3URFE Engine Exposed

[XR8tt]

The new V8's here go through about a litre over 10,000 klrs..

 

[bjowett]

It dosn't sound like lifters, it sounds like loose pistons to me... I'll also say it is all speculation. Some say it is the dual VVTi.... I'd be happy if I am wrong. Toyota says that machining precision has been improved so only one piston size is required, yet the 2UR-GSE is still select fit... how precise can they be?

The above info on the 2UR is incorrect... only one piston size is used, just like the 3UR.

 

[WDoherty]

The 2uz also had cold start piston slap. The only recent sbc i know of to have piston slap in the U.S. was the early 6.0 truck engine, but it was revised shortly after like 2001.

Is that piston slap or could it be noisy lifters?

This engine uses hydraulic lifters which is a bit of an oddity for Toyota. Maybe they don't have their lifter design sorted yet?

We were moaning the other day about the poor quality SBC motors that come from the factory with audible piston slap, and the dealers claim it's "normal".

I would never have thought that Toyota would allow this in their motors.....

 

[XR8tt]

The 2uz also had cold start piston slap. The only recent sbc i know of to have piston slap in the U.S. was the early 6.0 truck engine, but it was revised shortly after like 2001.

The alloy block too..We suspect they were sent where there's no lemon laws...
http://www.ls1.com.au/forum/archive/index.php/t-36039.html

 

[Lextreme II]

Rings

The rings were taken out and got some specs on them.

First Ring: 1.20mm
Second Ring: .40mm
Third Ring: 2.30mm.

From some experts said the oil rings are too thin and the engine will experience some oil issues. As you can see little later how all of the pistons face are very dirty due to oil.

 

[Lextreme II]

Piston

Got the pistons out and my engine builder took a look at it and he stated the pistons are cast. There is another thing we found out is that these pistons were made by Mahle. Mahle is a German company. Here is what the OEM manual have to say:
Piston

The pistons are made of aluminum alloy.

A compact combustion chamber is provided on top of the piston to realize stable combustion. Together
with the pentroof type combustion chamber of the cylinder head, this realizes a high compression ratio,
resulting in both high performance and excellent fuel economy.

A taper squish combustion chamber is used to improve anti-knocking performance and intake efficiency.
In addition, engine performance and fuel economy are improved.

In order to reduce weight, cast holes have been provided on the bottom of the piston head near the pin
bosses as shown in the illustration below.

The piston skirt is coated with resin to reduce friction losses.

The groove of the top ring is coated with alumite (anodic oxide coating) to ensure abrasion resistance.

By increasing the machining precision of the cylinder bore diameter in the block, only one size piston is
required.

Here are some photos.

 

[bjowett]

Mahle produces good stuff, nice to see those in there...

Rings keep getting thinner in order to reduce friction... better materials have allowed it to happen. Too thin, though? Guess we will see...

 

[cribbj]

Very little metal between the top of the piston and the top compression ring. That ring will certainly take a beating if anyone tries to turbo or SC this motor.

 

[XR8tt]

Yes I guess its also to get better emissions.. Well ?? Better at low miles...
I doubt they would take much boost or detonation? The ring lands are thin..

 

[bjowett]

We can speculate the pistons are of a high silicon content and that funky crown shape for good combustion may give additional strength.

The Japanese have used steel top rings for years in many applications... being that close to the chamber the 1.2mm ring would have to be steel.

Remember, Toyota sells the TRD supercharger pushing 6 - 7 psi and keeps the 5/60k mile powertrain warranty on this engine. They must have some faith in it. Will it go 300k with one is the real question.

Some info right from Mahle...

Continually redefining limits while improving perfomance

The requirements on pistons for gasoline engines have become ever greater over the past few years. The thermal loads have risen as a result of higher power demands. The stresses at average ignition pressures have increased through knock control, direct fuel injection and turbocharging, while high speed concepts have led to an increase in inertia load. MAHLE has responded to these requirements by utilizing longstanding experience and innovative concepts, which continually adapt the existing product program to the challenges of tomorrow.

The MAHLE program for gasoline engines
The piston program for gasoline engines comprises weight optimized aluminum pistons with diameters from 65 to 110 mm for the highest requirements. The pistons are produced from cast or forged, high-temperature resistant aluminum silicon alloys. These alloys and the refined casting technology from MAHLE enable an ideal combination comprising pistons with low weight and high structural strength to be produced: for example the MAHLE ECOFORM® pistons. Based on the ECOFORM® piston, the next generation of MAHLE lightweight pistons was developed: the EVOTEC® piston. The optimized design enables further weight reduction, while increasing the load-bearing capacity.

