Install Valve Stem Seal

[DaveP]

Getting back to the rebuild of the 1981 GS 650 engine and I am starting to reinstall the valves and have new valve stem seals to install. I have only attempted one so far and used a deep, 10mm socket to try and push the seal down while it was on the shaft of the valve. I am not too confident that I am getting the seal fully pushed on to the valve guide.

Any tips or tricks to making sure that the seal is fully seated?

Thanks,
Dave

 

[Cipher]

is the head off? If so why not install seal then valve? You should be able to see that it is seated and hove no risk of marring the valve tips

 

[Nessism]

I use a 10mm deep socket too, the 1/4" drive type. I use a driver handle on the socket and tap lightly with a small hammer to assure the seals are seated.

 

[DaveP]

is the head off? If so why not install seal then valve? You should be able to see that it is seated and hove no risk of marring the valve tips

The head is off. I thought having it on the valve stem would have it aligned better to push it on.

The seal was lubed first before trying to install.

 

[DaveP]

That is what I had. 10mm deep socket on a 1/4" screw driver handle. Did tap a bit with a rubber mallet.

 

[GregT]

If it's lubed, once it's on you should be able to turn it. That lets you see if you've got it completely on and square.

 

[DaveP]

If it's lubed, once it's on you should be able to turn it. That lets you see if you've got it completely on and square.

I do feel that is not going to go on any further now, but it also is not going to turn. Although it does lock over a lip on the valve guide, I am not sure that it would be able to spin. Of course I can barely get my fingers down there to try and turn it...

 

[GregT]

I do feel that is not going to go on any further now, but it also is not going to turn. Although it does lock over a lip on the valve guide, I am not sure that it would be able to spin. Of course I can barely get my fingers down there to try and turn it...

Long nose pliers....

 

[bwringer]

It doesn't take much.

Last time I used high quality aftermarket Viton valve stem seals, and these had a distinct "pop" when they went into place. OEM seals sort of just squish on, so there's not a distinct pop. That said, all it takes is a push by hand (I also use a 10mm socket on a 1/4" driver handle), so you should be fine. If you're super paranoid, you could measure the height of the valve guide, the depth of the seal, do a little math, then measure the installed height to make sure they're seated.

Whatever you do, don't use the seals from an aftermarket gasket kit (Vesrah, Athena, etc.). They're complete junk that turn glass brittle in a few thousand miles.

 

[DaveP]

I have the OEM seals. I was trying to gauge if it was seated by measuring...

It has been a while since I removed the old ones, but I don't recall them turning when I was trying to remove them and pretty much destroyed them all when getting them so wasn't anxious to go after the new ones with a set of pliers.

Dave

 

[bwringer]

The old ones do get stuck pretty hard and get destroyed or damaged when you yoink them out.

If you're reasonably gentle and have a tool shaped to fit, a new valve stem seal will come out pretty easily without damage. But if you just grab it with a pair of pliers, then you're probably going to damage it.

Install a few more, then stick something down in the hole (straw, piece of paper, etc.) to gauge and compare the installed heights.

I think you're fine -- these don't take much force to install, and there's no "pop" or "click" when they're seated; they just stop.