warm up,EGR gasses are also a defacto retarder.---that said advanced timing gives a hot burn and improoves idle due to extra burn time and im guessing the retard control is to counter a fully advance system caused by other devices.
one device to counter another..

2 some cold area nissan feed the return line back to the pump or filter untill the fuel warms up from heat within the pump to reduce waxing.temp control can be electrical or thermol.

3 cold start electrical shut off solinoid is part of the return outlet banjo.
this increases the pressure inside the pump.so from my understanding this would slide the advance piston to the max poition as it is controlled by fuel delivery pressure that is now at maximum.some problem occures when an electric fuel pump is used.
asavage wrote:I don't know. i also dont

On the LD28s LD20that smoke, I've come to believe that the internal advancer no longer functions on most of them, the timing remains more or less static, and that's the cause of the smoke on the ones I've had through my hands. Just a guess, but an educated guess.

Fix: rebuild the IP.
most of the JAP import engines here have the black smoke tail.
this also occured with rare batches of brand new vehicles.TD27 is aa classic as the van and some D21 models have problems.officially i was unable to find a cause but its stange when the new ip is sent to have the calibration tested or a pump was swaped from another engine it cures the bad habbits.

the used engines ive owned I added petrol,kero or some other additive in colder weather[mild australian winters] this is due to the poor quality of local sold diesel compared to japanese domestic soudi deisel.

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asavage
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#9

Post by asavage » 12 years ago

davehoos wrote:cold start electrical shut off solinoid is part of the return outlet banjo. this increases the pressure inside the pump.so from my understanding this would slide the advance piston to the max poition as it is controlled by fuel delivery pressure that is now at maximum.
Yes. Timing is advanced, not increased fuel volume.
some problem occures when an electric fuel pump is used.
Because an external fuel pump cannot make the internal housing pressure (which can top 100 PSI) to work correctly. If there is a housing pressurization issue (worn/pitted lift pump, etc.), adding an external fuel pump will not work correctly.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

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