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Driving along and the car suddenly died. It made a clicking noise when it died. I tried to start it up but heard a rattle coming from under the timing cover. Had the car towed home and when I popped off the valve cover, timing belt cover I saw the cam gear was loose and I can turn the bolt with my finger. I also noticed a bunch of metal shavings and the cam journal wear the cam gear locking pin inserts is damaged.
So.... I am guessing the valves hit the pistons? Should I do a leak down with the cam out? What are the odds of the valves being damaged? Is the cam repairable (welding?) or should I opt for a new cam (or used in good shape).
What caused this? I am guessing I did not torque down the bolt tight enough or did not put lock tite on it? I did change the head gasket 5K miles ago and remember being worried about over torquing this bolt from all the threads I read on here from guys that snapped it.
Re: Engine Died, cam gear came loose, bent valves?
Originally Posted by dgreen78
remember being worried about over torquing this bolt from all the threads I read on here from guys that snapped it.
Can you reference those threads? 27 ft-lbs for the cam shaft bolt.
If you wore the cam shaft key and the pulley was loose from the slot then who knows what kind of damage you did. I'm sure valves being bent are in the equation.
Re: Engine Died, cam gear came loose, bent valves?
Your pretty much into it for a head rebuild and a bottom inspection. Mostly just pistons on the bottom to make sure everything is okay. The valves however will be bent 90% of the time they are. I'd replace the cam, you don't want this happening again if you weld the cam back together it may. I'd replace the pulley too it may have been the culprit that destroyed the cam.
Re: Engine Died, cam gear came loose, bent valves?
i would say there is pretty much a 100% chance of at least a few valves damaged....you are going to have to pull the head to inspect at least....
the million dollar question is.....did you use a torque wrench on the bolt?
if not, why not???
im assuming the answer is no, because i cant see how this could happen if the bolt was tightened to spec
i used a bit of lock tite on mine and torqued to spec....
in my opinion the cam and crank bolts are a poor design....i think it would be better if they built the cam and crank with a large round flange on the end of them, then used 4 bolts to fasten the crank pulley to the crank, and 4 bolts to fasten the cam sprocket to the cam....kind of like putting a wheel onto the car
Re: Engine Died, cam gear came loose, bent valves?
Originally Posted by mikey1
i would say there is pretty much a 100% chance of at least a few valves damaged....you are going to have to pull the head to inspect at least....
the million dollar question is.....did you use a torque wrench on the bolt?
if not, why not???
im assuming the answer is no, because i cant see how this could happen if the bolt was tightened to spec
i used a bit of lock tite on mine and torqued to spec....
in my opinion the cam and crank bolts are a poor design....i think it would be better if they built the cam and crank with a large round flange on the end of them, then used 4 bolts to fasten the crank pulley to the crank, and 4 bolts to fasten the cam sprocket to the cam....kind of like putting a wheel onto the car
No I did not use a torque wrench, my mistake.
Couldnt I just put some air into the cylinders with the cam out to see if the valves are open? Wouldnt that be easier than pulling the head?
Re: Engine Died, cam gear came loose, bent valves?
Originally Posted by dgreen78
No I did not use a torque wrench, my mistake.
Couldnt I just put some air into the cylinders with the cam out to see if the valves are open? Wouldnt that be easier than pulling the head?
yes you can try that first....i believe the cylinders should hold about 170psi but im not positive on that exact number....but your odds on none of the valves having any damage is extremely slim to none
Re: Engine Died, cam gear came loose, bent valves?
You have the cam and rockers out of the way.
Lay a straightedge across each bank of valves. See if any are stuck down further than the rest. (All should be nearly the same height, any stuck down significantly are bent. When there are any bent, it is usually really obvious when the straightedge is laying on top of them.)
If the cam and rockers were still in place, I would have looked for some seriously excessive clearances.
Couldnt I just put some air into the cylinders with the cam out to see if the valves are open? Wouldnt that be easier than pulling the head?
YES.
i believe the cylinders should hold about 170psi
Mikey, are you thinking of a compression test, or are you thinking of the shop air pressure I use to check head gasket leaks?
You can't do an accurate compression test, because there aren't any valves that can open (except the bent ones).
A cylinder leakdown tester usually uses regulated low pressure.....but right now he can apply direct pressure from whatever compressor is handy since all we care about is bent valves at the moment. He will have to listen for leaks though, since there is no gauge set to watch.
The crank may spin, so be ready for it.
Re: Engine Died, cam gear came loose, bent valves?
Originally Posted by ezone
You have the cam and rockers out of the way.
Lay a straightedge across each bank of valves. See if any are stuck down further than the rest. (All should be nearly the same height, any stuck down significantly are bent. When there are any bent, it is usually really obvious when the straightedge is laying on top of them.)
If the cam and rockers were still in place, I would have looked for some seriously excessive clearances.
YES.
Mikey, are you thinking of a compression test, or are you thinking of the shop air pressure I use to check head gasket leaks?
