1979 240D checking chain stretch - Page 8 - PeachParts Mercedes-Benz Forum

snapped_bolt · #**106** 06-22-2016, 05:19 PM

The "FSM" specifies the continuous chain ONLY for an overhaul. This is NOT an overhaul. If Mercedes considered the clip-on master link for timing chain replacement, I am certain that no Mercedes engineer would shake their head at me for crimping the master link on the new chain.

Curious- how you would go about having the entire front of the engine available to place an endless chain? The entire front of these engine blocks are cast integral to the cylinders.

? Machine the front of block, fabricate new cover to ease access
? Remove upper oil pan, pull crank pulley, balance plate, crank seal, sprocket, slip the continuous chain over the crankshaft...

Now why would I want to cherry pick a procedure, take it out of context completely, add it to what I am already doing

...and find the time to do it?

You are aware that "endless chain" is at one point "non-endless chain"? To get a serviceable number of links, the final joint is crimped in place. So the chain I just installed has the same procedure-it came to me cut to length, I made it an endless chain by using the same procedure that IWIS used. When the "FSM" was written, the standard timing chain repair procedure was to use a clip style master link. Times have "chainged".

According to the Sacred Text,

"Note

________________________________________________________

A timing chain with a split link is available for repairs.

If you have only an endless timing chain you can open
it prior to installation (see item 4).

For an engine overhaul, always use the endless type of timing chain.

Check sprockets for scoring and pitting."

- the Sacred FSM, 0.5-4-320/1
© 1980 Mercedes-Benz of North America

In this case, the FSM refers only to "repair" (timing chain, pins, rails guides) and "overhaul" (the whole nine yards; crankshaft OUT). You are incorrect.

I chose:

Quote:

If you have only an endless timing chain you can open
it prior to installation (see item 4).

I returned that chain to being "endless" with the crimping tool.

Did you also notice?

"9 Now proceed in reverse order of removal."

FSM 0.5-4-330/6
© 1980 Mercedes-Benz of North America

This should be welcome news to Haynes manual readers!!!!

Cheers,

snapped_bolt

snapped_bolt · #**107** 07-14-2016, 11:11 AM

to put this car back together!!! It seems like 3 months have passed...

I was waiting on the "not-so-off-the-shelf" parts to arrive. I have no fingernails left.

The 6170520106 "plain shaft" (WTH? there is no shaft, this is a bushing!!!) arrived, and comparing the overall length there is over .020"; the service manual calls out .012mm maximum allowable thrust play at the timing device, this has now been brought back within spec.
The 6151800144 "thrust piece" has a couple of mm worn off, so it was replaced, hopefully now preserving the oil pump drive gear from damage or becoming disconnected from the drive.
I replaced the timing device main body (the "racetrack plate" was removed from my original and reused. My old timing device had rough-looking sprocket gears. The "unfangled" tool I made for installing the timing device was a section of HDPE cut from a 2 1/2 gallon water jug that had not been recycled yet. I just stuck it in on the left side of the timing device, and slid it to the right, around the sprocket, lifting the chain until it sat roughly from 12 to 6 o'clock; the timing device was then pushed onto the shaft. The HDPE "spacer" was removed and the chain snapped onto the timing device sprocket. The chain tensioner was reinstalled, and I am back to a tight chain!
The first time, the timing device didn't want to go, I got it a little off from the Woodruff key and it popped out, so I re-set it in the shaft and the install went smoothly.
Now I have to get the new oil pump installed, lower oil pan, and on to the radiator; installing the injection pump, drip timing, and we're off!!!

