valve seal replacing with head on car, lost valve

[Bryan_Tran]

hi guys im doing the valve seals on my toyota corolla and one of the valves dropped into the combustion chamber when i took off the spring! is there any way to get it back through the valve guide without taking off the head? I tried turning the engine with a wrench and it gets stuck both ways

 

[Steve S]

You are supposed to use a fitting screwed into where the sparkplug goes to use compressed air to hold up the valve. Have you tried a magnet? You may have to pull the head.

 

[Colt45ws]

Originally Posted By: Steve S
You are supposed to use a fitting screwed into where the sparkplug goes to use compressed air to hold up the valve. Have you tried a magnet? You may have to pull the head.
Yup. Pretty much everything is non-magetic except the valve so a magnet might do it. If not, you may have to remove the head.

 

[crazyoildude]

How far did it go in if the piston was at or near the top it may not go so far if it is still in the valve guide then i would take out the plugs and try to turn the engine by "hand"
slowly! that may bring the valve back up far enough to possibly get a small magnet on it and pull it back up..

 

[Bryan_Tran]

okay im going to try blowing in compressed air and using a magnet at the same time. wish me luck cause i don't want to pull the darn head.

 

[Steve S]

Originally Posted By: crazyoildude
How far did it go in if the piston was at or near the top it may not go so far if it is still in the valve guide then i would take out the plugs and try to turn the engine by "hand"
slowly! that may bring the valve back up far enough to possibly get a small magnet on it and pull it back up..
I forgot to add bring the piston to TDC then use the adaptor to use compressed air to hold the valve up.

 

[PT1]

Pull the head. If it gets stuck when you rotate the engine that tells me it dropped out of the guide and is holding the piston.

 

[Familyguy]

Originally Posted By: PT1
Pull the head. If it gets stuck when you rotate the engine that tells me it dropped out of the guide and is holding the piston.


Ding ding. We have a winner.

 

[mechtech2]

No offense Bryan, but what method did you use to keep the valve up where it belongs?
You almost certainly have to yank the head now.
Sure you may get it aligned again somehow - it could take 5 minutes or 5 weeks.

 

[soldierman]

Pull the head. I can't see you ever getting the valve back unless its still in the guide and not sure even then.


If I do that job or something similar I usually stuff 3ft of 1/4" rope into the clyinder and rotate to compress the rope. Valves won't go anywhere like that.

 

[onion]

Oh you poor [censored]. It's neither here nor there now, but as others have pointed out, you HAVE to have the cylinder at TDC when you do this.

If I was in your situation, here's what I'd do: I'd find a strong magnet that's small enough to fit down through the guide- one of those telescoping magnets MIGHT do the job. Then remove the spark plug and insert a coat hanger wire through the hole- bent if necessary so that you can move the valve around. With some tinkering and LOTS of luck, you MIGHT manage to stick the top end of the valve stem to the magnet and pull it back up through the guide.

But if you can't do it that way, then your only option is to pull the head. Also, seeings how you've turned the engine- it's going to be a real judgement call here. Did the piston impact the valve hard enough to bend it? I've no way of knowing, and you can only guess. Again, if that's the case, you have to remove the head.

 

[onion]

Originally Posted By: soldierman
Pull the head. I can't see you ever getting the valve back unless its still in the guide and not sure even then.


If I do that job or something similar I usually stuff 3ft of 1/4" rope into the clyinder and rotate to compress the rope. Valves won't go anywhere like that.


That's a great idea. I work on diesel engines 99% of the time, and in these engines, there's so little clearance between the valves and the piston that you can simply put the piston at the top, and the valve can only drop maybe 1/4". I've done the same on gas engines a couple times, and it works- but the valve does drop further and it's a little more difficult to deal with. I've heard of using compressed air, but never tried it- seems like it would just push the piston down. But that's a great idea with the rope.

 

[wapacz]

If you know some one that has a bore scope borrow it and see what it looks like in that cylinder. At least you know where you stand then.

 

[soldierman]

Originally Posted By: onion
Originally Posted By: soldierman
Pull the head. I can't see you ever getting the valve back unless its still in the guide and not sure even then.


If I do that job or something similar I usually stuff 3ft of 1/4" rope into the clyinder and rotate to compress the rope. Valves won't go anywhere like that.


That's a great idea. I work on diesel engines 99% of the time, and in these engines, there's so little clearance between the valves and the piston that you can simply put the piston at the top, and the valve can only drop maybe 1/4". I've done the same on gas engines a couple times, and it works- but the valve does drop further and it's a little more difficult to deal with. I've heard of using compressed air, but never tried it- seems like it would just push the piston down. But that's a great idea with the rope.


With air if you get it true TDC it should stay.... it is however a good idea to lock the crank down somehow. I know what you mean on those diesel's. Those old Mack 235's pistons and valves are in such arrangement. Its amazing they run with such little valve spring pressure. I can take those spring keepers off by hand alone. I've done a couple of head jobs on those.... They don't take kindly to untrained drivers downshifting since there's so little to keep the valves from floating.

I do the rope because I rarely do valve seals without more work to the head... and I don't like to hear pssssss... all the time I'm trying to concentrate on working.

 

[andyd]

I have used the rope trick on my chainsaw to lock the crank so I could remove the clutch. I would defintely invest/waste a few hours on retrieving the valve. You may get lucky.

 

[Gary Allan]

Quote:
forgot to add bring the piston to TDC then use the adaptor to use compressed air to hold the valve up.


If he has compressed air on that cylinder ..that piston is most assuredly going down. He would have to find a cylinder already down that assures that the piston in question remains up. Then, with balanced air to both, they might just say put.

I guess if you have a gorilla on the crank with a cheater pipe you can manage it to keep the piston up.