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why did timing belt interval change to 90,000 in 1998

Old 01-04-08, 10:59 PM
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WDoherty
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Default why did timing belt interval change to 90,000 in 1998

I'm just curious why the recommended interval when from 60,000 for the sc400 to 90,000 in 1998, especially when the sc400 engine went interference in 96? The real question is i have a 92, the first belt was changed at 63,000 and i'm now at 128,000 and have the new timing belt kit, but considering all the labor, do i really need to change it now or wait for 90,000 miles to roll around, my father didn't change the timing belt on his 95 corolla till 120,000 miles and had no problems so i just wonder.
Old 01-04-08, 11:09 PM
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O. L. T.
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You're asking a question about an engine part. This can go either in maintenance or the engine forum.

To answer your question, simple............. VVTI.
Old 01-05-08, 11:22 AM
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JBrady
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When I changed my 99 at 95k miles it looked very good. Toyota/Lexus is very conservative so the 90k interval on the interference engines is very SAFE. Your engine has the same basic parts and belt construction. It is also non-interference as you pointed out. I would go ahead and adopt the 90k interval.
Old 01-05-08, 05:54 PM
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KC95SC400
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Originally Posted by O. L. T.
You're asking a question about an engine part. This can go either in maintenance or the engine forum.

To answer your question, simple............. VVTI.
What does vvti have to do with anything? It doesn't affect belt wear.

The answer IS simple, it's marketing. Low maintence sells....

KC
Old 01-08-08, 02:07 PM
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WDoherty
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Originally Posted by KC95SC400
What does vvti have to do with anything? It doesn't affect belt wear.

The answer IS simple, it's marketing. Low maintence sells....

KC
Thanks, i knew the 98 went to vvt-i and that more likely answers the question: marketing. I couldn't imagine how this change would affect belt wear either. So i pulled of the cam cover last night to look at the belt and it looks brand new, so i am going to extend the interval to 90,000 and sell the timing belt kit that i bought.
Old 01-08-08, 03:51 PM
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link13
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The interval on my '94 GS300 was 90K. I had a former Lexus tech tell me the engine in the 1994s were non-interference and the belt could esily go 120K miles. When I had it changed at 120K miles, the mechanic told me the old belt looked fine, but he replaced it. I think you're fine going to 90K miles.
Old 01-08-08, 05:52 PM
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Originally Posted by O. L. T.
You're asking a question about an engine part. This can go either in maintenance or the engine forum.

To answer your question, simple............. VVTI.
That doesnt answer anything. Nice try though.
Old 01-08-08, 09:45 PM
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I have a 92 SC, the T-belt was changed at 109 000 km (about 68 000 miles), and on the advice of a Lexus tech, he said adopt the 150 000 km interval (93 000 miles). I plan to change the belt at 259 000 km (161 000 miles).

I'm at 253 000 km (157 000 miles) with no ill effects as of yet.
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