Timing Chain - PeachParts Mercedes-Benz Forum

cbum33 · #1 11-06-2014, 11:43 PM

1982 300D

Have a few questions. I bought new timing chain and all the stuff to replace it. Just wondered from looking at another site and his write up what others have had luck with. When I start by cutting the chain do you line up the marks on the cam housing or do you line up the marks on the the balancer to TDC. One site says cam other says balancer and does it really mater?

I have a few pictures to show little confused. First picture is just of the pin. Second picture is where I believe TDC is and the 3rd picture is my chain stretch when the cam housing mark is aligned. I can read that marks on the balancer and can count them down from 80 but there is a pin installed in it that appears to be at about 5 degrees and there is no good indication of 0 or TDC then you go past and can see the numbers going up 10 to 20 and so on. Any insight on what the pin is for or for sure what degree it is set at so I know. Appears to me that my chain has 8 degrees of stretch. Seems pretty straight forward changing this just wondered some thoughts on which to line up and what to expect once get new chain on and tensioner. Will I have to adjust the cam sprocket or anything to get it timed correctly. Any input is greatly appreciated. Pretty new to this but enjoy working on this old girl. Thanks

mach4 · #2 11-07-2014, 01:11 AM

Here's a thread from when I did mine - Chain Replacement Tool

The beginning of the thread is about building a chain tool, but it covers the replacement operation too. The latter posts talk about the crimping operation and how many people have not gotten it right. Make absolutely certain you use the right crimper and have the die positioned properly and you get a good crimp. Don't even think about using the HF chain tool - one member lost an eye trying!

It's immaterial where you start. The idea is to roll in the new chain so everything stays aligned. My tool is one way to ensure that, but you can use zip ties, two people and other strategies. Go slow and be very deliberate. You don't want to allow the chain to jump a tooth. If you roll it in properly everything will be in proper time.

engatwork · #3 11-07-2014, 07:33 AM

Quote:

Go slow and be very deliberate.

x2

Easy job if you follow above instructions. I always use zip ties.

Stretch · #4 11-07-2014, 08:10 AM

I agree too that it is a simple task - however it is mostly simple to those who have done it before! I remember the first time I did something like this on an OM617 and I was pretty nervous. You don't want to cock it up. For this reason using (unnecessary) clues to make you feel better about the job you have done / are doing is totally reasonable. By all means set the crank at TDC and the camshaft notch close to where it should be.

If you are at all worried about doing this job remove the rocker arms from the engine. In this way you can arse about to your heart's content fiddling with the chain - pissing about with the tensioner - whizzing it around (but only in a clockwise direction!!!!) - safe in the knowledge that no valve is going to be hitting a piston crown. Sure removing the rocker arms is extra work - but it enables a pleasant stress free replacement of the timing chain where you only have to concentrate on not dropping the chain down the front of the engine. You don't then have to worry about anything else...

Before you replace the chain, however, remove the camshaft sprocket bolt and check to see if someone has fitted an offset key.

mach4 · #5 11-07-2014, 09:30 AM

Quote:

Originally Posted by Stretch

...Before you replace the chain, however, remove the camshaft sprocket bolt and check to see if someone has fitted an offset key.

Great advise that I don't recall reading anywhere. Wish I'd checked mine to be sure...

Stretch · #6 11-07-2014, 10:06 AM

Quote:

Originally Posted by mach4

Great advise that I don't recall reading anywhere. Wish I'd checked mine to be sure...

..tis an easy check to make if you are willing to undo the bolt on the camshaft sprocket.

KarTek · #7 11-07-2014, 10:23 AM

I find it completely appropriate and somewhat humorous that a guy named "Stretch" is advising on timing chain replacement...

Carry on.

vstech · #8 11-07-2014, 10:46 AM

the pin on the balancer is for the tach sensor on the front of the motors, it's used on turbos up to 84, the pin on other motors is for MB tech diagnostics in shop.

if you go the pull the rocker path, be sure and also remove the glow plugs, or injectors... make it REALLY easy to spin over the motor...

Stretch · #9 11-08-2014, 02:04 AM

Quote:

Originally Posted by KarTek

I find it completely appropriate and somewhat humorous that a guy named "Stretch" is advising on timing chain replacement...

Carry on.

