fencera

Hello all,

I have used this site for many years as a source of invaluable information on how to best maintain my '90 LS400. It's a phenomenal resource; thank you.

I am now faced with a dilemma: my family's 1990 LS400 just blew its head gasket. We have owned the car since it was new and with over 320,000 miles, it has served us well.

The car has four new struts+springs etc, a new alternator, new starter, new a/c compressor, new steering rack and pump, new radiator, new upper and lower ball joints, new strut rod bushings etc etc all within the last 10k miles. Worst of all, it also just had its timing belt etc replaced at about 320k. We planned to keep the car forever. It has become a member of the family...

I have been looking into getting a used engine to put into the car. There are a number of higher mileage engines available from US cars available. There are also "low mileage" 1UZFE JDM engines available. I am leaning towards a JDM engine, but have a number of questions/ concerns about them.

First and foremost is emissions: there is no EGR equipment on these engines. Does anyone know if an engine without EGR equipment will pass Maryland (or, for that matter, any other state's) emissions? This swap seems to be commonly done, but I have had a very hard time finding any definitive answer on whether or not it will pass. I know EGR blocker plates are sold, but I have not been able to find anyone who then directly said their car still passed emissions and what state they were in.

Alternatively, can the EGR equipment on the old engine be retrofitted onto the JDM engine? Is there a hole in for the lower EGR exhaust pipe connector? I assume the intake manifold (and throttle body with appropriate vacuum lines+traction control) can be taken off the old engine and placed on the JDM one. Has anyone done this or know where I could find more specific information?

I am also afraid of what I don't know if I try to retrofit the egr equipment... ie the egr temperature sensor. Can that be retrofitted to a JDM engine?

Regarding engine selection itself, I am aware that many of these JDM engines are advertised as being compatible 90-97 but there were some major differences between the 93, 94 and 95 years. Namely the injector firing sequence and air intake sensor system seem to have changed from 94-95 (in addition to the addition of an exhaust temp senor for EGR OBD2 systems from 93-94). Even the egr exhaust pipe set up changed. Does anyone know if a 1990 ECU will operate the newer engine? Does the injector firing sequence and different compression mean the ECU won't work? I simply don't know enough to figure this out on my own....

In testing and installing the engine, I have also looked into the recommendations of people on this forum who have purchased used engines in the past. Here is a checklist of what I have come across. Does anyone have any other checks they would suggest?

-compression for each cylinder / leak down test
-spark plug condition (engine oil in the cylinders can give higher compression numbers and spark plug fouling etc could help indicate this)
-freely rotating water pump to indicate engine overheating did not occur
-freely rotating crankshaft


In installing the engine, preventative maintenance ideas I have are to:
-replace rear engine seal
-replace torque converter
-replace valve cover gaskets
-replace starter (have new one in old engine-- only started the old engine a few times!)
-replace compressor, alternator, PS pump w/ air valve,
-replace timing belt + water pump, cam+ crank seals, bearings and tensioners
-check valve seal condition, valve shim clearance (w/e this is called)
-check fuel injector condition, clean+ reseal
-replace spark plugs + rotors+ caps+ spark plug wires
-replace oxygen sensors

Any other ideas while the engine is out? The old engine's mounts are almost new with only 20k miles on them...

If I could, I would upgrade the headers also, but I can't justify the cost. Ugh!

Clearly, if I went with replacing the engine and keeping the car, my main concern is doing it right with an eye to the long term goal of keeping the car in top condition. My main problem however is the lack of hard information I have been able to find regarding the EGR situation as well as the inherent unknowns of buying a used engine. Any help or information would be greatly appreciated. If I do go ahead with this, I will make sure to update the thread with any potential problems, resolutions and the eventual results.

Thanks!

fencera

Ok, I have found a picture of the EGR pipe here that shows it connecting from the intake manifold to the exhaust manifold (makes sense given how the system works... duh).

This seems to indicate it should be possible to retrofit at least this part of the EGR system to a JDM engine. Does anyone know of any potential problems with this?

Really is too bad that one of the weakest components on this engine has to be transplanted...

Legionofon

man, if your going to do the work to get a new engine in there... just rebuild yours... you will know that your engine has been taken care of...

fencera

Thanks for the suggestion. I have been considering this, but with the cost of the machine shop inspecting/machining the head being over $200 and then potential other costs like piston rings, the head gasket, replacement block bolts and the labor of the whole project, it seemed to make more sense to just replace it. Spending the money to try to save the existing engine and then finding out it was warped or had minor cracks would be pretty disappointing....

