720 Gas to Diesel Conversion Bits

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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philip
Deceased
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Joined: 15 years ago
Location: Southern California, USA

#46

Post by philip »

bacho wrote:SNIP- ...and no combination of mounts will allow the motor to bolt up in place. SNIP
Could you take a photo of the frame mount site for the passenger side engine mount of BOTH your '85 KC 4x4 and the '82 KC/SD22?

Frame pads
-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"
bacho
Posts: 121
Joined: 14 years ago
Location: Greenville South Carolina

#47

Post by bacho »

Sure, They look the same but a tape measure proves they are different.
1992 nissan pathfinder 4x4
1985 KC 720 4x4
1982 KC 720
bacho
Posts: 121
Joined: 14 years ago
Location: Greenville South Carolina

#48

Post by bacho »

Forgot the frame pads, here is the current oil pan in progress.

Image
1992 nissan pathfinder 4x4
1985 KC 720 4x4
1982 KC 720
bacho
Posts: 121
Joined: 14 years ago
Location: Greenville South Carolina

#49

Post by bacho »

Got the oil pan finished, Fits good now.

On the motor mounts, a 2wd MIGHT bolt up if your lucky, but I doubt it. The tranny pushes the diesel 1.5 past the mounts forward. And trying to bolt it in with the right mount in the forward location leaves the motor sitting crooked. I decided to modify the mounts themselves with the gas mounts in the stock location. I cut the studs off and welded them into a piece of .25 plate about 1.5 or so forward, and then welded that plate very carefully to the gas mount. Works alright. I also lowered the front diff one inch so it clears very well.
1992 nissan pathfinder 4x4
1985 KC 720 4x4
1982 KC 720
bacho
Posts: 121
Joined: 14 years ago
Location: Greenville South Carolina

#50

Post by bacho »

Ok, got the motor fired up today. Runs as well as it used to. I planned on wiring the motor to use some of the factory gas gauges, water temp, voltage and so forth, and then run a pyrometer, boost and oil pressue gauge of my own.

The current issue is that most things in the 720 do not work at the moment. Only the headlights, right blinker, horn, wipers and fuel pump work at the moment. I know the blower did work on the gas but it doesn't now. I have no bad gauges and the positive power is the same as it was before the conversion. Any ideas?
1992 nissan pathfinder 4x4
1985 KC 720 4x4
1982 KC 720
bacho
Posts: 121
Joined: 14 years ago
Location: Greenville South Carolina

#51

Post by bacho »

Got some work done, alternator is wired and charging well. Got a tag on the truck and I have been driving it. The rubber hose between the vac pump and the block is leaking. I plan on having a new hose made locally with a T in it for an oil feed to the turbo. I have yet to be able to make the temp gauge work so I am gonna install a mechanical one in the dash.
1992 nissan pathfinder 4x4
1985 KC 720 4x4
1982 KC 720
abumariah
Posts: 21
Joined: 14 years ago
Location: kentucky

#52

Post by abumariah »

I haven't posted in a while, new kid #2 has been taking up a little time. i don't think the transmission issue ever got fully clarified. the main shaft on the 4x4 trans is shorter because its feeding the transfer case and not directly to the drive shaft. when i get around to actually doing the engine swap, i'll have to put the bell housing and front bearings from the diesel onto the trans assy.

Now "Bacho", when you say you lowered the front diff, do you mean you installed a suspension lift? how high do you think we'd have to go clear the differential without modifying the oil pan? 4"?
1985 720 kc 4x4 z24
1981 720 kc 2wd sd22
bacho
Posts: 121
Joined: 14 years ago
Location: Greenville South Carolina

#53

Post by bacho »

I unbolted the front diff from the front mount. Removed that mount and drilled a new hole as low as I could.

You right on the tranny part.
1992 nissan pathfinder 4x4
1985 KC 720 4x4
1982 KC 720
bacho
Posts: 121
Joined: 14 years ago
Location: Greenville South Carolina

#54

Post by bacho »

Sorry I missed that last question. The diff would have to be lowered 5.5" to clear the unmodified oil pan. It seems there was another cross member on the 4x4 that would have to be modded too. In the end you are looking at much more work to do an IFS lift kit and you probly will not have enough power to push it through the wind anymore.

If you were even to think about doing that I would suggest a dana 30 or hilux axle in the front end.
1992 nissan pathfinder 4x4
1985 KC 720 4x4
1982 KC 720
abumariah
Posts: 21
Joined: 14 years ago
Location: kentucky

#55

Post by abumariah »

man its been a while.

hey bacho...i've was looking at that differential today, and i've got 2 questions before i lower it (if you're still lurking around here)...

1. when I lower the diff, won't that spread the front wheels out? or did i miss an adjustment somewhere?

2. did you end up with the engine and tranny angling down towards the drive shaft? I can't see how i can possibly get everything in line again.

i gotta get this thing finished.
1985 720 kc 4x4 z24
1981 720 kc 2wd sd22
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