Ha! Purists would be more tickled to hear this advice coming from a chap called "Elongation"!

cbum33 · #10 11-08-2014, 10:49 AM

Thanks for the input. I have the HF crimper and was planning on using it. One highly respected member here recommended it to me. So that comment makes me a little worried.
I have pulled the GP didn't think about leaving the rocker arms off. While I was in here I went ahead and changed the valve stem seals and obviously adjusted the valves. Was starting to get a little smoke out the pipe during warm up and there is a little smoke coming from the oil filler when you take it off. So figured change those while I had the cover off. Hoping to get time to roll the chain in tonight.

mach4 · #11 11-08-2014, 11:39 AM

Quote:

Originally Posted by cbum33

Thanks for the input. I have the HF crimper and was planning on using it. One highly respected member here recommended it to me. So that comment makes me a little worried.

The Harbor Freight tool is not a crimper. It's used to separate a chain. Here is a quote from the post I was referring to...

I am sorry it has been so long since the last update. I had an accident about a month ago, involving this engine. We were attempting to crimp the new masterlink on the timing chain with a tool that we found at harbor freight that we thought might suffice. The tool was a harbor freight chain breaker. (see picture 3) It worked fantastic on the first one. I walked over to watch the second one and the rod on the end(very high carbon cheap steel) shattered. I had just come in the garage and didn't yet have my safety glasses on. So of course out of everywhere it could have gone a 4mm piece entered my left eye. We rushed to the emergency room and thought that the black spot in my iris (see picture 2) was the steel and they would be able to remove it. We later found out that the black spot was just a hole where the steel passed through my iris, shattered my lens, passed through all of the viscerous gell, and punctured my macula, which is the center of your retina, the part that you read with. So I was then rushed to Emory for intensive surgery. I no longer have a lens. Its been an intense recovery process and it has left me partially blind in my left eye(still healing, God is good).

ANYWAY! The moral of the story is wear saftey glasses always and dont buy harbor freight for anything important!!!!

Link to post - Slow and Clean OM617 Turbo Complete Rebuild

Do yourself a favor and rent the correct tool from Rollguy or another member - risking losing an eye is just not worth it. If you're worried about getting the chain rolled in without slipping a tooth you can rent my chain tool as well.

leathermang · #12 11-08-2014, 12:07 PM

Not only was he not wearing his goggles..
BUT they were using it for something IT WAS NOT DESIGNED FOR.....

The idea that people need a special tool for this particular 'crimping' process amazes me.... Many times in these threads the process of using a center punch and two hammers, one as the anvil , has been described..
and for the record .... THIS IS NOT CRIMPING....
it is PEENING....

here are some special tools ...
http://www.amazon.com/s?ie=UTF8&field-keywords=peening%20tool&index=blended&link_code=qs&sourceid=Mozilla-search&tag=mozilla-20

but due to the very tight fit... which to do correctly may require the tool made for this operation....
the actual amount of PEENING needed to keep the chain together is very slight..

It can easily be accomplished by using two two lb hammers and a center punch... and goggles...

hold one hammer solidly against the back side of the pin you need to spread the head on... and hold the center punch in the center OR closer to the edge.... this may be recognized by some of you as the same process of locking Steelite valve seats in place....
You do not have to hit the center punch particular hard ... OR FAST....
careful deliberate blows with the center punch in line with the pin to be mushroomed is all you need... and not much due to the very low side pressure produced by a double roller chain and the very tight fit of the pin.

mach4 · #13 11-08-2014, 02:44 PM

While it may be possible to use the two-hammers-and-a-center-punch method for this job for all the reasons mentioned, as long as there is a proper tool for the job that doesn't put at risk the cam gear and other such things and doesn't cost much to rent, I can't see a lot of upside to the proposition.

...but that's just me - not that I haven't done my share of "make-shift engineering" over the years.

I actually believe that it would be very doable to modify the HF tool to do a proper crimp, safely and professionally...in fact I may just do that just for fun one of these days.

leathermang · #14 11-08-2014, 02:55 PM

How many people have ' the proper tool '?
and it looks like you are not going to accept that what this is is Peening...
the crimping part of the tool's name has to do with the pressing of the side plate on to the pins....
Not spreading the head of the pins....

engatwork · #15 11-08-2014, 05:32 PM

I've got the proper tool and a small ball peen hammer. I have used both to successfully accomplish peening the chain.