Sequence of events for installing Timing Chain - PeachParts Mercedes-Benz Forum

jassz · #1 05-11-2004, 12:14 AM

Hi guys! I can find a number of threads on timing chain replacement, but none when referring to installing the timing chain after a rebuild. If there is a step by step how-to for engine rebuilds, please direct me there!

To recap... this is a 1981 300TD motor that will be going in to a 1985 chassis. We are at the point where things are reassembled, and it will soon be time to connect the timing chain. We will have to rent a tool to actually crimp it.

The question is about the sequence of events for this. How should things be positioned/aligned at the point when we do the crimping? I assume this is critical for the timing to be correct. If this information is in the manual, hubby can't seem to find it (there are often things that don't seem to follow in logical sequence though).

Thanks!

Stevo · #2 05-11-2004, 12:50 AM

#1 piston at TDC of compression stroke
Cam Notch lined up (lobes more or less pointing up on #1)
now connect the chain
turn engine to 23 degrees BTC (theres a mark on the ballancer)
now line up the mark on the IP and bolt it up
Thats how I did it as I remember. You should get lots of help on this one but thats the general idea if I remember right. Sounds like your making good progress. You can adjust things if you wind up a tooth or two off by bunching the chain and working it around the cam sprocket, which is what I had too do, best of luck

Brad123D · #3 05-11-2004, 01:36 AM

FM says - "The split timing chain with connecting link is used for repairs." and "During an engine overhaul, always install an endless timing chain."

leathermang · #4 05-11-2004, 07:30 AM

Stevo, In your instructions it seems that you are saying to turn the engine ' backwards' to get to 23 degrees BTDC.... did you mean it to sound that way ? The shop manual usually warns against turning it backward .... except for one procedure where it is only turned a couple of degrees.....to take out slack....

By ' connect the chain' ... since this is a rebuild chain install this can not mean connect to the old chain to begin roll in.... (?)....so should the new chain be ' connected ' to itself after moving the crank to 23 BTDC ?
It does present a whole different situation when one can not just attach to the old chain, keep tension on it, adjust the tensioner and slide rail and roll it in....

Brad is correct in what the manual says about endless chains...but I expect that yall already have your replacement chain in hand...

P.E.Haiges · #5 05-11-2004, 09:30 AM

jassz,

For a complete engine rebuild, you would have the crankshaft out of the engine and all the parts out of the chain cavity. So you could use an endless chain by putting it over the crankshaft sprocket, install the crankshaft and let the chain drop thru the empty chain cavity (engine upside down), then install all the parts, including the IP drive sprocket et al, in the chain cavity afterward.

P E H

jassz · #6 05-11-2004, 10:18 AM

Thanks for the replies gentlemen!

We did try to find an endless timing chain, but were told they are not available.

PEH, we did have some discussion about putting the chain in before crankshaft et al, but there was a problem with that. I'm trying to remember what it was, but I think that there was no room to crimp the chain (since it's not endless).

Yes Stevo, please do clarify 23 degrees BTDC. Hey, since you've done this before would you mind coming up and supervising the whole process? :p When you did yours, did you use an endless timing chain?

leathermang · #7 05-11-2004, 10:23 AM

It must have been some other problem.... you could have just put the chain together off the engine and treated it like an endless chain install...
The problem is that you don't have an old chain connected to the sprockets to attach to... to ' roll in' the new chain....
Is the engine already in the car ?

Stevo · #8 05-11-2004, 10:55 AM

"turn the engine ' backwards' to get to 23 degrees BTDC"

I shouldn't think it wouldnt matter which way you turn the engine as long as the IP is NOT installed. What I would do next time is make sure the chain is correct BEFORE installing the IP. (see that the TDC timing mark and cam mark line up) As I remember I could not get an "endless" chain. I used a ball peen hammer and body dolly which worked fine to secure the split link.

jassz · #9 05-11-2004, 10:58 AM

No, the engine is not in the car yet. Should it be?

I'm having a few synaptic misfires this morning (and every morning :p ). I can't quite remember what the deal was with the timing chain going in first. I remember "There is no room to---" and then it's a blank.

I'm pretty sure it was a space problem. If the synapse doesn't restore itself, I'll ask him when he gets home.

GermanStar · #10 05-11-2004, 11:08 AM

Yes, the endless chain is rather like the Yeti -- oft reported, never seen... At least MB doesn't supply them...

leathermang · #11 05-11-2004, 12:11 PM

OK,, if you connect the chain to itself.... then you only want to turn the engine in the normal direction so the chain tension will pulled tight on the side which has the IP ( at whatever point)....Anyway I think the manual says regularly not to turn the engine backwards.....it would turn the oil pump backwards... just everything.... I would avoid it on principle...

R Leo · #12 05-11-2004, 12:23 PM

Be sure to release the tensioner also.

Stevo · #13 05-11-2004, 12:29 PM

"the endless chain is rather like the Yeti "

I got to admit, I didnt look real hard but it just didnt seem that biga deal one way or the other.

Greg..."roll in' the new chain...." I put the new chain around the crank sprocket, and timing device before the pan was installed. Then I set up the cam and conected the chain then turned the engine (either way) to make sure crank & cam were correct. Then stop at 23 degrees BTDC and install the IP with its mark lined up.

bodyart27 · #14 05-11-2004, 01:13 PM

There is a great web article on this site -

http://www.pindelski.com/

it's fee based, but a good picture answers a lot of questions!