What wears out on pedestrian v8's? lexus 1uz's

Lacking all common sense, I want to put a lexus 1uz v8 in my miata. Call it a challenge. I'm aware of the roadblocks.

Anyways my favorite local yard just got a 1991 ls400, it was put there as it was struck in the passenger door. My hesitation is it has 180,000 miles.

Now if I were looking to buy a ls400, I wouldn't hesitate to buy one with that mileage if it appeared in good shape and well taken care of, however my plans are different.

I dont really want to spend the next few years of my life engineering this thing to fit only to blow it up bouncing it off the revlimiter at an autocross.

So realistically, logically (I know.. ironic), what wears on high mileage aluminum lexus stuff. If it is as simple as (assuming engine has had clean oil kept in it) timing belt/water pump, gaskets, idler pulleys, seals and go another 100,000 at 7,000 rpm or am I in for heartbreak?

My second option is to look for a ls400 for sale whole, drive it for a little then steal its heart. But that will cost more as I'm no pro at parting out vehicles.

the demographic of the typical LS owner would likely mean the engine has never been abused, and likely has never even been pushed hard, and that it has been well maintained. This is a smart play.

The early ones (up to 96) were built with slightly heavier/stronger rods. The engine itself is overbuilt and should not see any significant issues at the mileage listed.

Well... If you have the talent to fab whatever is necessary to shoehorn that lug into a Miata's engine bay, do you not have the talent to do a refresh of the bottom end - bearings, rings etc? Not trying to be a dic, just curious...

A complete VVTI 1UZ half cut with 45k from japan runs about $1200. That's the route I would take.

As for what wears out? Seems like the car around the motor goes first, engine last.

daytonaer wrote: But that will cost more as I'm no pro at parting out vehicles.

I find this statement odd in comparison to your project.

If you boost them make sure you have a proper crankcase ventilation setup...other than that...they seem to be rock-solid reliable.

Go browse around lextreme.com for lots of info on the uzfe engines. Miata swaps have been done. I'm contemplating putting one in a TE27 Corolla for some fun.

Yeah, there's not a lot that's going to give you big problems. If they look old, I would do the timing belt and water pump. They're cheap and easy to do anyway. But it's a non-interference engine, so no big deal if the belt breaks. The valve cover gaskets and distributor caps have been pretty beat in some of the junkyard engines we've gotten for the Wreck Racing miata. Otherwise, they've been pretty good.

About boost - we've had really, really lousy luck boosting high-mileage 1UZs. They do great with abuse otherwise, but don't like the boosts. I have no doubt the engine would do fine with boost with fresh rings and bearings, but with a lot of miles, that seems to be pushing things just a little too far.

That said we've never broken any engine internals, just spun a LOT of bearings.

Oh, and I'd probably replace the starter motor while the engine is out of the car...

98+ had VVT on the intake, and were interference engines, so be aware of that. Having worked on these engines for over 10 years, I never saw one break under normal use or even neglect (save the timing belt breaking on a 98+). I've seen them with over 450k on the clock having never been opened up past replacing valve cover seals. They are just plain rock solid. Because they never break, there's a good supply in the junkyard, and they are dirt cheap. Pitty no manual trans was ever offered bolted to them.

Boosted, I imagine reliability nose dives, but I have no experience there. Edit- replacing the starter is a good point as its under the intake, and its kind of a pain to get to in the car. Starters are pricey though!

Manual gearboxes are doable, but not cheap or easy. I've got a Richmond gear 6 speed behind mine, thru a bellhousing from Australia and a tilton 3 plate. That bellhousing will adapt to most any GM box.

JohnyHachi6 wrote: Yeah, there's not a lot that's going to give you big problems. ..... That said we've never broken any engine internals, just spun a LOT of bearings.

Thanks for the reply.

I have no plans for boost.

What bearings did you tend to spin?

Rod's take a pounding from increased cylinder pressure? Or mains take a hit from dropped oil pressure? Or cam bearings get washed out?

I would assume the cam bearings are simply the aluminum head surfaces? Any problems with them?

Do you think running new bearings before boost would have helped? I don't mind changing them but I'm trying not to fix things that don't need fixed.

And as for the starter, I understand its precautionary due to location however have you tried rebuilding one?

I've never had much trouble with Japanese starters but never had ones that cooked in the valley of an engine. I would be unhappy to put in a reman and have it conk out as remans tend to do.

Thanks again, Mike

As cheap as these are, you're probably more likely to screw something up by replacing the bearings than just pulling it and replacing it. In the scheme of this swap, an engine R&R after the fact should be no biggie.

I've done it both ways with swaps. I did one where I disassembled the bottom end and refreshed the bearings. It blew up in about 1500mi after that. I did one where I just plunked the 232k mi engine in and beat it mercilessly without problems. Ruined me on trying to rebuild anything that isn't rare and/or expensive.

I think the starter issue is the contacts more than anything else. Some people just put new contacts in. I've done the starter on our 99 and my 98 came with it already replaced. I put a NAPA starter in the 99. I think it was four bills at the time. Valve cover gaskets should be replaced when it's out. I would go 98-up for the VVT-i, although if you put the earlier one in, you could always just swap the motor out for a later model. It's then an R&R and not a total fab job.

