t/b blown, crank out of TDC - no marks? HELP

[JMAC2876]

My t/b split into two pieces and slipped due to a w/p lock up, which chewed all the t/b teeth off. Basically, I have replaced both the w/p and the t/b lining up the cam to TDC markings - I tried to find the crank TDC but there is no mark. To add to it, I know the crank has to be off due to the slip. Now, it wont start with everything back together. I assume I am out of time. I realize that it maybe a exhaust valuve issue, but feel I need to get everything back to time before I remove the head and rebuild.

How do I put the crank back to TDC with out removing the head etc?

[fitch303]

Umm unless ours cars are non interference do a compression test to make sure you aren't wasting your time on a bombed motor.....no?

[DenverNoob]

i would be far more concerned with bent valves and pison damage at this point. I dont know that you can really get away with a repair without taking a peak inside your head and combustion chambers at this point. that would be my first move in this situation. Given that this is an interference motor, there is a pretty high probability that some damage has been done in that regard (i.e. your valves and pistons shook hands so to speak). If that is the case, a bottom-end inspection will also be a good idea to inspect rods and piston condition from that angle...end of story is that just trying to get ur motor to fire could result in further damage than has already been caused. I would really stringly consider getting a good look inside that motor before you try and start it again...

[AudiA4_20T]

i would be far more concerned with bent valves and pison damage at this point. I dont know that you can really get away with a repair without taking a peak inside your head and combustion chambers at this point. that would be my first move in this situation. Given that this is an interference motor, there is a pretty high probability that some damage has been done in that regard (i.e. your valves and pistons shook hands so to speak). If that is the case, a bottom-end inspection will also be a good idea to inspect rods and piston condition from that angle...end of story is that just trying to get ur motor to fire could result in further damage than has already been caused. I would really stringly consider getting a good look inside that motor before you try and start it again...

doesnt hurt to set the timing right and try to run it through with a socket on the crank bolt to see if anything is stopping it

[DenverNoob]

doesnt hurt to set the timing right and try to run it through with a socket on the crank bolt to see if anything is stopping it

agreed, but it also doesnt hurt to pull the spark plugs and get a flashlight in each hole to look for metal shavings, small pieces of debris, or marks on the pistons. pretty easy. I got the impression from the OP that he was actually trying to start the motor....which in my opinion is about the last thing i would try given the failure.

[dougyfresh]

How do I put the crank back to TDC with out removing the head etc?

(Clint & Larry know this trick )
1) Pull the valve cover off
2) Rotate the exhaust cam clockwise until the arrow in the bearing cap all the way in the back of the engine (closest to the timing chain) lines up with the keyway in the exhaust cam. The head is now timed to TDC for Cyl#1
3) Pull all four spark plugs out
4) Put a 19mm 12pt socket with a 1/2" breaker bar on the crank pulley
5) Insert a welding rod or something equivalent into cylinder #1 (closest to front of engine)
6) Rotate the motor over (clockwise) by hand and watch the welding rod. When it starts to stop moving and is sticking all the way out stop turning the crank. Mark where the crank pulley indicator is on the timing belt cover. Continue rotating clockwise until the welding rod starts moving down. STOP. Mark where the crank pulley indicator is on the timing belt cover. The middle of those two marks is your TDC for cyl#1 on the crank
7) Install timing belt and tension timing belt accordingly

Now that that is done. Rotate the engine by hand to feel for any resistance. If none, then do a compression test on all four cylinders to determine if there are any bent valves.

[Papachristou]

[QUOTE=DenverNoob;2837248](i.e. your valves and pistons shook hands so to speak). [QUOTE]


no they had rough sex!

[Affinitive]

[QUOTE=Papachristou;2839076][QUOTE=DenverNoob;2837248](i.e. your valves and pistons shook hands so to speak).

no they had rough sex!

