M117 valve stem removal

[khimani_mohiki]

So I made a valve spring compressor to remove the rockers and replace the valve stem seals on my SEC....

It works OK and I removed one of the rockers on my spare engine, however I cant get little half cone bits out which hold the valve onto the spring retainer. the manual says to use a special magnetic finger, which I obviously dont have and probably wont be able to get hold of, although I cant even see how a magnetic finger could pull these cone halves out, they seem very firmly in place.

Any ideas?

 

[ched999uk]

On other cars I have used a scriber (metal sort of pencil) to split the 2 collets apart. Sort of sick it where the 2 collets sit next to each other. Then use a magnet on a stick sort of thing to grab the collets.
Good Luck.
PS hope you have patented your great tool

 

[EDZ649]

That's a familiar sight, I'm having one of the camshafts replaced in my 450 SEL at the mo, same 117 engine.

 

[khimani_mohiki]

On other cars I have used a scriber (metal sort of pencil) to split the 2 collets apart. Sort of sick it where the 2 collets sit next to each other. Then use a magnet on a stick sort of thing to grab the collets.
Good Luck.
PS hope you have patented your great tool

So do I need to keep the spring compressed while I split the collects?

 

[ched999uk]

Yes you need the valve spring compressed to remove the collets. The collets are tapered on the outside and have a sort of step on the inside where they meet the valve stems. They are held against the valve by the spring cap. So I would say depress the spring, hold it down, then use a scriber to separate the collets then the magnetic tool or a pair of long nosed pliers to grab the collets. Be very careful as on some engines the collets are small enough to fall down the oil galleries.

As I say I have no experience with mercs but all other engines I have worked on have worked this way. From Ford, Vauxhall, BL, VW, Lister Petter, and all sorts of unspeakable engines. They all had split collets that required the spring to be compressed to remove collets.
Its a tricky and fiddly job. It may be worth temporarily using rags to cover any oil galleries just in case.
Good Luck.

 

[ched999uk]

I take it its too much agro to remove the cam shaft? As then you just need to rotate piston to tdc for each valve set in turn then compress valve spring and remove collets then replace steam seal.
You do need to be a little careful not to scratch the cam lobes with your tool. As they normally have a coating on to make the lobes harder and to hold oil better. The force on the can lobes is quite high as they start to compress rockers. This is why high lift cams wear quicker than normal as they sustain a higher force due to quicker opening and closing of valves to give more duration.

 

[jaymanek]

What ^ says...

We removed the cam shafts... You have to be very very careful doing this job... Ensure that you put everything back exactly where it came from, especially the little rocker shim things... otherwise you will get a tappy engine after.

The collets only come out with the springs fully compressed like has been pointed out.

Also you will need something to keep the valves up whilst you change the seals. My mechanic friend has a special tool for this, its simply a spark plug sized connector that plugs onto the air line to keep the valves up. However many just feed rope into the bore through the plug hole.

 

[Druk]

What he says^ The rope trick works fine. This is the magnetic tool referred to...Laser Tools | 3990 | Pick Up Tool - Extending Magnetic

 

[khimani_mohiki]

the tool sits each side of the lobe so it doesnt touch the surface at all. I didnt even think about holding the valves up, good job i didnt remove any collets yet.

 

[jaymanek]

Its not an easy job at all mate... a lot of potential for things to go wrong!