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Car Forum / Driving, Maintenance, Tuning / General Car Topics / April 2007Crankshaft & Camshaft Timing Marks, Re-align Camshaft Mark
Hi everyone! This is my first attempt to I installed a new timing belt on my 1989 3.0L Caravan LE. I checked the crankshaft and camshaft marks by rotating the crankshaft 360 degrees the front camshaft mark did not match the outside mark. The front camshaft must have moved while I was installing the belt. So I removed the timing belt and turned the front cam nut (about 10-17 notches) with a wrench, so the mark on the cam would match the outer mark. I reinstall the timing belt again rotated the crankshaft 360 and the cam mark it was still off. The marks on the Crankshaft and rear Camshaft match up ok. How can I adjust the front camshaft so all the marks are aligned? If I rotate the front Camshaft a full 36O will this align the marks? Can you please help me I am really desperate? Thank You! Jim BTW. I found this forum very helpful and enjoy reading all the posts Camshafts turn at one half crankshaft speed . . . the mark moves to the side opposite where it's starts doesn't it? Turn the crank another 360 and see what happens!!!! -- Budd Cochran > Hi everyone! > [quoted text clipped - 17 lines] > > BTW. I found this forum very helpful and enjoy reading all the posts There are four cycles in your engine(4 piston movements), intake(fresh air and fuel in), compression, explosing, clearing(exhaust). One complete revolution on the crank only covers two of these stages, since you only had two piston movements, so you will need to rotate twice on the crank for all four strokes. You'll probly notice where the belt goes over the crankshaft is about halft the size of where the belt goes over the cam shaft, so you can physically see that it will take two crank revolutions for one cam revolution. Hope this helps, tom >Hi everyone! > [quoted text clipped - 17 lines] > >BTW. I found this forum very helpful and enjoy reading all the posts ********************************************************************* http://www.CarFleaMarket.com http://www.VirtualLotteryPool.com http://www.FreelancingProjects.com ********************************************************************* Thanks Guys, for your remarks they are very helpful! I have no problem seeing all the timing marks on the Crank & Cam shafts. But my concern is that I have moved the front Cam (10 to 17 notches) clockwise with the "timing belt off" in order to set the front Cam timing mark, will this cause any problems with the timing on the front cam itself? Can you turn the front cam ccw (10 to 17 notches) back to reposition its timing mark? Or do I have to rotate it 360 cw to set the timing mark. I guess my question should be. Can you relocate the camshafts (CW or CCW) with the "timing belt off" in order reset the timing marks if the cams moved? My present settings with the belt installed are: ... Crankshaft timing mark, ok ... Rear Cam mark timing, ok ... Front Cam mark (10 to 17) notches advanced CW from the timing mark. With the timing belt off can I turn the front cam CCW (10 to 17 notches) to align the timing marks? Or do I just turn the front cam 360 CW to set the timing marks. Wow I think I'm going crazy! But to tell you truth its simply a lack of understanding how all the cams and crankshaft work together :-( Thanks Again! > There are four cycles in your engine(4 piston movements), intake(fresh > air and fuel in), compression, explosing, clearing(exhaust). One [quoted text clipped - 36 lines] > http://www.FreelancingProjects.com > ********************************************************************* [snip] > With the timing belt off can I turn the front cam CCW (10 to 17 notches) to > align the timing marks? Or do I just turn the front cam 360 CW to set the > timing marks. Yes, turn the front cam any which way you see fit to line up the marks. The 3.0 is a non-interference motor, so there is NO risk of any damage by moving the cams in any direction to re-align them. Clockwise is always best because it eliminates any risk of loosening a sprocket retaining bolt. > Wow I think I'm going crazy! > > But to tell you truth its simply a lack of understanding how all the cams > and crankshaft work together :-( The cam sprockets are twice the diameter of the crank sprocket, they (cams) turn half the speed of the crankshaft. 360* of crankshaft rotation = 180* camshaft rotation. 720* of crankshaft rotation = 360* camshaft rotation. Set the crank sprocket, set the cam sprockets, install the T-belt (keeping it taught between sprockets) starting at the crank sprocket and working your way counter clockwise towards the front cam, then the water pump, then the rear cam, behind the tensioner, release the tensioner so it tensions against the belt, lock the tensioner down, rotate the crankshaft two full turns (720*) and recheck the timing marks. The small spring steel binder clips sold in office supply stores can be used to hold the T-belt in place once it's properly positioned on the cam sprockets, be sure to remove them before you turn the engine and check your work... THANKS! I Neil I got it :-) with your help :-) I re-aligned all the timing marks on the cam and rotated the crankshaft 720 and yes they were right on. I did notice that the tensioner slides up and down but not always keeping the timing belt between the water pump and the rear cam tight, but as I slowly rotate more it would tighten up. It seems as I rotate the crankshaft it would go through different cycles it would be harder then turn easier. Is this normal? > [snip] > [quoted text clipped - 30 lines] > properly positioned on the cam sprockets, be sure to remove > them before you turn the engine and check your work... > THANKS! > [quoted text clipped - 6 lines] > I rotate the crankshaft it would go through different cycles it would be > harder then turn easier. Is this normal? Good to hear... The tensioner should not move, it gets bolted down tight once it has sprung back against the belt. IOWs, the T-belt tensioner does NOT act like a spring loaded tensioner would on a serpentine belt, the attached spring is there to set the tension but then the whole shee-bang gets tightened down in place. On the harder-easier thing, sounds like you are rotating the engine by hand and experiencing the normal resistance of cylinders coming up on their compression stroke. Mr. Nelson, sound like a very knowledgeable person or great mechanic, Have a problem with Honda that wont start, was told to replace the crank shaft, would you happen to know anything about these, and would you know if you are getting the crank, would it be possible to get another solution in order to start the car, since if its broken I dont think, you would get any try at starting the car. Sounds like if there is no spark to get the final start Any idea as to what the problem is???? Ralph >[snip] > [quoted text clipped - 30 lines] >properly positioned on the cam sprockets, be sure to remove >them before you turn the engine and check your work... |
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