1987 Nissan D21 SD25

Dealing with all subsystems specific to the diesel powered Datsun-Nissan 720 pickup trucks.

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asavage
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#31

Post by asavage » 12 years ago

If the CSD is not working, or is adjusted so that it does not properly rotate the shaft into the housing, it will not advance the base timing for a cold start. This might be a factor in yours' reluctance to start in cold weather. Compare your VE's warm advance of 6° BTDC to the base timing of the SD22 (Inline IP, external advancer) of 18° BTDC.
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.

jozsef61
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#32

Post by jozsef61 » 12 years ago

thank you so much for the replies guys...very much appreciated!!!

yeah the vw tool i have looks similar to that in the pic., I will give it a try tommorow and see if i can set the timing, then start my adjustments from there.
I don't exactly understand how the CSD you are talking about functions and how can I check the advancement at cold?

I had backed off the idle screw so far that it no longer touches the throttle, and still my idles up high. So i'm starting to think somebody adjusted the CSD maybe?
The thing that just doesn't fit in my head here is that my engine has almost 500,000kms, and even though the adjustments are all messed up, still runs smooth and doesn't smoke. Are these engines really that good?
VW engines would smoke even if set to spec. at such mileage.
1987 Nissan D21 - SD25

plenzen
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#33

Post by plenzen » 12 years ago

Yes Al that is what it states in the specs page at the end of the section. (S.D.S.)


"Plunger Lift" mm (in.) 0.95 - 0.99
(0.0374 - 0.0390)
( equivalent to 6 B.T.D.C.)


Cant make the little degree sign by the 6 but it is there.

Paul
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

plenzen
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#34

Post by plenzen » 12 years ago

jozsef61!
That small screw that you refer to in your second photo is what is keeping your idle high. That is what is operated from the CSD. Near as I can figure the CSD works on internal hydraulics. The two water lines going to the rear of it operate a thermo switch near as I can tell. Once enough water temp is reached it then disables that hydraulic passage. When extended at cold it presses against that lever at the bottom and rotates it forward pressing on the screw that I mentioned. This raises the idle at the same time as advancing the timing I assume. "IF" the CSD adjustment has not been messed with, then someone has turned that screw at the front of the pump in order to adjust the idle. If you back that one out now with the "idle screw" backed all the way out it will stall. AFAIK. It would also appear from that same photo that the CSD is in its operating position. If you put your finger under the little screw at the rear of that device that goes through a small spring just behind those two holes and lift against the bottom of that screw ( its a pretty good lift) you will hear the idle increase more and see that adjustment screw at the front move. I happened upon this by accident trying to do the very thing that you are doing now. I do not know how the timing is advanced internally or how any of it works inside the pump nor does the FSM have any specs on that.

Paul
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

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asavage
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#35

Post by asavage » 12 years ago

plenzen wrote:"Plunger Lift" mm (in.) 0.95 - 0.99
(0.0374 - 0.0390)
( equivalent to 6 B.T.D.C.)

Cant make the little degree sign by the 6 but it is there.
See this post to learn how to make the '°' symbol.
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.

plenzen
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#36

Post by plenzen » 12 years ago

6° ! ! ! !

Not only a "Fixitall Al" but a "computer geek" too!!

WHY DO YOU KNOW THIS???? :roll:

I still have an aneurism from trying to see how to post a thread.
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

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philip
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#37

Post by philip » 12 years ago

Haemorrhoidal aneurisms are not that uncommon in older men, especially when they spend too much time sitting. :wink:
Last edited by philip 12 years ago, edited 1 time in total.
-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"

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asavage
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#38

Post by asavage » 12 years ago

plenzen wrote:6° ! ! ! !

Not only a "Fixitall Al" but a "computer geek" too!!
Really, I'm only a minor diety ;)
WHY DO YOU KNOW THIS???? :roll:
Um . . . I'm old, and I've been doing this a long time?

One can "understand" computers as much or as little as one wants. I can even talk on keyboard scan codes, as well as ASCII tables and OS codesets.

However, in recent years I've severely dialled back my involvement with computers at that level. I rarely solder and almost never code anymore.
I still have an aneurism from trying to see how to post a thread.
Hover your mouse over a post's "Quote" button. Look at the status bar at the bottom of the browser. Note the one-to-five digit number after "p=". Write down the number.

In your post (while composing), use the number. Example:

Code: Select all

See [gotopost=12345]this thread[/gotopost] for details.
That's not so bad, is it?

