Just got a 1980 Datsun with 50k miles

SD diesels were widely available in the US in the 1981-86 Datsun/Nissan 720 pickups, and in Canada through '87 in the D21 pickup.

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karotto
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Joined: 15 years ago
Location: Southern Australia

Just got a 1980 Datsun with 50k miles

#1

Post by karotto »

Hi folks,
Just bought a pickup with only 50k miles on it with an SD22 engine. Actually 80k kilometers, since I am in Australia. This is my first diesel. I would appreciate any general tips regarding this engine. Also, does anyone know what the valve gap is (cold) ? I would like to adjust the valves. Also, how can I adjust the timing if this is the correct term (or whatever it's called to adjust the timing when the pump injects)? Also, is there a way to slightly increase the injector pressure? I will run this engine on vegetable oil and need to increase the pressure. Also, what type of diesel engine is this? A prechamber, swirlchamber? Direct or indirect injection? What type and make of injection pump do I have?
Thanks for all your help. Kent
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philip
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Re: Just got a 1980 Datsun with 50k miles

#2

Post by philip »

karotto wrote:Hi folks,
Just bought a pickup with only 50k miles on it with an SD22 engine. Actually 80k kilometers, since I am in Australia. This is my first diesel. I would appreciate any general tips regarding this engine. Also, does anyone know what the valve gap is (cold) ? I would like to adjust the valves. Also, how can I adjust the timing if this is the correct term (or whatever it's called to adjust the timing when the pump injects)? Also, is there a way to slightly increase the injector pressure? I will run this engine on vegetable oil and need to increase the pressure. Also, what type of diesel engine is this? A prechamber, swirlchamber? Direct or indirect injection? What type and make of injection pump do I have?
Thanks for all your help. Kent
Welcome Kent. Most of your questions are addressed in various existing threads in this forum.

With so little knowledge of this particular engine, what makes you think raising injection pressure for commercial quality biodiesel or waste vegetable oil is actually needed?

You should also check the LD diesel forum for some biodiesel tips.

Also, I assume your Australian SD22 has a VE injection pump instead of the US vers Bosch inline pump. True?
Last edited by philip 15 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"
Carimbo
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What he said (phillip)

#3

Post by Carimbo »

philip wrote:With so little knowledge of this particular engine, what makes you think raising injection pressure for commercial quality biodiesel or waste vegetable oil is actually needed?
I would agree with this.
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asavage
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Re: Just got a 1980 Datsun with 50k miles

#4

Post by asavage »

Hello, Kent:
karotto wrote:does anyone know what the valve gap is (cold) ?
There isn't a good equivalent to the hot lash specification. The hot lash spec is .014" for both intake and exhaust valves. There are some basic specs such as this on the back cover of the FSM.
I would like to adjust the valves.
The valve lash adjustment procedure is outlined in this thread.
Also, how can I adjust the timing if this is the correct term (or whatever it's called to adjust the timing when the pump injects)?
Philip started on this in this thread, but didn't really finish up. He's detailed the procedure he uses somewhere; perhaps he hasn't finished pulling that article over from the "other" SD22 site.
Also, is there a way to slightly increase the injector pressure?
I do not know the upper pressure limitation of the IP, but I'm certain that the injectors themselves can be recalibrated to a much higher pressure. This involves changing the number of injector spring calibration shims, and in extreme cases also replacing the springs. This requires some specialized test equipment. One way to decrease the cost of this is to build a test rig yourself, as Carimbo linked in this post.
I will run this engine on vegetable oil and need to increase the pressure.
Elsbett &/or Greasel modify injectors for SVO use by changing the orifice(s) size and diameter and shape. I don't know if increased pressure is required for SVO operation; I am not a fan of WVO/SVO, as I've detailed toward the bottom of this post.
Also, what type of diesel engine is this? A prechamber, swirlchamber? Direct or indirect injection?
Indirect injection, prechamber. I am not certain about the "swirl", but I doubt it.
What type and make of injection pump do I have?
Kiki-Diesel, licensed from Bosch.

Philip, can you find and copy that post from "over there" that you and I did that contains the inline's model numbers?

