Maplebacon

Greeting fellow sc owners!

Well I have spent the last 6 tmonths looking for a clean sc400. In specific a pre 95 model. 1 for the OBD1 being less "sensitive" so to speak with mods. and 2 because of the thicker connecting rods.

so i finally found a 1992 dark blue sc400.... 177km..... bought it off an old couple that had bought it brand new. They lived in like a 3million dollar house. Car looked mint! not a spec of rust any where under neath. Motor looked brand new. I noticed that it had the timing belt done in 2000 at 134km. so in the last 15 years its done only 42000km= lots of sitting.

anyways fast forward to today. just got the car back from lexus. They said that they found this build up between the head and the block and they said what probablly happened was the head gasket blew.... and someone dumped in some head gasket sealer... NO!!!!!!!!!!!!!!!!!!!!!!!!!
Also the said #7 intake lifter is really sticky/fu*ked. So anyway knowing that head gaskets failures are really rare on the 1uz. I really this I want to get this one out of there and start with a better platform.
I have located a 94sc400 with only 150km and it runs great. And the guy will sell me the motor for 900$.

So I am going to go ahead and put the 94 engine into my 92. And then i'm going to tear down the 92 block and re-seal it and clean up the heads. Not going to touch the bottom end.

So my question to you guys is..... What excactly do I need from this doner car to make this work? It comes with wireing harness... will my 92 ecu work on the 94 engine or should I buy the 94 ecu as well?

My 92 has the Trac and I dont think the 94 does.

Thanks for any imput guys.

once I figure this out. I will be going to go get the 94 motor. LOTS OF PICTURES TO COME!

Maplebacon

My biggest conern really is the ECU and wireing harness working.

i know that the 92 for instance has a cold start injector. the 94 does not.. I found this over at Lextreme

Wiring Harness:
Crown UZS131 - does not have provision for oil level gauge.
Crown UZS 141 & UZS151 –Oil gauge in alloy intermediate plate below alternator
SC400 - some models do not have Trac so a different loom
SC400 - Active is unique and won’t interchange to another engine.
LS400 – same as Celsior.
Celsior – Same as LS400

Whilst you can interchange the harness between different engines some differences do occur. Oil level gauge sender on LS400 and Celsior models are on the right hand side at the front (behind the power steering pump)whilst the gauge sender on SC400’s is in the centre of the engine on the left hand side (behind the air conditioning compressor).


Compression Ratio:
Early 1UZ 1989-1994 10.1:1
Later 1UZ post September 1994 10.4:1

Power output:
The Crown puts out less power (around 10-15hp less) than the SC400 or LS400 partly because of the restrictive exhausts.

ECU:
Crown UZS131 - has two modules the ECU runs the engine and the ECT runs the transmission. The ECU is happy to run without the ECT
Crown UZS 141 & UZS151 – has single ECU/ECT and can be hard to run without the transmission or external sensors.
SC400 - uses single ECU/ECT.
LS400 - uses single ECU/ECT.
Celsior - uses single ECU/ECT.

Whilst the Crown UZS 141, UZS151, SC400, LS400 & Celsior use a combined ECU/ECT they are not interchangeable.

pogoism9

iTrader: (1)

The 94 should drop right in to the 92. The Sc didn't get the gen2 1UZ until 96. To be safe, you will need the 94 ECU and harness. Any provisions for the cold start injector would be present in the fuel rail and harness for the 94. I would also use the trans from the 94 too.

t2d2

iTrader: (8)

AC may be different, as '92 used Freon. (I'm assuming Canada got the same setup as the US.) The ECUs are definitely a difference, but no one really has much to say about which one will work on other years. The general assumption is, you can use a newer ECU on an older model, as long as you stay within the related generations, but vice versa may not work well. Beyond that, everything should be very similar, if not identical, as far as I can come up with.

matguy

I'm no expert, but it would seem to me the path of least question would be to strip the 94 engine to the long block (keep the heads on, pull the intake) and put everything from the 92 on that. The block and head shouldn't have changed between those years, but a few other things we know of have. Why take a chance on things we haven't thought of?

Now, that said, I would still get as much from the donor car as possible, assuming it's cheap to free to grab. Anything that is the same saves you a trip to a junk yard or an ebay wait.

Again, I'm not an SC, Lexus, or Toyota expert, but I've done a few non-year-matching engine swaps and that's what I would do.

You're basically trying to get a head rebuilt without pulling a head. Not completely illogical. So, I'd say to replace only what you have to in order to get that done. The block and heads. Who knows that little stuff changed that hangs off the intake or other accessories. Someone already mentioned AC changes, ECU changes, possible cold start injector changes.

While you're at it, while you've got the intake off, get a new starter. Way easier with the engine out and intake already off. Might as well do the timing belt and water pump. Maybe a new alternator and P/S pump?

Being the long blocks are pretty sturdy, you'd almost have a fully refreshed heart to your beast.

Experts, please tell me if I'm wrong.