LMAO

The Crank TDC mark is on the pulley (harmonic balancer) and the timing belt cover. Very tough to see on the cover you'll see if you look close. If you look straight down from the top, the mark on the cover will be slightly to the left and line up the line on the crank pulley respectively.

When it's on TDC and it's down to just the timing belt sprocket, you'll notice one of the teeth perfectly in line with one threaded bolt holes will line up perfectly with a casting line on the front seal housing. Don't have one here right now to take a picture of, sorry.

Though, not to burst your bubble. I have yet to see a 1.8 survive a broken timing belt. Best case scenario I ever saw was only a couple of the center intake valve slightly bent..........but that's still kaputs. Good luck

C

[Affinitive]

[QUOTE=Papachristou;2839076][QUOTE=DenverNoob;2837248](i.e. your valves and pistons shook hands so to speak).

no they had rough sex!

LMAO

The Crank TDC mark is on the pulley (harmonic balancer) and the timing belt cover. Very tough to see on the cover you'll see if you look close. If you look straight down from the top, the mark on the cover will be slightly to the left and line up the line on the crank respectively.

When it's on TDC and it's down to just the timing belt sprocket, you'll notice one of the teeth perfectly in line with one threaded bolt holes will line up perfectly with a casting line on the front seal housing. Don't have one here right now to take a picture of, sorry.

C

[dirtybrd]

Were you driving when it happened? If so how fast?

[dougyfresh]

Were you driving when it happened? If so how fast?

Ludicrous Speed

[DenverNoob]

Ludicrous Speed

They've gone to plaid.....

[JMAC2876]

About 35mph - heard a slip, then she shut down and coasted to a stop. It was over - I knew it was the belt by the way the slip sounded. Towed it home, set the jacks and started at it!

[dougyfresh]

About 35mph - heard a slip, then she shut down and coasted to a stop. It was over - I knew it was the belt by the way the slip sounded. Towed it home, set the jacks and started at it!

Exactly what I did to my 2.0L 16V VW engine. Bent almost all 16 valves. I sheared all the teeth in the timing belt and also the keyway for the timing belt cam gear. I knew there was something wrong when the lights on the dash went on, the rpms dropped to 0rpm and I was coasting while still in 3rd gear.

If that is the case I am willing to bet you're valves are f'd. Its a shame, I just sold my spare AMB head last Friday otherwise I'd have a complete head I could sell you.

[JMAC2876]

(Clint & Larry know this trick )
1) Pull the valve cover off
2) Rotate the exhaust cam clockwise until the arrow in the bearing cap all the way in the back of the engine (closest to the timing chain) lines up with the keyway in the exhaust cam. The head is now timed to TDC for Cyl#1
3) Pull all four spark plugs out
4) Put a 19mm 12pt socket with a 1/2" breaker bar on the crank pulley
5) Insert a welding rod or something equivalent into cylinder #1 (closest to front of engine)
6) Rotate the motor over (clockwise) by hand and watch the welding rod. When it starts to stop moving and is sticking all the way out stop turning the crank. Mark where the crank pulley indicator is on the timing belt cover. Continue rotating clockwise until the welding rod starts moving down. STOP. Mark where the crank pulley indicator is on the timing belt cover. The middle of those two marks is your TDC for cyl#1 on the crank
7) Install timing belt and tension timing belt accordingly

Now that that is done. Rotate the engine by hand to feel for any resistance. If none, then do a compression test on all four cylinders to determine if there are any bent valves.

Will I recognize this "KEYWAY" - I am new to vc removal, and cam system, but a quick learn.

[JMAC2876]

Exactly what I did to my 2.0L 16V VW engine. Bent almost all 16 valves. I sheared all the teeth in the timing belt and also the keyway for the timing belt cam gear. I knew there was something wrong when the lights on the dash went on, the rpms dropped to 0rpm and I was coasting while still in 3rd gear.

If that is the case I am willing to bet you're valves are f'd. Its a shame, I just sold my spare AMB head last Friday otherwise I'd have a complete head I could sell you.

