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TIMING CHAIN HELP!!!

1K views 8 replies 5 participants last post by  Ears 
#1 ·
Hello all,

please excuse this if you have seen on another board. I am in need of some timing chain wisdom.

I have a 1985 Euro 380 SL. After 107,000 miles one of the timing guides broke and the chain developed some slack. Thankfully i discovered this before anything serious happened.

Cut to the wonderful adventure of trying to get at the timing chain which requires too many things to be taken off!

I am now ready reinstall the new chain. I have all new guides, both upper and lower, and a new chain tensioner.

The Number One cylinder is @ TDC and the timing marks on both cam shafts are aligned.

Question: Every time i thread the new chain through and make a complete circut I always seem to have too much slack. I do not have the tensioner installed to make things easier but i even tried installing it once, and rotating the engine, which was a complete disaster because the crank pully skipped a tooth and the drivers side camshaft was so far off that i had to remove it to align the timing marks again.

What am i missing? I am never off any teeth, it just seems like there is to much free play in the chain.

I consulted the MB Service Manual CD (which is worthless BTW) and it provided no insight.

I know i must be doing something wrong but what?

Please, its my only car and i neeed to get back on the road. ANy and all info would be appreciated!

thank you!
 
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#2 ·
Euro380SL said:
Hello all,

please excuse this if you have seen on another board. I am in need of some timing chain wisdom.

I have a 1985 Euro 380 SL. After 107,000 miles one of the timing guides broke and the chain developed some slack. Thankfully i discovered this before anything serious happened.

Cut to the wonderful adventure of trying to get at the timing chain which requires too many things to be taken off!

I am now ready reinstall the new chain. I have all new guides, both upper and lower, and a new chain tensioner.

The Number One cylinder is @ TDC and the timing marks on both cam shafts are aligned.

Question: Every time i thread the new chain through and make a complete circut I always seem to have too much slack. I do not have the tensioner installed to make things easier but i even tried installing it once, and rotating the engine, which was a complete disaster because the crank pully skipped a tooth and the drivers side camshaft was so far off that i had to remove it to align the timing marks again.

What am i missing? I am never off any teeth, it just seems like there is to much free play in the chain.

I consulted the MB Service Manual CD (which is worthless BTW) and it provided no insight.

I know i must be doing something wrong but what?

Please, its my only car and i neeed to get back on the road. ANy and all info would be appreciated!

thank you!

Is the tensioner new? If not, and the plunger is collapsed you will not have proper chain tension for start up.

Dave.
 
#4 ·
You must count the chain links and compare it to the old chain.
 
#5 ·
Thank you all for the responses.

The chain and the chain tensioner are both brand new. Links on the old chain and new chain both match up.

I am beginning to think there is a correct direction to install the chain, so that the slack ends up on the side with the tensioner, thus aloing the fully compressed tensioner to take up the excess.

Has anyone had this happen to them before?

Thanks
 
#6 ·
Euro380SL said:
I am now ready reinstall the new chain. I have all new guides, both upper and lower, and a new chain tensioner.

I missed the part about the new tensioner. Sorry 'bout that. I've done two timing chain replacements, a 4.5 and a 3.8. I did the tensioner and upper guide rails, but not the lower guides. I rolled the chain in from the right bank head with the tensioner in place. Here is a link to the procedure I used. MercedesShopWiki: M117TimingChainI hope this helps.

Dave
 
#8 ·
UPDATE:

Couldnt resist working on it over lunch:

Installed a primed chain tensioner and started from the passenger side camshaft sproket. It threaded nicely all the way around the crank, distributor gear, drivers side sproket. As i threaded it arount the guide sproket and back onto the Pass. cam sproket i was TWO links short.

I dont know how this happens.

There has to be some trick to this, especially since people had to convert eariler cars with the single row timing chain. So someone out there has to know how to thread this chain from scratch (i.e. not linking it to the old chain and rotating it through)

Should i be taking off one of the sprockets, threading it on the chain and then trying to reinstall it on the camshaft?

Anyone.... anyone
 
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