Timing Belt alligment (GoFaster's Replacement Method)

[bbridgerb]

Timing Belt alligment (GoFaster\'s Replacement Method)

Hello everyone, I have replaced the timing belt and water pump on my 1996 VW Passat using GoFaster's mark and pray method. I marked the belt, cam sprocket, pump sprocket, and crank sprocket with a marker and transferred the marks to the new belt. All went well and I think the car is ready to be cranked but before I do that I want to be 100% sure that everything is aligned correctly. I rotated the engine clockwise using a range at the crank sprocket for at least two full revolutions and didn’t hear any noises. Would it be loud if the valves were hitting pistons? What should I listen for? Is there another way (using TDC) to make an easy check that everything is aligned right? Just curious - What would happen if crankshaft and camshaft were aligned correctly but the injection pump was off by quite a bit? Thanks.

 

[DIESEL DAZZLER]

Re: Timing Belt alligment (GoFaster\'s Replacement Method)

Mark and pray ,good luck,if pump is out of time it will not start , so now you have to start over because now you don't know if pump is early or late,also the cam timing will be incorrect when you adj tb tension,the cam sprocket must be able to move when adjusting tensioner the cam sprocket is the last thing to be torqed in the whole proceduer , as a vw tech, mark and pray is not a good practice ,2 weeks ago a person came in and asked for advice to change tb ,person messed up trying to save 200$ ,car came in on the hook and had #1 intake valve head buried in valve pocket and ruined head and piston now it cost 3000$ for repair so use the proper method to be safe.I can't believe that Gofaster would use mark and pray!

 

[GoFaster]

Re: Timing Belt alligment (GoFaster\'s Replacement Method)

I think that post was written before anyone outside of VW dealerships had access to the correct tools, before anyone had VAG-COM to be able to check anything, and before anyone figured out how easy the procedure is using the CORRECT tools once they became more generally available.

I wouldn't recommend using the mark-and-pray method now. Get the correct tools and get VAG-COM. It's easier to do the job correctly than to use this method.

The correct method is linked to in the TDIFAQ and has been posted several times; this is a reference to something very old and outdated. I don't have access to the archives to go in there and eliminate this method ...

 

[Drivbiwire]

Re: Timing Belt alligment (GoFaster\'s Replacement Method)

The consolation is resetting the timing after a botched mark and pray is not all that bad.

You need to remove the cam pulley, lock the pump, then lock the cam and then set the crank at TDC. Once everything is set, reinstall the cam pulley THEN set the belt tension on the tensioner. Make sure the injection pump lock pin is centered in the pump pulley hole so you can adjust equally in either direction. On the A3/B4 simply install the in and move it up and down until the belt drops easily into the teeth on the belt. Now torque the cam pulley THEN the pump bolts (A4 only) and you are ready to pull the engine through.

Without locking everything down as has been mentioned many times you are playing Russian Roulette to the tune of a $3,000 oops.

DB

 

[christi]

Re: Timing Belt alligment (GoFaster\'s Replacement Method)

I did the wife's Audi 80 TDI by mark and pray.

I turned the engine over first (fifth gear, jack up a wheel, turn tyre.

No resistance to turning tyre.

Started engine and got a horrid "clack clack clack" noise.

It turned out that I had gotten it one tooth out.

I am guessing that there was not valve / piston contact until oil pressure built up and pumped up the hydraulic lifter....

Anyhow, the engine seems to have survived.

 

[jjvincent]

Re: Timing Belt alligment (GoFaster\'s Replacement Method)

Some people use the mark and pray method and it works. It doesn’t really save any time using this method. Even if you worked slowly, it probably would only tack on an extra 20 minutes but probably not. Since installing the belt is much easier with the cam pulley off, I look at it as no increase in time. With the locking pin on the A4 engines, it is actually easier yet. The price of the plate isn’t that much either. With the tools readily available and at a cheap price, it makes no sense not to use them.

I changed many belts on the old IDI engines. If you used the mark and pray method and had the cam off one tooth, the valve would hit the piston. I’ve seen many repair shops try that method and come up on the loosing end of that one.

bbridgerb; If by some chance you could not get a cam locking plate and really needed to get the car going, it would not be that difficult. Since you marked the pulleys before you took the belt off, just turn the engine over by hand until you are on TDC. If the marks on the cam and pump are off by 180 degrees, then turn the engine over another 360 degrees. Now check both marks, they should be close. You should be able to tell if they are off by one tooth. If they are, you need to correct it and then repeat the previous steps again. (Look at all the extra time that takes)

I assume that you marked the pulleys with the engine on TDC. If you just marked the pulleys wherever the engine stopped, then shame on you. You know better. If you overlooked something like that, I would suggest that you get the car towed in to a VW repair shop or dealer and let them take a look at it. Usually there is something else wrong where you tried to take a shortcut on also. This could lead to a catastrophe down the road and cost you thousands. Is it worth not having that peace of mind?

 

[Boundless]

Re: Timing Belt alligment (GoFaster\'s Replacement Method)

I used the mark method. Don't have a vag-com either. I'll be using it again in 10,000 miles.

I set the engine to TDC. Used an old little wrench to lock the cam. Never took the cam pulley off either. Used a socket to lock the pump. Used the bellhousing & flywheel marks to locate the crank. Marked the crank, pump & cam wheels & belt. Transferred the marks to the new belt.

Put new belt on, lined up the marks, and fired it right up. Never even rotated the engine by hand to check. Checked the timing a couple months and few thousand miles later, right on.

I had the timing checked and set when the OEM belt had about 40,000 miles. So a new belt might result in a wee bit different timing until the belt stretched out. I really don't care, since I doubt a belt stretches that much. The few times I had my timing checked, it was what it was the time before.

You see, the crank, cam & pump pulleys, along with the belt are a gear train. Real, real simple. If you let it be.

I'm not recommending or discouraging one way or the other, but if you know what you are dealing with, it's easy.

 

[RabbitGTI]

Re: Timing Belt alligment (GoFaster\'s Replacement Method)

Before you fire that puppy up pull the valve cover and bellhousing plug and make sure the cam and flywheel are at TDC. Only takes a few minutes to check those things. There are photos in the FAQ that explain it. If those are OK, you won't hurt the engine trying to start it, but if the inj pump is a tooth off I don't believe it will start. The little hole in the inj pump sprocket should face forward and be directly over the hole in the bracket when cam and flywheel are at TDC. You can use a small mirror and flashlight to check if the inj pump sprocket is aligned with the hole. The cam lobes on #1 should point up with the #1 piston at TDC. The notch in the driver side end of the cam should be parallel with the surface of the head.

[ January 21, 2003, 09:45: Message edited by: RabbitGTI ]

 

[Boundless]

Re: Timing Belt alligment (GoFaster\'s Replacement Method)

I locked the cam with that little old wrench that happened to fit perfectly in the slot at the end of the cam, with the valve cover off.

[ January 21, 2003, 13:10: Message edited by: Boundless ]

 

[Lug_Nut]

Re: Timing Belt alligment (GoFaster\'s Replacement Method)

If I had a free set of cam tools, I'd have used them. Now that I've done it without, I don't want them.

 

[christi]

Re: Timing Belt alligment (GoFaster\'s Replacement Method)

I think that after my experience I would say that after doing a mark and pray method you would want to set the crank to TDC and verify that the cam is at TDC too before starting it up.

Just because you can turn it over by hand doesn't mean that you won't get valve strikes once the hydraulic lifters have pumped up. As oil isn't too compressible this would not be good.