So how did you recover - rebuild the engine or just the head?? What was the cost?

[JMAC2876]

[QUOTE=Affinitive;2839458][QUOTE=Papachristou;2839076]

(i.e. your valves and pistons shook hands so to speak).


LMAO

The Crank TDC mark is on the pulley (harmonic balancer) and the timing belt cover. Very tough to see on the cover you'll see if you look close. If you look straight down from the top, the mark on the cover will be slightly to the left and line up the line on the crank respectively.

When it's on TDC and it's down to just the timing belt sprocket, you'll notice one of the teeth perfectly in line with one threaded bolt holes will line up perfectly with a casting line on the front seal housing. Don't have one here right now to take a picture of, sorry.

C

If I took a pic could you point it out?

[dougyfresh]

This is the back of the head:


See those arrows on the cam bearing caps? The last two caps before the timing chain. The cam on the left is your exhaust cam (driven by the timing belt). The cam on the right is your intake cam (driven from the exhaust cam via the cam chain).

TDC for the head will have the keyway in the exhaust camshaft aligned with the arrow on the bearing cap. I do not have a picture of the exhaust cam and bearing cap aligned but here is the intake for the sake of a photo:


Due to the variable valve timing (that solenoid that the timing chain is sandwiched between) the intake cam may not directly line up with the arrow on the intake cam bearing cap. Do not fret. That is perfectly fine. The concept is to get the exhaust cam aligned. If you are removing the cams and/or replacing them I'd continue with some more info, but until then, I'll refrain for sake of not confusing you.

Does this make sense?


(Thanks Jordan 'CO AVANT' for those pictures. I can't find mine right now so I used yours.)






You recover by either method:
1) rebuild your existing cylinder head with all new valves (or replacment of valves that are bent) in conjunction with a valve face grind. [labor to remove/install valves and grind faces is about $300. valves are $460 for all 20. depending on mileage you might need new valve guides too.]
2) find a used cylinder head in tact and just bolt that on. [market price]

Both cases require new head bolts and a new head gasket. Both cases require a visual inspection of your pistons to verify they are not damaged due to contact with the valves (most likely not damaged).

[JMAC2876]

This is the back of the head:


See those arrows on the cam bearing caps? The last two caps before the timing chain. The cam on the left is your exhaust cam (driven by the timing belt). The cam on the right is your intake cam (driven from the exhaust cam via the cam chain).

TDC for the head will have the keyway in the exhaust camshaft aligned with the arrow on the bearing cap. I do not have a picture of the exhaust cam and bearing cap aligned but here is the intake for the sake of a photo:


Due to the variable valve timing (that solenoid that the timing chain is sandwiched between) the intake cam may not directly line up with the arrow on the intake cam bearing cap. Do not fret. That is perfectly fine. The concept is to get the exhaust cam aligned. If you are removing the cams and/or replacing them I'd continue with some more info, but until then, I'll refrain for sake of not confusing you.

Does this make sense?


(Thanks Jordan 'CO AVANT' for those pictures. I can't find mine right now so I used yours.)






You recover by either method:
1) rebuild your existing cylinder head with all new valves (or replacment of valves that are bent) in conjunction with a valve face grind. [labor to remove/install valves and grind faces is about $300. valves are $460 for all 20. depending on mileage you might need new valve guides too.]
2) find a used cylinder head in tact and just bolt that on. [market price]

Both cases require new head bolts and a new head gasket. Both cases require a visual inspection of your pistons to verify they are not damaged due to contact with the valves (most likely not damaged).

Bottom line - remove the vc - to line up the exhaust cam with the arrow on the cam bracket and a mark or indicator on the chain. Will this mark be easy to see/find? Then, the intake arrow may be off a bit, but not enough to concern myself with.

[dougyfresh]

Bottom line - remove the vc - to line up the exhaust cam with the arrow on the cam bracket and a mark or indicator on the chain. Will this mark be easy to see/find? Then, the intake arrow may be off a bit, but not enough to concern myself with.

