126 timing chain guide question
 

I opened up the cam covers (the driver's side has two thick lines connected to what looks like the ac system that goes to the intake under the airfilter that gets in the way. I was afraid to disconnect ...what are these lines and how do I get them out of the way so the cam covers can clear the cams?) yesterday on my 85 500 sel to replace the timing chain and guides.... How do the guides come off? I have the MB cd and there is no section covering this. It looks like the rods/pins that hold the guides don't have access ports/holes.

Do I loosen the chain tensioner? what is the tightening specs for the tensioner?

I read some how to's on chain replacement and thought it wouldn't be too hard but when I looked at the guides I closed everything back up.

The guides 'looked' like they have no wear but the replacements I have are white while the ones in the car are yellow/orange...I want to change these asap so pls. help! :o

I am not too happy w/ the MB cd...is there another source that has the timing chain/guide instructions?

Thanks,

Don

I am going to bump this until somebody helps me! :rolleyes:

You will get more responses if you indicate what engine you have. There is quite a variety in the 126 car. Everything from a diesel five cylinder to a V8.

Good luck,

Regarding the lines that cross the valve cover and need to be removed to removed the valve cover: these are fuel lines which route the fuel to a cooler which is part of the A/C low side hose. You can undo these fuel lines; you will lose a bit of fuel but no refrigerant. Make sure you counter hold well at the fuel cooler.

You will probably have to to swing ancillaries out of the way and perhaps the cooling fan and radiator to gain enough access to pull out the slide pins which secure the rails. It's been 5 years since I did this on my 560SL, so the details are a bit hazy.

The tensioner on the V-8 is non-ratcheting so it is just unbolted and rebolted with a new gasket.

there are tons of info here if you do a search. You can also subscribe to pindelski.com. The site is mostly 126 related. It has a detailed procecedure on how chain R/R..

Sorry for the sermon. I perused it quickly and did not see the 500SEL part and did not pay attention to cam covers being plural.

I am not an MB V8 officionado but I do know the importance of guide replacement. If one breaks it will take the chain with it when it jams up.

Good luck with it,

Thanks for the responses.
It's a 500 sel 1985. V8.
The pins holding the guides have no access.
I have searched and read everything under timing chain, tensioner, guide...etc. I couldn't come up w/ anything specific about the removal of the guide pins.

I'll give it a go again and report back the disaster story. :D

The pins have plenty of access, you just have to get to them. Everything has to come off the front - Radiator, fan & clutch, alternator, power steering pump, their brackets as well. Once the fan belts and accesories are off you'll see the pins, or at least the end of the pins. You'll need a proper sized bolt to fabricate a puller out of washers and sockets (or buy the proper tool $$$$), the fan bolts are the correct thread, believe they are M-6.

I just got finished buttoning up my timing chain job. I did not take out the radiator, but blocked it with cardboard to prevent dings.

Here's a run down:
remove air cleaner housing
disconnect fuel lines on drivers side
remove sparkplug wires and sparkplugs
remove valve covers
remove alternator
remove powersteering pump (don't disconnect lines, just hang it aside)
remove alternator and PS pump brackets
now you can see the pins
mark your distributor housing to engine alignment
mark your distributor rotor to housing alignment
plug your distributor hole with a rag
remove fan
use a socket wrench on the crankshaft to align the timing mark to "0" while mark behind passenger side camshaft sprocket comes close to lining up with mark on camshaft bearing (stretched chain will cause mark to be off)
remove tensioner
mark your chain to sprocket relationships in several places (oily surface can be hard to get marks to stay)
you will have to remove the sprockets (only one side at a time) in order to get the guides out
use an appropriate tool to hold the sprocket while you remove bolt
if the sprocket moves, it can move everything
don't let the sprocket keys drop in the engine
I was most concerned with slack causing the distributor sprocket to jump teeth
try to keep as much slack out of the chain as possible
I used a bungie cord attached from the chain to the hood to maintain tension
buy varying sizes of M6 bolts and get some washers
put a bolt through a socket that will allow the pin to rid up in it
as you work the pin out, you can add washers or change bolts for more room
some pins are pretty stuck in there, so you may have to be creative
hold your guides as you remove pins to prevent them from dropping in
replace guides
replace sprockets
block off the opening below the passenger side cam sprocket
grind off a link between zip ties being careful where dust is going to wind up
use spray solvent and a rag to get all the grinding dust off of chain and cam sprocket
link new chain to drivers side end of old chain
slowly, slowly work the crankshaft while you add and remove zip ties to keep the old and new chains on several teeth of the sprocket in order to prevent the chain from jumping teeth
it takes a while to work the 6ft or whatever worth of chain around this way, but it was safe and nice to see those two ends meet up again
link up new chain

I've left off the obvious reversal of assembly on everything. Study your car and the procedure and take my guide with caution as it may be as incomplete as my memory is.

Needed:
23mm socket for cam sproket bolts
27mm socket for crankshaft bolt (turning engine)
heavy zip ties
valve cover gaskets
valve cover washers (8)
guides
chain (comes with master clip)
tensioner (comes with gasket)

Notes:
I broke both of my sparkplug wire anchors on top of the valve covers
I cut my belts off because they were old and it was fun :)

Enjoy!

:bowrofl: :bowrofl: :bowrofl: :bowrofl: :bowrofl: :bowrofl: :bowrofl:

I just remembered that you will want to replace your oiler tube fittings while you have the valve covers off. These are small plastic bits that fit over an aluminum tube and snap it into each of the cam bearings to provide lubrication to them all. These get brittle just like the guides do and only cost a few buck for prevention of a failure.

I did get the oiler thingies. Thanks