valve stem seal nightmare

[jmitro]

I bought a 06 x5 4.4i with N62 engine. Decided to change the valve stem seals myself using the AGA toolkit; unfortunately I managed to drop a valve into the cylinder on #2 (engine was supposed to be at TDC or very close but somehow it must have been off, and the air pressure must have been too low to keep the valve in place).

Anyway, stupid question, but I assume my only option now is to remove the head?

To remove the head, my options are:
1. do it myself (I need all the camshaft locking tools, timing tools, etc)
2. take it to a shop.

This is (was) my daily driver, so now I'm without a car. I'm mechanically inclined but don't have the tools for removing the head, and I've never done this job before, so I need suggestions from anyone who has performed a head removal on whether to try it myself or not, where to get tools from, what to change "while I'm in there" and what kind of head reconditioning to do while it's off.

[upallnight]

Did the stem of the valve drop all the way down that you can't pull it back up? With the cylinder at TDC I find it hard to believe that it could fall that far into the cylinder. Perhaps a magnetic probe can lift the valve high enough for you to complete the job.

Nice bikes, I have several bikes including a Cervelo, Felt, Motobecane, Cannondales and Gary Fishers.

[BigBlack48is]

I would at least try to find a magnet that will fit into the hole where the valve needs to pass through into the cylinder head and try to pull it through ( without the seal in place )

I feel your pain... I am not looking forward to this procedure myself!

[bcredliner]

I would also try a magnet but not one that could possibly drop into the cylinder.

[jmitro]

Well I pressurized the cylinder tonight and even gently rotated the crankshaft, but to no avail. The valve is all the way in the cylinder. When I pressurized it last night, it must have rotated the engine farther than I thought, or else I was a stroke off TDC. The engine won't rotate all the way now, indicating the valve is obstructing the piston movement.

In any event, I called AGA and spoke to a tech today. He said the only other option before pulling the head is to try and reach the valve through the exhaust port after removing the exhaust manifold (which I would be doing anyway). If I can't get it, then the head comes off.

Problem is, now that I can't rotate the engine to TDC, I can't install any of the camshaft tools like this:
BMW N62 and N73 Camshaft Alignment Kit. Is that OK as long as I reinstall it with all the correct tools?

I'm getting in over my head

[ants_oz]

When an engine is at TDC, only cylinder 1 is at TDC. Unless the cylinder you are currently working on is also at TDC, a valve will quite happily drop all the way down the bore.

Rotating the engine was a dangerous mistake. If the valve was indeed down the bore and free of the valve guide, you could easily bend it, damage a piston crown... Even if the valve had not been completely free of the guide, you risked exactly the same damage if the valve had become jammed in the guide as the piston went through its stroke.

There are no shortcuts here. The head MUST come off.

When doing jobs like valve stem seals in-situ....lets just say there are plenty of traps for the inexperienced. Having adequate air pressure is absolutely essential - and having a compressor that can output adequate volume is equally essential. You WILL leak air through the valve seats to a very small degree if the engine has any wear on it, but you will ALSO leak air through the piston rings. They are not gas-tight - they are simple labyrinth seal.

One of the reasons head removal is a preferred method of dong valve step seals is that the valves and seats can be re-faced at the same time.

Anyway, good luck and hope the head comes off cleanly.

[crystalworks]

^Yikes... now I am really not looking forward to doing this job. Is there another way to support the valves while working on them other than air pressure? Maybe magnets or even long nosed vise grips wrapped in electric tape or other non-marring material? I guess anything you use would just get in your way while you were trying to replace the valve though...

I've pulled and replaced I6 heads (m50, 52, etc) and I really don't want to pull these heads... lol.

[ants_oz]

Originally Posted by crystalworks

^Yikes... now I am really not looking forward to doing this job. Is there another way to support the valves while working on them other than air pressure? Maybe magnets or even long nosed vise grips wrapped in electric tape or other non-marring material? I guess anything you use would just get in your way while you were trying to replace the valve though...

I've pulled and replaced I6 heads (m50, 52, etc) and I really don't want to pull these heads... lol.

Not really, no. You not only need to be able to remove the collet and valve springs, but then you need access to the valve stem in order to remove the seal.

[crystalworks]

Originally Posted by ants_oz

Not really, no. You not only need to be able to remove the collet and valve springs, but then you need access to the valve stem in order to remove the seal.

Yeah, figured. Shortly after posting the Sailor Jerry's wore off enough for me to realize I was asking a stupid question...

Well, looks like I might be that much closer to trying the old Lucas additive method and hope the seals swell up. I don't have a compressor I would trust to supply the necessary air pressure consistently.

[ants_oz]

I just can't be bothered doing some jobs myself anymore. I'm a qualified mechanic, but have many more enjoyable things I would prefer to do with my time that struggle in a home garage with things like lifting heads, doing timing chains, etc etc.

As much as it hurts the hip pocket, I would prefer to be shooting hoops with my son, or going for a ride with my wife on the motorbike than spending a day under the bonnet of a car.