Timing Belts: time limit spec

[ESBkevin]

It's not always the obvious cost of the new belt so much as the option to choose when!

I'll have the change done next Tuesday morning and not need the vehicle for a couple of hours -v- **** how do I get home now at this hour and how will I get to xxx early in the morning and get little xxx to school and collected again?

You can bet the chances of it being at the most inopportune moment are pretty high when it pillages your bank balance too.

 

[HHR]

(Knock wood) I can have that kind of luck.... :duh: that's part of why I don't buy lottery tickets. A couple of Winters back, I heard a request for assistance on one of our local 2m repeaters. A local ham was heading down our version of an interstate, when his not-that-old TDI died. Even for Feb. , it was a pretty good cold snap - so when I couldn't raise anyone at his house, I got a tow truck on it's way to him. Not a night you would want to be sitting in a car with a dead engine for long. (For those of you who don't know older ham radio guys...... they are infamous for not spending money; possible exceptions being 2 way radios, and sometimes vehicles. The dead-TDI owner didn't own a cell phone). On the radio, he said he thought the engine computer had died, from the way the car shut down. Saw him a few months later........ as you may have guessed (a few paragraphs ago :laughing, it was the timing belt that broke. He hadn't considered that possibility when sitting on the side of the road, as he was something like 700 km below the mileage where the change interval allegedly was. When you come across incidents like this, it sheds some light on why Honda derates my Civic belt for harsh climates. Rgds, D.

Our VW Jetta TDI was taken to the dealership for it's 80k service and they installed the belt wrong and bent the valves in the head. That was the beginning of the end and the car had multiple issues after that was "fixed."

 

[3930dave]

It's not always the obvious cost of the new belt so much as the option to choose when!

I'll have the change done next Tuesday morning and not need the vehicle for a couple of hours -v- **** how do I get home now at this hour and how will I get to xxx early in the morning and get little xxx to school and collected again?

You can bet the chances of it being at the most inopportune moment are pretty high when it pillages your bank balance too.

Timing matters to the engine, but it can also be a pain for us to manage our time.

Rgds, D.

 

[3930dave]

Our VW Jetta TDI was taken to the dealership for it's 80k service and they installed the belt wrong and bent the valves in the head. That was the beginning of the end and the car had multiple issues after that was "fixed."

I hope that you were appropriately compensated for that "service".

While not an easy belt to do, there is no valid excuse for what happened to your car.

VW's belt design does not seem to lend itself well to stretching (pun intended) out the change interval. I've also seen a problem with using after-market water pumps on a TDI. One had a thicker wall casting on the impeller - normally you'd think thicker = stronger.

May be, but the problem was the increased wall thickness of the impeller actually reduced the volume of each individual little bucket cast into the impeller. Modern econo-car water pumps are designed to be low-drag from the get-go, so this after-market pump installed on this tdi produced so little flow through the heater core that you were freezing inside the car in the dead of Winter here.

Once that WP was replaced with an OE one, the car had plenty of heat.

Design margins are getting pretty thin, on some things today.

Rgds, D.

 

[HHR]

I hope that you were appropriately compensated for that "service". While not an easy belt to do, there is no valid excuse for what happened to your car. VW's belt design does not seem to lend itself well to stretching (pun intended) out the change interval. I've also seen a problem with using after-market water pumps on a TDI. One had a thicker wall casting on the impeller - normally you'd think thicker = stronger. May be, but the problem was the increased wall thickness of the impeller actually reduced the volume of each individual little bucket cast into the impeller. Modern econo-car water pumps are designed to be low-drag from the get-go, so this after-market pump installed on this tdi produced so little flow through the heater core that you were freezing inside the car in the dead of Winter here. Once that WP was replaced with an OE one, the car had plenty of heat. Design margins are getting pretty thin, on some things today. Rgds, D.

Dealer installed a remanufactured head while we got to drive an Audi 2000 loaner car.

 

[3930dave]

Dealer installed a remanufactured head while we got to drive an Audi 2000 loaner car.

The Audi would have been fun, for a quick fling.