I always work with at least two browser windows open and pointing to NissanDiesel, so I can go look up a post for its post number, while in the other browser window I'm composing a post.
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.

plenzen
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#39

Post by plenzen » 12 years ago

Just for fun this morning @ -13C, I started the truck with the CSD disabled. It did in fact start, although it did not seem to like it. :(
The idle was very slow and stalled once after initial start up and then kept going after the second start. A lot of shaking. With the engine running I re-engaged the CSD linkage and the "compression ignition cackle, rattle" ( call it what you will) increased as did the idle by approx 2 - 300 RPM
( best guess by ear).
It seemed to like that a lot better, although was much quieter with the device shut off. :) No doubt a side effect of the advance.
At cold idle the truck will pull itself along at 22 KPH in 3rd gear ( on GPS, flat road).
Warm will pull itself, and complains a bit at 19 KPH in 3rd gear.( on GPS same piece of flat road)
Seems to like the shift to 3rd with the cold idle a lot better no doubt due to the advance in the timing and a couple more RPM.
For what it's worth. :roll:
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

jozsef61
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#40

Post by jozsef61 » 12 years ago

ok so thanks to all your help, I finally had a chance to check the injection timing on the pickup. it was on teh low side at .95mm so i'm gonna leave it there. I was able to bring the rpm down to around 800 ish, and det the fuel screw as far in as i could just before it would start to smoke when blipping the throttle. Still have to play around with it more to make the the CSD is actually functional.
As a side note, I guess with all the playing around with the throttle on the IP, it loosened something up and now its leaking when cold just below the spring it looks like. It sort of has a bit of play side to side. I've never noticed the leak there before!
1987 Nissan D21 - SD25

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#41

Post by asavage » 12 years ago

That leak point is extremely common on the VE-style IP. You can buy a seal kit with the seal for that shaft, and you can purchase the shaft bushing separately too. Look for the parts at VW IP supplier or rebuilder.
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.

jozsef61
Posts:8
Joined:12 years ago

#42

Post by jozsef61 » 12 years ago

So the IP on my truck is a VE rotary Boasch style by Diesel Kiki, am I right? And you say that the VW IP's have the same seal kit?
1987 Nissan D21 - SD25

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#43

Post by asavage » 12 years ago

jozsef61 wrote:So the IP on my truck is a VE rotary Boasch style by Diesel Kiki, am I right?
I think so.
And you say that the VW IP's have the same seal kit?
AFAIK, yes. Many parts for the Bosch version directly fit the non-Bosch version.
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.

jozsef61
Posts:8
Joined:12 years ago

#44

Post by jozsef61 » 12 years ago

Hey guys...so after a heck of a lot of screwing around with the pump settings I've come to realise that my CSD device is nto functioning. There is no movement from the plunger at all. When the engine is running it seems as though there is pressure running through it because when i turn off the engine I can push back the plunger. So are these things serviceable at all?
So after spending hours trying to figure it out, I figured out why my engine was so guttless to begine with, it was running always advanced.
Now that I have it set so that there is no advance it runs pretty good when hot. Howver when cold smokes real bad due to the csd not functioning.

So basically what I believe is that when the engine is cold the pump needs advancing by not allowing the csd to be pressurized. Ones hot the thermostat opens allowing pressure to the csd which in turn pushes on the lever disabling advance and in turn lowering rpm at idle.

Correct me if I'm wrong but I'm pretty sure I do not have this backwards because if you look at the function of the pump the advance lever only raises the rpm with plunger in, and removes contact on idle lever when plunger extended.

Any thoughts or am I really confused here?
Jozsef
1987 Nissan D21 - SD25

plenzen
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#45

Post by plenzen » 12 years ago

Rather than say nothing, I will reply with "I don’t know". :roll: Once the weather gets a bit warmer I will go and mess with mine and see what I can come up with. Sounds to me like you are already ahead as to how the danged thing works.
There is something that I have found in the FSM that you may want to try.
It says to disable the CSD by rotating it to the rear of the engine. They show a screwdriver shaft for doing this inserted through those two holes at the front of the CSD. Once that it is disabled they say to set the block length (plunger) to 15 mm (0.59in) between it (plunger) and the CSD linkage. There is a set screw with a lock nut at the bottom that the plunger pushes against. I trust that this is all done with the engine off.

Paul
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

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