valve stem seal change

[zetor crystal]

Hi guys, did anyone replaced the valve stem seals on YM1610D or any other YM without taking the head off the engine? (don't want to drop the valve to the chamber)

 

[ch47dpilot]

One trick I've heard but never tried is to use compressed air into the cylinder. On a gas you can modify an old spark plug not sure if possible on a diesel. The compressed air will keep the valves closed.

 

[jtokc]

Manually rotate the crank until one cylinder is at the top. Replace the seals on that cylinder and then rotate the crank until the next cylinder is at the top and replace the seals on that cylinder .... repeat until all cylinders are complete.

 

[Winmac]

Like stated with the piston at tdc the valves will only drop about 3/16 to 1/4", I've changed seals without the use air pressure at all. I'm not familaure with your particular engine, the room you have to work around the valve springs, will determine how easy of a job this will be.

 

[zetor crystal]

Thank you guys very much for help !!! Can't wait till weekend to do this project :confused2:

 

[California]

I think on these high compression diesels the valve-to-piston distance is just the thickness of the head gasket. And the valve spring tension is surprisingly light. Replacing the seals without pulling the head should go ok.

 

[winston1]

I have wondered how much valve to piston clearance there is. I know when you pull the compression release you are opening the exhaust valve. Must be just opening a few thousands. Doesn't take much to relieve compression. Next time (if ever) I have my rocker arm cover off I am going to look at the little cams that open the valves and see just how much they open the valves. I expect the exhaust valves are nipping at the piston during this time.

 

[Car Doc]

Wondering how it turned out zetor crystal?

Yes as California said the valve spring pressure is very light- 2 fingers light I was amazed myself.

Just for conversation but when I did my head gasket/valve job on my 3810 I had to mill the head .009" it was warped so bad. I was concerned enough about even the pre-chambers clearing the pistons I added 1 extra copper shim under each of the chambers to be safe.

My engine didn't even have valve seals when I tore it down. fwtw my 336 manual shows them but who knows who's been working on these things.

On mine there is a slight chamber in the head but it isn't much more of a slight depression around the valves than anything dont know about a 1610.

 

[murphy1244]

Some use clay to check the clearence

 

[California]

I was looking through my YM240 shop manual and noticed the crush space, head to block, is specified as 0.0425" (measured by crushing a piece of lead wire solder, I think). That's about the thickness of the head gasket.