Timing chain stretch & woodruff key - PeachParts Mercedes-Benz Forum

Robby Ackerman · #1 10-14-2014, 09:50 AM

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mach4 · #2 10-14-2014, 10:26 AM

The consensus around here seems to be to replace the chain every 200k miles or so. If you're at 400k you're definitely due...and at this stage fixing a few degrees of timing is nothing compared to a chain that lets loose - cheap insurance, as they say.

I just did mine and it's not that big a deal...of course I built a guide tool so I could do it without a helper.

leathermang · #3 10-14-2014, 10:27 AM

If you will describe exactly how you got your current measurements it may help...
points on the sprockets are not a legitimate indicator... if you got to that point you would be WAY past needing corrective measures...

Usually it is the things which touch the chain which really cause a LOT of damage when they give way... if you replace the chain.. those things need renewing too....

DieselPaul · #4 10-14-2014, 11:20 AM

If you've got 5* of stretch there is your timing chain wear. Iwis chains are cheap and not hard to roll in. It can be done at home for like $100. I would roll in a new chain.

leathermang · #5 10-14-2014, 11:37 AM

and the appropriate slides and rails.... etc...

Diesel911 · #6 10-14-2014, 11:40 AM

I will let you decide if you want to change the Chain or use the offset Key.

The lowest degree offset key is for 4 degrees of correction. However, you need to use the 2mm Methond for the calculation and look at the chate to be sure.

From what I have read Timing Chain Failure is most often caused by the Intermediate Shaft Bushing being worn to the exthent that there is too much end play in the Timer. Too much end pay ruins the Vacuum Pump and the Pieces of that fall into the Timing Chain and or Gears.

The other Vacuum Pump issues is on the Vacuum Pumps that had Bearings with a Plastic Retainer/Cage that held the Balls apart and or unshielded Bearings.
The Vacuum Pumps on the later models have a Steel Bearing Cage and Washers that limit the chance of bearings coming out.

However, on any of them if you hear noise from the Vacuum Pump Timer area it is time to stop the Car and get it towed Home till you can fiture out what the cause of the Noise is.

Anyone wanting more detailed info:
Repair Links
Fast navigation http://www.peachparts.com/shopforum/diy-links-parts-category/146034-fast-navigation-do-yourself-links.html

http://www.peachparts.com/shopforum/forumdisplay.php?f=82
http://www.peachparts.com/Wikka/DoItYourSelf

Robby Ackerman · #7 10-14-2014, 01:18 PM

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mannys9130 · #8 10-14-2014, 05:44 PM

Also, I believe if you install a 2* key, it shows up as a 4* change on the crank. So if you're measuring 5* of stretch at the crank pulley, a 3* key would be good.

vstech · #9 10-14-2014, 06:08 PM

Going by the crank by aligning cam marks is not wise...

leathermang · #10 10-14-2014, 08:58 PM

What Vstech said....
I had suspicions ... that is why I asked him to describe how he got his original degree reading....
The chances he used the 2mm movement of the correct valve.... slim....

Diesel911 · #11 10-14-2014, 10:34 PM

Quote:

Originally Posted by Robby Ackerman

Diesel 911 The lowest degree offset key is for 4 degrees of correction

I'll put a 4* key in, adjust the pump about 2* and call it a day. There are a number of keys in my shop and I'm feeling lucky that I'll have a 4 on the shelf. This +/- 1* isn't going to make a noticeable difference to me.

Thanks for everyone else that has weighed in on this. I've read the relevant stretch posts on this website in the past, but don't recall if the break-in spec of 2* was taken into account when talking about total stretch and correction.

Cheers,

While the Timing Chain Stretch changes the Fuel Injection Pump Timing changing the Key on the Camshaft Gear does not change the effects of the Timing Chain Stretch in the Fuel Injection Pump. Since there is no other way to do it the Fuel Injection Pump needs to be retimed seperately.

Diesel911 · #12 10-14-2014, 10:40 PM

Parts of the Manual; but was for use in conjunction with the 2mm Method.

Robby Ackerman · #13 10-27-2014, 10:34 AM

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mannys9130 · #14 10-27-2014, 12:18 PM

0 would be ideal. With everything bang on, the engine will be able to function optimally. 0* difference between cam and crank, with injection timing dead on. That will give you the best possible running.

Robby Ackerman · #15 10-27-2014, 12:30 PM

Thank you!