Timing belt replacement - What else should I get done at the same time?

[Sigr6]

So can somebody tell me why you would design an interference engine now instead of a non-interference engine?

[KFlash]

Lesson learned, be nicer to your 180k motor

[ctbale]

Originally Posted by kathyricks

The Tundra motor is an interference motor. There was one Tundra V8 owner on this forum who changed the belt at 90K, but didn't change the tensioner. Then at 174K miles, just before he was getting to change the timing belt again (at 180K) the tensioner seized during a full throttle passing manuver causing the belt to come off. Instantly his engine was destroyed when the pistons collided with the engine valves at full throttle. Lesson learned: Replace the tensioner at every timing belt change or live dangerously. Or change the timing belt sooner than 90K the second time it is changed and change the tensioner at that time.

ok, ok, replace the tensioner. My point is if you do a carefull inspection IAW the book, you will make 180k, then replace it.

[Matador98]

Originally Posted by ctbale

ok, ok, replace the tensioner. My point is if you do a carefull inspection IAW the book, you will make 180k, then replace it.

Whatever you say, but that is your risk to take. I'd rather spend the $50 bucks or so for the tensioner. The one on my wife's LC was pretty sticky at 180K.....I wasn't too pleased.

[HOGWILD]

06's had TSB for tensioner replacement due to noise and they were new , i would change it at every TB cycle along with oil seals x 2, water pump, thermostat, and coolant. the idler bearing #1 & #2 should have no issue going to the second TB cycle and they can get loud just before that time comes and no question change them both then! a few change them every time but the will make it to the second cycyle! Some people just do the kit every time and they are smart but have less money than you!
The world's most trusted name in belts, hoses & hydraulics | Gates Corporation surf around here could help with any other questions and thank DJ for the link!!

[kathyricks]

Originally Posted by Sigr6

So can somebody tell me why you would design an interference engine now instead of a non-interference engine?

For better power and fuel economy.

Imagine if Toyota offered two versions of the 4.7 V8, a non interference one with 225 HP and an interference one with 275 HP. Guess which one 95% of buyers would buy?

[ctbale]

ok, shoot ... now you guys got me worried! maybe I should have replaced more stuff when I was in there? I just did TB, pump, t-stadt, and fresh coolant. belt was crackin, pump was squeekin. I inspected the tensioner, and idler bearings. They were perfect. I got the truck at 119k, did it at 119.5K Maybe I will just go 60k, and get it back in 90k intervals, then replace everything. I hope it makes it. Just did headers, and stearing rack bushings, steering shaft seal is next! Should have done it when I was under there givin the rack some lovin ...

[ddvk]

Can someone educate me on why there are belts in many Toyota engines?

Shouldn't they have migrated to chains since chains have been on MB/BMW/Nissan's for decades?

[kathyricks]

Chains have chain tensioner problems too over time. Just like belts do. And replacing a chain mechanism is significantly more costly and labor intensive than changing a belt. Chains also stretch over time, retarding valve timing. Timing belts don't stretch. So there are pros and cons to chains vs. belts.

Unlike belt tensioners which come with sealed bearings, chain tensioners are lubricated by engine oil. So chain tensioner life is greatly influenced by oil change frequency. The owners who follow the tried and true 3-6 month / 3,000-5,000 mile rule with either dino or synthetic oil are the ones who typically get 400,000 miles or more of life out of their chain tensioner.

[Sanosuke]

Timing belts don't stretch? Thats not true. They do stretch over time.

Sanosuke!

[kathyricks]

Originally Posted by Sanosuke

Timing belts don't stretch? Thats not true. They do stretch over time. Sanosuke!

Technically you are correct, but timing belts don't stretch enough to retard valve timing. A stretched timing chain, on the other hand, can retard valve timing by up to 12-16 degrees.

[KFlash]

Hey folks.. I thought I saw a post that mentioned the timing belt kit offerred on ebay for $220, but couldn't find it again. It includes water pump, belt, seals tentioner and idler bearings, and serp belt.

Anyone have any thoughts on this kit. I don't know whether it comes with WP gasket and those two o-rings.

[KLINDSEY]

Originally Posted by KFlash

Sounds like there are a few of us out there ready to tackle this job. Between the TSM tutorial and the one based on the Lexus, this really doesn't seem bad at all. I have a few days in early Feb where I am going to give it a shot. Should be around 92K by then. Hope it isn't freezing!

Where did find the TMS tutorial I'm @ 88500 now looking to do this in March time frame.
Kevin

[ctbale]

this is the item number on ebay. 310017516915 seems like a good price for good parts. although, not sure if the Koyo idler bearing, SKF tensioner bearings are as important as the tensioner? if you want to to everything, get the tensioner from dealer, and thermostat, coolant, and o rings. then you will be good for another 100K!!

[kathyricks]

Koyo is an OEM supplier to Toyota, but SKF is a Mexican brand. I've noticed the metal finish on the roller of the tensioner of aftermarket brands of bearings is not a smooth and finely polished as on the OEM brands like Koyo and NSK. Rougher surface could = more belt wear. If the tensioner bearings of aftermarket tensioners are not as high quality either, tensioner life may be shorter.