You can't do an accurate compression test, because there aren't any valves that can open (except the bent ones).
A cylinder leakdown tester usually uses regulated low pressure.....but right now he can apply direct pressure from whatever compressor is handy since all we care about is bent valves at the moment. He will have to listen for leaks though, since there is no gauge set to watch.
The crank may spin, so be ready for it.
Didnt even think about the straight edge idea, thanks! Ill take a peak this week at it and also use a leak down to see if air gushes out the tail pipe or TB. FINGERS CROSSED! That was a bitch doing the head gasket in this car! I dont want to pull it again
What does it cost roughly to repair a bent valve? I am thinking it might be cheaper to grab one used from an auto wrecker. I found a few on car-part.com for $100.
Re: Engine Died, cam gear came loose, bent valves?
Originally Posted by dgreen78
Didnt even think about the straight edge idea, thanks! Ill take a peak this week at it and also use a leak down to see if air gushes out the tail pipe or TB. FINGERS CROSSED! That was a bitch doing the head gasket in this car! I dont want to pull it again
What does it cost roughly to repair a bent valve? I am thinking it might be cheaper to grab one used from an auto wrecker. I found a few on car-part.com for $100.
i cant remember what thread it was in, or who it was....but there was somebody on here recently who purchased a completely refurbished head for about $300 bucks from a place in florida....that might be cheaper and easier than having any valves replaced
Re: Engine Died, cam gear came loose, bent valves?
Originally Posted by mikey1
i cant remember what thread it was in, or who it was....but there was somebody on here recently who purchased a completely refurbished head for about $300 bucks from a place in florida....that might be cheaper and easier than having any valves replaced
If valve(s) are bent, someone is gonna have to pull the head no matter what.
Re: Engine Died, cam gear came loose, bent valves?
Hmm... It's the same as the timing belt breaking. The bottom of the engine keeps spinning and the top stops... It makes very little sense, the direction the cam gear spins in it should actually tighten not loosen over time. So, this was probably caused by the cam getting shredded, not loosening off.
Re: Engine Died, cam gear came loose, bent valves?
Originally Posted by 04 Honda Civic
I never heard of this happening before.
If the cam just loosened up, I would say there is a good chance the valves are still ok.
Originally Posted by BlueEM2
It makes very little sense, the direction the cam gear spins in it should actually tighten not loosen over time. So, this was probably caused by the cam getting shredded, not loosening off.
Guys, the OP did not properly torque the cam gear bolt, it came loose because of this:
Originally Posted by dgreen78
No I did not use a torque wrench, my mistake.
Originally Posted by BlueEM2
Hmm... It's the same as the timing belt breaking. The bottom of the engine keeps spinning and the top stops...
Close. Biggest difference is this thing SHOULD have had some horrible scary sounding rattle while running with a loose cam gear.......I bet it rattled like a diesel at idle.
Definitely shouldn't have sounded like the normal sewing machine.
It is entirely possible there are only a couple valves bent......instead of half or all of them.
OP should buy lottery tickets if none of the valves are bent.
Re: Engine Died, cam gear came loose, bent valves?
Problem I have with buying a used engine is you could be buying someone elses problem. I don't really believe in installing a used engine without doing some kind of work to it. I'd at least remove the head and inspect the piston walls and check the head for damage. Changed the head gasket, timing belt, etc.
Buying a refurbished head is a different story, it's been checked. You still need to check your bottom end though.
Re: Engine Died, cam gear came loose, bent valves?
This exact scenario just happened to me last night! Minus the really bad noises. I had no power, oil light came on, then died. I pulled the timing components today and found the same wear on the shaft and pulley. I found the little cam pulley key at the bottom of the timing covers near the crank pulley. I literally loosened the bolt by hand as well. I'm thinking probably new camshaft, pulley, and belt (minor fraying almost like nothing happened to the belt) and see if I can get it started. Worried about bent valves though.. Also, I tapped on the tops of the pistons with a long screwdriver through the spark plug wells and they sounded fine. The timing was definitely off - couldn't even start the car, it just whirred like only the starter was spinning. Just did the head gasket almost a year ago and its been great ever since. Then this little sh*t came loose somehow. Looking for advise or if OP ended up with bent valves, etc. Not sure if necroing is cool here but it was too similar of an experience to not. Not sure where to go from here, don't want to pull the head just to check?
Re: Engine Died, cam gear came loose, bent valves?
Originally Posted by iSamoStefan
This exact scenario just happened to me last night! Minus the really bad noises. I had no power, oil light came on, then died. I pulled the timing components today and found the same wear on the shaft and pulley. I found the little cam pulley key at the bottom of the timing covers near the crank pulley. I literally loosened the bolt by hand as well. I'm thinking probably new camshaft, pulley, and belt (minor fraying almost like nothing happened to the belt) and see if I can get it started. Worried about bent valves though.. Also, I tapped on the tops of the pistons with a long screwdriver through the spark plug wells and they sounded fine. The timing was definitely off - couldn't even start the car, it just whirred like only the starter was spinning. Just did the head gasket almost a year ago and its been great ever since. Then this little sh*t came loose somehow. Looking for advise or if OP ended up with bent valves, etc. Not sure if necroing is cool here but it was too similar of an experience to not. Not sure where to go from here, don't want to pull the head just to check?
