new to the forum,good evening.was driving home a couple night ago and the truck turned off on me.wont start.i took the head cover off the head and started cranking the motor,the chain doesnt move but is not broken,notice the twin cams arent moving eather.to my belief the bottom sproket is broken or the teaths are of.my only concern is.is it worth opening it up to fix the problem,because maybe the pistons hit the valves,or am i better of just buying a used motor.u r opinon is appreciated thank u god bless thank u tx -forgot to mention the starter does turn the motor around but the timing chain is not moving or the cams thanxz.
Modified by gilltexas at 6:19 PM 12/21/2007
help, 2000 frontier 4 cyl, timing chain is not moving the upper twin cams
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NM50
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Re: help, 2000 frontier 4 cyl, timing chain is not moving ... (gilltexas)
Try turning the crank backwards a few degrees and see if the cams move.Ihave never seen a KA24DE do this.I am curious about this.
Re: help, 2000 frontier 4 cyl, timing chain is not moving ... (NM50)
You never said if the starter was able to turn anything at all.
If the you hit the key and nothing moves (including the starter gear) chances are a piston did hit some valves. Do as NM50 suggested and manually rotate the engine backwards using a wrench or rachet on the crank pulley. If you can turn it backwards and the cams turn your chains and sprockets are probably ok. Now rotate it clockwise (MANUALLY) and see if it stops.
If it stops, you probably did bend something. Either a valve (or a couple of valves) or worst case is you have a bent connecting rod. I have seen this myself but only on engines that swallow water and hydrolock. This could happen if a chain jumped a tooth on one of the sprockets.
If you bent a valve you can get the head repaired and be back in the road within a week. If you bent a connecting rod it will be bit longer. A new / used motor is your choice but you could be hard pressed finding one.
If the you hit the key and nothing moves (including the starter gear) chances are a piston did hit some valves. Do as NM50 suggested and manually rotate the engine backwards using a wrench or rachet on the crank pulley. If you can turn it backwards and the cams turn your chains and sprockets are probably ok. Now rotate it clockwise (MANUALLY) and see if it stops.
If it stops, you probably did bend something. Either a valve (or a couple of valves) or worst case is you have a bent connecting rod. I have seen this myself but only on engines that swallow water and hydrolock. This could happen if a chain jumped a tooth on one of the sprockets.
If you bent a valve you can get the head repaired and be back in the road within a week. If you bent a connecting rod it will be bit longer. A new / used motor is your choice but you could be hard pressed finding one.
Re: help, 2000 frontier 4 cyl, timing chain is not moving ... (Big-Bird)
sorry forgot to mention,the starter does turn,the motor does turn exept the timing chain and the cams are stopped whan u turn the starter.feel free to call me at 832-434-688
Re: help, 2000 frontier 4 cyl, timing chain is not moving ... (NM50)
hi and thank u for u r intrest in u r opinion.the starter does turn the motor around but the chain is not moving or the cams
Re: help, 2000 frontier 4 cyl, timing chain is not moving ... (gilltexas)
Just a thought, but are you aware that the KA24DE has 2 chains? (You probably did see this when you pulled the valve cover). One runs from the crank shaft up to an intermediate gear. Then a second shorter chain connects a smaller sprocket to the 2 cam shaft gears. Check out the image I attached.
Put a wrench/ratchet on the crank pulley and turn the engine by hand. See if the chains and cams move. If they still don't move then there is a very good chance you have broken the main timing chain. Or at the very least the chain has jumped off the lower sprocket. If a chain guide broke or the oil pressure tension guide (item 17 on the image) failed the chain could easily jump off. But these are only theories. I have never seen or heard of a KA24DE doing either.
The only other thing I can think of is one of the keyways that aligns a sprocket with a turning shaft broke or sheared off. This is even harder to beleive because that little engine can't generate enough torque to do that unless a keyway was already damaged.
I am confident the main chain will be the source of your problem.
Put a wrench/ratchet on the crank pulley and turn the engine by hand. See if the chains and cams move. If they still don't move then there is a very good chance you have broken the main timing chain. Or at the very least the chain has jumped off the lower sprocket. If a chain guide broke or the oil pressure tension guide (item 17 on the image) failed the chain could easily jump off. But these are only theories. I have never seen or heard of a KA24DE doing either.
The only other thing I can think of is one of the keyways that aligns a sprocket with a turning shaft broke or sheared off. This is even harder to beleive because that little engine can't generate enough torque to do that unless a keyway was already damaged.
I am confident the main chain will be the source of your problem.