6.9 timing chain replacement

[WGB]

Today I removed my camcovers, alternator mounting bracket, plugs and leads and then removed the chain tensioner.

I had an original chain so ground the ends off a link with my Dremel and then connected and pulled through a new M-B genuine chain (Chain and tensioner purchased from the Classic Centre, Irvine, California).

As I do not own an M-B valve spring compressor I could not remove the cam followers to disconnect the Right Hand Cam so carefully using the "three Vice-Grip Method" I slowly fed through the chain turning the motor over with a 22 mm spanner on the end of the power steering pulley as recomended by Styria.

I own the necessary 50mm socket but it would probably have required removing the fan to use it and the power steering nut was perfectly adequate after the belt tension had been set to specifications (using a Crikit).

I found religeon a few times when the Right cam would go down the back of the cam and cause the sprocket to jump forward with a lurch but I never jumped a tooth and was greatly relieved when the first link came around and slotted into exactly the correct adjacent sprocket to the other end - just required the master link to be fitted and the spring clip fitted.

End result was 16 degrees of chain stretch is now 2 degrees.

I have not fitted the tensioner as I need a new sealing ring and I 'll see what is in the local shops tomorrow but have ordered one at the agents.
I also have a package coming from AutohausAZ and this includes a selection of offset keys.
The Right and left cams appear to be in perfect alignment so I am assuming 2 degrees of advance to the RH sprocket will correct all - we will see.

I have taken photos of the whole procedure and am happy to make a pictorial of them if anyone is interested.

Bill

 

[Styria]

Hi WGB, if not too time consuming for you, photos would be great. Last time we replaced a chain, I used plastic ties to hold the chain onto the sprockets - you use a lot of them but it's pretty foolproof - just don't forget to cut the ties as they start disappearing down the black holes ! Regards Styria

 

[WGB]

I will do the pictorial when I have time Styria.

I used the plastic tie method when I did my 450 chain and found I needed two per time or the chain would jump.

The "Vice-Grip" Method I found on the M-100 site and was more secure and probably quicker.

While doing it I had a sudden recall of seeing Frank Burton of Franks Auto Services in Caversham , Dunedin, New Zealand (Probably the best known Mercedes Mechanic in New Zealand for about three decades) pulling a chain into a 126 using the starter motor. It was in the early 80's and at the time M-B had tried fitting single row chains to M116/7 motors and they all needed replacing at 20,000 Km. I guess he removed the right bank rocker arms first.

Bill

 

[Styria]

Hi WGB, I reckon it would take a brave, and very confident, man to use the starter motor to fit in the new chain.

I guess every once in a long while you'll come across a person with that sort of mechanical knowledge and gift - but they are very few and far between. Regards Styria

 

[s class]

wow - winding the chain through with the starter sounds like russian roulette. I'll stick to the vise-grip method thank you.

Bill I'll be interested to hear how you get on with the offset keys - I found that I had to separate the chain again over each cam sproket to get the sprocket off. Be very careful as once you lift the two ends of the chain off the sprocket in question, both cams are likely to rotate one way or the other due to valve spring pressure. Make sure you mark the chain and sprockets with alignment marks.

Its probably a bit of a butcher technique, but I held each camshaft very firmly with a visegrip, and held the visegrips by wiring them to something immovable to prevent the cams turning. Obvousl the visegips go on the camshaft between the cam lobes, not on the lobes.

 

[Styria]

Sorry to butt in guys, but I had seen the vise grips in one of the pics. and had scratched my head as to why they were there and their purpose. S-Class - the plastic tie method - it does not appeal to you / I thought that the use of vise grips was a bit chancy. Regards Styria

 

[s class]

I tried the plastic tie method on the 450 and ended up switching to the visegrip method. It goes quickly, but I think the trick is to clamp the visegrips with JUST enough pressure to hold, and not so much as to mark the chain. Wrapping the jaws of the visegrips with duct-tape is helpful in this regard.

In my limited experience, I have nothing against the cable tie method. I'm sure it works just as well if proper care is taken. My post was not suggesting that I think the visegrips are superior to the cable ties - I was merely relating how I did the job.

 

[Styria]

Hi S-Class, that was fully understood. I had only ever seen the plastic tie method being used and was not aware that visegrips would do the job as well, if not better. Regards Styria

 

[WGB]

I have used both methods and feel the Vice-grip method is easier and more secure. My 450 chain jumped twice when I used Cable-ties until I started using two ties at a timebut I had no way of removing the lifters from the RH Cam.

The timing chain is so hardened that it would be almost impossible to mark the chain with the sort of pressures required to hold the chain with vice-grips.

I originally viewed a pictorial via the M-100 site and purchased a pair of Vicegrips with the same jaw pattern as was on that post. I tried to purchase three but could only find two on the day and decided that the old chain was of less significance so I would use what I had on that.

The Jaw pattern can be seen on the pictorial I have posted here.

I will either make or buy a valve lifter before I tackle my next chain.

Bill