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Timing Belt Broke - what to do?

Old 03-31-2014, 09:40 PM
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Default Timing Belt Broke - what to do?

My timing belt broke yesterday on my 2004 Elantra while I was going 65mph. No noise, car just shut off. I have 152k mile on the car. I tried several things today and want to post my results to see what advice i can get.



Today I replaced the timing belt, following a YouTube video. Never done it before, but i lined the camshaft/crankshaft marks up like the video said to do. In the video the guy was just replacing a belt, but mine broke..so i ended up having to separately turn the top and bottom gear to get the marks lined up, then I put the timing belt on. I think i did it right. The car started up after that but sounded horrible and shut off on its own. I then tested the compression of each cylinder. These are the readings I got: 155, 140, 150, and 0. So then as another test, I removed the fuel injector plug to the cylinder that read 0 compression, and started the car up again. it ran better, but was still really rough and sounded bad and felt like it was going to cut off.



I'm looking for advice on what to do next. I have no idea how to inspect the valves or open the head and whatnot. I did see that I can get a used cylinder head on ebay for about $300 after shipping. Is this something I should look into? Or could there be more damage beyond just the cylinder head? Or based off my description would it be better to try and repair what i've got?



One thing to note - I figured i might have valve damage and what not so I didnt fully replace everything I took off when i was putting the new timing belt on. I left the alternator, water pump, power steering, and AC pulleys disconnected. I figured running the car for 10 seconds wouldnt hurt anything. Does anyone know if this could affect my results in any way? I'm pretty sure i have some damage given that I have 0 compression on one of the cylinders...but just want to make sure leaving all that stuff disconnected wouldnt cause issues or skewed results. I know I shouldnt run the car for long w/o the water pump running, but i just wanted to see if it would even start with the new timing belt on.



What should my next steps be? I'd really like to keep the car, but dont want to spend a fortune on it.
Old 03-31-2014, 11:07 PM
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Having the auxiliaries disconnected will not affect the running.

Your pistons will most likely be damaged also as that's what hit the valves. Cheapest option to source a second hand engine. Or if you want to add power etc strip down and do a full rebuild head porting, pistons valves etc.
Old 04-01-2014, 04:13 AM
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Talking about adding power is useless advice. Also, the pistons and valves can hit and not damage the pistons; only bending the valves.



Check the timing again, you can be slightly off, the car will start, but run like crap. If you do have bent valves, its not the end of the world. You can remove the head have it rebuilt or replace it. You did a timing belt job so you seem mechanically incline enough to remove a head. EBay is cool but If you have a local junkyard you can get a head for half the price and no wait if you're willing to pull it yourself.
Old 04-01-2014, 05:12 AM
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Having 0psi in a cylinder is bad news and pretty much guarenteed valve/piston failure



I wouldn't be surprised if you damaged a piston or 2 aswell as bent some valves



Gonna have pull the head off to see the extent of the damage and go from there. Hopefully you got lucky and just bent a couple valves.
Old 04-01-2014, 07:33 AM
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To the response that my timing might be slightly off: I'm pretty sure it is on. I have the cam and crank gears lined up exactly like I saw to do it on several videos and websites. Which is, for the top one look through the little hole and have the red mark centered in the hole when looking straight on. For the bottom, line up the white paint on the gear with the marker on the engine block. As seen here: http://www.elantraxd.com/forums/show...ng-belt-change

Is there any other way besides using those 2 guides to know if the timing is off?



What is the % chance you would say that I have damaged pistons? I'm thinking about taking the head off and taking it to a local machine shop, they said it would be maybe $200-$500 depending on the extent and how many valves need replaced. But I dont know what I'm looking at to know if I have piston damage. Should it be obvious to me, or would a pro need to make that call?
Old 04-01-2014, 12:40 PM
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Either get a new head and hope that the pistons are fine or get a new engine. I've been there...twice...



I suggest a junkyard engine.
Old 04-01-2014, 08:30 PM
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I've seen valves bent so slightly that you had to look close to see which were damaged and which were not, with zero visible piston damage. I've seen valves bent so bad they hammered and dented the piston crown with the EDGE of the valve. I've seen valves BREAK and destroy the combustion chamber and score the cylinder before putting a hole in the piston and heading on down to the sump. You have to pull the head to see which is the case with your engine. Depending on how reluctant you are to open the top end, it may be worth it to get a junkyard engine and just slap the whole thing in there and trust the warranty you got from the scrap yard.



If you are lucky, you need to replace one $20 valve and install $100 worth of gaskets and coolant, plus an oil change. If not . . . well, I'd say to just pull the head and see what you've got first.
Old 04-02-2014, 01:47 PM
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Search for the thread I started on this exact same issue about a year ago. My timing belt blew while driving. I didn't realize it so while I was being towed I tried popping the clutch to start the engine a couple times even (probably causing more damage). When I tore it apart it was just one dead cylinder (0 psi compression) with a couple bent valves. There was a tiny knick in the one piston that had bent valves. I just sanded it down smooth and replaced the entire head with a junkyard head. I've been good for probably 10k+ miles now (knock on wood).



If I were you I'd just pull the head to see the extent of the damage. It's not too hard, only takes a few hours to pull everything apart for the layman. If it's just a minor blemish, I say just replace the head or have it rebuilt with new valves and sound down the blemish smooth again. Should only be a few hundred dollars in parts max.
Old 04-02-2014, 06:52 PM
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So good news...I think. I got the head off tonight. Here are some pictures of the piston and the valves, for the cylinder where I had 0 compression. May be a little hard to see, but theres 2 little dings on the piston, and on the valves i didnt see any dings but on the edge of the metal frame next to where the valve comes out, there is a little ding. Not sure how bad that is...will take it to a machine shop tomorrow and see what they say. But I'm hoping for the best. Seems like it could have been a lot worse.



Speaking of the head, should I take the cams off or leave them on when i take to the machine shop? Again, I'm a newbie, so i dont want to be the one taking them off unless I know its easy to get them back on right without any special tools or without risking messing anything up. I've taken a lot of risk us to this point since I'm new to this, but figured its an old car, if i screw up an old dead car, i'm not losing much! But i'd absolutely love to revive it!
Attached Images
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piston.jpg (119.5 KB, 14 views)
File Type: jpg
valves.jpg (102.0 KB, 14 views)
Old 04-02-2014, 08:31 PM
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You have to have the cam out to work on the valve train. If you are taking it to a machine shop, call and ask what they want. They may say to bring it in whole and they'll be happy to charge you more to break it down for you . . . but then YOU aren't the one breaking camshafts!


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