your opinion?

[HeWhoKillz]

This is a video i made for my sentra which I think the engine is locked. Any ideas? Sorry about the quality.

http://www.youtube.com/watch?v=oqW5-BE6llc

I took the starter off and found it to be ok. I tried to turn the engine by the fly wheel by hand(obvious fail) and with items such as a screw driver, crow bar, but no luck. Someone mentioned it might be the timing belt. However, correct me if im wrong but I dont think the timing belt could have anything to do with the engine missing out. The popping I heard I believe it to have been rod knock. Is there any other tests I could do? I thought of taking the oil pan off and seeing if there wasn't any obvious damage from the bottom.

[shorod]

Did you have the spark plugs installed when trying to turn the engine over? If not, try that and see how well the engine can be turned over by hand/long bar.

-Rod

[HeWhoKillz]

Originally Posted by shorod

Did you have the spark plugs installed when trying to turn the engine over? If not, try that and see how well the engine can be turned over by hand/long bar.

-Rod

The spark plugs were in it. i changed them about a year ago plugs, wires, etc.

[curtis73]

Socket on the crank bolt, try to turn clockwise. If it won't go, try going counterclockwise. If it moves, go back clockwise and see if it clunks to a stop. If so, its probably a valve timing issue. If it won't turn either way, its probably seized.

Depending on where it is in the cycles, it will have varying degrees of difficulty, but you'll be able to tell the difference between the springy effort as you overcome compression versus the obvious clunk of hitting a valve. You should be able to turn a healthy engine with a 1' breaker bar and a socket with about 50 lbs of pressure. If you're getting a hernia or turning the bolt before you turn the crank, something isn't right.

[MagicRat]

Wow, I wish everyone could make such a comprehensive video and history on their problems. It would make advising others super-easy.

Originally Posted by HeWhoKillz

Someone mentioned it might be the timing belt. However, correct me if im wrong but I dont think the timing belt could have anything to do with the engine missing out. The popping I heard I believe it to have been rod knock.

Let me correct you. Most modern engines use an 'interference' design of valve gear. This means that if the timing belt or chain fails, the valves no longer have synchronized movement ("timing") relative to the piston.

A modest drift of valve timing kills power and can cause a popping noise, likely as valves open at the wrong time, allowing combustion chamber gases to burn in the intake manifold.
As the timing drifts more, the pistons will get shoved into the still-open valves, thus locking up the engine.

In your case, probably, as you drove, your timing belt (which drives the camshafts) started to come apart. Probably the 'cogs' on the belt got sheared off, which allowed the cams to turn for a short time, but lose their timing quite quickly, which explains the progressive nature of the failure.

If the belt simply broke suddenly, the engine would not fail over time, but would simply lock up suddenly.

This is a common failure for people who neglect to change their timing belt(s) when required. A good rule of thumb is to change the belt every 50,000 miles, or when the owners manual tells you to.

In your case, expect to have to remove your cylinder head and install a rebuilt one, or a good used one. Your head may be damaged or cracked.

If you are lucky, the rest of your engine will be okay. However, if the pistons are gouged or have holes (your rods may be bent, too) the engine needs rebuilding or replacing.

[HeWhoKillz]

Originally Posted by MagicRat

Wow, I wish everyone could make such a comprehensive video and history on their problems. It would make advising others super-easy.



Let me correct you. Most modern engines use an 'interference' design of valve gear. This means that if the timing belt or chain fails, the valves no longer have synchronized movement ("timing") relative to the piston.

A modest drift of valve timing kills power and can cause a popping noise, likely as valves open at the wrong time, allowing combustion chamber gases to burn in the intake manifold.
As the timing drifts more, the pistons will get shoved into the still-open valves, thus locking up the engine.

In your case, probably, as you drove, your timing belt (which drives the camshafts) started to come apart. Probably the 'cogs' on the belt got sheared off, which allowed the cams to turn for a short time, but lose their timing quite quickly, which explains the progressive nature of the failure.

If the belt simply broke suddenly, the engine would not fail over time, but would simply lock up suddenly.

This is a common failure for people who neglect to change their timing belt(s) when required. A good rule of thumb is to change the belt every 50,000 miles, or when the owners manual tells you to.

In your case, expect to have to remove your cylinder head and install a rebuilt one, or a good used one. Your head may be damaged or cracked.

