lobuxracer

iTrader: (2)

The NCF documentation is finally available and all manuals appear to be complete.

flipside - the info you posted is not consistent with what I've seen for the 2JZ series. Recommended intervals for 2JZ shim over bucket engines is 60k miles or 100k km. If experience is any guide, my Supra has not required a single adjustment in 145k miles - all valves are within spec since new, and I've checked them myself, so I'm not relying on any other mechanic's work.

Tech info currently available does not address the inspection frequency, however, the description from your Lexus source does not match the tech documentation. There is a shim, it is mounted on top of the valve stem. There is no bucket and there are no bucket bores. The cams must be completely removed for shim replacement with the current tooling.

The cams are formed using a process called net shape sintering: So they may be polished, but they surely are not ground as are most cams.

Here's a pic of the new valve actuation method used in the 2UR-GSE - note - no bucket, only a shim:

BJM711

Thanks lobuxracer. Please share with us any additional information you obtain on this subject. For example how often will the valve clearance have to be inspected/adjusted, and what will be the maufauturer's suggested charge for this service?

Bruce

flipside909

Hmmm interesting. The text I typed verbatim from the 08 Lexus IS-F spec sheet that was given to us at the techical briefing at the Monterey Press Event. It was all drafted by Lexus College.

lobuxracer

iTrader: (2)

Some more interesting stuff from the docs - the rear suspension is 108mm lower than the IS350/250 RWD and the front is 20mm lower than the standard suspension and 10mm lower than the sport suspension. I am pretty certain part of the reason for the difference in the rear is the 19" tires and wheels.

There is still no adjustability to the alignment except toe . The suspension components are identical save the upper control rod in the rear suspension (the NCF says two rods are different, but the service manual's measurements don't agree with this - weird). The IS-F's rod is 3mm longer to compensate for the massive drop on the rear. Also, the rear camber spec for the IS-F is -0.78 +/- 0.75 degrees where the ISx50 RWD is -1.23 +/- 0.75 degrees. This certainly reduces rear grip and makes the car much closer to neutral handling compared to the ISx50 RWD platforms. Add to this increased front camber at -0.87 degrees, and you've got something not seen on a production car in 40 years - more front camber than rear! Wow. There can only be one explanation for being able to give this much mechanical grip: VDIM.

Along with the shock, spring, and swaybar differences it is clear the IS-F is much better balanced for a skilled driver than the ISx50. It also appears it would not be difficult to convert an ISx50 to IS-F spec in the suspension department. Maybe expensive, but not hard at all.