Nissan SD22, SD23, SD25 - Fuel consumption and reliability

[DieselTok]

Hello! DieselTok (DieselCrazy if you will) is what I'll be calling myself here!

I bought myself a Mazda B2000 RWD last summer and I have some questions regarding its powerplant.
It's a 1987 truck with a Nissan SD22 from a 720 Pick-Up, 1982-1984-ish. It has, from what I can see, a Nissan, 4 speed manual transmission with the original standard Mazda axle.

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I'd like a straight answer, no fantasy numbers, what kind of fuel economy might I expect from this engine in the long run? I know that the SD22 is a 2.2 liter engine and has 60/45 hp/kw of power and 125/92 Nm/lb-ft of torque. No rocket exactly.

I've seen people claiming down to 5.5-6.5 l/100 km, 45-50 mpg with this engine, with 4 spd and 5 spd transmissions. My estimate does not come far from that as I've driven this thing for roughly 250 km, 155 miles since I got it, and it has used less than 20 liters of diesel, 5.3 gal. Note that this is also accounted for idle running and spilled from when I had the injectors apart and bled the system for air. I must say that this engine is amazing in this regard, and I barely believe it myself!
But I haven't had the oppertunity to drive it on the highway, just backroads and old dirt roads to keep myself hidden because it's not road legal yet...

If I'd like to have the benefit of more power and torqe, and to fit either a SD23 or a SD25 - will I expect a massive decrease in fuel economy? Or will it be negligible?
Wich of the SD engines is the most reliable in general?

Thanks in advance!

[waynosworld]

Welcome DieselTok, When I had an SD22 that was running good in my kingcab, the best I did was 36mpg on the hiway, but I drive fast, so I normally only get about 29mpg going 70mph, and I normally got at least 25mpg in the city, I have one friend that got over 40mpg on country roads going about 50mph.
My SD25 gets about 28mpg going 80mph on the hiway, never figured out what it gets in the city, but I suspect 25mpg like the SD22 did, I rarely take it over 3000rpms, as that seems to be where it starts sounding over revved, and one has to floor it to do that anyway.
I cannot see you being able to get very good mileage with a 4 speed, as it will over rev the engine on the hiway, unless your hiway speeds are 50mph or less, it sounds like you are getting about the same as me(29mpg).
I drive just a little faster than most, if most the cars are passing you, you will get great mileage, if your passing most the cars, you will get poor mileage.
I bought a turbocharged SD25 engine from a guy that used to be on this forum, it will not go very fast because it gets to hot(EGTs), but he drove 50mph on the hiway and stated that he got 48mpg on a 250 mile hiway trip, he kept the engine under 2000rpms, the engine was in a heavy Volvo wagon at the time, I have never been able to drive it the way it is, as I cannot drive 50mph, so rather than ruin the engine, I just don't drive it at this time, some day I will figure it out.

Hello! DieselTok (DieselCrazy if you will) is what I'll be calling myself here!

I bought myself a Mazda B2000 RWD last summer and I have some questions regarding its powerplant.
It's a 1987 truck with a Nissan SD22 from a 720 Pick-Up, 1982-1984-ish. It has, from what I can see, a Nissan, 4 speed manual transmission with the original standard Mazda axle.

WP_20150714_16_24_22_Pro.jpg

WP_20150714_21_46_02_Pro.jpg

I'd like a straight answer, no fantasy numbers pulled out from a porcupines' bunghole, what kind of fuel economy might I expect from this engine in the long run? I know that the SD22 is a 2.2 liter engine and has 60/45 hp/kw of power and 125/92 Nm/lb-ft of torque. No rocket exactly.

I've seen people claiming down to 5.5-6.5 l/100 km, 45-50 mpg with this engine, with 4 spd and 5 spd transmissions. My estimate does not come far from that as I've driven this thing for roughly 250 km, 155 miles since I got it, and it has used less than 20 liters of diesel, 5.3 gal. Note that this is also accounted for idle running and spilled from when I had the injectors apart and bled the system for air. I must say that this engine is amazing in this regard, and I barely believe it myself!
But I haven't had the oppertunity to drive it on the highway, just backroads and old dirt roads to keep myself hidden because it's not road legal yet...

If I'd like to have the benefit of more power and torqe, and to fit either a SD23 or a SD25 - will I expect a massive decrease in fuel economy? Or will it be negligible?
Wich of the SD engines is the most reliable in general?

Thanks in advance!

[plenzen]

I have an 1987 D21 with the SD25 in it. I am the second owner as it was my dads truck who bought it new.
The best I have ever done with this mileage wise is 39 mpg Imp ( 7.2L/100 km) and that was average 90 kph on a warm summer day on a 600 km trek from Calgary to Kelowna.
I usually get 36 mpg imp ( 7.8L/100 km ) in the summer combined (75% highway ) and 32 mpg imp ( 8.8L/100km) winter.
I live at 4000 feet.
Spoke to my dad and he said that's about all he ever got with it from when it was new. Maybe a bit better as he lives at pretty much sea level in Vancouver B.C. When I visit out there I really notice a difference in power.

He had 82 720 with SD 22 in it and said that it did better MPG than this one buy a good margin. ( 4 or 5 mpgs)

Not sure if it's the gearing or the different fuel pump or the weight of the truck.

I have a little over 300,000 km on it now. Getting a bit harder to start in the cold but still runs like a champ.

As for which one is more reliable.
They are all about the same to be honest. The 25 has 5 main bearings and the 22 has 3. If you get one out of a D21 it will have a different fuel pump on it and different glow system. Other than that not too much different between them.