If you are lucky, the rest of your engine will be okay. However, if the pistons are gouged or have holes (your rods may be bent, too) the engine needs rebuilding or replacing.

sorry about the video, it was pretty lame. new video camera, so all i really wanted to do was play with it.
For a about a week the car had a small popping to it. I thought it was the bearings on the axles going out and needing replaced. Can a damaged timing belt last that long without causing any trouble while making the popping? I hadn't considered the timing belt, even though it still sounded like rod knock. However, i could and probably am wrong. It almost sounds like it would be easier to just swap out the engine.

[vgames33]

If it matters, that GA16DE has a chain, not a belt. Perhaps he was hearing the chain rattle due to a faulty tensioner?

[HeWhoKillz]

Originally Posted by vgames33

If it matters, that GA16DE has a chain, not a belt. Perhaps he was hearing the chain rattle due to a faulty tensioner?

yeah...chain...that actually makes more sense thinking about it as a chain rather than a belt cause i couldn't see how a belt would make a popping noise. pprehaps i haould get the cover off and take a look and prehaps post another pathetic yet personally entertaining video of it or prehaps i can get down to the chain itself but it would take a little time. Can you still turn the engine with a breaker bar or anything with a broken timing chain? cause it sure won't budge.

[vgames33]

If it won't budge, its probably locked up. I would think it would move at least a little if the chain was broken.

One of my teachers in school told us a story about another tech that he worked with a few years back. He thought the engine was locked up on a chevy truck, but it turned out to be the alternator bearings were locked instead and the belt was keeping the engine from moving. He didn't realize until he had stripped the engine down and was trying to get at the torque converter bolts and the engine spun freely. Just for the hell of it, try taking the accessory belts off and see if it will spin then. Maybe you'll get lucky.

Have you looked at the oil? Drain it out and see if its full of metal shavings.

[oldblu65]

Shorod asked if your plugs were in place when you tried to turn the engine by hand ? Your answer was yes . Have you tried removing the plugs then trying to turn the engine ? The engine would be very difficult to turn , by hand , if the plugs are installed .

[HeWhoKillz]

i have the plugs out along with the belts. I have taken the cover off the top and the one on the side. The first chain looks ok and no teeth or gears seem to be messed up I can't see the second chain though. However, I was able to turn a little bit. See for yourself. In the video I didn't have much place to sit it but the side cover for the timing chain is off and I'm turning the engine by the cam shaft sprocket.

http://www.youtube.com/watch?v=IYpaVgVey8U

[curtis73]

Certainly seems like something is messed up internally... rusted bores, spun bearing, something. With the plugs out, that should be steady, easy movement. On the crankshaft, it should take about 20 lb-ft of torque to move the crank, and it should be the same effort the whole way around with minor differences every 90-ish degrees for a valve opening event.

Looks like its time for a teardown.

Oh.... and use a wrench instead of vise-grips :O

[Moppie]

I have, to say, having the videos is really cool.


Unforuntatly I would put money on it being wrecked. I wonder if a rod has snapped and that is what is stopping it from turning more than what looks like about a 1/4 turn.

[HeWhoKillz]

Originally Posted by curtis73

Certainly seems like something is messed up internally... rusted bores, spun bearing, something. With the plugs out, that should be steady, easy movement. On the crankshaft, it should take about 20 lb-ft of torque to move the crank, and it should be the same effort the whole way around with minor differences every 90-ish degrees for a valve opening event.

Looks like its time for a teardown.

Oh.... and use a wrench instead of vise-grips :O

I don't have a wrench that fits it. I think its like 1/2 or something.

[HeWhoKillz]

Originally Posted by Moppie

I have, to say, having the videos is really cool.


Unforuntatly I would put money on it being wrecked. I wonder if a rod has snapped and that is what is stopping it from turning more than what looks like about a 1/4 turn.

I am this far so I might as well get the cylinder head off. I have to find something to fit the crankshaft pulley cause thats one of the items that comes off when getting the timing chain off which is part of getting the cylinder head off. I want to see what happened. At this rate, if i have to get the engine out, ill only have to get the bottom of the engine out ha. And I didn't think the videos were that great. Dumb question but ill ask. The part where the intake connected to, or sat on top of, thats also part of the cylinder head right? Or is that another part that needs separated. Other than that, its just the timing chain I have to get off. I'm guessing Ill have to get a bigger wrench to fit the crankshaft pulley. Unless I try the vise grips on it. I do thank everyone for helping me. When and if I get the cylinder head off, Ill post another video of it.