Doesn't sound like the dealer really fixed the tdi in the end - too bad, as they are decent to drive if maintained well.

Rgds, D.

 

[crazyal]

T-belt driven water pumps can seize. So can Idlers, Tensioners.

Can we possibly load more chambers, in this mechanical version of Russian Roulette ?

Some manuf. do seem to over-design / under-stress their Tbelt applications.

While I do like chains, I much prefer them short - modern OEM practices of wrapping the chain half-way around the engine compartment, then beating the heck out of your supplier on price don't impress me. GM was getting enough chain-stretch on the Torrent class V6s that they had to do an emission recall.

Aside from bad oil, or DI contamination, another problem source for chains is cheap or defective oil filters. A faulty Anti Drain Back Valve can take too long to build oil pressure at start-up. Bad news, esp. if the cam-chain is hydraulically tensioned.

Rgds, D.

In the case of the Tundra, no. The water pump, idler, and tensioner are all driven by the back side of the belt, not the teeth. If one seized the belt would just slip on it. The idler/ tensioners are made from what looks like stainless steel and are very smooth. I would guess either would overheat but the noise would be more than enough for anyone with common sense (yes I know that leaves a lot of people out) to stop to find out why. As for the water pump, if it were to seize I think you would overheat before the belt was damaged enough to break.

I'm not a big fan of either a belt or a chain. Belts break and because of this mfgs set replacement times that are much shorter than needed. What company is going to say 200k when they can say 100k and not have to deal with upset people plus they get the benefit of selling people work they may not of needed. Chains stretch as they wear, that changes your timing. Shorter is better but that isn't always an option. I think GM is the last company to use pushrods. That means a timing chain on a V-8 or V-6 must go to both heads. In the case of my Tundra the timing belt was probably 5' long (I didn't measure it). That's a lot of chain.

 

[HHR]

Ford's new 1.0L 3-cylinder Ecoboost engine uses a timing belt that is immersed in oil. This is what Honda has been doing in their GCV series small engines for a while now.
Ford says the belt is good for "life" or every 10 years. Couldn't find any mileage limitation.

 

[3930dave]

In the case of the Tundra, no. The water pump, idler, and tensioner are all driven by the back side of the belt, not the teeth. If one seized the belt would just slip on it. The idler/ tensioners are made from what looks like stainless steel and are very smooth. I would guess either would overheat but the noise would be more than enough for anyone with common sense (yes I know that leaves a lot of people out) to stop to find out why. As for the water pump, if it were to seize I think you would overheat before the belt was damaged enough to break.

I'm not a big fan of either a belt or a chain. Belts break and because of this mfgs set replacement times that are much shorter than needed. What company is going to say 200k when they can say 100k and not have to deal with upset people plus they get the benefit of selling people work they may not of needed. Chains stretch as they wear, that changes your timing. Shorter is better but that isn't always an option. I think GM is the last company to use pushrods. That means a timing chain on a V-8 or V-6 must go to both heads. In the case of my Tundra the timing belt was probably 5' long (I didn't measure it). That's a lot of chain.

Nice design. I hadn't seen a WP driven that way. Toyota does seem to design to keep their Tbelts under-stressed. It would be interesting to see the flow curve for that pump..... obviously it does the job fine, but I'm having trouble seeing really high volume being moved w/o a tooth drive...... looks like even pickup truck engine WPs are getting designed for lower drag too.... makes sense.

Agreed on the long chains. Can still have problems, but IMO, correct oil (SAE) grade, viscosity, and change interval matter even more now, on these new long chain designs.

Rgds, D.

 

[3930dave]

Ford's new 1.0L 3-cylinder Ecoboost engine uses a timing belt that is immersed in oil. This is what Honda has been doing in their GCV series small engines for a while now.
Ford says the belt is good for "life" or every 10 years. Couldn't find any mileage limitation.

Oil of Olay, for timing belts ? Neat.

Hard to imagine a 5' long belt on that engine displacement, but looks like the target is good lifespan/mileage + low (?) cost + quiet. Attractive, for the small car market.

Will be interesting to price those belts.

Rgds, D.