1UR Engine

[Lextreme II]

Got some connections from people in high places. I got a hold on some information on the 1UR engine.

Lets talk about the new 1UR engine in general. Its very interesting how the new engine comes with cam housing.

 

[TundraEddie]

More info please :tongue2:

 

[Lextreme II]

LOL.... Ok... Here is a sheet of the engine spec. Since the all new 1UR engine is using timing chain. Would it be little louder then timing belt?

 

[Loroh]

Hows the Compression Ratio at 11.8:1:shock:
You won't be putting much boost into a stock one of them with out a cooler.

 

[Lextreme II]

11.8:1 is pretty high. Its not much room for FI for sure. Due to high compression any problem with the timing will destroy the whole engine. I think that is why they used timing chain instead of timing belt. I have some VVTi engine with valves (the the whole engine) destroy because of faulty timing (broken timing belt, wrong timing belt installation or other timing related issues) I wonder how many miles you need to change timing chain?

 

[Anaema]

not often is my best guess. the (steel) timing chains are pretty tuff. Ferrari uses timing chains in their newest V12(the one in the Enzo and the new 599 GTB), thats good for something. the only timing system stronger than the chain is gears, used in, buess what, endurance racing. ive never heard of a racecar having timing problems.

 

[UZZ30-Québec]

amazing, the engine block is in 2 pieces just like mazda's KL series engines. The camshaft housing is pretty cool too, looks like a strong assembly made to handle a lot of stress. say "thank you direct injection" for the 11.8 comp ratio, the pre-ignition problems are reduced a lot.

 

[Anaema]

ya, direct injection is magic. i wonder if its used in F1 cars.

 

[cribbj]

amazing, the engine block is in 2 pieces just like mazda's KL series engines. The camshaft housing is pretty cool too, looks like a strong assembly made to handle a lot of stress. say "thank you direct injection" for the 11.8 comp ratio, the pre-ignition problems are reduced a lot.

Did I miss something? The block looks like a single casting to me, however as you said, the heads do have a separate camshaft housing - not sure what Toyota's rationale is for that - perhaps to provide replaceable wear surfaces?

Also noticed they've reverted to a roller rocker design for the valve train, with hydraulic lash adjusters. I'm guessing the initial lift profiles were too aggressive for direct actuation of the valves? Maybe a camshaft guru could jump in and comment on this. Seems odd that the company who is best known for its direct actuated DOHC engines has gone to a rocker arm design.

 

[turboandrew]

I thought it was odd that the left and right bank have different valve timing ranges. Also, notice that they publish the weight now. How does 511 lbs compare to the 3UZ?

 

[SCV8]

The IRL engines use a similar valve arrangement, and the compression is high to work with the longer duration cams.

 

[striker]

No direct injection is not used in F1, the video's around on google suggest that at least Renault is still doing it with Douche injection, which means that the injectors are suspended outside above the up and down moving intake trumpets.

the dynorun form that set-up recorded 20.002rpm MAX, offcourse compression is not known,

I wouldn't want a direct injected petrol engine for tuning, there's virtualy no aftermarket for bigger injectors and higher combustion temp than stock can easily kill them. also High rpm atmosation for tuning seems pretty difficult to get at to me.
If it was very much better power wise the motorcycle lads would use it and they don't. it is just emissions.

just a pitty about the rollerrockers though.

grtz Thomas

 

[Pro]

a 1UR? what, is it the next gens of UZs? or are we talking diesel here with direct injection and all that? i thought diesels used 18.0:1 + ?

me confused. me lie down now.

 

[Lextreme II]

Hey Pro,

You have been away for too long. Welcome back! The next generation Toyota V8 Engines are the 1UR, 2UZ and 3UR. Likewise the first generation of the V8 engines were the 1, 2, 3 UZFE.

 

[Pro]

sweet - thanks.

 

[Anaema]

dont forget the 4UR(i think).

 

[TundraEddie]

One of the Lexus engineers said the roller rocker design was to reduce friction and maintenance. I was going to pick his brain about the different valve timing,but we ran out of time because of a discussion about fuel economy,octane,and hybrids.

 

[rarson]

Did I miss something? The block looks like a single casting to me

Instead of having main caps and an oil pan, the entire bottom half of the block is another piece. The new Honda K-series engines are this way as well, and it's a very strong design. Kind of like a main girdle on crack.

I agree though, direct injection is too new to have any fun with on the tuner end of things. Nice to see some new engine progress though, and they are making some pretty good power from the factory!

 

[toad007]

Roller rockers

The reason for the roller rocker design is to have a cam design with minimal lift but longer duration. At least that was the rational for the roller design for the 1gr v6's, which use a similar setup, so I would assume the cam setup on the 1ur is for the same reason.

 

[Anaema]

Instead of having main caps and an oil pan, the entire bottom half of the block is another piece. The new Honda K-series engines are this way as well, and it's a very strong design. Kind of like a main girdle on crack.

do you have a pic of that?