HTH

Paul

[DieselTok]

So, after some scavenging on this forum I found that these engines are featuring 3 main bearings, according to a user. But further investigation revealed that the SD22 engine also features 5 mains on some markets and in different ranges of vehicles.

Because I was curious whether mine has three or five mains, I simply took down the the oil pan and took a look for myself. And guys, mine has 5 bearings. Check out the pictures.

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I will be posting this to the thread were this was discussed.
And also, thanks for your inputs!

[plenzen]

Interesting.
All I had ever seen was 3 main engines for the 22.

That being said, all the ones I had dealings with were industrial "truck" engines that were either converted to generator sets or marine applications, and, in the late 70's as well.
Appears there was a serial number stamping relocation occur in May of 1980.

Just wondering where your engine number fits into that chart you supplied. ( I found the same webpage )

Can you take a photo of the number that's stamped on the block just under the #1 injector on the boss ahead of where your ser. please?

Thanks

Paul

[DieselTok]

Of course! Here you go!

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[plenzen]

Again,,,,,,,,

Very interesting

It would appear that any of the SD22'S in 720 trucks whose serial number starts with a "7" have 5 bearings?

I only assume that because of the chart you included and your engine number starts with a 7, it would appear that from 703579 and on have 5 brgs. ( thats a guess on my part )

The other thing I notice is that some of these engines are "regional" as to where they were sent and can only assume that because your in Sweden then that may be the case.
You say yours came from perhaps an 84 720 That is just about the time that the SD25 started appearing in the 720's in North America. Could be that those higher engine serial numbers were being used in the European destined 720's.

This was the same kind of thing with the D21 diesel that I have. They were sent to Canada but not to the US.

[DieselTok]

The SD22 was fitted in a variety of vehicles throughout it's service, and I think Nissan knew what they were doing by making higher end engines with 5 main bearings. As you say, 3 main bearings are mainly common amongst industrial applications, in forklifts and so on.

But I have to say that this engine is a real piece of work, never been a fan of Japanese work but, this engine is amazing. It's amusing to drive also, no rocket mind me, but it has very special characteristics and a distinctive sound.
It starts every single time, it doesn't even hesitate, it has even started below -15 *C without block heater, not that it's good for it but it just spun around and fired right up. And because it is a diesel it still runs rough when it's cold, but it starts. I run 10W-30 in it, Mobil Delvac MX, and I think it will be running just fine with it.

But I think I will be doing a overhaul of the engine, since this is a car I enjoy and like to drive around with.
And regarding that this engine been this reliable thus far, despite the flaws it has, I think it deserves a little turn over.
just of curiousity I took off a bearing cap to get a picture of what condition the engine was in, whilst I have the oil pan down for service. And I encountered this...

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I don't think it's terrible, but it is definitely in need of a little overhaul.
I don't believe the previous owners' claim of around 200.000 km (125.000 mi) on the engine, or they've been running this old truck with the wrong oil.

I will be gathering parts for some time and do the overhaul on a occassion, most likely this summer.
Please stay tune and thank you for your interest!

[waynosworld]

I have to say when it comes to these engines, if it is not broke, I am not going to fix it.
My daily driver don't like starting anything below 45 degrees Fahrenheit, but once it is run a few minutes it runs like a champion, unless it is knocking, using a bunch of oil, or it will not start I will not be touching it, as it could be worse.

[plenzen]

Agreed.
Mine complains a bit now at -15c. Have to hit it 3 or4 times for it to go. That began right after I had the fuel pump redone. (Should have just let it drip....oh well )

Once started it will start the rest of the day even after a 4 hour cold soak.
400,000 kms and uses 5 - 600 mil oil in 5000km.
If I just keep it in town it don't use any.
I will just leave it as is.

[waynosworld]

Agreed.
Mine complains a bit now at -15c. Have to hit it 3 or4 times for it to go. That began right after I had the fuel pump redone. (Should have just let it drip....oh well )

Once started it will start the rest of the day even after a 4 hour cold soak.
400,000 kms and uses 5 - 600 mil oil in 5000km.
If I just keep it in town it don't use any.
I will just leave it as is.

My 521 diesel is the same, once warmed up it kicks right over the whole day even after sitting for 6/8 hours, but if it is cold at night it starts hard in the morning, I have given up before when it got into the 20s, I need to use the block heater to get it started when it is that cold, but I have not used it in years now, I just drive a gasser instead.
The 720 turbodiesel is different though, that one starts easy every time, it only misses maybe 2 or 3 times on a cold start total, it idles a little rough at first, but it is a different engine now, the way Larry had it set up it did not start easy after sitting, but maybe it starts easy now because I drive it a lot more.

[handcannon]

Interesting info about the number of main bearings, and the pics. A year or so back I found that same chart showing when the 5 main block started, but everything else I found said that these motors had only 3 mains. I appreciate the pics. The info about fuel mileage is also appreciated as that has been a big question for me.

Just to give a little background, I have been reading this forum for about a year now. Over a year ago I picked up a 1981 or 1982 SD-22, with transmission, radiator, and air filter housing. But did not have the electric modules for the IP controller. I have a 1973 Datsun 620 pickup that my Dad bought brand new. The original motor messed up (maybe jumped time) and I never did anything with it, except park it. The plan has been to eventually put the SD-22 in the 73 pickup. I have had the SD-22 running for a short time while setting on the shop floor, so I do know it runs. But, how well is still to be found out.

I knew this motor would be an almost drop in to the 73, but motor mounts?

Don