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The inline 6 in the Lexus IS300 is a chain driven engine. This is also the same engine that was used in the late Toyota Supra. I remember reading a review comparing Nissan's 300ZX Turbo with Toyota's Supra Turbo. They mentioned that because the 300ZX's engine was belt driven that it was smoother than the chain driven Supra.... I guess it makes sense that a belt driven engine would be smoother than a chain driven one... It seems that a chain driven engine would be more precise and reliable though... Which is better and are most manufacturers switching to chain drive engines?
Eric....
 

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Um, the MkIV Supra Engine (2JZ-GE/GTE) uses a timing a belt. Here's proof (I apologize for the size of the pic):

 

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For one thing, replacing a timing belt is easier than changing a timing chain. I know the Nissan Maxima uses a timing chain, and so do a lot of American vehicles, particularly trucks. I think the trend is to go with timing belts since they're cheaper, easier to replace, and smoother.
 

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If it uses a belt, then I hope it is a "non interference" engine. If the belt brakes and it is an "interference" engine then the pistons collide with the valves and things get very expensive.
 

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All current Lexus use timing belts. The older LX470 was a chain driven 4.5 L six cyl. Some claim that chains are more reliable and don't require replacing. Guess what, they can break too. Mercedes made an alloy 3.8L V8 that had a very long timing chain. When it was worn it would break and they retrofitted a double chain system. Belts are cheaper and quieter. The 4.0 V8 in EricK's GS400 only needs a new belt every 90,000 miles. I replace my mountainbike chain every season or when it shows stretch.
 

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Well, Well, Well..isn't this interesting.

The E30 chassis BMW M3 used a chain driven engine.....

see any similarities?
I'm glad Lexus is using race-bred technology.
By the way.
Are race cars belt driven?? ( honest question)
 

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So it looks like the IS300 2JZ-GE engine uses belt-driven cams and non-interference pistons.

Belts are cheaper and run smoother...
More quiet too.
Something about not transmitting harmonic vibrations.

I bet a chain costs alot more to replace, but they probably last alot longer.

I think that both belts and chains are used in racing.

Based on what I know, I can't really say that I prefer one over another.
 

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By the way - the timing belt on my MR2 just broke and it is at the shop ($400 to replace!)

I guess I prefer chains this week!
 

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Far Performance fixed my MR2 in 24 hours (new timing belt, tensioner pulley and lower cover) for a total of $444... Ouch. At least I am back on the road.
 
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