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'89 2.4l WD21 Restoration Project - With lots of Photos!


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Hi!
As you can read here in my "new member" introduction post, http://www.nissanpathfinders.net/forum/topic/44173-wd21-from-italy/, I'm slowly restoring my '89 WD21.

Some of you might like to take a look to some photos of the "work in progress", so...

My engine developed a rod knock which I believe is due to debris from a broken timing chain tensioner which clogged oil passages in the crankshaft (I will check this later). Anyway, I decided to buy another motor.

Z24 engines are very rare in Italy (where offroads vehicles are mostly diesel because petrol prices being insanely high); the only one I could find was 700kms away. I could have it shipped, but did prefer to go to pick it up in order to check it as thoroughfully as I could (was off the car). Crank was good, compression seemed to me a bit low (turning it by hand), but was very clean under the valve cover and decided to take the risk. After all, I can always use the head from the other engine in case compression leaks should be imputable to the head.

 

 

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4wuo6VYh.jpg

 

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As said, in spite of the dirt on the outside, the inside is super clean, surely a sign that the engine had correct maintenance.

rV7ItHJh.jpg

 

 

 

Oil pan super clean, too.
hdnHnFSh.jpg

 

 

Clutch is pretty worn
N6TK2TPh.jpg

 

 

The engine will receive a new timing chain kit, new spark plugs, new oil seals, new air and oil filters, new distributor cap & rotor, a new clutch and 0w40 full synth oil. Water pump and crank pulley, slightly bent from the impact (the engine is off a crashed car) will be taken from my old engine (this will be a budget repair).
aMOcJdDh.jpg

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In the meanwhile, a little cosmetic won't hurt (even the eye wants its share, as we say here in Italy, I'm sure you have a saying for it, too ;-) )

noNzfrKh.jpg

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Yesterday I dropped the front differential, which seems to be mandatory, since otherwise the oil pan won't allow enough clearance for the engine come off. A pain I wish I could avoid, but did it in the end.

Also, I'm thinking about blanking the EGR with a 2c coin, since I have the engine off the car. Any advice about this and how to do it properly will be greatly appreciated.

More photos will come.

Edited by Killermiller
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2T4Cctsh.jpg

Differential down.
Manual says to drop the diff with the crossmember still attached. Didn't work for me. I've spent almost an hour sweating and cursing under the car, till I've finally decided to remove those three studs securing the diff carrier to the crossmember. Two minutes to remove the studs, 10 seconds to drop the crossmember, 10 seconds more to drop the differential.

TjQRxGuh.jpg
A couple of bellhousing upper studs a little tricky to get at...


... and off it came with no particular hassle.
A0lvGmNh.jpg



This is the inside of the oil pan:
YyiQ31lh.jpg

The grayish slime is mostly iron dust. You can see, on the right, one of the pieces of the timing guide. The rectangular thing is a magnet I've previously dropped inside the pan in an as desperate as unuseful attempt to limit the damage. I have no idea about the round thing that looks like a broken washer. I will investigate this, just for the record.
More and more amazed by the fact that, in spite of the knock, the missing tensioner, that mysterious washer and all this ferrous debris in its guts, this engine was still going without burning any oil.

Oo1Wiush.jpg


... and voila - that's the reason for the knock:

OhR21Kph.jpg

#1 rod bearing spun and broken.

This is the crankshaft...
NhEX6NEh.jpg


... and that one on the background is the rod.
PNo4eqmh.jpg


Maybe can be reground, maybe not, but - since I went to the route of an engine swap - I think is pointless for now. Perhaps, if not beyond repair, I will keep both crankshaft and rod as are and, in case I should need them in the future (knock on wood) I will have it machined then.

That's all for now.

Edited by Killermiller
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Yes! Just like Mary Poppins' oil pan! ;)

By the way, why double tightening torque on the manual? Is that a minimum and a maximum?
Also, is it mandatory to replace the six flywheel studs or can I reuse them, perhaps using some thread lock just to be on the safe side?

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Like how wheel lugs will say 87-108 lb ft? Yea it's just the torque range. Don't know about the studs, but if they're easy to remove and find new ones I'd say best to go for it.

Edited by jjonez
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Thanks, jjonez.

.
Today I started the engine for the first time. Has some issues I believe due to something injection/related* and/or some vacuum hose disconnected, but otherwise sounds pretty good.

*The Z24, unlike KA24 and the VG30, has a single-point injector. As far as I've figured out, it doesn't have a fuel rail, but sprays fuel inside the intake manifold from above, acting more like a carburetor. It sat for years, so it might need to run a little to clear up.

Edited by Killermiller
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  • 1 month later...

After fixing the air/fuel mixture problem by swapping the whole throttle body that was off the old engine (vacuum was ok, injectors, maf and tps too... perhaps there was some dirt clogging some duct or some vacuum valve sticking closed or open, I don't know), I performed a compression test. Values 1 to 4 cylinders are 155 - 150 - 150 - 155 psi with COLD engine (specs are 131 min and 173 max with HOT engine, so I should be on the high side); squirting some oil inside the chambers made me gain an additional 20ish psi per cylinder. I think this is ok for a 30 y. o. junkyard engine. 
The engine pulls strong and sounds good; only when going on LPG is not perfect yet (as said elsewhere, this car has an additional LPG fuel system fitted by the previous owner, with a 58lt LPG additional tank). Having zero experience with LPG fuel systems, I still haven't figured out what's the problem, but it shouldn't be anything major,

N6rKrXih.jpg




Also, a new window regulator has been installed (being the steel wire of old one messed up)
 

cIgWxvYh.jpg

... and a new rear window switch
0osY8qWh.jpg

Edited by Killermiller
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  • 3 months later...

Hi KillerMiller, hows it going with your restoration... Looking good. I started a similar project with a 1988 Terrano 1, 2.4  Z24 petrol (identical in many aspects to the Pathy from the same era). If I can offer my tuppence worth of knowledge (Haha), if you  can see your engine cooling system has had water instead of antifreeze in it, then take a close look at your  core plugs before it all goes back in (is it already too late !!!) I saw markings on mine and popped them out in situ (tough to get access on some) and found they were corroded and ready to leak, but also, a huge build up of sludge, rust and muck in the block just behind the plug, which was greatly reducing the coolant circulation and causing overheating. The other thing you might want to check, is the coolant thermo choke (on the right hand side of your carb photo). If there has been a lot of muck and sludge in the cooling system, it almost definitely has accumulated in that housing rendering the auto choke inoperative, provoking higher revs at start up but not dropping off. If its completely clean inside, it should work, but if not, its really hard to find a replacement and in my case, I just had to block mine off. Good luck...

Coolant auto choke.jpg

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