ka24e to sd25t 4x4 swap

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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ehtrain
Posts:141
Joined:8 years ago
Location:regina, sk

#16

Post by ehtrain » 7 years ago

found sd22 and sd25 timing information for the injection pump. all the written info seems to be hit or miss.

http://www.autozone.com/autozone/repair ... 528004f489

it also seems to be the same as this post
http://nissandiesel.dyndns.org/viewtopic.php?t=2813

ehtrain
Posts:141
Joined:8 years ago
Location:regina, sk

#17

Post by ehtrain » 7 years ago

well it would seem I was doomed from the start. Since I've had this thing together I've had nothing but hard times starting it. lots of torque... but falls on its face in the top end. SO I went though the whole fuel system suspecting the hard starting/misfire was coming from poor fuel operation or flow restriction. After gutting the fuel tank and checking every filter, clamp, line, o-ring. I came up with nothing. So my attentioned turned to the injection pump again. the pump body is from the blue truck, and the back plate with timing mark is from the black truck. So I was under the impression then my timing must be out significantly in comparison to the factory mark.

Since my stupid timing light still refuses to work. I don't have the dial gauge adapter tool for the injection pump. So bit the bullet and took it to the local fuel shop that rebuilt the injection pump and injectors. I figured they can time it, and if anything is wrong with the injection pump.... it's there warranty.

almost 2 weeks later I hadn't hear from them.... not a good sign. I call them to have them tell me. the factory mark was very close -1 degree. so they played with timing from 6 degrees- 10 degrees where they said fuel knock started. Nothing would get the truck to start better. So they gutted the injection pump just incase and put it on the test bench.... still perfect. they checked my glow plugs and circuits... perfect. 650 dollars later

they did a compression test. 400psi. which is very low. So Now I'm truely upset. I went and tested my compression hot and cold. I could not produce 400psi even on my gauge. usually a gas motor is 4 gauge pumps per cylinder is compression. 7 pumps for a diesel.

I got 350psi or so across the board. My guess is they pumped the guage until it quit.... which is not accurate to get 400psi. SO 350psi is at the very bottom end of SPEC 359-427psi.

I searched around and found common psi is more like 430-490 psi on most smaller diesels.

I called my machinist and had several very long conversations. even being on the higher tolerances of valve protrusion/cylinder protrusion. we would find it highly unlikly say 5cc of extra cylinder volume would create a 80-100psi drop in pressure. the fact the pressure is even all the way across hot and cold tells me its not likly a valve seating issue or ring issue. So the only explenation can be is the cylinder head pre-combustion chamber must be larger? which really makes no sense to me at all. even the industrial engine compression is only 1 point lower. and my guess is from piston design. as 5 ring vs 3 ring. and it's compression rate is still 430psi according to book. makes no differentiation between industrial/auto

So far everyone I ask scratches there heads. IF ANYONE has any ideas please tell me. beyond taking the head of AGAIN and CC out the pre combustion chambers from my forklift head to the truck head.

I called nissan also to see if there are different head gasket thickness options. many diesels use headgaskets to correct combustion pressure. Nissan only lists 1 part number so no luck. When I got the factory cylinder head number and had it cross over into SMH material handling (forklift parts supplier) to get there part number which led me to the wrecker in arizona. The heads looked identical in every way too.

I've swapped heads before on motors. generally from one to another type they look different, shape, port shape/size, bolt positioning. SOMETHING that's evident. I'm waiting for response back from roo dogs 4wd spare now. see if they can point me in a different direction. I had a friend say he had a magazine somewhere from a long time ago that talked of these motors and several different cylinder head types. no luck on finding though.