New challenges – optimum processes
Modern engines with variable valve train or different direct injection concepts require pistons with a complex geometry. This often leads to a higher piston weight due to involved crown shapes. To achieve as ideal as possible a combination of low weight and high stability despite this, the suitable choice of material is just as crucial as an optimum production process. MAHLE utilizes its longstanding development experience to best effect here, both in forging and casting technology.

Improved coating for less friction
The piston skirt for gasoline engines with cast or steel cylinder surfaces is usually coated with GRAFAL® at MAHLE. GRAFAL® helps to reduce friction and hence increases the scuffing resistance. A further advantage of GRAFAL®-coated pistons: They enable a closer fitting clearance which leads to significantly lower engine noise in conjunction with complex piston forms.

 

[cribbj]

I'd forgotten the TRD SC was available for this engine.

Sorry but that piston just looks like an accident waiting to happen. No way would I try to push any boost or elevated combustion temps with that setup. It certainly does have light weight going for it, though.

I've forgotten, did Toyota provide piston crown oil squirters on this motor?

David, your photo expose on this motor has really been enlightening. Thus far, from a performance perspective I don't like:

The tangless rod bearings
The rods themselves
The piston design

Can't wait to see the heads and valves to see if they have any redeeming qualities. To me, this motor looks like it'll be a real money pit to hotrod.

 

[XR8tt]

The top ring was sealing o/k.. Keep in mind its the compression that forces rings against the bore..

 

[cribbj]

Graeme it's not so much the compression that concerns me as the close proximity of that ring to where all the hot stuff is happening.

It may work OK for an NA motor, but I'd really have doubts about using that piston/ring design for a forced induction setup.

 

[XR8tt]

Exactly I would like to compare it with the supercharged V6..
Mind you the early blown V6's had issues down under ...
A good ECU would keep things in check .. Like measuring exhaust temps etc..

 

[Lextreme II]

I'd forgotten the TRD SC was available for this engine.

Sorry but that piston just looks like an accident waiting to happen. No way would I try to push any boost or elevated combustion temps with that setup. It certainly does have light weight going for it, though.

I've forgotten, did Toyota provide piston crown oil squirters on this motor?

David, your photo expose on this motor has really been enlightening. Thus far, from a performance perspective I don't like:

The tangless rod bearings
The rods themselves
The piston design

Can't wait to see the heads and valves to see if they have any redeeming qualities. To me, this motor looks like it'll be a real money pit to hotrod.

John,

TRD supercharger at 5-6 psi is yielding 500 hp & 550 tq. However, I am concerning the aluminum tangless bearing. They are good for like 500 hp or so. However, the main bearings are steel with resin coating. As we speak, I am currently having an engine guard made. They are using digital tracer for accurate fitting. I am also working on a Forged H Beam rods too. They should be ready in 8-10 weeks or so. The newer motor does have oil squiters. FYI, the rods we are making will have lots of choices on the bearings too.

David

 

[cribbj]

David, it's good that you're getting some stronger aftermarket parts ready; this motor looks like it will need them (just my opinion).

I notice that Toyota changed its firing order on these UR motors to match up again with chebbie's new firing order for their LS engines.

 

[Lextreme II]

I will have some pictures little later about the block. It is a VERY strong but need an engine guard with good rods and pistonsm this motor will be in 3 digit hp. 6 bolt main surely help too.

 

[FIG]

Thanks for the tear down, great info. I may want to get in on this swap and the info you are providing is gonna save me some time.

Is that a friction coating on the skirt sides of the piston?

Thanks,
Fig

 

[XR8tt]

Yep looks like coating to me..
I must say ... Most engines that have this coating have warranty issues..
You just cannot beat a well clearanced / blueprinted engine!!
To a point manufacture's use coating as a cheap form of getting around good assembly...
I have NEVER had issues with either Diamond or C.P pistons on N/A engines I have turbocharged...
They don't have this coating on the skirts...

 

[v8gz20]

here in austraila the some 2uz in landcruisers had piston slap from factory, they fixed it with thicker teflon coating on the sides of the piston, but this was only done if the owner noticed it. all new toyota motors i have seen have tagless bearings. all the new block are throw away they can not honed or boared.