How do I keep the cam from moving while trying to take the sprocket and chain off on a560sl engine ( for chain guide replacement)
Do I have to take all the rocker arms off to prevent this??
Won't the valve springs cause the cam to move with not chain attached and bend a valve???
Is their any trick way to do this?
Or will the cam just sit where its at ?
It seems like the spring pressure can push it either way causing a vlve to hit a piston.
Any ideas are appreciated

__________________
[B]Mike Y.
00 sl500 sport
88 560 sl (sold)

I just did this on my 560SEL They will just sit there. What you do is remove the front bolt (24mm I believe) Then the best trick is to use a small block of wood as a cushion and a hammer to firmly tap around the sides of the sprocket. (I gave it a couple of whacks from the rear at 12 o'clock, 4 o'clock, and at 8 o'clock and kept going around the cycle, if you see it budge a little bit go to the next point. When I say a whack, I mean choke up on the hammer and grab it near the head or halfway on the handle. Once it budges it should take a few dozen taps to bring it off the front. JUST BE CAREFUL ABOUT THE WOODRUF KEY!!! It's at the TDC mark on the cam and is about 2mm, 10mm long and if it comes out it has a half-moon profile. DO NOT LET THIS FALL INTO THE BLOCK!!! If you're careful and not over aggressive it should be easy. I had my rockers removed due to other repairs and If you remove them, make sure they go back in the same spot!!!

If you're using the same chain and sprocket, use whiteout to mark where the chain was on the sprocket. A dot on the sprocket next to a dot on the chain is sufficient. There is only 1 way to install the sprocket on the camshaft so this alignment dot is pretty much the only thing you'll have to make sure you've kept the cam timed properly.

Once removed, the cam will probably not move, especially if the rockers are still in. If it does, when re-installing the sprocket, drape the chain over the sprocket so that the dots are aligned, then spin the shaft to mate with the sproket. Then tamp the sprocket onto the cam shaft and torque the retaining bolt to 100Nm and you're set.

Good Luck!

Thanks for the information
The only thing I'm wondering is did you have your rockers off before taking the sprocket off???
Will the sprocked come off the cam with the chain still there
or do you take the tensioner off first?
How did you hold the cam when you torqued the center bolt ?

__________________
[B]Mike Y.
00 sl500 sport
88 560 sl (sold)

One quick rap and the sprocket retaining bolt was loose when I did mine. Be sure to clearly mark the sprocket and chain prior to removal. I also loosened the tensioner, but did not remove it for the guide rail replacement. This gives just that little bit extra slack needed to reassemble when the new guides are in. I marked my sprocket and chain with Testors silver paint after cleaning thoroughly with carb cleaner. No rockers were removed at the time.

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Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Thanks for the help
here is a pic of the old guides
I am behide with this job because I just finished up with the 02 sensor replacement and readjust duty cycle
Works great now
The 02 was shot
Different tread!!!

Attached Thumbnails

 

__________________
[B]Mike Y.
00 sl500 sport
88 560 sl (sold)

Those guides haven't gone beer bottle brown yet, but they're getting there. Mine had almost gone black, I was definitely on borrowed time. The hardest part of this job is getting ALL the accessories off the front of the block. Use care with the 6mm cap screws for the alternator bracket. A shorty 6mm allem works way better than a longer allen on the alt bracket.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

I wanted to fab a pin puller for the pins
What tread size were they and how long were they if you don't mind asking
By the way thanks I feel you are ahead of me in repairs
so I can check in and find out what your new project is
that should keep me right in sequence

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[B]Mike Y.
00 sl500 sport
88 560 sl (sold)

For a pin puller for the guide rails I used a bolt and spacers. This is probably the best way!!! Off the top of my head I believe it's an M5, although it may be an M4. What I did was used a bolt, threaded a nut all the way to the head, used 2 washers sized to the bolt then a hollow steel tube which had an inner diameter larger than the hole drilled in the head for the guide pin. I then used another washer so that the narrow walled tube would not dig into the Aluminum head. Then use a wrench to back the nut back down the bolt and viola, instant press, worked like a champ. The bolt I used was about 2-2.5 inches long (in metric speak) and it theaded about 5mm into the pin. more than enough to get a good grip. The bolt should thread into the pin with just your fingers.

I had my rockers off when I did mine. It's probably helpful to remove them so that any possible axial motion will not scar the rocker mating surface either on the rockers or the cam.

Definatly take the tensioner off, it's held on by 2 bolts and not difficult to put back on. This will give you the slack in the chain you will need to avoid a case of turets when trying to get the sprocket back on.

To hold the cam while torquing the center bolt there are 2 ways:

1) Have someone hold the cam with a wrench. Midway on the cam are two rectangular tabs which are for this purpose.

2) Once the sprocket is on the cam and chain is attached, the chain will hold the sprocket/cam while you tigten the bolt to 100Nm

It is my first day back to work after 5 weeks...limited duty, but busy enough to keep me off the computer.

The fan blade bolts are the perfect size to thread into the guide pins, in fact I use a fan blade bolt to drive the pins back in. Not certain on the size, 6x10 I think.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Good stuff there czarFC
I like that
thats seems like a nice way to attack it
I guess you changed cam oil plastic pieces also
You need a spring compressor to remove rockers ????
Did you guys have any ideas on this one
I have a milling machine and a welder
so any pics or dimensions on the compressor would be appreciated.
Thanks a bunch guys this is great suff
Lots of good usable information
Makes life a lot easier.
Again thanks to all of you

__________________
[B]Mike Y.
00 sl500 sport
88 560 sl (sold)

I don't have any pics of my compressor, but if you have the mill to make the compression face, and can bend some 1/4 inch wire, you could probably use a prybar for your compression arm.

Here is a link for a guy whose put up how-to stuff on his 560SEC. I fount his pictures of the valve stem seal and head remove most helpful. I hope he doesn't mind me posting his link!

http://mywebpages.comcast.net/chwilka/car_stuff.htm

he has a picture of how the valve spring compessor works and you may be able to reverse engineer one from that. Basically the wire claw holds onto the camshaft and uses it for leverage where the fulcrum is nominally where the compression arm connects to the lever. I hope this makes sence!

Good Luck! and I hope you can make one for less than the $180 the tool costs!

I thank you very much
This is nice stuff
I must go get an MRI on my knee tonight
My wife yelling as usual that I am late
Got to go will be back later

Again thanks again

__________________
[B]Mike Y.
00 sl500 sport
88 560 sl (sold)