maniek_LS Posted January 6, 2006 Share Posted January 6, 2006 Hi, My engine has a poor condition and I have two options: 1. do rebuild 2. buy 'new' used. Today I found SC400 after rear accident with excellent condition of engine. And now is IMPORTANT question: is it possible to do exchange those engines ? As I know SC400 had more horsepowers than LS400, but I suspect if it will fit my car ? I thinking about adjust of ECU and other (which ?) thinks ? On Monday I'll visit my mechanic and ask him, but your opinion will be valuable. My LS is from 1992, damaged SC400 is from 1995. Thank you Quote Link to comment Share on other sites More sharing options...
RFeldes Posted January 6, 2006 Share Posted January 6, 2006 Should not be a problem............same engine. Quote Link to comment Share on other sites More sharing options...
Threadcutter Posted January 6, 2006 Share Posted January 6, 2006 Hi, My engine has a poor condition and I have two options: 1. do rebuild 2. buy 'new' used. Today I found SC400 after rear accident with excellent condition of engine. And now is IMPORTANT question: is it possible to do exchange those engines ? As I know SC400 had more horsepowers than LS400, but I suspect if it will fit my car ? I thinking about adjust of ECU and other (which ?) thinks ? On Monday I'll visit my mechanic and ask him, but your opinion will be valuable. My LS is from 1992, damaged SC400 is from 1995. Thank you maniek_LS: Your 1992 LS400 has a 1UZFE engine in it and it is a "non-interference" type. In 1995, Lexus increased the horsepower/compression ratio from about 10.2:1 to about 10.6:1 on the 1UZFE engine, thereby making it an "interference" type. Lexus got about 30 more horsepower out of it by doing so. Oddly (more like maddeningly), they did not change the 1UZFE designation. The problem then becomes one of people believing that their 1995 through 1997 LS400 1UZFE engine(s) are non interference, when in reality, they are. My first suggestion is to entirely forget about re-building your existing engine......You won't be able to afford the parts. My second suggestion is to do a nationwide search for a "junkyard" 1UZFE motor from 1990 through 1994, preferably 1992. If you stay with a 1992, you won't have any problems with ECU compatibility. You shouldn't have to pay more than $1,000 for a good motor. You might be able to get it for a lot less. You will buy it as a long block, which means that you will have to transfer your starter, P/S pump, A/C compressor & a few other items from your existing motor. It will probably cost you between $800 & $1,200 to have a shop do the transfer. Forget about having a dealer do it......Too much money & they'll probably say no anyway. Quote Link to comment Share on other sites More sharing options...
blake918 Posted January 7, 2006 Share Posted January 7, 2006 maniek_LS: Your 1992 LS400 has a 1UZFE engine in it and it is a "non-interference" type. In 1995, Lexus increased the horsepower/compression ratio from about 10.2:1 to about 10.6:1 on the 1UZFE engine, thereby making it an "interference" type. Lexus got about 30 more horsepower out of it by doing so. Oddly (more like maddeningly), they did not change the 1UZFE designation. The problem then becomes one of people believing that their 1995 through 1997 LS400 1UZFE engine(s) are non interference, when in reality, they are. 1990-1994 models have 250hp and 1995-1997 models only have 260hp. The 30hp jump came in '98 with the addition of VVT-i. ;) My first suggestion is to entirely forget about re-building your existing engine......You won't be able to afford the parts. My second suggestion is to do a nationwide search for a "junkyard" 1UZFE motor from 1990 through 1994, preferably 1992. If you stay with a 1992, you won't have any problems with ECU compatibility. You shouldn't have to pay more than $1,000 for a good motor. You might be able to get it for a lot less. You will buy it as a long block, which means that you will have to transfer your starter, P/S pump, A/C compressor & a few other items from your existing motor. It will probably cost you between $800 & $1,200 to have a shop do the transfer. Forget about having a dealer do it......Too much money & they'll probably say no anyway. I couldn't agreed more. ;) Quote Link to comment Share on other sites More sharing options...
90LS400Lexus Posted January 7, 2006 Share Posted January 7, 2006 You say that your engine is in "poor conditions". What exactly is wrong with it? These engines typically go 300K+ miles with little fanfare. Just wondering what the situation on this engine was. Quote Link to comment Share on other sites More sharing options...
kcpth Posted January 7, 2006 Share Posted January 7, 2006 I think you should stay within the generation range of the vehicle just to make things more simplier. If u go to a junk yard... u can probably get the engine for pretty cheap. Cause when i drive to the junkyards here... they always tell me they can't get rid of the Lexus engines... just b/c they aren't in high demands... n even one junk yard owner said... they r INDESTRUCTABLE assuming u dind't get into an accident. Looking by eye... the LS n SC engines are the same. My sis's b/fs 93 SC n my 92 LS r exactly the same... with exceptions to a few components. So i think swaping shouldn't be a problem. But just stay within ur generation range. Inspect the motor before u buy it. Cause when i go to the junkyard... they have some of the motors out on the side... n exposed to the rain n other elements.... which kinda gets me nervous about buying a motor if i ever need to. Check when the vehicle was brought in... n hopefully they had a regular service done to the engine... n hopefully it was a rear end accident. If it was front... hopefully it wasn't serious. Jot down the vin n do a search to see in the past if that vehicle has been in n e prior accident or if it has been maintience regularly... n i'm sure u can get the background check from a lexus dealership. Good luck ;) Tom B) Quote Link to comment Share on other sites More sharing options...
