Alright my friend has a 1993 pickup with the above engine. Him and his other buddy decided to change the timing belt along with the water pump and other misc stuff. They ended up taking the timing belt off without setting the ENGINE to TDC. They ask me for advice and I have no experience with this engine or truck and I am definetly not a great mechanic.

What would be the next step? We tried to line the timing belt up with the marks on the crank shaft and the cam shafts but they dont seem to line up right.

Read the FSM that is posted at the top of this page. It is for a 93. Here is the link.

http://personal.utulsa.edu/~nathan-buchanan/93fsm/

Engine needs to be set to TDC, on compression stroke. Remove all the spark plugs. Find #1 cylinder. If your standing in front of the engine, its the cylinder closest to the front of the engine, passenger side. LOOSELY thread a spark plug in the #1 cylinder, only one or 2 turns. Turn the crank clockwise untill you hear a hissing noise (NOT a sucking noise) Take the spark plug out. Stick a straw or something in the #1 cylinder and turn the crank. Watch the straw-it will go up, and then begin to go back down. Back up the crank until it starts to go back up. Look at your timing marks on the timing belt cover and set the mark on the crank to the 0 mark on the cover. Thats TDC.

Now align the cams by lining up the marks on the cam and the marks on the back timing cover.

Install the belt, and tensioner as noted in the manual.

Turn the crank over 2 full revolutions, and make sure your timing marks on the crank AND cams still line up.

Similar question asked in the T100 section;

linky for pic <img src="/forums/images/graemlins/kewl.gif" alt="" />

Easy- put the crank at zero and the cam sprocket marks pointing straight up. Done!

(AdamF, you make it sound waaaaay more complicated than it is!)

Erik, it sounds like they messed up the cam/crank alignment when they had the belt off. Therefore, they could be 180 off on the crank (intake stroke) and still align the marks up. The only way to make sure its at TDC on the compression stroke is to do what I explained. Otherwise, it will be 180 out and backfire through the intake when you try to start it, and could cause an explosion in the intake manifold and cause some damage.

<img src="/forums/images/graemlins/lol.gif" alt="" />

If the cam sprocket marks are pointing straight up when the crank is at zero, then cylinder 1 IS at TDC on the compression stroke. End of story. Not 180 out, etc. Put the belt on at that point and you are good to go. Turn the crank twice to make sure its still aligned afterwards, but that is all there is to it.



For the crank to be 180 out from the cams, the cam marks would be pointing left or right (90 or 270) when the crank is at zero. Then the crank would be pointing 180 from zero when the cam marks were straight up or down.

If the cam marks were pointing down (180) when the crank was at zero, then all that means is you are at TDC of the exhaust stroke. It is still "aligned" there, you are just on the wrong stroke. Turn the crank one more turn and then everything will be lined up (cams up, crank zero). <img src="/forums/images/graemlins/smile.gif" alt="" />


The only time you would need to listen for the "hiss" as you described to try to find TDC compression is if you can't see the cam marks (timing cover is on, etc.) to see whether they are pointing up or down, like if you are trying to align the distributor or something. And for those of us without distributors (3.4L), we don't ever have to worry about that... <img src="/forums/images/graemlins/notooth.gif" alt="" />

When you are installing a timing chain/belt, you can always see where the cam is pointing, and the cam is what determines which stroke you are on, so point it up and you are good to go.