Need help ASAP - How to set timing belt

[jonlong]

Hey guys, I recently changed the valve stem seals on my P5 and now need to reset my timing belt. There is a marker on the crankshaft pulley, as well as a guide that is marked with a 10 and a T. It looks like if I'm aligned with the 10, then I'd be at 10 degrees off from top dead center. I currently have my cams aligned (with the I and E facing each other) and the crankshaft lined up at TDC. My car is NOT starting this way. Do I need to line up the crankshaft with that 10 marking?

Any help would be appreciated. Thanks!

 

[Tiajaunatoad]

No, you should have the marks on the intake and and exhaust cams facing each other with the crankshaft TDC on the compression stroke. I think there is a how to with pics that will show how to line everything up. It's been awhile since I've done a t-belt on one of the engines but as I recall it's easy to get one of the cams off a tooth. If that's the case, it's possible you may have flooded the engine hince the no start. Hope this helps.

 

[jonlong]

Thanks for the reply. Why would there be a 10 degree marker, then? Some reading online seems to suggest that many engines are set with the timing 10 degrees before TDC. I don't think I flooded the engine, since I've had the spark plugs out for a while before I tried to start it.

 

[Tiajaunatoad]

The 10 deg mark is used for checking the ignition timing with the engine running using a timing light. When you replace the belt, you are basically setting the base engine timing. The ECM controls timing by controlling when the spark plugs fire so when the engine is running at idle it fires the #1 plug at 10deg before TDC. When you use a timing light you see the mark on the crank pulley line up with the 10deg mark on the cover. The T mark on the cover refers to TDC (top dead center).

 

[Tiajaunatoad]

I didn't mention it earlier, but the #1 piston should be at TDC on the compression stroke while installing the t-belt. With the lower cover on and the crank pulley correctly installed this shouldn't be a problem. When you first installed the belt, did you rotate the crank twice to see if the marks lined back up?

 

[jonlong]

Tiajuanatoad - Sent you a PM

 

[mutiny5050]

I didn't mention it earlier, but the #1 piston should be at TDC on the compression stroke while installing the t-belt. With the lower cover on and the crank pulley correctly installed this shouldn't be a problem. When you first installed the belt, did you rotate the crank twice to see if the marks lined back up?

How do you know when you are on the compression stroke?

 

[Madzman]

How do you know when you are on the compression stroke?

Can anyone answer this?

 

[P-Funk!]

As you rotate the engine you see th intake valve open. Rotate some more and no valves open (compression stroke). Keep rotating and then an exhaust valve opens. As you rotate enough you will see what i mean.

You can stick a soft phenolic rod in the cylinder to see the piston movement as well.

 

[Madzman]

Finding TDC on the compression stroke is guaranteed if the crank mark is lined up and the "I" and "E" marks are lined up. Any time those cam marks are lined up, the valves are set at TDC on the compression stroke. When the crank mark is lined up, the #1 piston is at TDC. If you rotate the crank a turn it ends up at the exact same spot. If you rotate the cams, they end up at the exact same spot. You can't have either out by 180 degrees. If the marks are all lined up, you'll always be at TDC on the compression stroke. So line up the marks, put the belt on, and you'll always have done it right.