If the engine has good compression, passes the leak down test and has all of the preventative maintenance done on it I have mentioned, wouldn't I be in pretty good shape? Replacing the head gasket, inspection and bolts costs about as much as a complete JDM engine. That is if everything went smoothly upon block inspection.

I am no expert so perhaps I am missing something here or not taking into account other factors. Thanks for your suggestion and I will definitely be double checking on my calculations with that route before I make any firm decisions.

Legionofon

unless you plan to rebuild the replacement engine you run the risk of having the same problem again... I believe that if you really want a quality fix to your car you need to have it actually repaired instead of the throw a new engine in it... you will have new parts that will last you another 300k miles instead of a old engine that might fail... also if you rebuild it completely you will restore power, might even get some more if you deck the head/block a bit...

Thermactor

iTrader: (1)

hi fencera,
you can use a '90-97 motor and your '90 ECU will run it fine. The thing is that you need to strip the motor down to almost just the heads and block so you can retrofit your sensors (cam and crank too!) and manifolds into the motor.

PureDrifter

iTrader: (10)

95-97 wont run properly on a 90 ecu due to the electronics, without a good bit of modification.

if you want a drop in, plug and play motor, you'll need one from a 89-92 LS. there are plenty of USDM motors to choose from, no real reason to go JDM.

fencera

Thanks for the info. Do you happen to know what changed in '93? If the old engine harness is used, can a 93-94 engine be used?

Thanks!

3UZFTE

If it were me, I would keep the existing motor in there and just have a independent shop do the HG is that it truly your issue. If you buy a newer motor, yes the mileage will be less, but you would need to invest a few dollars and hours in building the eBay motor to be fit to drop in. If you keep yours it is a lot easier of a process, theres not much downtime and if something happens to the eBay engine, your S.O.L. for more than a day. I know 320k sounds like a lot of rings and bearings, but these things will go another 300k if you take care and baby it. Pull the plugs, read them, check compression test, blow-by if you want it, obviously check the oil and coolant, check the exhaust ports and that should be good. Water pump is a little tricky, and even if they engine overheated, the pump will still rotate. You can check if the crank rotates by turning over the starter, if the belt moves, your crank is moving. Usually a bad HG will not grenade the motor, it will if it is ran for a long period of time, but you seem to be ok.

fencera

Thanks for the suggestions. The more I have look in to getting a used engine, the more uncertain I become about it... and the more likely I am to rebuild what I have.

One main cost consideration however is the replacement head studs. At $359, the ARP ones seem to be overkill for someone trying to just trying to get back to OEM. I can't even find the things listed on the typical OEM part sites.

More fundamentally however, and I realize this goes against traditional wisdom, do these head studs need to be replaced? The lexus engine rebuild directions (p EM 64) says that: "If any one of the bolts does not meet the torque specification,replace the bolt." and that: "If any one of the bolts does not meet the torque specification, replace the bolt." I thought these bolts were supposed to stretch... why doesn't the manual say to replace them?

Lastly, if it's thought they should definitely be replaced, does anyone know of any sources for non-high performance standard head studs? I put in a few calls to Lexus dealers, but would appreciate any other suggestions.

Thanks!

Sixdown

You should always replace headbolts/studs when rebuilding an engine. Check out Autopartsaz.com, Rockauto.com, partsgeek.com, all sites I've used often over the years.

vietunit

iTrader: (5)

+1, go with the rebuild. Get it done right and it'll last you another 300k

fencera

Thanks guys. I am going in for a rebuild estimate tomorrow.

In case anyone in the future is ever interested, the Lexus part number for the head studs is 90910-02088. They are pretty cheap @ about $4 a piece. I also ordered an engine gasket overhaul kit for under $250 shipped (04111-50020) from a Lexus dealership. Pretty ridiculous price... I am waiting for them to say it was a mistake on their site.

Hopefully in a week or two I'll have a rebuilt and working engine again!

j2b4o

why not just pull the heads and replace the gasket and studs. if you haven't driven it long with the gasket failure its likely that it will run just fine. Ive had a few cars that I did the HG on after I drove them for a few weeks smoking like crazy and all of em ran like a top after the replacement.
an engine re-build couldn't hurt but it sounds like you want to save some cash.

Good Luck either way!

fencera

Update:

So today they finally had the engine out, apart and got a good look at what is wrong. It's not good...

Apparently, an inner metal cylinder ring from the head gasket got sucked into one of the cylinders somehow. This deformed the piston slightly, the valves slightly and then shot through the exhaust system like a bullet destroying one of the catalytic converters. The coolant poured into the engine, mixed with the oil and left a complete mess. Quite a bizarre occurrence... I couldn't really believe it until I saw what happened.

Anyways, I'm now trying to decide what to do with the car/where to get an used engine from.