What is causing this?

[Zero]

When I was doing some investigating into a no compression issue I came across this.....the valve spring sticks on one cylinder, sometimes it will happen sooner, sometimes later into the revolutions, but what could be causing it?

Now after it gets stuck, I can pop it back up to normal again with a screw driver.

Posting pics of the spring stuck down, and of it when its normal. Also posting a video. I do have a brand new lifter for that one as well already installed.

https://www.youtube.com/watch?v=Q9T3jSW4uFU

http://postimg.org/image/ooykvabv1/ View of being stuck

http://postimg.org/image/7zx4zdf9p/ another view of it stuck

http://postimg.org/image/ksc5p2ibf/ Not stuck

Anyone? I will be removing the spring in a few days but I was curious now lol

Broke spring? Rusted spring? Bent Valve? Bad valve seal?

 

[CactusJacked]

Likely a dropped valve seat (not uncommon on these engines), getting stuck down and holding the valve open.

 

[Zero]

I forgot to state the engine, it's a 3.7.

I do not have a rattle so hopefully it did not fall into the cylinder head if that's the cause for this.

 

[CactusJacked]

I do not have a rattle so hopefully it did not fall into the cylinder head if that's the cause for this.

A "dropped seat" doesn't mean that the seat totally falls down onto the piston. A dropped seat will lower itself out of the head, but the valve still holds it from falling completely out. So no, in that instance you wouldn't hear parts rattling around...that is, as long as the seat doesn't crack apart and split into pieces.

 

[MarkJ]

A "dropped seat" ...that is, as long as the seat doesn't crack apart and split into pieces.

Good reason to stop running it and get it fixed before it breaks and instantly gets more expensive.

 

[Zero]

I have not run it since I had the misfire, so if the seat didn't fall down into the piston then I shouldn't have to take the head off right?

 

[dougmac]

I have not run it since I had the misfire, so if the seat didn't fall down into the piston then I shouldn't have to take the head off right?

Yes, the head has to come off to repair a seat that has come loose.

If you run it with a loose seat, it can damage the piston and possibly the engine block. The engine will need to be rebuilt if either occur.

 

[CactusJacked]

I'm fairly confident about what your issue might be (legal disclaimer definitely needed in this forum, lol). But, before you go ripping the cylinder head off, grab your 25% off coupon and head on down to Harbor Freight for one of these toy.... I mean tools: High Resolution Digital Inspection Camera with Recorder
Also works great for inspecting your own hemorrhoids, or so I hear! :happy175:
They do have a $90 model if you can live with a low res one.