Image Image Image
Last edited by asavage 13 years ago, edited 2 times in total.
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.
karotto
Posts: 10
Joined: 15 years ago
Location: Southern Australia

wow! so many responses!

#5

Post by karotto »

Thanks everyone for all your replies and help. It's true that I know very little about this engine or diesels in general but I have a fairly good mechanical understanding and have done plenty of work on other cars. I am just not familiar with diesels. Is there any publication or website out there that could help me learn the basics about my engine or driving diesels in general? How it works, what all the settings are, what all the things are that I see when I open the hood, what it is that I am looking at when I lift the air filter cover, etc.. By the way, what should the gas milage of this vehicle be? I was shocked to measure 23 miles/gal (10l/100km). I thought I could get twice that driving about 45 mph on the highway. Thanks again.
Kent
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philip
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Re: wow! so many responses!

#6

Post by philip »

Kent. You need operational diesel theory and specific SD diesel instruction. The former will come from a text book on basic diesel operation that you can get from a public library or college or Amazon.com. The latter instruction from a factory service manual (FSM) on your particular vehicle / engine. The FSM will NOT tell you the "why" of the "what" you are doing with an adjustment. Diesels are a law unto themselves, quite apart from gasoline engine operation.

So what I'm telling you is there is no single source for everything you need to know about diesel engine theory, driving a diesel, maintaining your SD diesel, or converting to some alternative fuel.

Let's move along to your fuel mileage inquiry. Now let me preface that I live in the southwestern United States where the weather is fairly arid year round and altitudes of paved roads range from 287 feet below sea level to about 10k feet above sea level.

My SD has about 165k miles and has the Bosch inline pump like the one Al posted previously. Fuel mileage on the road at 60 MPH on flat Interstate highway is 35-37 Mile Per US Gallon (1 US gallon equals 3.78 liters) with optimal conditions returning as high as 40 mpg.

Using 35 miles per US gallon, I estimate 6.7 liters (1.77 US gallons) per 100 km (62.1 miles).

You are getting 10l/100km which to me is 2.64 US gallons per 62.1 miles (23.5 mpg). YES, with fuel mileage this low (barring hours of idling per tankful of fuel and fuel leaks) I would want to find out what was wrong with my engine.

First, is the engine sound? Compression needs to be over 400 psi on all cylinders. Are all the intake and exhaust valves opening and closing? Is the valve lash clearance somewhere close to spec (spec is .35mm for both intake and exhaust valves). Are the intake and exhaust systems free of restrictions? If so, then you can move along to fuel system diagnosis provided you possess fundamental knowledge on this complex hydraulic / mechanical subject.
-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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Re: Just got a 1980 Datsun with 50k miles

#7

Post by asavage »

philip wrote:Down under, VE pumps rule.
A VE on a SD22? SD23/25, sure, but the SD22??

Kent, even for a diesel, the SD series are a little "weird", and even seasoned dieselheads have a few things to learn about them. Specifically, if you have the inline IP, it uses an unusual pneumatic governor and intake throttle (not at all common on diesels, except very old MB); it has an electric motor to control the mode of the IP -- usually poorly understood and often bypassed by the unwashed; and two different GP systems, the early one being a little odd.

If you have the VE IP, it is much more like other diesels. You can tell if you have the VE IP if the injector lines all come off the rear end of the IP horizontally.

(click on any image for larger)
Image Image

That is a right-hand drive SD25 model 720.
Last edited by asavage 14 years ago, edited 1 time in total.
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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philip
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Location: Southern California, USA

Re: Just got a 1980 Datsun with 50k miles

#8

Post by philip »

asavage wrote:
philip wrote:Down under, VE pumps rule.
A VE on a SD22? SD23/25, sure, but the SD22??
Yes indeed, refer to thread "VE Pump Drawings." I lifted these pictures from the Nissan SD22 suppliment.

If you refer to the Nissan diesel suppliment books for the SD22, you will find three possible injection pumps.

1) Bosch RBD-MZ (pneumatic & flyweight governors) and MZ (pneumatic only) versions of the inline pump.

2) Bosch VE rotary pump.

3) CAV-DPA inline pump
-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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