RFeldes Posted January 7, 2006 Share Posted January 7, 2006 Question guys, Are the engines compatible as far as exchange? I understand the interference/non- interference concept, but are they interchangeable? Just for future reference in case this comes up again. If he gains 10HP and understands the re-percussions ie: engine seizure without proper maintenance of the belt, what's the harm other than making sure the belt is A-one? Just curious Quote Link to comment Share on other sites More sharing options...
Threadcutter Posted January 7, 2006 Share Posted January 7, 2006 Question guys, Are the engines compatible as far as exchange? I understand the interference/non- interference concept, but are they interchangeable? Just for future reference in case this comes up again. If he gains 10HP and understands the re-percussions ie: engine seizure without proper maintenance of the belt, what's the harm other than making sure the belt is A-one? Just curious RF: That is an absolutely superb question. I am uncertain at this point, so I won't speculate. However, I do know one thing with absolute certainty; 1995 1UZFE IS an INTERFERENCE engine. If I had a '94 1UZFE that needed replacing, I'd replace it with a '94 1UZFE (Mostly because of ECU compatibility) Food for thought; Think about having to replace a cylinder head. You don't know any better and get one from one vintage and put it into another vintage. One side of your engine now runs with slightly higher or lower compression than the other side. "That oughta do wonders for that nice, smooth as silk Lexus ride".......... That is what absolutely floors me about Lexus NOT changing the 1UZFE designation............... Quote Link to comment Share on other sites More sharing options...
RFeldes Posted January 7, 2006 Share Posted January 7, 2006 Excellent Threadcutter and all you guys that have chimed in ..Good input...but "hello"..maniek_LS is in Poland ,love that country, and I do think his options in a junkyard are "very" limited. "Really", can he swap the "Effin" engines? Bottom line , Please..............You guys are good...give him a comfort zone and non complicated. Quote Link to comment Share on other sites More sharing options...
Threadcutter Posted January 7, 2006 Share Posted January 7, 2006 Excellent Threadcutter and all you guys that have chimed in ..Good input...but "hello"..maniek_LS is in Poland ,love that country, and I do think his options in a junkyard are "very" limited. "Really", can he swap the "Effin" engines? Bottom line , Please..............You guys are good...give him a comfort zone and non complicated. RF: You're right......... maniek_LS: I believe that you can use the 1995 SC (1UZFE) engine in your 1992 LS400 (also 1UZFE). BUT; I would make D*MNED Sure that I also got the ECU (Engine Control Unit ie; Computer) from the 1995 SC400 to go along with the engine. That way, if you have any problems with your 1992 ECU with a 1995 engine, you then have the 1995 ECU in hand to replace the old one. Quote Link to comment Share on other sites More sharing options...
monarch Posted January 7, 2006 Share Posted January 7, 2006 That is what absolutely floors me about Lexus NOT changing the 1UZFE designation............... Historically, Toyota hasn't changed the engine code designation just because small changes were made in compression ratio and horsepower ratings. Codes were changed when more substantial engine changes were made such as switching from 2 valves per cylinder to 4 valves, changes in cylinder bore and piston stroke, changes in valvetrain design, changes in the method of fuel delivery, etc. Quote Link to comment Share on other sites More sharing options...
kcpth Posted January 7, 2006 Share Posted January 7, 2006 maniek... do u have a junkyard around ur area? If so... do u think u can pick up a 1st gen LS or SC? Check other towns around ur area for lex parts. Good luck on finding it. Tom Quote Link to comment Share on other sites More sharing options...
JBrady Posted January 7, 2006 Share Posted January 7, 2006 Ok, most of the above comments are very good advice. Let me make some small changes and additions that may be of interest to many. The 1st generation 1UZFE engine from 1990-1994 in the LS400 was 10.0-1 compression non-interference and rated 250hp/260tq. These engine are OVERRATED on power. Based on multiple chassis dyno numbers I rate the 1st gen motors at 230hp/240tq. Now, Lexus changed the power rating for the LS400 in 1995 but did NOT change it for the SC400 until 1996. The new engine in the LS400 in 1995 has 10.4-1 compression and IS an interference engine. It also has slighty more timing on the exhaust camshaft and has dual tube exhaust manifolds vs. the single tube design. These engine are correctly rated at 260hp/270tq. Note that the 1995 LS400 is SIGNIFICANTLY quicker than the 1990-1994. A full second 0-60 and 1/4 mile. The mystery is why the SC400 did not get the higher rating until 1996? I am not certain but the SC400s NEVER got the dual tube exhaust manifolds. Maybe rating the 1995 SC400 at 250hp/260tq was now correct with the other changes. Maybe Lexus used up there 1st gen stock of engines on the 1995 SC400, hard to know. The SC400 and LS400 share engines except for exhaust manifolds and oil pans. Personally I would not have a problem using the 2nd gen 1UZFE in an earlier car in fact IMO it is desireable. It would be the same as rebuilding with slightly more compression and better exhaust camshafts. This is not too much for the stock ECU to compensate for. You will need to change manifolds and oil pans between the two engines (LS vs SC). Would also be a great time to add headers. Quote Link to comment Share on other sites More sharing options...
kcpth Posted January 7, 2006 Share Posted January 7, 2006 nicely said n summarized Jbrady ;) Quote Link to comment Share on other sites More sharing options...
RFeldes Posted January 7, 2006 Share Posted January 7, 2006 I'm impressed JBrady, you are a breathe of fresh air. Quote Link to comment Share on other sites More sharing options...
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