Caflashbob

The maintenance manual on my 2008 sc says to inspect and adjust if noisy or vibrations present.

seen a few references to vibrations but no references to adjusting the valves.

they are not hydraulic and can need adjustment.

anyone needed or done it? Did it fix either a noise or vibration issue?

Caflashbob

I have been told that these engines have hydraulic lifters.

this is from my 2008 maintence book on page 68:

Engine Valve Clearance(SC)

inspect for excessive lifter noise and engine vibration and adjust if necessary.

(all other models are equipped with hydraulic valve lash adjusters that require no periodic clearance inspection or adjustment.)

Did the model years vary?

What does the other years books say?

FlopTop04

I believe that the engine is the same in all years of the SC430. The HP rating changed from 300 to 288 around 2006 due to the rating system used. I have the full 3 volume shop manual set for my 2004 SC430 and in Section 14, page 8 it gives the full valve clearance adjustment procedure. There is a nice chart with a list of the 40 different size shims used to make the correct clearance adjustment. Seems to me that this might be a dealer only job due to the variety of shims required.

Caflashbob

So I thought. Little or no failures with shims.

Dealer job IF required.

But measureable by an enthusiast probably. Especially if noisy and/or vibrations present.

Are the other Lexus models dual overhead cam variable valve timing?

are both the intake and exhaust cams variable?

JDaveSC430

I've had my '02 for 5 years. I read that same adjustment statement when I got the car, and, in my Lexus dealer inspection asked about having it done. Service said at that time, no adjustment is needed or made in any kind of normal operation. I have repeatedly asked different advisors at Lexus dealers since then and always get that same reply. No adjustments needed in scheduled maintenance, and none in normal operation.

Caflashbob

Good news. The need for adjustment, according to the maintenance book, would be evidenced by noise or vibrstions.

gasahol is probably not what the 4.3 engine was made for. May or may not need more adjusting.

time will tell. Pretty high tech engine for this kind of car.

seems way tuned down. Anyone make a aftermarket engine tuner?

redline seems low for a DOHC VVTI variable length intake runner V8.

i drove many MR2's long ago with a similar design four cylinder engine and they revved much higher,