2.4l dohc timing mark alignment

Question

QUESTION: Roland, I just finished replacing the water pump on my 2002 Caravan, 2.4L DOHC [ thanks to your help :) ]. It seems that I missed the timing belt by one tooth, as it is idling rough. I disassembled everything again and adjusted the exhaust cam sprocket one tooth so that the tooth with the exhaust (rear) timing mark is pointing ? tooth under the intake (forward) cam sprocket. I have a nice picture of the alignment to send to you if you want to see it. My question is, is it the timing MARK which is positioned ? tooth below the intake sprocket tooth, or is it the TOOTH containing the timing mark? Thanks for your time as usual!

ANSWER: Hi Eric, That is a very interesting question! The '02 manual shows the timing mark on the exhaust sproket to be positioned differently, e.g. it is centered on a tooth instead of off-centered as your photo shows. I don't know why that is unless this was an error in the marking of the sprocket when it was made or an error in the drawing. Is the picture taken before you pulled the pin on the tensioner or after and then rotated the crank two full revolutions? Because what you show is like it should look (approxiamtely accept for the above noted discrepency) before pulling the pin. Afterward the marks should be exactly opposite one another. Also, are you aware that the timing mark on the crank sprocket is at the trailing edge of the marked tooth, and that trailing edge is supposed to be aligned to the mark on the oil pump cover for the engine to be at TDC. So it could be that you have it OK, but you don't have the crank at TDC. Roland

---------- FOLLOW-UP ----------

QUESTION: OK, thanks for all your help! So, in the final analysis, if the crankshaft timing mark on the block is aligned with the mark on the crankshaft sprocket (along the trailing edge of the tooth), then the cam sprocket timing marks should be exactly aligned, and not 1/2 tooth off? The picture I took was after 2 full rotations and the tensioner engaged. You are the man!! -Eric

Answer

You have it correct, Eric. What you photo'd is how it should appear before you pull the tensioner pin. Once the tensioner is released it brings the marks into direct opposition at TDC if everything works out. You have to turn it through a couple of rotations just to get the belt set up as it will be. So be sure it looks like your photo (intake sprocket horizontal exhaust 1/2 tooth below), to be at TDC before you start putting the belt on. And put the belt on starting at the crank pulley and go counterclockwise: water pump sprocket, idler pulley, cam and crank sprockets, and finally around the tensioner pulley. Then rotate the exhaust sprocket counter clockwise to take up slack and bring the marks on the sprockets into alignmment. Then pull the pin on the tensioner, then rorate the crank two full turns. Verify that timing marks are aligned at TDC.