Now I really wish at least 1 of the stupid motors had run before hand to test stuff. nobody around here knows much if anything about these motors... which does not help. the whole flying blind by the seat of my pants and spreading my wallet is really pissing me off.

ehtrain
Posts:141
Joined:8 years ago
Location:regina, sk

#18

Post by ehtrain » 7 years ago

a friend in town that I helped rebuild his toyota surf 2.4L chimmed in with his headgasket thickness. 1.4-1.5mm/ 1.5mm-1.6mm/ 1.6mm- 1.7mm

thats .0039 inch between headgaskets. which is insane! the toyota block also has piston protrusion measurements(piston exits the block). where as far as I saw there isnt for the nissan, they use the cylinder protrusion to adjust and the piston never exits the block. so being that im on the top end of protrusion at .003in that alone is a headgasket difference in the toyota. I also know they did not replace my valve seats but they did surface the head. I never rechecked the valve protrusion when headgasket was out again to know its position. but if they are in the recessed side of the measurments. then could easily equal out atleast 2 of those headgasket ranges..... very interesting.

if .003in can alter his compression fairly drasticly I'd imagine. Now I wonder if the after market piston is even the same hieght from the pin boss to piston crown, or even ring land depths. if the piston is even .002 shorter then factory it would drop the compression a fair amount. that's realy super lame.... I really dont wanna tear down AGAIN just to measure it all out lol....

Nissan_Ranger
Posts:266
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Location:Canada

#19

Post by Nissan_Ranger » 7 years ago

What is your starting routine?

N_R
The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.

ehtrain
Posts:141
Joined:8 years ago
Location:regina, sk

#20

Post by ehtrain » 7 years ago

well from repairing another friends sd25 NGK says peak temp for glow is 7 sec.

originally I was 7 sec glow 10 sec intake heat. after start up. just kept glow 7 seconds and 15 seconds off or atleast some turning over before cycling again.

now I 10 sec intake and 8 sec glow. giver a try. then I usually glow 7 sec and intake heat 10 sec and 7 sec glow again. it usually tries to fire along with start speed by this point. sounds like it wants to go but just can't quite get enough bang.

i usually glow 8 sec more wait 15 seconds. glow another 8 sec. then try again. if not then I start cycling intake heat in again.

after it finally starts up on the couple cylinders/misfire. usually pukes grey smoke (indicating poor/low combustion) and puke black carbon bits all over the snow. makes a nice black mess everywhere lol. usually runs on a couple cylinders for atleast a minute (even started indoors) until gauge starts to lift sometimes.

after shes hot it will start just touching the key no problem. BUT leave it outside for an hour at -20C and it has trouble starting again. if it cold soaks over night. I have 0-40 synthetic in, oil pan heater and block heater. it always has issues starting again. best I've got is randomly 1-3 tries it starts. usually its atleast 5-25min cranking

i have 2 redtop optima batteries all with fresh wiring in 2ga welding cable, starter is freshly rebuilt. block heater is 400watts, oil pan heater is 120watts, and they both work

Nissan_Ranger
Posts:266
Joined:13 years ago
Location:Canada

#21

Post by Nissan_Ranger » 7 years ago

I've got the glow plugs that don't ever seem to burn out. I usually feed them for about 20 seconds before cranking this time of year and I keep feeding them while I crank. If I don't glow this long, it WON'T start. I also make sure my fuel control cable is set to full enrichment by pushing it ALL the way in. Once started and running smoothly -with the help of after-glowing as required-, I pull it out to the 'no-smoke' position. Like yourself, I run synthetic oil. (10W30) The block heater makes a huge difference in the -20C to -30C nights we've been having this week.

Can you run your glow plugs longer??

Andy
The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.

ehtrain
Posts:141
Joined:8 years ago
Location:regina, sk

#22

Post by ehtrain » 7 years ago

I can yes. But at 180 bucks a set. after buddy burnt out 3 sets. I refuse to run any longer then 8 seconds. I have an extra set of glow plugs, but after all this cash into the motor last thing i want is to spend 200 bucks to start it every time lol

Nissan_Ranger
Posts:266
Joined:13 years ago
Location:Canada

#23

Post by Nissan_Ranger » 7 years ago

If your friends glow plugs are being run by the timer, I'm not surprised that they burn out. The engine I'm using now used to burn them out when it still had the original timer running them. That was gone after I built this truck back in '04 and I have not burned out a plug since then running them the way I do. Now I will say again that there are apparently two different kinds of plugs, one of which does not take to my method of operation. I'll look at one of my spares if I can find them and post what brand it is. I suspect that if you crank after after your initial warming period AND keep glowing while you crank, you won't burn out a plug even if they are the fragile kind since the swirling air/fuel mixture will cool them while cranking.

