Extremely tight timing chain

[gordon]

Hi, I'm rebuilding my 230 sl engine,  that head is back on and I am now fitting the new timing chain (item 09271 from SLS).  The tails of the chain when they meet the cam sprocket appear to be 1 link short even though the chain tensioner is not yet fitted. I removed the tensioner sprocket and was then able to  join the chain.  I have been able to lever the chain tensioner sprocket into place but this gives an extremely tight chain and this is without the chain adjuster fitted.

I haven't yet rotated the engine.  Should I be worried?      I couldn't find this topic on the forum.  Thanks, Gordon

[ja17]

Be careful you have it routed correctly Gordon. Make sure it is on the correct side of the oil pressure relief valve in the block. Sounds like you might have it routed incorrectly or might have it kinked some place.

[gordon]

Should there be some slack in the chain prior to operating the tensioner?  I would imagine there should be even with a new chain or are they usually tight?

[cfm65@me.com]

Hi Gordon,
There should be quite a bit of slack with the tentioner removed. I am with Joe, recheck the routing and also check the valve timing. In other words, check if the cam and crank are in the correct position before hooking up the chain link. One of the shafts( cam or chrank) might be a few degrees off, causing the chain to hang loose at the bottom or the chain riding on one of the teeth.
I think the difference between a new and old chain could be very little and only really noticeable that the marks don't quite line up.
Regards
Chris

[Pawel66]

Maybe just from simple minded amateur perspective (just been through chain replacement): it sounds quite serious if experienced fellow members are talking routing and timing. I would also, as a first step, pull it out again and both count it's pieces (there is info on forum how many should there be) and compare it's length with the old chain. Well, unless you did that already...

[gordon]

Hi, thanks for the responses. I checked for kinks and routing again  and as all looked as it should be I rotated it all and all is well. Everything returned to the previous timing settings The chain is tight and the unfilled  chain adjuster is in place.

Iam just surprised that there is no slack in the chain for the adjuster to take up at this stage!    Have others experienced this?

[ctaylor738]

No.  That's not normal at all.  There should be slack for the tensioner to take up. You may have installed the slide rail on the left side of the engine upside down.

[gordon]

Hi Chuck,  I didn't remove the chain guide as it looked ok.    Can it be installed upsidedown as the fixings appear to be symmetrical on the SLS schematic and the chain fed down and around the crank without difficulty?

[ja17]

The correct timing chain has 134 links.  Count every pin as one. You should have 134 total.

[Pawel66]

If you find there is something wrong with the chain length from SLS, in MB they are not terribly expensive (I think ca$80 when I bought it in November LY). The only caution is I got it with press-in link, which was difficult for me to install. Good when I bought the chain, I also ordered a spare joining link, which I ended up using (it was with two clips).

[ctaylor738]

The guide on the lower left, shown as 36 in the SLS catalog, can be installed with the long side up or down.  The Haynes manual shows it up, and SLS shows it down.  I believe down is correct.  I put an engine together several years ago as shown in Haynes and the chain would bind.

[gordon]

Thanks for the info. There are 134 links on the new chain, same as the old one.  Regarding the chain guides  my book shows the lower small chain guide pointing  upwards and the SLS drawing shows the other way which is the way I fitted it.  I wonder if the long guide is the wrong way round although I didn't move it.

Can anyone saw for sure which way they should face although the long guide looks symmetrical to me

[mbzse]

.../... chain guides  my book shows the lower small chain guide pointing upwards and the SLS drawing shows the other way which is the way I fitted it../...

You can look at this posting
https://www.sl113.org/forums/index.php?topic=12444.msg84310#msg84310
I made that illustration showing chain routing (SLS later "borrowed" it)
What is the "my book" you mention?  The most relevant literature is of course BBB workshop manual from M-B.