Having done a complex and stupid engine swap similar to this, just seal any leaks up. The amount of fabrication required for the engine swap is so high, the engine itself isn't really a big deal. They are cheap and available, that's all you need to know. If it blows up, buy another one and swap in in a day. You'll have so much experience pulling the engine in and out with a project like this, dropping in a new one will be a minor annoyance.

I've had several cars with the UZ family of motors and been deep inside one of them. They just don't wear out in their typical application. Racing stresses them more obviously but if you're starting with a healthy motor I would do very little to it prior to installing it in the car.

On the starter, the contacts are what goes bad. Get new ones from Toyota and install them and it'll be good for a decade or more. The disadvantage is you'll need about $75 in gaskets to get to it and close it back up.

I rebuilt the top end on a 3uz that had a broken timing belt. The cylinder walls were perfect at 240k miles and didn't have a perceptible lip. I didn't check the rod bearings. I replaced the heads with lower mile (75k mile) heads since I found them cheap locally. The only wear I found in the motor was the camshaft thrust bearing in one of the cylinder heads, it was pretty worn. So I was happy I found the 75k mile heads.

My wife's old '92 LS400 had 240k miles and it appeared to have had nothing done to it in its entire life. Even the plug wires and water pump had 1991 date codes on them when I swapped them. An idler pulley had seized taking out the timing belt which is how I got it for $500. I fixed it up and she drove it for years. Sold it on to pubburgers on here for $500 and he's still enjoying it I think.

It is a shame these motors don't have a cheap manual transmission option. But then I bet they would be really, really popular with the hot rod crowd. They're pretty sweet.

I thought there was a company that sells adapter plates for 1uz to r154? I think they are called Toyota v8 or something like that.

Castlemaine rod shop in Australia has complete bellhousings to convert to typical manuals, but they are not cheap anymore... I got mine fro about $200 years ago.

daytonaer wrote:

JohnyHachi6 wrote: Yeah, there's not a lot that's going to give you big problems. ..... That said we've never broken any engine internals, just spun a LOT of bearings.

Thanks for the reply. I have no plans for boost. What bearings did you tend to spin? Rod's take a pounding from increased cylinder pressure? Or mains take a hit from dropped oil pressure? Or cam bearings get washed out? I would assume the cam bearings are simply the aluminum head surfaces? Any problems with them? Do you think running new bearings before boost would have helped? I don't mind changing them but I'm trying not to fix things that don't need fixed. And as for the starter, I understand its precautionary due to location however have you tried rebuilding one? I've never had much trouble with Japanese starters but never had ones that cooked in the valley of an engine. I would be unhappy to put in a reman and have it conk out as remans tend to do. Thanks again, Mike

We have spun both rod and crank bearing on different engines. But again, only after boosting them. NA the engines seem to be rock solid even with high miles and little maintenance. Never had problems with the camshaft journals.

I think new bearings would have helped with the boost. Though I think in at least one case the failure could have been from excessive blow-by around the rings. These engines don't have a crankcase vent in the block - only the heads. So with excessive blow-by the huge amount of oil vapor and exhaust flowing up through the oil passages keeps the oil from draining back to the sump from the heads and can lead to low oil pressure and killing crank bearings.

So, if I were to boost another junkyard engine, I would probably look at doing bearings (or at least checking their specs) and rings. If you aren't going to boost it, I wouldn't touch the internals. Just do any leaky gaskets/seals and call it good.

With the starter, it's honesty not THAT hard to replace. If everything looks to be in good shape, maybe don't worry about it. Just be aware that it's trickier to get at than on most cars.

Having used these engines for 7 years or so at Wreck Racing, I only remember running in to a bad starter on one occasion.

JohnyHachi6 wrote: With the starter, it's honesty not THAT hard to replace. If everything looks to be in good shape, maybe don't worry about it. Just be aware that it's trickier to get at than on most cars.

This is true; honestly people make it sound like you're swapping wrist pins on the motor to get to the starter or something but it's just under the intake. It's no harder than pulling the intake on any 4-cam V-engine. Yes it takes longer than on, say, a 2JZ but no it's not that hard.

Impulses got the better of me.

Any ideas how to move this thing (hoist not local currently) Little too heavy for two people to deadlift.

Back up real fast and hit the brakes? Or find more buddies...

The only thing I run into on those older Lexus V8's is the injector harnesses get cooked and breaks up and they're NLA from Toyota. Really only an issue if you're going to have the intake off but it is something to be careful of. I LOVE those engines, looking forward to following your build.

Collecting parts phase.

I'm still in an apartment with street parking, but when the right parts show up at the right price... My spare bedroom smells of motor oil.

Mini honda hatchbacks!

Also plan on running the 94+ rear as I don't expect to get much more power than the turbo miata's out there and this is the simple fit for now.

In other plans; I found a relatively cheap bathroom scale that reads to 500# on amazon, I think I will get it during mock up phase to see how much weight I am really adding.

So what transmission did you snag?