Andy

Edit: Just found one of the old boxes; NGK (New Number= NGK 1232) (Old Number= NGK Y-112TS)

And this: http://www.ebay.com/itm/NGK-1232-Glow-P ... 3c&vxp=mtr

22 dollars plus shipping, but I'd ask him if he'd combine shipping as there is no way I'd pay 4 times 18 dollars per item for shipping...
The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.

ehtrain
Posts:141
Joined:8 years ago
Location:regina, sk

#24

Post by ehtrain » 7 years ago

well this explains a lot....
Image
Image

would appear to be improper sleeve installation. I can't even believe that... 1 is broken right off and other 3 appear to be cracked. I was always told to put block in oven to get it warm, freeze the liners. If your quick out of the freezer the liners should be small enough to just drop in. I'm not sure how my machinist did it... but it didn't work.

Nissan_Ranger
Posts:266
Joined:13 years ago
Location:Canada

#25

Post by Nissan_Ranger » 7 years ago

I tried that method a few times back in the 'good ole days' before we knew releasing freon was a bad idea... The old oven/freezer trick was also tried by many folks who put crank bearings into Triumph motorcycle casings. The temp difference really needs to be very significant for it to have even a chance of working; I never had good results with the temp difference found with the freezer/oven method.

So back then, I trickled liquid freon over sleeves until the boiling stopped, which indicated that the sleeves were at minus whatever freon boils at; ridiculously cold at any rate... Then used to pick up the sleeve with a leather glove and shove it down into the bore. You've got about a second -two at the most- to get it down into place. This meant pushing it down pretty fast. I sheared a couple of sleeve lips off when they impacted against their seats and that convinced me to do it the proper way which is to use the proper sleeve press jig, a huge ass press, and lots of time... Glad you found the problem, sorry it was such a f/up...

N_R
The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.

ehtrain
Posts:141
Joined:8 years ago
Location:regina, sk

#26

Post by ehtrain » 7 years ago

well I stopped by the machinist today. they use a press and jig to install. Not oven method. He doesn't think he would have forgot to check the lip recess on the block and sleeve. But that is likely the issue. either the sleeve was not recessed at all/enough. or the block edge was sharp. 2 straight edges cause stress.

kinda makes me wish I could afford more then just assembly tools and be able to do all the machining myself. oh well... I get to rip it apart now. He didn't really say if they will replace the sleeves for free. this really sucks.

Nissan_Ranger
Posts:266
Joined:13 years ago
Location:Canada

#27

Post by Nissan_Ranger » 7 years ago

Is your machinist an actual engine re-builder?
The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.

ehtrain
Posts:141
Joined:8 years ago
Location:regina, sk

#28

Post by ehtrain » 7 years ago

yes! hes the head machinist at the only diesel rebuilding shop anyone trusts. I was even reffered to him by name from several people because of his good work. I have even seen stuff in his shop he has taken way beyond anything my engine even needed. Either the sleeves weren't reliefed enough or the block relief isnt enough. there is relief cut into the block.

just visiting him the other day i counted 10 diesels and 4 gas motors just in his 20 foot vicinity lol.

Nissan_Ranger
Posts:266
Joined:13 years ago
Location:Canada

#29

Post by Nissan_Ranger » 7 years ago

I've put more than a few of those 'tin-can' sleeves in myself; mostly into Perkins diesels. Those sleeves broke so easily, it was hard to believe.
The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.

ehtrain
Posts:141
Joined:8 years ago
Location:regina, sk

#30

Post by ehtrain » 7 years ago

im beginning to wonder if I should measure up my other block and see how bad its worn.... maybe im better off just re-ringing an old block.

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