timing chain replacement-jammed?! - Page 2 - PeachParts Mercedes-Benz Forum

Tirebiter · #16 02-25-2010, 12:35 AM

This may sound odd, but it happens. If you grind off the ends of the two posts holding one chain link; the outside piece will come right off. The inside piece comes right out from the back side and retains it’s two posts. If you aren’t very careful the piece in the middle of that double roller chain will fall straight down and gravity will keep it between the crank sprocket and the chain itself. You can rotate the engine clockwise but not counterclockwise because the small chain center piece will fall right back down into the same spot.
Take a very strong light and look to see if that is what is happenings. A strong magnet will retrieve it unless you are being stopped by a valve/piston collision. In that case you must rotate the cam sprocket until it no longer hits. This should allow you to turn a bit clockwise so your magnet can fetch it out.
I hope that’s all it is. I learned this the hard way but almost every Mercedes mechanic has seen this or had this happen to them.

compress ignite · #17 02-25-2010, 01:52 AM

LM,

Lightened my Evening.

layback40 · #18 02-25-2010, 06:35 AM

LM,

How does that old saying go "when all else fails, .................."

How many on here have read the instruction book for their mobile phone? Or more likely, how many know where it is.

Maybe we could start a poll ; Who has read the owners manual for their diesel Benz?
Who has a work shop manual for their Benz?
Who has read their w/s manual for their Benz.

leathermang · #19 02-25-2010, 07:56 AM

Quote:

Originally Posted by layback40

LM,

How does that old saying go "when all else fails, .................."

How many on here have read the instruction book for their mobile phone? Or more likely, how many know where it is.

Maybe we could start a poll ; Who has read the owners manual for their diesel Benz?
Who has a work shop manual for their Benz?
Who has read their w/s manual for their Benz.

That saying... 'when all else fails'... is said in JEST in the USA... and usually applies to smaller less complicated and cheaper items than you have tackled.

Who has read their FSM ? Usually people who own one and understand how hard a job they are about to start on.

That saying ... ' when all else fails' also assumes ' no harm done' and being able to backtrack and get the information needed... whereas in your case by not following the instructions and warnings you have created for yourself a huge mess.

leathermang · #20 02-25-2010, 11:15 AM

LOL, since it was a defense of not reading instruction manuals I did not look at the name closely enough..
but the answer applies to YOU.
You have created such a mess by 1. not keeping tension on the chain 2. using the power steering nut to rotate the engine instead of the crank bolt that I think you are going to need to take the front of the engine down a long ways and work back up to get things back into proper position....and extricate the chain.
The good thing is that if you do that you will be able to use a non link chain...just like when they put the engine together originally .... but you know that since you have a Factory Shop Manual....
The FSM has pictures of how to keep the cam sprocket braced in position.

laidbback · #21 02-25-2010, 12:34 PM

Ok well a little update.

I removed the rocker arms and was able to reel the new chain in.

I zeroed the crank and moved the cam to line up in the compression stroke.

I reinstalled the rocker arms and cranked the chain through two times over and no interference.

Next is the ip. Would there be any chance the ip is somewhat close enough to do a drip test? I only say this because it was always moving with the crank and i zeroed everything off the crank at 0.

leathermang · #22 02-25-2010, 01:43 PM

Quote:

Originally Posted by laidbback

I zeroed the crank and moved the cam to line up in the compression stroke.

I reinstalled the rocker arms and cranked the chain through two times over and no interference.

Next is the ip. Would there be any chance the ip is somewhat close enough to do a drip test? I only say this because it was always moving with the crank and i zeroed everything off the crank at 0.

The instructions in the Factory Shop Manual involves setting the IP with regards to a 2 mm movement of the number one valve.
As compared to ' zeroing ' the crank.
Also, I think you mentioned using the dot on the cam sprocket as an indicator... the Factory Shop manual says that is only to be used as a general indicator WHEN PUTTING THE ENGINE TOGETHER ON INITIAL BUILD...thus the chain elongation and things having to do with timing should be determined from something other than that cam mark to be safe.

laidbback · #23 02-25-2010, 01:52 PM

Ok well with all that said, If I did it incorrectly and had it off more that one tooth then it wouldn't cycle through with out interference. I cycled it through a few times with no interference. So I think I am on the right track.

jt20 · #24 02-25-2010, 02:03 PM

if you can cycle through completely, then return the marks to matching positions you are in the clear. You are doing well, keep it up.

was the chain ever disengaged from the injection pump gear?... like when it fell?

leathermang · #25 02-25-2010, 02:09 PM

Quote:

Originally Posted by laidbback

If I did it incorrectly and had it off more that one tooth then it wouldn't cycle through with out interference.

More than one tooth of the cam or the crank ?
Do you have something to reference with regards to that statement .... or are you assuming that ' tooth tolerance limit ' ....and does that apply in both positive and negative tooth offsets ?

laidbback · #26 02-25-2010, 02:19 PM

from what i understand is one tooth off the cam would be 18degrees off the crank.

As it stands now I have both the 0 and pointer on the crank lined up and the notch on the cam lined up and roll it through a complete turn of the cam and its back to 0 on the crank

As far as when my assistant dropped the pass side of the old chain back in, it was still on the crank down below because i dropped the oil pan to make sure of this.

I am going to try a drip test and if im not close it's time to remove the ip

jt20 · #27 02-25-2010, 02:25 PM

Quote:

Originally Posted by laidbback

from what i understand is one tooth off the cam would be 18degrees off the crank.

correct, but one tooth on either cam or crank will return the same result at the crank

Quote:

As it stands now I have both the 0 and pointer on the crank lined up and the notch on the cam lined up and roll it through a complete turn of the cam and its back to 0 on the crank

golden. ...most likely.

Quote:

As far as when my assistant dropped the pass side of the old chain back in, it was still on the crank down below because i dropped the oil pan to make sure of this.

ONLY the passenger side fell? not the side with the IP on it?

your Injection timing may be preserved.

Quote:

I am going to try a drip test and if im not close it's time to remove the ip

perfect.

laidbback · #28 02-25-2010, 03:16 PM

drip test looks good

A little hard to distinguish 1 drip per second since it flows pretty fast then slows to about 1 drip per second for about 10 seconds then it stops about 10 seconds after that. I will search around to make sure thats how it's supposed to be but it seems pretty dead on.

jt20 · #29 02-25-2010, 03:19 PM

your description does not sound right.

you should be timing the drips while the pump has some fuel pressure in it. You can do this a few ways, the most common is to pump the hand primer on the side of the injection pump.

jt20 · #30 02-25-2010, 03:24 PM

a more effective means of using this approach would be:

placing the crank @ 33* before TDC and pump the primer and continue to check the drip while pumping the primer.

advance the crank a little, pump the primer, check the drip rate.

advance the crank a little more, pump the primer, check the drip rate... continue until you find the spot where the drip just about stops completely when you pump the primer.

check the balancer marks, and thats your IP timing.