Correct.

The indicator is on the camshaft itself. Its a keyway. Just make sure that keyway is lined up with the arrow on the cam bearing cap. I'll post pictures of my engine tonight when I get home (say, around 9pm EST). I took detailed photos when I installed my aftermarket cams.

[JMAC2876]

Correct.

The indicator is on the camshaft itself. Its a keyway. Just make sure that keyway is lined up with the arrow on the cam bearing cap. I'll post pictures of my engine tonight when I get home (say, around 9pm EST). I took detailed photos when I installed my aftermarket cams.

Schweet! Im going to run out now and pull it apart - and line things up accordingly. I will look for your post later this evening!

Now to verify if the valves are shot? Any suggestions on that?

[dougyfresh]

Now to verify if the valves are shot? Any suggestions on that?

The best way is to use a borescope and insert it into your combustion chambers via the spark plug hole. However, you do not have a borescope and are not going to drop the serious cash to buy one.

SO, the next best thing is to do a compression check. If you have zero compression in any cylinders than that means your valves (or some combination of the 20 valves) are bent and its time to pull the cylinder head off the engine to repair and/or replace and also visually verify bent valves. You can pick up a compression tester for about $20.

Here is a DIY on compression test: http://www.audigeeks.com/forums/index.php?topic=2769.0

Here is a DIY on removing the cylinder head: http://www.audigeeks.com/forums/index.php?topic=2811.0

[AudiA4_20T]

if you set everything right, when you go to turn the motor over, it wont go... that will tell you also

[bananas]

This is the crank TDC mark... See the notch on the pulley and the very small notch on the tbelt cover. Make sure the engine is PHYSICALLY at TDC #1 when this notch lines up (use some rigid wire, or a welding rod, and turn the engine over as stated above):

... from a slightly different angle. The mark on the timing belt cover can be pretty hard to see...



Exhaust cam pulley mark... there is a notch on the exhaust cam pulley and a notch on the valve cover (ignore the white paint in this pic):



Just to be thorough, here are some more pictures. Since you didn't move the cam chain, your cams should be timed properly already.
Exhaust cam timing:


... intake cam timing...


... and here is the bentley for timing the cams...


... and how it looks in real life (count the rollers)...

[dougyfresh]

Thanks Chris! Now I don't have to go find my pictures. You've touched base on everything.

[Affinitive]

[QUOTE=JMAC2876;2840779][QUOTE=Affinitive;2839458]

If I took a pic could you point it out?

Bananas posted a good pic of the TDC mark on the crank pulley. In the pic it's lined up and you'll notice just a very slight dimple, so to say, on the belt cover.

As for the Camshafts, I'm no sure what the idea of pulling the valve cover is since there is a mark on the mark on the Belt sprocket and valve cover to line up and the chain is not going to jump when a timing belt breaks. I don't mean any disrespect to dougy..... but it's a whole lot of unnecessary work. You can really start the engine with the valve cover off. It may very start if the damage is isolated to only one or two cylinders.

Though considering that major damage has most likely occurred, I guess pulling the valve cover is not really all that unecessary. I guess it would be a good idea to also look for clearance between the lifter and camshaft (off the lobe that is) which would indicate a majorly bent valve.

C

[dougyfresh]

I am just used to pulling my valve cover off because it takes less than 5mins (no SAI in the way) and is more accurate than the notch in the valve cover. That notch is a byproduct of casting variations within the valve cover. I'm also very meticulous and don't cut any corners (not saying the valve cover notch is cutting corners).

My particular engine also has an aftermarket, adjustable, cam gear that has no notch in the cam gear to line up with on the valve cover.



Will you even see anything between the lifter and cam lobe? I don't think so, they are hydraulic lifters.

[A4 TSCHUSS]

I have a stock AMB head in perfect working order if you end up needing a head. You can have it for $300 plus shipping, I see them listed on ebay sometimes for $500-750 range and are like $2000 from the dealer