Swapping 1UZ VVTi for 3UZ

[aniesigh]

Hi,
So i've been running a 1UZ VVTi in my offroader for the last few years, but i've killed the motor (sump got dented up which blocked oil pickup)

I'm wondering if i can replace it with a 3uz but retain the wiring harness/ECU etc from the 1UZ (i've only recently bought a new ECU for it from Yury so don't want to have to change that)

I know the VVTi 1UZ and 3UZ are very similar, but i guess it would only take 1 small difference to make it not work.
Other option is to rebuild the spare 1UZ motor i've got (bought with snapped timing belt) , how much damage do these do when the belts go?

Thanks for any input!
Adam

 

[Zuffen]

I can't answer your first question but a snapped belt isn't going to do any damage.

The engine is non-interference (the valves will never hit the pistons) so no damage.

Have you thought about pulling the 1UZ cranks and swapping them over?

Could be an easy way out of a problem.

 

[gloverman]

Rod the Uz engines became interference when they swapped from Gen1 to Gen2. VVti are interference but every now and again you get lucky. I've got one 3uz atm that the grommet for the cam sensor wire was pushed in and found it's way (in about 10 pieces) between the cambelt and crank pulley. Timing had jumped about 5-6 teeth. I have my fingers crossed atm.

I've run a 3uz on 1uz Vvti management before. Swap over the throttle body and confirm they are both running the pick injectors (1uz Vvti and early 3uz share injectors. Late 3uz went bigger) They don't run perfectly but I only knew that as I ran it up on the dyno and noticed a few mixture differences. Driving it you wouldn't have known.

I've presently got the grommet problem 3uz that I'm going to run up using a UZS171 crown 1uz VVti ecu. The looms going overseas so two birds with one stone. Test loom and run engine to confirm if its ok.

 

[Zuffen]

Kelvin,

Forgot about the Gen2.

Once had a Porsche 911 snap a cam chain and they are a real interference engine.

The chain stopped the cam in just the right spot.

Had a new split chain fitted and all was good. Sometimes you can get lucky.

 

[aniesigh]

Thanks guys for your replies,
I do remember hearing that the VVTi's are interference. My plan is to pull the heads from the spare engine and see if/how bad the damage is. If i've got lucky then i will give that motor a freshen up and fit that. Using my old heads with the block of the spare engine was an option but i'd rather not use any parts from the old engine as it was run for a little while with the oil pressure issue (long enough that it had spun one of the big end shells, making that con rod U/S) so there is a reasonable chance that the heads have been damaged too. Also it would be nice to have a motor ready to do a straight swap rather than having to remove the old one, make one decent engine and then refit.

If the heads on the spare (snapped belt) engine are badly damaged then i will look for a complete replacement engine, either 1uz or 3uz as it seems like 3uz is an option. Is there likely to be any real power gain from the extra capacity of the 3uz (bearing in mind it will have to be running on the 1uz inlet/ecu)

Thanks

 

[gloverman]

The 3uz intake is almost the same as the 1uz intake. I have another 3uz running on a 1uz ecu on a stand at the moment. Ill do a video and put it onto you tube.

3uz is 300cc more so 300 cc more power and quite a bit more torque. The bore to stroke ratio is different so they do respond differently.

 

[gloverman]

3uz running on a 1uz ECU.

 

[eicca]

@gloverman how hard was that to set up? If I remember right, all of the sensors like cam and crank and knock will swap across if the plugs are different, so I assume you just had to use a 1UZ throttle body?

 

[gloverman]

Very easy but i do uz wiring all the time. The cam, crank ,vvti position, vvti solenoid and avis plugs are all the same. If you have early 1uz vvti then either swap coils or swap coil plugs to run later model coils (which I prefer). Them swap to 1uz throttle body. Or swap upper or complete manifold as the pcv and air fittings are different on some models. If you have later 3uz injectors are bigger too so use injectors which match ecu. This was an early 3uz so same injectors .

 

[eicca]

Huh. Well I know what I’m doing if the ol’ 1UZ craps the bed.

 

[George_R]

I would generally advice to buy another 1uz vvti if you can't afford proper ecu
I believe that you will run into more troubles trying to run everything right with 3uz + 1uz ecu, than to have your 3uz ecu serviced by Chris (Somerset, UK) or me