i have heard refernce of a "sticking valve"

[wgargan]

can some one explain to me what a "sticking valve" is?
for a baseline: I know what a valve is, I know how they operate, I just cant visualize how one would "stick".

thanks, I am liking this site!

 

[tonkadoctor]

Glad you enjoy the site.

A sticking valve or a diagnosis of a stiking valve can be several things. Could be worn in the guide causing it to stick or a problem with the seat. Often too, a bad hydraulic lifter will be diagnosed as a sticking valve.

If it sticks in the open position it can cause major damage with contact with the piston. If it's open but not contacting the piston you will have low compression in the affected cylinder.

Sticking closed is usually the result of a lifter going bad and if bad enough it can throw or snap the pushrod and again cause alot of damage to the valvetrain as well as put metal throughout the oil system of the engine.

Hope this helped answer some of your questions and I'm sure others can add to it as well as convey their experiences with this.

 

[swampdigger]

...on a related note, how exactly do you "drop a valve"? I've heard this a couple times around here too...

 

[towcat]

...on a related note, how exactly do you "drop a valve"? I've heard this a couple times around here too...

that's easy.
its when the piston hits the valve hanging open and its done often enough to the point the valve head breaks off the stem and starts bouncing around the cylinder. you can let your imagination of the carnage that will cause.

 

[LUCKY_LARUE60]

Sometimes the valve keepers wear and won't hold the valve stem any longer and the whole valve drops and then you end up with a hole in the side of the block. In my case on my L10 Cummings the head of the valve just dropped for no reason other than bad valve.

Jim

 

[Agnem]

Generally, I think we've used the term "swallowed a valve" to describe a lost keeper (seems the most descriptive).

 

[sle2115]

can some one explain to me what a "sticking valve" is?
for a baseline: I know what a valve is, I know how they operate, I just cant visualize how one would "stick".

thanks, I am liking this site!

Bent valves will also "stick" if there is contact made, like floating a valve (generally with high rpm motors but could happen with a runaway as well) then the valve gets bent and will not move in the guide. Oil starvation can cause a sticking valve as well because the valve seizes in the guide.

 

[sle2115]

...on a related note, how exactly do you "drop a valve"? I've heard this a couple times around here too...

From the amount of valve keepers I have seen listed for this motors, I assume there may be issues with them coming loose, then the valve drops into the cylinder, hitting the piston and as towcat says "you can imagine the carnage!"

 

[sle2115]

Sometimes the valve keepers wear and won't hold the valve stem any longer and the whole valve drops and then you end up with a hole in the side of the block. In my case on my L10 Cummings the head of the valve just dropped for no reason other than bad valve.

Jim

Was it a sodium filled valve (Exhaust valves only to my knowledge)? We ground some of them and they sometimes would break where the stem is hollow toward the big end, just the pressure applied sideways on the head of the valve would break them off. We wouldn't grind them if we knew they were filled, but sometimes, one would sneak by, generally they were no problem, but when they broke, they made a mess of things!

 

[LUCKY_LARUE60]

Was it a sodium filled valve (Exhaust valves only to my knowledge)? We ground some of them and they sometimes would break where the stem is hollow toward the big end, just the pressure applied sideways on the head of the valve would break them off. We wouldn't grind them if we knew they were filled, but sometimes, one would sneak by, generally they were no problem, but when they broke, they made a mess of things!

Not sure if it was sodium filled but it did break just as you described and it was a exhaust valve. Needless to say it took out a piston, liner and head. And the head on a L10 is a one piece. I bought a complete used head and now I have a miss on one hole. Have not been able to address it yet as I had some surgery a couple of weeks ago and will have to wait a couple of more weeks.

 

[typ4]

Every one of our engines I have seen in wrecking yards around here with velve problems has had a broken valvespring and lots of miles. I know from doing hundreds of heads that some engines are harder on springs than others. It is not usually the keepers, although I have seen some soft ones on high spring pressure uses that fail but that is not the case with our diesels
Make sure you get new ones on rebuilt heads no matter how good they test out. My 2c

 

[rubberfish]

you can let your imagination of the carnage that will cause.

It will look like this powerstroke cylinder.