Previa JDM 2TZ-FZE Teardown and Rebuild

[pdgizwiz]

This is a sequel to a post of mine from almost ten years ago.
One of my Previas is a '97 Alltrac DX. I love it. I won I in a Copart auction for $150 many years ago after it had been donated by someone who was behind on some mechanical maintenance and apparently didn't want to spend any money on it. Their loss, my gain. Anyway, it's been a faithful steed in my herd, especially in snow, for some time now. If I could buy a new one I might do it, but that would break with my longtime tradition of "pay cash and tow it home".
It has 270K on it now, and so far as I know has its original engine, so I've worried some about how long it will be before it blows a head gasket and strands me somewhere. A year or so ago I decided to buy a JDM engine, do a "scratch" rebuild on it, and swap it out. The gal at Foreign Engines said, "oh, we don't get those in very often anymore". Ooops. Had I waited too late? I called to check now and then, and a few days ago whaddaya know, they had one. I bought it and it was delivered to my door the next day. So I got it on a stand and began to tear it down.
Overall it's what I expected/hoped for. The external parts will wind up being replaced by those on my van's original engine, as there are a number of differences, and they tend to be used as "packing" anyway. The oil pan is beaten in pretty badly, the distributor cap and the coolant sensors have been bashed off. None of this is a surprise and it all has to come off for a rebuild anyway. At this point I've stripped it to a long block.
It looks very clean inside the valve cover.
cam-drive.jpg

Although it's clean inside it looks like it has been sitting for a while. The oil on the surface of the cams has all drained off and a couple of intake lobes had some light rust on them. It cleaned up reasonably well and I'm not worried about it.
cam-lobe-rust.jpg
cam-lobes-spiffed.jpg

There are deposits in the intake ports, but I've seen a lot worse. The plugs all looked good so I'm optimistic.
intake-port.jpg

I'll get the head off in the next day or two to take a look at the other critical innards.

[Previologist]

A year or so ago I decided to buy a JDM engine, do a "scratch" rebuild on it, and swap it out. The gal at Foreign Engines said, "oh, we don't get those in very often anymore". Ooops. Had I waited too late? I called to check now and then, and a few days ago whaddaya know, they had one.

I have seen very few appear at Foreign Engines since I bought mine 4 years ago. Good find! Almost makes me wish I had kept my old one. Almost but not quite. I'm pretty sure it was cursed. I am about to hit 300K on my van, with close to 50K on the engine (plus whatever it had in Japan). I wanted to have the head gasket changed on it before the install, but that would have voided the warranty and i couldn't take that chance.

[pdgizwiz]

I have it all torn down now and have found it to be in excellent condition, as I'd hoped. The seals are old, of course, and there is evidence of corrosion seeping through some of the seals, so I'm glad I'm taking the time to refresh all that.
This site logs me off before I've had a chance to put much effort into a post, so I'll submit this quickly and edit as I go along. When I'm done I'll delete this disclaimer.
The cylinder walls show some very slight scoring and spots of wear at the top of the stroke on the "up" side.

CylinderWall_Upper-side.jpg


For the most part, though, the cross hatching is still present. The ring gap is still in spec as well. The pistons have some light deposits on them, but the oil holes are all clear and the skirts don't show much wear at all.
The crank looks like new and so do the bearings:

main-beg-3.jpg
main-cap-brgs.jpg


The rod bearings look new, too:

Rod-brg-cap-w-shell.jpg


All five of the main bores are grade "2", and the bearing shells are marked to match:

MainBearingGrades-on-Block.jpg

The FSM allows a millimeter of wear on the cam chain guides. The guides on this engine have a lot of life left.
The oil pump parts look clean and nice but the cover was a bear to get off because the pins that locate it have seen some corrosion:

Oil-Pump_Cover_.jpg


I have found that a good way to get the oil pump cover off of the timing chain housing is to put the housing on a solid surface and go after it with my old fashioned hand impact driver with a close fitting JIS bit:

JIS-Bit-Fit.jpg
Oil-pump-removal.jpg
Oil-pump.jpg


The gland that the big O-ring seal fits into has some corrosion that I will clean out. This would have started leaking soon, I think. All three O-ring glands that seal the water pump are corroded. I'll need to clean them up too.
So I'm not going to need many new parts at all. Mostly gaskets and seals. I'll take the head to a shop and have it cleaned up, faced off, and fitted with new guide seals. More pics soon as I get things cleaned up, before and after.

[Previologist]

Cool. It's nice to see what mine probably looks like inside. How does/did the head gasket look?