Timing belt jumped a tooth

**Trigger Happy** · 04-02-2010 02:43 PM

So my timing belt jumped a tooth. How do I realign the timing belt without the cam lock bar? I'm doing this NOW so I really need quick responses if possible. Thanks guys

**rms-s4** · 04-02-2010 02:46 PM

its really hard unless you have marks that where painted on. just do it right and rent or borrow a cam bar and lock pin. not something you wanna mess up

**ThirdStrike** · 04-02-2010 02:50 PM

you can 1) pull the valve cover off and line up the tick marks on the cam shafts - easy route
2) make a mark on the sprocket and cover plate, slide the belt off the sprocket and turn it back a tooth by hand.
either way without a locking bar good luck getting the belt back on without moving the sprocket. its a bitch.
how do you know you jumped a tooth????

**A4Rob** · 04-02-2010 02:53 PM

Make sure your valves are not bent. I just did the full valve job on my S

**ThirdStrike** · 04-02-2010 02:55 PM

Originally Posted by A4Rob

Make sure your valves are not bent. I just did the full valve job on my S

1 tooth wont bend/strike valves.....

**sparkyvw** · 04-02-2010 03:05 PM

Originally Posted by ThirdStrike

1 tooth wont bend/strike valves.....

Niether will jumping 5 teeth.

**quickglx** · 04-02-2010 03:25 PM

Interested too, how do you know it jumped one tooth without the cam locking bar? And more importantly, why did it jump one tooth?

**Trigger Happy** · 04-02-2010 03:42 PM

Not sure y it jumped, but my cam position sensor was throwing a "cam in wrong place" code right after I screwed a piece of sheet metal into my timing belt cover to cover the hole left by the old fan assembly. I'm getting the cam lock bar tomorrow and one of my buddies who is a Audi tech is comin over to help. I'm not sure if it only jumped one tooth, but as it ran I doubt it. Idle was slightly off, only I noticed. I'm going to do a compression test tomorrow.

**A4Rob** · 04-02-2010 05:37 PM

Originally Posted by ThirdStrike

1 tooth wont bend/strike valves.....

One tooth wont, but it doesn't take much more to give them a nice new shape:

**bigern45** · 04-03-2010 05:45 AM

Originally Posted by sparkyvw

Niether will jumping 5 teeth.

lol.. 5 will for sure.. 2 off itll run bad.. 3 off youve def bent a valve somewhere..

**The_Jerbel** · 04-03-2010 06:42 AM

Originally Posted by sparkyvw

Niether will jumping 5 teeth.

I wouldn't be so sure about that

OP,

You have to be really careful about where you insert screws into the TB cover. The TB must have hit the screw and jumped the sprocket. Make sure you check the belt for damage.

**Trigger Happy** · 04-03-2010 09:36 AM

Originally Posted by The_Jerbel

I wouldn't be so sure about that

OP,

You have to be really careful about where you insert screws into the TB cover. The TB must have hit the screw and jumped the sprocket. Make sure you check the belt for damage.

Thats exactly what I think happened. I'm only 5Kish away from needing a timing belt anyways so I figured just do the full timing belt job now and not worry about it. The timing belt thats in there looks fine, no obvious damage anywhere. Question: at TDC are the cam sprockets wings supposed to be completely horizontal or have a slight angle to them?

**Trigger Happy** · 04-03-2010 04:03 PM

So am I correct in thinking that if the holes on the cam lock bar match up with the holes on the wings of the cam sprocket the timing is spot on? This is with the crank at TDC.

**The_Jerbel** · 04-03-2010 04:20 PM

Yessir.

**DiscoPotato** · 04-04-2010 12:39 AM

id really suggest to get a camlock bar. Timing is something you cannot mess with.

Originally Posted by Trigger Happy

So am I correct in thinking that if the holes on the cam lock bar match up with the holes on the wings of the cam sprocket the timing is spot on? This is with the crank at TDC.

