1UZFE Rebuild - or Not?

[dlindemann]

This is my first post - this is a great site and I've done quite a bit of searching but I'd appreciate some input.

I've purchased a 1993 engine that is reported to have done 110,000 miles. It was purchased from out of state and consequently I have not seen it run and have no way of running it until it gets installed. I have no history on the engine other than it was out of a SC400 that was rearended. When I removed the intake plenum it had a pretty good buildup of black oily residue inside - not sure if this is normal? The engine will be going into a new kit from Race Car Replicas. My plan is to go with twin turbos and intercoolers running maybe 9 lbs of boost max.

I understand that these engines are pretty bullet-proof with good maintenance but given the above, should the engine be rebuilt? If not, are there things I can check to have some level of confidence that its in good shape before I do the install? If it should be rebuilt are there any special tools required or unusual aspects of the engine that make a rebuild difficult for a DIYer (I'd send the heads out)?

I already plan for a new timing belt, pullies, tensioner, water pump and starter.

Thanks for any and all input.
Dave L

 

[lafave]

I would just do the timing belts and take a chance on the rest of it being good.

 

[cribbj]

Hi Dave & welcome; I wondered when/if you'd turn up!

Not to dissuade you from your plan, but why go to all the expense of twin turbos if you only want 9 psi? You can easily hit that figure with a small supercharger, and you'll probably spend half as much as you would for a twin turbo setup.

If I were you, I'd first decide how much HP or torque I want this 1UZ to make, then choose the technology that fits that goal best.

Although I own two turbocharged Supras, I wouldn't consider twin turbos for the 1UZ unless I wanted to flow some serious amounts of air and make some serious horsepower - somewhere north of 20psi and 700 to 800 BHP. Anything less than that can be done with an Eaton or a twinscrew supercharger, and a lot easier. Superchargers are much easier to "package" on a Vee motor than turbochargers.

At 9 psi, you really don't need to modify the stock motor too much. Even with the stock high compression of 10:1, it'll "probably" take that level of boost if you're careful to keep the octane of your fuel high, and the charge air temps down.

If you're eventually going to make some serious boost with your twinturbo setup, then you really need to be thinking about putting some forgies in the bottom end of the motor for insurance, and you probably ought to think about dropping the compression a bit - maybe down to 9.5:1 or even 9:1, unless you plan on running on race gas all the time.

Even if you do stay with the low boost, and keep the lower end stock, I'd still drop the sump, and probably the upper oil pan and have a look at the mains and rod bearings, and inspect the crank journals. If you find a lot of sludge in the crankcase, then I'd still think about rebuilding the motor.

The black residue in your intake is from the EGR system; it's "probably" not anything to worry about, and is just indicative of a motor that wasn't run very hard or for very long intervals, ie a grocery getter.

If you decide on a rebuild, if I were you, I'd think about having a trusted machine shop turnkey at least the short block, if not the whole long block, and you do the final assembly of the manifolds, oil & water pump, etc.

Another option to consider is an exchange short or long block, which already has all the good stuff inside, and is ready for final assembly. Talk with David (Lextreme), as I'm sure he'd make you a fair offer to do something like this. In the end it might be easier and "safer" than trying to find a good automotive machine shop that has the expertise to work on these precision Japanese motors.

 

[sideshow]

these engines are throw away
if u blow em up just throw em away and buy another one

for 800 bucks u can buy just a bare enigne

so y would u rebilud it for 3000 bucksor more

plus its hard to find good rebiulders these days

i recond sometimes u will have more probs after u rebiuld it than what u would have buying a good 2nd hand one

 

[stevechumo]

Cribbj has said it all. He has a master mind.

 

[dlindemann]

Thanks for the responses! I certainly can't complain about the cost of the engine - mine was only $500 with the harness and all of the accessories - hard to believe considering the quality. What I hope to avoid is putting the engine in and finding out its toast and I have to pull it back out and rebuild it anyways.

John, I had a feeling you'd respond and wonder where the heck I've been! All I can say is that the RCR is almost ready to ship and winter is winding down......well, kind of we're expecting wind chills of -40F tonight! I'm ready to tackle the engine which prompted my post.

I initially considered supercharging but found that to get a new "kit" from Australia would cost well over $6K. In talking with Fran at RCR he's already done the development work on the TT including a pre-programmed ECU with harness, piping, exhaust, etc for the Superlite Coupe so its a matter of taking the path of least resistance. The car is so light that I'm not looking for a ton of power - something in the 400-500 hp range at most.

