Buying a 720 with an SD-22

#1

What should I look for as far as the engine goes? I am way ignorant to this little Nissan diesel so break it all down for me. I do own a diesel, just know NOTHING about this little guy other than HP, TQ, and it seems to get GREAT mileage.

#2

I don't know where you are (you can add this by clicking on the "Profile" link at the top of any page), but around here it isn't the engine you have to worry about, it's the cab and bed: they rust badly. Listen for noise in the transmission, they don't last forever and have a couple of weak brgs that are undersized for the diesel application, esp. if the oil is not changed regularly.

If you plan on doing your own maintenance, you will have to have a Factory Service Manual, you can't get by without it, as the GP and DPC systems are weird enough that you can't guess how they work or how to troubleshoot them.

The SD merely requires regular oil and filter changes to keep running forever

If it isn't working right, the SD guys here can help you diagnose it, but if it will start up cold without smoking out the neighborhood or requiring ether, and if it doesn't smoke under load, it's probably OK.

Watch out for "ether required", or for oil running off the engine, it's probably been abused if it's blowing oil.

#3

Sorry I should have remembered to fill out some of my profile. I'm an admin on another diesel board that has recently stepped up from phpBB. I'm glad i found you guys.

Thanks for the info.

According to the Current owner it leaks no oil so that is a plus. Truck has 190,000 on it with a 5 speed. So hopefully the Transmission is decent.

Anyhow, here is what I am looking at:

I'll be looking at it on Saturday. If the rust isn't TOO bad and it drives ok, I'll make him an offer. He did say the battery was dead. Is the Charging system pretty solid on these?

#4

No, the Hitachi LR150 does have weak diodes for its 50a rating. Replacement rebuilt units come up on eBay every couple of months in the $60 range. The Maxima diesel's LR160 seems to be a bolt-in and has an add'l 10a. I haven't seen the diode failure problem on the LR160s that I have seen personally on two LR150s. The LR150s are repairable if you are determined. Don't throw away any cores! The supply of LR150s and LR160s is good right now, but I expect them to dry up on a year or two.

#5

If that one doesn't have PS, the bigger wheels/tires will probably make low speed steering more difficult. Make sure to peel back the floor mats to see the steel (or lack of.)
Many SDs seem to start somewhat poorly when avernight temps are below 40* F. After all, the manual states that you should employ the "cold weather starting procedures" below 68* F.

These things aren't that slow. It should feel good. Also, from info on this board, if the trans is noisy in indirect gears (1,2,3,5) you've got bad bearings in the trans.

good luck,

#6

It looks nice with those wheels btw!

steve a

#7

Everyone, thanks for the input so far. If I get it I will let you guys know. I am looking pretty much for a commuter. If it is in good shape I will buy it. If it looks more like a project I'll report back with contact info in case any of you are interested in buying it.

#8

Ymmot wrote:I am looking pretty much for a commuter.

They don't like to run above 60 MPH very long. The gearing is wrong for the torque curve.

#9

No problem. Work is a 10 Mile drive. 5 of which is freeway.

Thanks for the tip though.

On edit: What about a re-gear of the rear end?

#10

Ymmot wrote:SNIP- On edit: What about a re-gear of the rear end?

The final drive has the 3.88:1 gearing. If you had the gasoline engine ... 4.11:1. With the 4x4 due the wheels ... 4.37:1 .

Agreeing with Al, I find (for several reasons) that 60 mph is the top for long time trips (more than 15 minutes). As is, 58-60 mph is 2500 rpm. Torque peak is the 1900-2400 rpm range.

#11

Would a 3.55 rear end be too tall if I could aquire one that fits?

#12

philip wrote:The final drive has the 3.88:1 gearing......

Agreeing with Al, I find (for several reasons) that 60 mph is the top for long time trips (more than 15 minutes). As is, 58-60 mph is 2500 rpm. Torque peak is the 1900-2400 rpm range.

Final drive or Rear end ratio? To me final drive = rear end * OD.

What is the stock tire size on these trucks?

A 3.55:1 would be about 10% drop in RPM if the rear end is currently 3.88:1. That would be 2,300 RPM's at 60 then.

#13

Ymmot wrote:Final drive or Rear end ratio? To me final drive = rear end * OD.

What is the stock tire size on these trucks?

Here's our we do it: Click on this

Ymmot wrote:A 3.55:1 would be about 10% drop in RPM if the rear end is currently 3.88:1. That would be 2,300 RPM's at 60 then.

I have driven 55,ooo miles in three years. For Interstates in lower states I've like to have 3.00 to 3.25 !! But that would require some special made pinion/ring.

#14

Wait a minute, Mine had 4.88 gears in the 2wd and the 4wd has 4.10 gears. Acceleration with the 4.10s was miserable with a top speed of below 55.

#15

bacho wrote:Wait a minute, Mine had 4.88 gears in the 2wd and the 4wd has 4.10 gears. Acceleration with the 4.10s was miserable with a top speed of below 55.

There was never a 4.88 finial drive in any 720.

3.88 was for M/T using (SD 2wd)
4.11 was for A/T (Z22 and 2wd)
4.37 was for M/T on 4x4 (Z22 and 4x4)

NissanDiesel Forums

Buying a 720 with an SD-22

Buying a 720 with an SD-22

Who is online