1.8T timing belt

[Slamtastic]

Re: 1.8T timing belt

Whoa bump from '05.

Although VW first recommended to be changed at 160k, they have been known to fail before that. I have been told that it is usually the idler pulley/tensioner that fail before the belt breaks.

Most people will recommend to do it at 100k (60000 miles). I did mine a few weeks ago at 98000 kms because I thought that I should play it safe.

Also replace the plastic water pump with an improved metal one so that doesn't break.

[100%VAGitarian]

Re: 1.8T timing belt

ok. here's the deal with timing belts and vw. disregard what the owners manual says. anything over 100kms or 4 years is too long to wait. they do say to check it at that interval but require you to take it off and check the toothed side for cracks. (if you see cracks on the smooth side, it's toast anyways.) if you are going to the extent to pull it to check it, you are just going to put a new one on, right?

take a belt, throw it in your yard for 4 years and tell me if you'd put it on your motor. severe climate we live in, that's why.

ugh. the myth about the metal water pump. sure the plastic one is known to fail, but the metal ones are crappier quality and tend to leak any where from 50000kms. i've seen it first hand all to often. sure it wont break, but at least you know you can expect 100000kms from the plastic one. besides, when that happens, you're due for a new one. it also has nothing to do with screwing up the tensioner. the water pump (along with tensioners and rollers) is changed for preventative maintenance. do it while you're in there.

go ahead and wait if you like to gamble. i've seen them cracked at 60000kms. motors are way more money.

1.8T, TDI, V6 will be destroyed for sure. 2.0L, not so bad, but i've still seen valves bend.

/thread.

[Lars]

Re: 1.8T timing belt

ok. here's the deal with timing belts and vw. disregard what the owners manual says. anything over 100kms or 4 years is too long to wait. they do say to check it at that interval but require you to take it off and check the toothed side for cracks. (if you see cracks on the smooth side, it's toast anyways.) if you are going to the extent to pull it to check it, you are just going to put a new one on, right?

take a belt, throw it in your yard for 4 years and tell me if you'd put it on your motor. severe climate we live in, that's why.

ugh. the myth about the metal water pump. sure the plastic one is known to fail, but the metal ones are crappier quality and tend to leak any where from 50000kms. i've seen it first hand all to often. sure it wont break, but at least you know you can expect 100000kms from the plastic one. besides, when that happens, you're due for a new one. it also has nothing to do with screwing up the tensioner. the water pump (along with tensioners and rollers) is changed for preventative maintenance. do it while you're in there.

go ahead and wait if you like to gamble. i've seen them cracked at 60000kms. motors are way more money.

1.8T, TDI, V6 will be destroyed for sure. 2.0L, not so bad, but i've still seen valves bend.

/thread.

Got a buddy of mine that changes it sooner (80000 km ) because hes chipped (stage 2) Says cause the extra wear on it.. what are your thoughts on this --just wondering .

[luunta]

Re: 1.8T timing belt

change it for preventative maintenance, not really sure what that isn't clear. if your motor is running more revolutions, that means the belt and pump are running more. scale the service based on the usage.

really not complicated.

[100%VAGitarian]

Re: 1.8T timing belt

Got a buddy of mine that changes it sooner (80000 km ) because hes chipped (stage 2) Says cause the extra wear on it.. what are your thoughts on this --just wondering .

makes sense. the teeth bare the load. increase the load, increase the wear.

[All_Euro]

Re: 1.8T timing belt

I changed mine at about the 100K mark. Belt was in perfectly good condition too but def glad I changed the belt, pump, etc. Was a pain but worth the peace of mind.

Plus now I can spend the money I would have spent on repairs on performance parts

[p951]

Re: 1.8T timing belt

makes sense. the teeth bare the load. increase the load, increase the wear.

How do you increase the load on the valvetrain or timing belt when you go to stage 2, 3, 1000? More HP is transmitted through the valvetrain?

Not trying to be difficult, I just can't logically get there.

[Stonewall]

Re: 1.8T timing belt

How do you increase the load on the valvetrain or timing belt when you go to stage 2, 3, 1000? More HP is transmitted through the valvetrain?

Not trying to be difficult, I just can't logically get there.

Faster spooling = more torque on the belt. More wear from a higher sustained RPM range. I can see the logic in his post.

[100%VAGitarian]

Re: 1.8T timing belt

exactly. the crank drives the valve train, not the other way around. it's the crank sprocket that shears off teeth, not the top end. hammer on the bottom end hard enough and somethings going to give. the valves are just collateral damage at that point.

[p951]

Re: 1.8T timing belt

Right, I understand the mechanics of the valve drive system, I've done enough timing belts to have a excellent understanding (every 30k miles on the porsche - I owned two and put well over 100k miles between them in 5 years). I've even rebuilt the head on the 944S2 (twin cam) and rebuilt the engine on the turbo. I still don't see the logic there. There is no more (or less) stress on the cam belt from the production of more horsepower. The faster spooling and high rpm running arguments just don't make sense to me, you can get the same rate of change in rpm from revving out of gear (or even faster change in rpm), the higher speed running will produce the same level of stress (same constant force required) to actuate the valvetrain regardless of horsepower - which due to the fact of more power throughout the rpm band when chipped people will tend to short shift and run at lower rpm typically.

Sorry, it doesn't make sense to me.

Having said that, I'm planning to replace my timing belt on the 1.8t this spring, I should have about 100k KM by then. Looking forward to seeing how it's done on this car. Should be easier than the Porsches!

[luunta]

Re: 1.8T timing belt

more RPM's sustained over time = more turns and stress on the teeth of the belt. It lists a KM value, since it's impossible to track RPM's, but if you were to drive it hard and fast every day, it would definitely see more stress than perhaps a low RPM slowly driven car would. The same wear and tear applies to everything in the car.

