Timing Belt Limits, HP and Torque wise.

Richard55

Vendor
Joined
Jan 26, 2006
Location
Rutledge, Georgia
TDI
2000 NB
I have a question about the "timing belts". Does anyone know what the HP and torque limits are for the 100,000 mile belt, for the ALH motors.and for the tensioners. I have have had two belts come in broken and two tensioners come in that have failed. But I quess the question is really for my car as I will be pushing 200 or more HP from my NB and want some peace of mind.
 

bhtooefr

TDIClub Enthusiast, ToofTek Inventor
Joined
Oct 16, 2005
Location
Newark, OH
TDI
None
What increases stress on the timing components is not an increase of power/torque, it's an increase in load on those components.

Increasing power and torque does increase load when you're using that power and torque, but you're applying all of that additional load to the flywheel end, not the timing belt.

Stiffer valve springs, more radical camshafts, and larger injection pumps can certainly increase load on the timing components, however. (That's why the 60k belt was only 40k on the automatic ALH cars, due to the 11 mm pump. However, VW felt the 11 mm was good to 100k on the 100k components.)
 

A5INKY

Vendor , w/Business number
Joined
Sep 4, 2007
Location
Louisville, KY
TDI
2006 Jetta TDI, 2002 Eurovan Westphalia VR6
This has been debated before and it is hard to come up with a definitive answer. I used to be in the camp that the belt would not see enough of an increase in stress with a built engine to warrant increased change interval. Then I had one break on my built PD.

Granted this was a PD which likely stresses the belt more than a rotary pump car. But I am now a believer in increasing TB change interval on a heavily modded car. Mine will be getting a fresh belt (only) every 50K miles and the full deal every 100K.

Modded engines with bigger turbos tent to run at a higher RPM on average. The torque induced pulses are stronger and who knows what is happening with harmonics! Better safe than sorry IMHO...
 

oldpoopie

Vendor
Joined
May 14, 2001
Location
Portland Oregon
TDI
2001 golf gl, 2006 jetta, 1981 ALH swapped rabbit pickup, 1998 beetle
This has been debated before and it is hard to come up with a definitive answer. I used to be in the camp that the belt would not see enough of an increase in stress with a built engine to warrant increased change interval. Then I had one break on my built PD.

Granted this was a PD which likely stresses the belt more than a rotary pump car. But I am now a believer in increasing TB change interval on a heavily modded car. Mine will be getting a fresh belt (only) every 50K miles and the full deal every 100K.

Modded engines with bigger turbos tent to run at a higher RPM on average. The torque induced pulses are stronger and who knows what is happening with harmonics! Better safe than sorry IMHO...
Agreed
 

Nash_TDI

Veteran Member -TDIClub Enthusiast
Joined
Sep 3, 2002
Location
Louisville, ky
TDI
2000 Silver Jetta TDI
I had 2 belts that didn't last 2k miles on my ALH. It was actually the lower roller bolt that failed. Sheered flush with the block both times. At a minimum I would start upgrading hardware. I will be changing mine very frequently from now on.
 

JamesTwo

Veteran Member
Joined
Jul 1, 2013
Location
GA
TDI
2004 Jetta
What mods do you have?

This has been debated before and it is hard to come up with a definitive answer. I used to be in the camp that the belt would not see enough of an increase in stress with a built engine to warrant increased change interval. Then I had one break on my built PD.

Granted this was a PD which likely stresses the belt more than a rotary pump car. But I am now a believer in increasing TB change interval on a heavily modded car. Mine will be getting a fresh belt (only) every 50K miles and the full deal every 100K.

Modded engines with bigger turbos tent to run at a higher RPM on average. The torque induced pulses are stronger and who knows what is happening with harmonics! Better safe than sorry IMHO...
 

mk3pd

Vendor , w/Business number
Joined
Nov 14, 2006
Location
Norway
TDI
Passat Quattro :)
This has been debated before and it is hard to come up with a definitive answer. I used to be in the camp that the belt would not see enough of an increase in stress with a built engine to warrant increased change interval. Then I had one break on my built PD.

Granted this was a PD which likely stresses the belt more than a rotary pump car. But I am now a believer in increasing TB change interval on a heavily modded car. Mine will be getting a fresh belt (only) every 50K miles and the full deal every 100K.

Modded engines with bigger turbos tent to run at a higher RPM on average. The torque induced pulses are stronger and who knows what is happening with harmonics! Better safe than sorry IMHO...
If you have bigger injectors the stress on the timing belt will be much less than stock
 

oldpoopie

Vendor
Joined
May 14, 2001
Location
Portland Oregon
TDI
2001 golf gl, 2006 jetta, 1981 ALH swapped rabbit pickup, 1998 beetle
I had 2 belts that didn't last 2k miles on my ALH. It was actually the lower roller bolt that failed. Sheered flush with the block both times. At a minimum I would start upgrading hardware. I will be changing mine very frequently from now on.
I had one of those go on mine as well.... Luckily didnt loose time.
 

A5INKY

Vendor , w/Business number
Joined
Sep 4, 2007
Location
Louisville, KY
TDI
2006 Jetta TDI, 2002 Eurovan Westphalia VR6
What mods do you have?
GTB2056VK with ceramic coated turbine on a ceramic coated tubular manifold into 3" SS exhaust, R783 nozzles on 8mm pump elements, custom aluminum dual plenum custom intake manifold, ported head and Frank's cam are the main engine mods. Lots done to trans and chassis too. You know, the usual.

If you have bigger injectors the stress on the timing belt will be much less than stock
I think I get your meaning, bigger nozzles may decrease injection total pressure and therefore decrease stress on the cam? Not so sure it works that way in reality though. My car is hard on cams, and apparently TBs too. And what about:

...Modded engines with bigger turbos tent to run at a higher RPM on average. The torque induced pulses are stronger and who knows what is happening with [edit for clarity: belt] harmonics!..
 

Richard55

Vendor
Joined
Jan 26, 2006
Location
Rutledge, Georgia
TDI
2000 NB
I really ran my tb past the 100,00k as I keep telling myself I would do it "next" month and was always working on other peoples cars. Stupid. i had at least 150,000 on the belt with lots of mods. Sad thing to say and do. This gave me the option of really going thru the car for the trip to Panama Central America.
I sent my head up to "Headbytes" in North Carolina, he only does highly modified NHRA and NASCAR style heads. He had years of working on and modifying 1.5 and 1.6 VW heads. I told him to make it flow. lol He is also having a "one off" cam built for the head by a major cam builder in California. I will let you know how it runs and holds up on the trip south.
 
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