Exactly.

**Trigger Happy** · 04-04-2010 11:54 AM

Originally Posted by DiscoPotato

id really suggest to get a camlock bar. Timing is something you cannot mess with.

Exactly.

Where could I get one on the cheap? I would much perfer to just rent or borrow it from somewhere. Anyone in the DC or Altoona/State college area have one that they would lend out?

**TWiST** · 04-04-2010 12:31 PM

the timing belt can look fine and still be stretched out, my first timing belt job was done according to the maint schedule I just did my second one at 197,000 miles and after marking everything and putting everything back on it was a hair to the clockwise which shows me that the stretched belt was out of perfect timing, Now she is running great and I have not had any sputters in the drive thru like I was starting to get before.

**awd2ks4** · 04-04-2010 12:32 PM

Purems rents them

**sparkyvw** · 04-04-2010 01:32 PM

Originally Posted by The_Jerbel

I wouldn't be so sure about that

i am sure on that. As iv done it as the tensonner arm bolt snapped. Had zero damage. Slapped on a new belt arm and bolt fired it up perfectly fine.

**The_Jerbel** · 04-04-2010 03:48 PM

How long did the engine run for after the bolt snapped?

**DiscoPotato** · 04-04-2010 03:54 PM

Originally Posted by Trigger Happy

Where could I get one on the cheap? I would much perfer to just rent or borrow it from somewhere. Anyone in the DC or Altoona/State college area have one that they would lend out?

I would lend mine to you but im all the way in Jersey.

**sparkyvw** · 04-04-2010 06:08 PM

Originally Posted by The_Jerbel

How long did the engine run for after the bolt snapped?

About 10/20 miles then a good half hour sat in the drive on idle trying to find out why it was running shitty and should different when i rev'd it lol.

**The_Jerbel** · 04-04-2010 09:32 PM

hmmm, interesting. So you're sure your belt skipped 5 teeth? That should cause damage...

**Trigger Happy** · 04-05-2010 12:18 AM

Originally Posted by sparkyvw

About 10/20 miles then a good half hour sat in the drive on idle trying to find out why it was running shitty and should different when i rev'd it lol.

As soon as you hit boost did it sound like your valves were smacking your pistons? Mine kinda sounded like that only more like engine knock, but not really. Kinda hard to explain.

**sparkyvw** · 04-05-2010 11:39 AM

Originally Posted by The_Jerbel

hmmm, interesting. So you're sure your belt skipped 5 teeth? That should cause damage...

Yep as i rang mike at vast in a panic thinking id have to rebuild it after i took the covers of and the left side cam was nearly a quarter turn out.

Originally Posted by Trigger Happy

As soon as you hit boost did it sound like your valves were smacking your pistons? Mine kinda sounded like that only more like engine knock, but not really. Kinda hard to explain.

Nope the only only reason i knew something was up was the exhaust sound sounded really strange like it was misfiring but it wasnt.

**petracca** · 04-05-2010 12:07 PM

Originally Posted by bigern45

lol.. 5 will for sure.. 2 off itll run bad.. 3 off youve def bent a valve somewhere..

Yep. And 4 teeth off destroys all 30 valves. That totaled my silver S4.

**The_Jerbel** · 04-05-2010 12:15 PM

Originally Posted by sparkyvw

Yep as i rang mike at vast in a panic thinking id have to rebuild it after i took the covers of and the left side cam was nearly a quarter turn out.

I think you got lucky.

**sparkyvw** · 04-05-2010 01:43 PM

ooo i know i got very very lucky indeed.

**ThirdStrike** · 04-05-2010 02:57 PM

these motors are called "interference" for a reason.. sparkyvw is the one whom got lucky. I've never heard of an interference engine that can withstand more than 2 teeth off on a timing sprocket.
with a 1.8t its a definite 2 tooth limit or pistons will strike valves...