Seriously, if you don't understand this, I'd be concerned.

[p951]

Re: 1.8T timing belt

more RPM's sustained over time = more turns and stress on the teeth of the belt. It lists a KM value, since it's impossible to track RPM's, but if you were to drive it hard and fast every day, it would definitely see more stress than perhaps a low RPM slowly driven car would. The same wear and tear applies to everything in the car.

Seriously, if you don't understand this, I'd be concerned.

I'm sorry to concern you Jess. . .

While I understand and agree that belts wear out due to use, if it was a major concern then the car companies would figure out a way to calculate the number of revolutions before failure and base it on that instead of a km figure. I know of family members running these engines in Europe that rarely get above 3rd gear therefore the timing belt has to endure at least double the revolutions to reach 160km (service recommendation) than someone in North America where they do a lot more driving around in top gear. I figure that the engineers have provided quite a safety margin when they wrote the specifications for the timing belt.

The age of the belt would be a more important factor in my decision to replace it than not. I've replaced numerous timing belt that only had a few thousand miles on them just because they were over 6 years old because the rubber ages even standing still.

But that's not the main issue that I was wondering about. My confusion still surrounds the idea that an increase in crank HP via aftermarket programming would shorten the timing belt change intervals since the valvetrain doesn't "feel" the effects of the increased HP at the crank. Does the 225 HP 1.8t in the Audi TT recommend a different interval? Does it have a different timing belt? The effort required to run the valvetrain doesn't change as the HP produced by the engine increases, does it?

[luunta]

Re: 1.8T timing belt

[100%VAGitarian]

Re: 1.8T timing belt

I'm sorry to concern you Jess. . .

While I understand and agree that belts wear out due to use, if it was a major concern then the car companies would figure out a way to calculate the number of revolutions before failure and base it on that instead of a km figure. I know of family members running these engines in Europe that rarely get above 3rd gear therefore the timing belt has to endure at least double the revolutions to reach 160km (service recommendation) than someone in North America where they do a lot more driving around in top gear. I figure that the engineers have provided quite a safety margin when they wrote the specifications for the timing belt.

The age of the belt would be a more important factor in my decision to replace it than not. I've replaced numerous timing belt that only had a few thousand miles on them just because they were over 6 years old because the rubber ages even standing still.

But that's not the main issue that I was wondering about. My confusion still surrounds the idea that an increase in crank HP via aftermarket programming would shorten the timing belt change intervals since the valvetrain doesn't "feel" the effects of the increased HP at the crank. Does the 225 HP 1.8t in the Audi TT recommend a different interval? Does it have a different timing belt? The effort required to run the valvetrain doesn't change as the HP produced by the engine increases, does it?

enough already. the valve train has nothing to do with it. the extra load isn't on the valve train. it's on the crank. what is so hard to understand? the time is factored into it. that's why they give an interval of 120-160, and recommend it be checked earlier, because these factors are a concern. seeing different wear patterns on belts on same engines is proof. we also live in a severe climate with severe weather conditions that put extra strain and loads on moving parts. that's why it's recommended to change earlier. perhaps an hour meter would be a better gauge of wear. plus if you are rev matching when the clutch is pressed in, there is no load, but the load hits when you dump the clutch.

cranks strip teeth off. not cam gears. have you ever seen chain stretch on a small block chevy? ever wonder why high HP motor builders switch from a single roller chain to a double roller? it's stronger because of the increased loads combustion pressure in the cylinder puts to the crank. it's not even connected to the valve train. TDI belts are stronger and of a different design than gassers, because of the extra load. hell even the 2.slow belt is different than the 1.8t. so would it be a far stretch to assume the audi one is also different? hope that clears things up.

BTW, i change 1.8T belts for 300 cash.

[p951]

Re: 1.8T timing belt

enough already. the valve train has nothing to do with it. the extra load isn't on the valve train. it's on the crank. what is so hard to understand? the time is factored into it. that's why they give an interval of 120-160, and recommend it be checked earlier, because these factors are a concern. seeing different wear patterns on belts on same engines is proof. we also live in a severe climate with severe weather conditions that put extra strain and loads on moving parts. that's why it's recommended to change earlier. perhaps an hour meter would be a better gauge of wear. plus if you are rev matching when the clutch is pressed in, there is no load, but the load hits when you dump the clutch.

cranks strip teeth off. not cam gears. have you ever seen chain stretch on a small block chevy? ever wonder why high HP motor builders switch from a single roller chain to a double roller? it's stronger because of the increased loads combustion pressure in the cylinder puts to the crank. it's not even connected to the valve train. TDI belts are stronger and of a different design than gassers, because of the extra load. hell even the 2.slow belt is different than the 1.8t. so would it be a far stretch to assume the audi one is also different? hope that clears things up.

BTW, i change 1.8T belts for 300 cash.

Ok, I think I get where you're coming from now. Are you saying that due to the increased power of the impulses that happen as the engine is running (at 180 degree intervals in the case of the 4 cyl engine) through the crank that THIS tends to shear the teeth from the timing belt? I'd hate to think that these belts are so woefully weak that it would have a significant impact on their life expectancy.

I was coming from the side of the power transmission standpoint of the timing belt (which is it's purpose) to operate the valvetrain and saying that this equation (or the power required to actuate the valvetrain) won't change regardless of the power output of the engine.

I guess I'll just have to wait until I actually do the timing belt on the A4 to see why there should be an issue with increased power. I've had cars with double the original HP they left the factory with and no issues at all with premature timing belt wear or failure. Maybe the VAG 1.8t engine went with smaller pulleys on the crank and cam and therefore put more load on fewer teeth. I fully understand the single versus double roller cam chain point your making, it's all about load distribution.

Thanks for explaining your point.