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?

[pdgizwiz]

The head gasket looks fine. No signs of leakage. Nowhere did the engine have signs of leakage, even around the valve cover. But I think these things get a pressure-washing. The top of the block had a fair amount of rust, especially under the insulator block.
When I say the top of the block, I mean what would be the left side of a normal inline four cylinder engine, but being a Previa, the right side is where the head attaches.
The OEM parts number for the later S/C head gasket is 11115-76040. This superseded the 11115-76030, but is backwards compatible with the earlier N/A engines. According to this document, the difference is a "wire ring around the bore grommets"
HeadGasketRevisionS_C.jpg

Toyota apparently isn't selling the "head gasket Kit" any longer, but only the head gasket itself. I opted for the FelPro kit, which is labeled as if it is equivalent to the new one. I can say that it certainly looks the same, but I'm not going to section it to look for that "wire ring"
Fel-Pro_gaasket-kit.jpg

[pdgizwiz]

One area where this engine was headed for failure was all the corrosion on the sealing surfaces of the timing cover. The oil pump, oil filter stand, and water pump are all sealed against it with O-rings, and the contact surfaces were all crusty. Like this:
H2O-pump-port-before.jpg

I cleaned them up by scrubbing wads of 320 grit wet-or-dry sandpaper around on them:

H2O_gland-w-sandpaper.jpg


.. until they were smooth and clean again. Not perfect, really, but I'll put a think smear of Permatex on them anyway, so they'll be fine for the next 20+ years:

H2O-gland-clean.jpg
oil-filter-stand-mount-clean.jpg
Oil-pump-housing-clean.jpg

[pdgizwiz]

A very tardy update- I don't work quickly! Summer activities have taken precedence.
I got my cylinder head cleaned up and re-installed. The valves didn't need to be ground, so when the cams were back on the clearances were all still in spec.
I'll likely not get around to putting it in my van until spring, so this thread will continue to languish.

[timsrv]

Nice work. I probably would have been doing that to one of my Previas by now, but I decided to sell instead (too many vehicles). I worry a bit about the FelPro head gasket, but if you can't get Toyota what else are you supposed to do? I look forward to seeing your future posts. Tim

[daytonatrbo]

I’m working on rebuilding a USDM engine.

I recently picked up a 1996 Previa with just under 300k miles and a bit of rodknock. Upon dropping the crank cover, I discovered the thrust bearings were totally gone and the crank was chewing on the mains caps. So that block is basically trash.

I picked up the only donor engine I could find within a few hundred miles, only to find out it had filled with water and had severe rust pitting in 2 cylinders.

I'm paying a small fortune to have that block sleeved, and I’m paying a buddy of mine to rebuild the head for me.

I’m buying OEM pistons, rings, bearings and other parts for it. I went with the Mahle gasket set and the OEM head gasket. As long as the timing cover gaskets you have are the correct metal type, you should be in good shape. I plan to try to use ARP head studs for the 2RZ application.

Once I get it running and driving, I have a larger Ogura Clutch supercharger I may try to fit to it.

[pdgizwiz]

Wow, I can imagine that having a block sleeved back to the standard bore would be an expensive job. There were lots of Previas around just a few years ago but that isn't the case any more. I hope it all turns out as you are planning.
My project is on hold until warmer weather in the spring. I have the long block back together but wrapped up for now. Swapping engines is an outdoor job for me as my shop isn't tall enough inside.

[daytonatrbo]

The shop doing the machine work is charging me $75 per hole plus materials. I’ll be into the sleeve job for around $500 I think. Plus $100 to clean and deck the block, $100 to polish the crank and inspect the rods.

The parts I’m ordering from Japan are going to run more than the labor, that’s for sure. I’m still waiting on confirmation on a couple of the parts before I can place the order. But I expect that any day now.