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Discussion Starter #1
1> Interference engine?
2> Timing belt or chain?
3> Maint schedule?
(vavle adjustment, new belt/chain, major items?)
4> Whats the deal with turning circle/radius curb-curb wall-wall? 34.1ft? 37.4ft? help!

Thanks-
 

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2. Timing belt. As far as I know, current Toyotas don't have timing chains.
 

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Maintenance is the same as the GS300. The LX450 has a Timing Chain.

*Factory recommends T-belt replacement at 120k, 90k if you alot of stop and go driving.




[This message has been edited by DevilDog66 (edited June 01, 2000).]
 

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Discussion Starter #4

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Discussion Starter #5
Also, from the Supra 2JZ-GE description - it is a non-interference engine with a timing belt...
 

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Hmm...I looked at the page where it describes the non-interference part before, but I missed it the first time.


Your fears have been assuaged, TEG.
 

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Discussion Starter #7
Well not all my fears - I still don't know how often we will need to pay $ to have the timing belt replaced and the vavles adjusted.

With a non-interference engine you can drive it until the belt breaks, but then you might be "stuck" somewhere inconvenient.
 

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But at least you'll know you won't bend your valves. Timing belts aren't too bad to change though...I think they can be a DIY job. Nowadays, they can probably last for 90,000 miles (but don't push it past that much). From the 2JZ-GE/GTE specs, I think it may have said that the valves are self-adjusting (or something to that effect).

I'm pretty sure that the regular maintenance schedule includes timing belt replacement also.

[This message has been edited by JW (edited June 01, 2000).]
 

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TEG-

At 10.5:1 compression ratio it would be hard not to hit the pistons when the belt breaks. It is an interferance configuration. Maintenance schedules? I haven't seen the published schedules yet, but I would assume that there will be nothing different from the other models. Our published Turning Circle is 37.4ft. I am aware that some measure from tread and others will measure the furthest point on the body. The second makes more sense. It should be measured from whatever point would hit the edge first. Maybe that's where the confusion is from.

BTW My two training units will be here today! One Sprectra Blue and one yellow. So if anyone sees a yellow one in the Chicago area this weekend, that's me. We just ordered $4k worth of tires and wheels for the two we are dressing up for the CART circuit. I will be able to answer alot more questions this afternoon, after I get the cars.
 

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You can have a high compression engine still be an non-interference engine. The pistons have indentations for the valves heads...
 

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Discussion Starter #12
daverav4 wrote:
>> It is an interferance configuration.

Huh?
The 1997 Toyota Supra documentation shows that 2JZ-GE engine as having cuts in the pistons to avoid interference... Isn't the IS300 engine basically the same?

A Supra Engine Manual says "The 2JZ-GE ... depression is built into the pistion head to prevent interference with the valves..."

daverav4 wrote:
>> Our published Turning Circle is 37.4ft.
WTF! I ordered my car (in part) based on the turning circle published on the Lexus web site: http://www.lexus.com/is/specs.asp
"Turning Circle 34.1 ft"
Why are they saying 34.1 if it is not the "published" turning circle?!
 

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The indentations in the piston heads are to provide clearance under normal operating overlap conditions, not when the belt snaps. Just because the pistons have valve recesses doesn't mean they can't hit if the cam and crank go out of time.
 

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Discussion Starter #15
The Lexus tech rep I talked to today at a dealership said that the IS300 is a "non interference" engine. So either daverav4 or he is wrong. I am still uncertain which is true.
 
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