I had a feeling the black residue was from the EGR system - I think I'll be eliminating that on mine since Minnesota doesn't have strict emission regulations.

I'll take your advice and check in with David on a possible exchange. I'm sure the cost is higher than doing a rebuild myself (actually, I have a friend who is a whiz with Lotus engines who would help/do the rebuild) but neither of us has seen the inside of a 1UZFE.

Thanks again for the input.

By the way John - what's the status of your engine?

 

[cribbj]

$500 with all the accessories is a helluva of a deal, congratulations!

I hear you on the pre-engineered setup from Fran, but once that pair of turbos starts boosting, 9 psi is nothing. The stock twins on the Supra motor are good for 15 psi, and people are making crazy levels of boost these days with built motors.

Of course it's all in the sizing, so if you match the turbines and compressors right, hopefully you can achieve what you want, but I have a hunch your wastegates are going to get quite a workout if you're going to limit the boost to 9psi.

But, as Sideshow points out, these are disposable motors, so if you blow one, it's only going to cost you another $500 to $1000 to get another vs $10K or so to get one "built". But then it's the hassle of pulling the motor and putting another in isn't it? Still, by not doing a full rebuild, you can be driving the car a lot sooner. For sake of comparison, most "built" motor projects wind up taking a year or more, and I'm sure you don't want to have the rest of that car ready and waiting while your engine is being "built".

That price for the supercharger setup sounds awfully high. Was that from someone like Bullet or another retailer? On this forum we have an "in" with Andrew Mueller, the owner of Richwood Technologies, who are the manufacturer of the cast supercharger manifolds. Andrew makes pretty attractive deals on the rest of the setup too. Matter of fact, there's a Whipple and one of his manifolds on eBay Australia right now for around $2400 AUS, so $6K sounds way high.

It'll be interesting to see how you get on with Fran's setup and with the Electromotive ECU. It's not one of the more popular ones here, as over half of our members are from Oz and NZ, and most of the better, modern ECU's are made in that part of the world. The Electromotive is still a capable ECU, but it's showing its age.

My motor is mechanically finished, but I need to get it wired up, 'cause I've got a date with the engine dyno in two weeks. This time we'll have the supercharger, EFI, meth/water injection, and AEM EMS on it, so these will be the real power runs. I'll be updating the "Supercharged Supra" thread in my signature with any progress.

 

[cribbj]

Dave, here's your solution: buy a 2nd motor!

Just give the 1st one a minimal going over, to make sure it'll still run, and the bottom end is OK, then install it and run it as is.

Then, while you're having fun driving the car, you can get the 2nd motor built up to handle the power (and the boost) that you know you're going to want in the future.

 

[dlindemann]

I felt like I hit the jackpot when I found an engine for that price - of course it was only a good deal if it runs!

The supercharger price was from Bullet and it included a pre-programmed ECU.

Fran's ECU is actually a Haltech. I purchased it from Venom Cobras in Australia - pre-programmed ECU and harness for $2500 US. I haven't received it yet but Fran speaks very highly of Scott at Venom so I have high hopes.

The 2nd engine idea is an interesting one....I've already checked in with David on the longblock. I've got some more research and thinking to do on this one. If I go the long block route I may go with the forged pistons and H-beam rods and lower the compression a bit so I can go with higher boost.

I'll be watching for your dyno numbers - good luck with the run!

Dave L

 

[stevechumo]

Dave,
You can also consider a single turbo, such as the T04E or the GT35. These turbos can put you in a 450-500 hp range. The old school T04E is the best bang for the buck. I'm currently running 6 psi on the T04E with .68 compressor (if my memory doesn't betray me ), and I have instant boost. I'm looking to make 12 psi in a very short time, and I'll be in the 450 hp range.

 

[dlindemann]

Steve -

The kit car I'm purchasing is set up for twins including a modified 1UZ intake. With your move to 12 psi have you modified your engine to forged pistons?

 

[stevechumo]

Steve -

The kit car I'm purchasing is set up for twins including a modified 1UZ intake. With your move to 12 psi have you modified your engine to forged pistons?

I'll keep the stock engine 100%. It's because several of the 1UZ owners have boosted to a little more than 17 psi safely with stock engines. And 9-10 psi is the average. You can have the thicker head gaskets and be safe at mild boost without the hassle of rebuilding the engines. I know you'll use the standalone ECU so you even got the advantage to tune the fuel and timing right.