Project LexRay :Lexus 1UZFE onto an Alpha 1 Sterndrive

The 1UZFE EGR Delete Kit is available for sale here.


New Member
Hey guys,

I am already enthralled with the brilliant 1UZFE and I havent even owned one yet...But Im planning to, in both an LS400 (arent they cheap now!) and also a 1993 Sea Ray Bowrider with an Alpha 1 Mercruiser sterndrive.
BTW I live in Sydney Australia.

My topic is as follows;-
After the demise of my 3 litre 4 cyl slug Im planning a power upgrade using the 1UZFE. Why not a mercruiser 350 you ask?
Theres a few reasons,
Im into car racing and I like japanese engines that rev and dont break.
The 1UZFE is seriously cheap as a standalone engine. One went on ebay last night for 910 with gearbox, loom and ecu. Bloody cheap.

However in all of my searching the internet I have not found one person who has attached a 1UZFE or any other type of engine for that matter to a sterndrive.

So I am going to bite the bullet and do this project. I love the boat, it steers and rides beautifully, and seats the family comfortably and looks sensational too with its timeless lines (in fact I think it looks just as good as the current models).

Ok from all Ive read there are people round who know what they are doing with these things which is great.
I have done engine conversions in cars with ecu's etc etc but Im on a really tight budget, and that experience didnt go down well. And I did most of the labour on the install work.
Any advice regarding good stuff and pitfalls would be appreciated.

So where Im up to at the moment on project LexRay...
  • motor costs (around $700-$1000) on a base engine.
  • ecu (advice needed here as this is a bit of a gray area).
I currently have an Autronic SMC on my SR20 powered race car. Can I use that to get me going until I get the marinised SMC, or does anyone have any suggestions otherwise (the Adaptronic looks good too).Ie does anyone have a base map for a 1UZFE for the SMC.Also I want it to be pretty much plug and play with the loom, ecu and base map and everything ready to go.
There is a guy in Brisbane i believe who modifys the loom so the ecu doesnt need o2 or gearbox inputs, so I was wondering if possible I can keep the stock loom and ecu.

  • should I run a flywheel with the coupling or can i just attach the coupling to the std auto ring gear and have it balanced? If I need to run a flywheel, does anyone have a manual flywheel or know where I can get one?
  • The bellhousing will need to be attached to the back of the motor and onto the inner transom assembly of the sterndrive. Would anyone know who manufactures these or know anyone in Sydney who would be able to line up the motor with the sterndrive.Im thinking if anyone has a dead 1UZFE I can use as a template that would be good.
  • Anyone know of a good heat exchanger system which whould be reliable and cheap?
  • Manifolds...who and where to get them. I have done some homework here, Rolco are about $1000, Jordy on this site makes stainless ones for about $700-$800 for the pair..I hopeI got that price right. Hytec do good stainless ones for about $2200 upwards.
  • Im trying to keep the whole lot for around the $4000 mark. I will be doing most things myself so I reckon $4k is a reasonable ask. Thats including and ecu setup. I may be unrealistic ...if so please tell me.
  • Maybe I should just convert the boat to a jet setup as this has been done with the 1UZ numerous times in NZ..your thoughts here are appreciated
I reckon it would be a magic package with this engine, and Im looking forward to the conclusion of this project.
Kind regards,

Welcome Craig,
Here is my ideas for you questions.
Use your SCM, just mount it somewhere it is not going to get wet. You can even place it inside something as simple as a plastic 'lunch box' with a wiring grommet to keep water out. That will keep you within your budget and if you can afford it later, go and buy the Marine SMC, I think the wiring loom plug is the same.

I have a SMC base 'map' around on my harddrive somewhere that I ran before I fitted the supercharger. Should be able to dig it up for you. It's not perfect, but I used it for several years and was quite happy with it.

Keep to your budget and just use the flexplate, (flywheels are about $400 I think). Only experience will tell you if the flexplate is too light. Worst case senario, you might have to pull the engine out and fit a flywheel later on. Obviously, make the flexplate drive adaptor so a flywheel can be interchanged later on if required. I spoke to a guy who fitted a lexus V8 into a 'Heatrbeat' hull (made on the Gold Coast) with a mercruiser leg and he used the flexplate. He said it idled just fine and a flywheel wasn't necessary. Also, if you use the idol controle on the Autronic, the engine will idle better. Just get a ford idol control valve from the wreckers (the Autronic won't operate the Lexus one)

Talk to Rollco, Dellow or Castlemain rod shop about an adaptor plate to fit the engine to your original bellhousing, or use the lexus bellhousing and an adaptor the the mercruiser leg. Rollco may make a proper belhousing for the lexus, but I doubt it.

Heat Exchanger is not necessary if you only go in fresh water. If not, Rollco can help you out or have a look on Ebay. New ones are expensive at about $1000. Keep in mind that secondhand heatexchangers can corrode holes through them. I have seen unused heat exchangers for well under $1000 on ebay.

I use Rollco exhaust manifolds and they work well. They are 'log manifolds, but if you are chasing more power, you would be better off fitting a supercharger, than spending big bucks on custom made watercooled extractors. The Lexus will provide oodles more power than your old 3 litre.....

Cost....... Motor $1000, new timing belt $80?, Adaptor Plate, $200?, Drive adaptor $200?, Water pump $300 (may be able to get the old one off your 3 litre), Engine Mounts ??? Manifolds $1000, Autronic engine loom $250?, Heatexchanger (2nd hand) $500. If you can fabricate stuff yourself and scavenge for secondhand bits from wreckers, ebay of trading post, you can probably do it at a realistic price.

