Gunbelt

Hey guys. I tried searching the forum for a good hour and there does not seem to be a direct answer to what I was searching for. I am going to purchase a 2003 GS430 with 67k miles, but I need to know if the '03 4.3 liter uses a timing chain or belt. Anyone?

GSteg

iTrader: (15)

Belt.......

Gunbelt

Thats pretty direct Its not what I wanted to hear but thanks. I am surprised that Toyota did not use a chain instead when they reworked the 4 liter V8. Benzes have had them since the early 90's.

Solo_D33A

Thought chains stretch over time and is a pain in the ****?

pitmanr200

i have never seen an advantage to a timing belt. I dont care what they say. you never heard of people forgetting to change there timing chain and it braking and destroying your cylinder heads. I believe it is a cheaper way out for car manufacturers if you ask me. i wished you could convert to chain.

dung0981

iTrader: (1)

Timing belt = more quiet
Timing chain you have to be careful with the tensioner.
I rather have timing belt than timing chain

GSteg

iTrader: (15)

Ya. Chains are noisier than belts. I can hear my sister's chain in her 05 honda accord.

pitmanr200

i have to disagree. i would rather hear a little then have to worry about breaking, but that is my opinion

rysbrnr

Timing belts are better for controlling harmonics... which can destroy an engine slowly over time. Those vibrations spikes and forces get into phase with the natural frequency of various engine parts and can kill bearings and the crankshaft. Using rubber as a dampener keeps vibrations isolated better than metal obviously.
It's not because the manufacturer is trying to take the cheap route. Ever see a OEM crank pulley on a car that is one-peice? Probably not unless it's some aftermarket underdrive pulley. If you look very carefully they are actually two separate pieces. There's a thin RUBBER layer that is in between the inner and outer sections of the crank pulley. It's there for harmonics dampening.
Manufacturers that use belts recommend timing belts intervals and a MAINTENANCE item. If you change it as suggested you won't have to worry about breakage. I'd rather have belts to control harmonics, maintain precise timing than to never change a chain and have it stretch and give inaccurate timing.

Timing Belts > Timing Chains

3UZFTE

Ok, that's fine, but you are not the majority or lexus owners. The new LS460 has the 1URFSE, which has a timing chain, but also has a TSB stating that customers may knocking noise is coming from engine compartment. Well Lexus redesigned the #3 chain tensioner and adjusted the ECM to control valve lash adjusters.

A timing belt on a GS400 60k, GS430 90k because the belt was reinforced with kevlar. I haven't heard of 1 3uzfe timing belt breaking.

Timing belt 4.5 hours
Timing chain 10 plus hours, lexus has not set a flat rate time yet.

DASHOCKER

iTrader: (2)

As the rubber goes snap.. I rather a timing chain ala Infiniti, BMW, Audi & Caddy. Rubber is susceptible to dry rot with age, so one can't rely on the 90k interval. Safe bet is to change the rubber belt before the 90k interval. I had mine changed at 68k. Good to see Lexus using the timing chain on the new LS.

PushinLEX

iTrader: (9)

Yup, my timingg belt is already showing signs of dry rot and slight cracks around the edges. I have 80,650 in my 99. I think time is just as much of a factor as mileage. I may opt to have my belt changed even before the 90k mark just for safe keeping. You never can be too safe.

350TPI

Our engines are non interference,right?

pitmanr200

if there non interference then you have nothing to worry about right? the pistons wont hit the valves anyways. Atleast that is what i was told. if that is the case then i would use a belt.

rysbrnr

The vvti versions of the 2jz and 1uz are interference, the older generations are not....