1986 "Arlington Truck" gasser->SD conversion

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asavage
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#16

Post by asavage »

In that case, I used what I have and I'm happy with the result, whose outcome is consistent with the intended use of the truck when completed.

I have been the victim of poor welds. Bolts seldom fail.
bryan81
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diesel vs Gas

#17

Post by bryan81 »

i bought a 1981 datsun 720 diesel that i like a lot but the body is shot. so i bought a solid 1985 gas job with a bad motor and am in the process of swapping motors. should i swap the rear end too or is it the same?
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asavage
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#18

Post by asavage »

Good Q, and I don't know the answer.
bryan81
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1981 diesel to 1985 gas body

#19

Post by bryan81 »

i had just planned on swapping the engine and tranny and flushing the gas tank out and filling it with diesel. i was also kill the motor by a choke cable since it does not kill from the switch as it is, also was going to put the glowplugs on a push button switch. any advice or comments would be greatly appreciated. thanks, Bryan
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asavage
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#20

Post by asavage »

Fuel tank: diesel & zinc (galvanizing) don't mix. We've discussed this previously; Search will help.

Radiator hose routing? Or swap radiator -- that's what I'm doing.

If you have early GPs, a pushbutton works OK. Late GPs won't stand for manual control, they'll burn up in just a few seconds if pushed too hard.

Cable shutoff works. But how will you get to overfuel position for cold starts? Not needed if your climate is mild, but in colder places . . .
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.
bryan81
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Location: bristol tn

diesel swap more power

#21

Post by bryan81 »

ok i will swap the tank too i didnt know there was a difference. i have a heavy gauge cable that i was going to push all th way in to start halfway to run and pull all the way out to kill. i wish i could fix it right but i cannot find a dpc module. my ipc works but i believe my dpc is bad. how do i tell if i have a early of late glow plug controller :? ? i have one on the fire wall and i have a glow after timer thing in the passenger side kick panel. also is there any way to unleash any extra power this engine might have, i noticed where the idle screw is across from it there is a stop screw what would happen if i backed it out :wink: ?
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asavage
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Re: diesel swap more power

#22

Post by asavage »

bryan81 wrote:i have a heavy gauge cable that i was going to push all th way in to start halfway to run and pull all the way out to kill.
That will probably not work, because the heavy cable will kill the feel of the IP's built-in detent-to-Run, which is purposely very light. You will end up with it partially in Start or partially in Stop.
i wish i could fix it right but i cannot find a dpc module.
They can be had, but they are not an item you can buy for $20. Last time I checked, you can even buy a new one from Nissan. Part No. 19850-31W02 fits 0679-1282 and is $184 or so. If it's still available. If you want a "rebuilt" one (with a new relay) for about half that and are serious, PM me.

Alternatively, with a bit of work, you can wire a dumb bypass of the DPC Module that will interface with your IPC motor and give you manual control of the three states: Stop, Run, Start. For details, see this post. One rotary switch and four wires. And, perhaps, a 10W 5 ohm resistor, after my testing of three IPC motors shows that they don't like to be run at higher voltages. The largest disadvantage of going this route is that you lose the automatic engine shutdown in the event of loss of oil pressure.
how do i tell if i have a early of late glow plug controller?
Over to you, Philip.
also is there any way to unleash any extra power this engine might have . . .
Unleash? Isn't that assuming there's some extra power leashed somewhere?

a) Convert the IP, intake manifold, front engine cover to use the non-throttled IP from the later SD23 or SD25, which are very scarce in the US and a lot of work for not a whole lot of add'l HP;

b) Add a turbo. See any of the several excellent turbo SD threads.

Other than that, no. Bigger exhaust won't help, noisy "Cold Air Intake" schemes won't work. Synthetic lube in the diff and esp. the transmission will give you some more power but more importantly will keep the front brgs alive in the trans; they are a high-failure item.
i noticed where the idle screw is across from it there is a stop screw what would happen if i backed it out :wink: ?
Nothing good.

The engine will rev higher but will make no more power, and will stress the rotating assy (specifically the pistons) beyond their rated load. In short, the engine in good tune makes as much power as is safely available without adding more air (turbo).

In fact, as Philip has seen on his new pyrometer, the stock EGTs are already higher than one would like to see for a prolonged period of time.
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.
bryan81
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finally got it on the road

#23

Post by bryan81 »

well i got it togeather and drove it up the road and it runs great although there was a lot more swapping than i thought. i had to change the e-brake bracket and cable because it was in the way of the exhaust and had to extend all the alternator/starter wires because they were on the left side for the gas motor. swapped fuel tanks replaced lines and did away with the electric fuel pump. i cut the glow plug section out of the old wiring harness and put it on a push button and it works great. while looking for some parts at the local junkyard i found a sd22 complete motor with transmission alternator,starter and ipc included. unknown miles but is clean and full of oil. the aluminum tailshaft case has been cracked from carelessly loading with a tractor but the gears and front part of the case is good. they asked me $250 for the whole deal was wondering if it is a good deal to keep around for a spare?
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asavage
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Re: finally got it on the road

#24

Post by asavage »

bryan81 wrote:i found a sd22 complete motor with transmission alternator,starter and ipc included. unknown miles but is clean and full of oil. the aluminum tailshaft case has been cracked from carelessly loading with a tractor but the gears and front part of the case is good. they asked me $250 for the whole deal was wondering if it is a good deal to keep around for a spare?
It's a good price if you get enough value from it.

Because you don't know the condition of the engine (why is it at the JY?), you have to consider it a core -- a non-runner. While the accessories (alt, starter, IPC) are valuable when you need them, you can spend a lot less than $250 acquiring any one of them; only if you needed several parts would your investment pay off.

Now, if you got the whole truck for that price, it might look more attractive. I've bought several 720 diesel PUs for under $200 where I am.
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.
TheDieseliminator
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Location: Florence, AZ

#25

Post by TheDieseliminator »

Bryan, did the SD22 bolt in to the 1985 pickup frame or in other words were the engine mounts/frame design the same under the hood between both the trucks? There is four years difference in the manufacturing date, different engine options, and I'm thinking there probably were differences. But getting more of an expert's opinion since you've done the swap already yourself. Thanks for your reply.
1982 Datsun Maxima diesel wagon w/ 228k miles
*occasional daily driver*

1982 Datsun Maxima diesel sedan w/ 252k miles
*now off the road as a parts car and sent to the yard :( *
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asavage
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#26

Post by asavage »

The windshield frame is rusty and leaking water into the cab. We've pulled the windshield and the floor mat & padding (seats were already out). Floor is solid, no rust. Rust repair on the windshield frame is about half complete -- all the rust is removed, fibreglas is behind the larger holes, and I'm using epoxy instead of body filler to build up the remainder of the voids. I'll use filler for the finish.

Color/Trim code is "119 C". Paint's bought and paid for, not picked up. Alternate tips for the SATA are on their way.
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