Don't fit a jet unless you really want a jet. It would completely change the handling and charactor of the boat.
It would cost a lot of money for the jet unit, and wouldn't make the job any easier.
Have you checket that the Alpha 1 Mercruiser sterndrive is rated for the power of the lexus V8? It would kind of suck if you went to all the trouble of fitting the engine and blew up the sterndrive!!!

Good Luck, and have a good talk to the guys at Rollco, they should know about any fitting problems you might encounter,
Thanks Andrew for your response.
Gee a few days down the track and the progress made has been great!

  • I really like Joel's manifolds from this site on his Jag supercharged 1 UZ in his boat, Im waiting back from him re a PM but from looking at his pics they are stainless and can accomodate the o2 sensor in a dry config as well as the water cooling can be recycled though the heat exchanger with the engine. That would massively extend the life of the headers.
  • I have spoken to Dellow Automotive (Jeff Dellow himself) and he said he would be more than happy to look at my application and he couldnt promise but will do his best to make a bellhousing that would suit the transom plate. He even has a block to fit it up ready to go. He is a big fan of these engines.
  • I have spoken to my dyno guy and he will do the base map for the 1UZ however if I can get yours too, Andrew that would be great. I am however going to try the stock ECU and bench test it in a jig so see how it goes, even in the boat it will be reasonably easy to change to the SMC system.
  • Andrew thanks for the flywheel advice. I reckon it should idle fine too without the flywheel, the engine coupler from the 3 litre is made of steel and is heavy like a flywheel anyway. Would just need balancing and to be fitted professionally. If the ring gear can take a torque converter at high revs i think it should be fine. Dellow also do a flywheel for the 1UZ for around 300AUD with your ring gear fitted.
  • The heat exchanger is a no brainer and I reckon getting a big block one which will do both the engine and headers would be the go. The 1 UZ already has its own pump and the mercruiser leg also has its own pump in the leg like an out board motor does. Money saved here!
  • The alpha 1 leg takes up to 500 hp, well short of the stock 270hp from the 1UZ. It would even do a supercharger application down the track. The bravo leg takes up to 800hp with massive torque from big blocks etc etc.
  • Engine mounts can be welded from plate steel. I did this for my racecar and would need to be custom made anyway.
The old 3 litre is coming out today, shes been adequate and for an iron block to last in salt for 15years I reckon that pretty good. Going from 115hp (and this engine is tired so I reckon its around 80hp now) to 270hp and drop from 14l/hr to 8l/hr will be great!!

Please keep the ideas coming as I am going to do this a cheap as possible and keep you all posted on the outcome.

Just spoke to Rolco

Headers are 995 and cast aluminum..(joels are by far the better option i reckon)
Flywheel is 650.
They do an off the shelf ecu and loom setup with igniters for 3000. The guy on the phone reckons they are a remapped stock ECU.
They do bellhousings but only for softclutch applications. Dellow are the same in this respect.
Ok just a small update, the old 3.0litre GM hunk of iron came out today. She was in bad condition the riser made of cast iron had gone and was causing the engine to fill with water.
I am taking the special mercruiser bellhousing and flywheel and coupler to Dellow tomorrow to get a bellhousing made up.
The Mercruiser one is made of alloy so it may be as easy as an adaptor plate or use parts of the existing bellhousing and adapt it to one of theirs.
Will update in next coupleof days.
yeah spoke to Jeff Dellow today and he will check it out. Its obviouslypossible just whether its worth his time to do it. I do have a backup plan to cut up a std auto bellhousing and jig it all up myself.
Ok update is that i have bought a mock up 1UZFE for my boat trial fit and i have also bought a 91 Soarer Limited which i will use the engine and bellhousing. I want to part out some parts on the car so please contact me if you need anything for your Soarer.
Thanks Hallj you are right I wouldnt push it. I reckon at the most I will keep it stock ......maybe with an M90 supercharger down the track. Once I start going for this power Id prefer to put the $$$ into a big block 247VLX Malibu.
The mock up engine is now in the boat and the engine is off to Sideshow to reconfig the loom. I have also sourced some Rolco manifolds from this club as well and Im looking forward to the boat being back in the water soon. Will post some pics soon
ok engine is back now from Jim at sideshow electrics, thanks Jim!! Will be installing the engine over the next couple of weeks for the final fit.
Hopefully in 6 weeks it will be all done!!
Ive enjoyed this conversion thus far. The support here on the club has been great and very professional. Look forward to posting some more pics and also the static and then the water test.
Hi Jeff looking at using the microswitch in the throttle handle which stops you starting the motor whilst in gear. This should hopefully give a momentary trigger to the ecu traction control inputs/outputs to momentarily cut ign. Will get Sideshow to have a look at this as well.
here is my 1uz in my boat low 90 mph

here are pics of my boat have all the specs to hook up to alha stern drive let me no what you want happy to help
here is my 1uz in my boat low 90 mph

here are pics of my boat have all the specs to hook up to alha stern drive let me no what you want happy to help
Well sorry for the delayed updates, guys, I got the bug to finish my house renovations off and buy a house near the water in Newcastle NSW, so this week I have resumed the project Lexray and have installed the enigine including the loom etc etc. Im looking forward to seeing it running and I will be working solidly on it until new Wednesday the 29th when i need to go back to work :-(...Anyway I have decided to go for transom exhaust as the Y-Pipe for the Mercrusier doesnt fit with the Rolco Manifolds....Will be taking to the muffler shop tomorrow to get a couple of S-bends made up to accomodate this and Im going to run a closed cooling system which also includes the exhaust manifolds. The reason for this is extended service life in salt water (primary use). I have a 8.1 litre mercruiser heat exchanger so it should be able to keep up the the manifold heat as well. If not I will simply run raw water through them. I will update with progress and photos next week.