Bent Valve?
#1
Bent Valve?
Well driving around today and all of a sudden my 96 with a 2.5 power goes away no ticking or anything just complete loss of power, I limped it off the highway, got it to a Autozone and put a scan tool on it and it came up with P0300 and P0301 Misfire codes, ok I changed the plugs in the parking lot, didn't know the REAL damage til it didn't work and got it back to the garage (mind the less 25 miles away), it was running on 3 cylinders. Did a compression test on it and this is what it showed Cylinder 1 - 0 lbs (yes right number), Cylinder 2 - 125 lbs, Cylinder 3 - 145 lbs, and Cylinder 4 - 150 lbs, so I'm thinking a couple of the valves are bent, I was wondering what ya'll might think.
#3
for a valve to bend either the belt would have to break (and i think that they are interfence but im not sure either) or youd have to have some other major failure. plus a bent valve or any valve train issue would most likely give you a ticking sound. i would sespect the head gasket as well. could have cracked the head maybe? i don't think the 2.5 was bad for that though. only one way to find out and thats to yank the head see what you've got.
#4
Yea I'm going to yank the head tomorrow, found a used head at a Junk Yard (only one within 100 miles) for $125 so hoping they still have it, if they do fly up go get it fly back to the garage and rip off the head and pull a all nighter if I have to, to put it in. I did all the testing I had to today, compression test, checked and strained the oil (thank god no metal fragments) I had done a oil change about 1000 miles before and it was clean as a whistle, new plugs. I'm more or less praying they still have the head at the junk yard tomorrow, gonna call them before I head up there, if not I know of another motor for $300 thats 200 miles away and it's unknown how well it runs.
#5
unless you have super high mileage (over 200,000) and your timing chain stretched, that's the only way to bend valves. The AMC 2.5 is a bullet proof engine. If the valves are bent, it wouldn't idle. Check your valve springs, make sure they didn't break and worse case, check your piston, make sure you don't have a hole in it.
#6
Well I yanked off the head, and to my surprise the one of the valves was bent alittle, I didn't take the picture of the underside of the head (letting it drain out a bit) but I poped a couple shots of the motor. The timing is on and the chain isn't stretched. I just replaced the chain when I rebuilt the lower end (only reason I didn't touch the top end was because it was fine and was all tight), and rechecked it today to make sure and she was all fine. But I did notice something that you might find interesting. In the first picture we all know what it's like working on a motor only the Valve Cover is shown removed, but in the second picture look at the piston, I got lucky the valve gave it a kiss, but it was good enough to bend one of the valves. But I went and got a rental today, I HATE the car but it's the only one they had and it was a 2010 Mini Cooper I like to call it a CLOWN CAR lol
Picture one is at http://i1138.photobucket.com/albums/...330_212346.jpg
Picture two is at http://i1138.photobucket.com/albums/...330_221039.jpg
Picture one is at http://i1138.photobucket.com/albums/...330_212346.jpg
Picture two is at http://i1138.photobucket.com/albums/...330_221039.jpg
#7
if you know of a machine shop near you, take the head there and have it pressure tested and flow tested and make sure that you don't have any other problems. Also have them check your rocker arm pivots make sure they aren't binding. Last thing to check would be your lash adjustment on the rockers, hopefully you don't have too much lash which would cause bent valves also.
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#8
Well I got it up and running, took a video of the first start. I didn't realize one of the vacuum hoses wasn't fully connected til a couple minutes later. But the link is here for it, let me know what ya'll think. I do have to warn you, use of the f bomb is used alittle bit, smoking and loud exhaust. No cigrits were harmed in the making of this video.
http://s1138.photobucket.com/albums/...401_003509.mp4
http://s1138.photobucket.com/albums/...401_003509.mp4