I'd probably install the pulley and bolt (assuming no major damage to pulley or cam as just the bolt came loose), install timing belt, see if it will start and run.
See how good or bad it runs, and decide what to do next from there.
Re: Engine Died, cam gear came loose, bent valves?
This is what my situation looks like.. As I said, very similar to OP's description and images... I feel like the tolerance might be a big concern even if the wear is minimal? Shaft/Pulley key fell out, not even sure if its meant to come out.. Probably what caused the failure in the first place? I have it though.
Re: Engine Died, cam gear came loose, bent valves?
Originally Posted by iSamoStefan
This is what my situation looks like.. As I said, very similar to OP's description and images... I feel like the tolerance might be a big concern even if the wear is minimal? Shaft/Pulley key fell out, not even sure if its meant to come out.. I have it though.
I don't have a good pic of a bare cam gear handy for reference.....
Will the dowel or alignment pin still fit in the hole of the gear?
Can it be reattached to the cam, and would it be secure enough to either crank it for a compression test or actually run it to see if it runs okay?
I was trying to come up with cheap ways to find out if there's actual damage to the engine, before spending a lot of money.
Re: Engine Died, cam gear came loose, bent valves?
After work I'm gonna get a cheap Harbor Freight leak down tester, hook it up to my air compressor, and check to see if there're any hints to bent valves.. If they are miraculously OK, then I will just reassemble (if the dowel fits and everything seems tolerant). I wanted to see since you've been so helpful - what would your advice be if it turns out they're bent to sh*t? Go all out and rebuild? Buy new head and slap it on? Should I just get the engine pulled and fix the whole damn thing? Gonna need a new clutch soon enough so maybe can just do that. I need my wheels back >.> I do have a fancy car loan that expires in 30 days maybe its time to bite the bullet :'(
Re: Engine Died, cam gear came loose, bent valves?
Originally Posted by iSamoStefan
After work I'm gonna get a cheap Harbor Freight leak down tester, hook it up to my air compressor, and check to see if there're any hints to bent valves..
Don't bother until you can put the timing belt on it correctly. You can't do a leakdown with valves open (there are always valves open on some cylinder or another at any given camshaft position), and you gotta be able to rotate the cam to close valves on one cylinder at a time. PLUS you can't just let the crank go free, air pressure will force a piston down and 2 other pistons will come up and flatten out whatever valves are open on those cylinders
If they are miraculously OK, then I will just reassemble (if the dowel fits and everything seems tolerant). I wanted to see since you've been so helpful - what would your advice be if it turns out they're bent to sh*t? Go all out and rebuild? Buy new head and slap it on? Should I just get the engine pulled and fix the whole damn thing? Gonna need a new clutch soon enough so maybe can just do that. I need my wheels back >.> I do have a fancy car loan that expires in 30 days maybe its time to bite the bullet :'(
I'd pull the head and replace bent valves if it came down to that. Pistons aren't usually seriously damaged and most of the 1.7 engines eventually need a head gasket anyway. Use a head gasket from Honda, not aftermarket.
Re: Engine Died, cam gear came loose, bent valves?
Okay.. So if I understand correctly. The air is enough to spin the camshaft. I was going to First: check the current status of timing since I haven't yet. Second: was going to move the crank to a position that it isn't possible to smash into valves by altering the cam position (intentionally putting the engine out-of-time, so all pistons are same height). ONLY AFTER THIS was I going to do the leak down by controlling just the cam sprocket and checking rocker contact on springs. But if what you say is true and the air will move the cam then I suppose I will have to install the belt first? So, if I follow my 2 step procedure it could still be worth a try, or is my thought process flawed and there's no way to make the pistons a safe distance? Thank you for your valued advice - I think I'm on board with that. Gasket is like a year old but may as well put new one in. Edit: I think what your also saying is that the air is also enough to push the pistons down if the valves are miraculously not bent, so hmm maybe not a bright idea then. Guess i'll just get her in time and put belt on before testing leak.
Re: Engine Died, cam gear came loose, bent valves?
Originally Posted by iSamoStefan
Okay.. So if I understand correctly. The air is enough to spin the camshaft.
Edit: I think what your also saying is that the air is also enough to push the pistons down if the valves are miraculously not bent, so hmm maybe not a bright idea then.
Guess i'll just get her in time and put belt on before testing leak.
Re: Engine Died, cam gear came loose, bent valves?
Yep. Go figure. Basically bent all the valves. Been busy with work but knocked it out today. This is what happens I guess. Thanks for all the help, sorry for bloating this old thread - but again, too similar of a situation I just had too!
02-17-2013
Engine Died, cam gear came loose, bent valves? 
Make sure the pistons aren't destroyed. It's rare but it does happen. 