Cheers

snapped_bolt

snapped_bolt · #**108** 07-19-2016, 10:06 AM

And the drip timing was easy, or so it seems.
When I was ready to install the IP, the marks were right on; the lock pin I got for it did not fit (newer version of the MW pump). Since it seemed to be content to be at that position, I installed it, and slightly snugged the nuts.
The balancer indicated 24°, so I loosened the line on top of the filter and gave a few pumps. Nothing. I loosened the nuts and rotated the pump a smidge toward the engine, and it was fire hose time. I rotated to retard, and stopped it, then back up near the factory marks, and got a steady drip, one second apart, then tightened the nut.
I replaced the vacuum pump with one off the 300TD since I had rebuilt it recently. My original pump was the newer type; I had removed it to clean it, which required disassembly. When I went to reassemble, for some reason it did not go together properly. I tried 3 times to get it back together, and failed. I'll look into this later.
The older pump was removed from the 300TD along with the metal bracket that bolts on top of the PS bracket. I also now had two lines, rather than a single line. I removed the plug I had installed in the air cleaner lid and dropped in the "exhaust" line from the VP.
While I had things apart, I changed the oil filter once again, this time I had ordered an bunch of small O-rings form that AZ place for the shaft on the oil filter housing. The old ones showed their age- I picked both off the shaft with a toothpick. Both old rings snapped, with pieces flying off with and audible *click* striking the wall. Crispy, and they looked like square section rings.
Remaining- alternator bracket, belts, hoses, top up the cooling system, refill the engine oil, crank it for a minute without the glow plugs connected, and we'll see if she's ready to go. Hopefully!

snapped_bolt

jt20 · #**109** 07-19-2016, 01:39 PM

in post 107, you mention the 'bushing'. is that the brass bushing on the timer shaft?

where did you find that?

also, when placing that 'racetrack', make sure to center it well. the bolt holes provide lots of slop in its placement.

snapped_bolt · #**110** 07-19-2016, 01:53 PM

The bronze bushing behind the timing device? This is the "plain shaft" (as Mercedes calls it) MB# 6170520106. Mine developed wear on the contact fact and the inner diameter. Combined the wear made for a sloppy fit. The new bushing makes it feel like new.
A web search will turn up a few.

snapped_bolt

snapped_bolt · #**111** 07-19-2016, 04:05 PM

I disconnected the glow plug line so I could crank the car and get some oil upstairs before actually starting. Once I re-connected the line, it didn't start.
While that rumbled around in my head I noticed that stupid separate wire going to the battery-hanging free, mocking me. I connected it. Car started. The weird shake at idle is gone, though I haven't even done a valve adjustment. Based on what I see, the engine will probably sit like a bronze statue at idle once the valves are adjusted. It is very responsive to throttle input.
But, so is a new strange noise coming from the front of the engine. It sounds like contact of sheet metal. I need to chase this before the car moves.

For those of you with an "idle shake"- especially if the valves have been adjusted- this car had an idle shake, hot or cold, persistent and regular, not an embarrassing shake, but enough to cause me concern. Replacing the timing chain is a good way to eliminate the shake.

I just want to DRIVE!!! But I have to eliminate that noise before I move the car.
I would post a video but most videos I have seen are inconclusive to me, and apparently to others as well. I would likely get a bunch of responses advising me to pull the crankshaft, adjust the glove box door, etc., I just need to FIX it, and get it over with. If I post a video, it will be one with the engine running smooth!

Cheers!

snapped_bolt

jt20 · #**112** 07-19-2016, 05:15 PM

metal tapping sounds at front of engine:

air filter

auto trans cooling lines

fan clutch

little, pissed off engine nymphs laughing at you for fixing things.

sometimes the engine dampers, or on yours, the rear engine mount.

Last time I replaced a bronze bushing the bolt on the IP shaft loosened up in 4k miles and let the shaft get destroyed. Yes I torqued it to spec. That bolt, once it backs out, will make a tapping noise. Locktite is worth the invested time and brake cleaner to have on there.

jt20 · #**113** 07-19-2016, 05:16 PM

of course.... thats assuming your shiny new chain isn't slapping around ; )

...not to worry you or anything.... just sayin. {diabolical laughter}

snapped_bolt · #**114** 07-19-2016, 05:23 PM

Quote:

little, pissed off engine nymphs laughing at you for fixing things.

It sounds exactly like that!
I did replace the vacuum pump, but that worked fine on the other car.

The bushing is brand new, it's unlikely the cause.

Sounds external. I just don't want to get on my back AGAIN and try to figure out where this is coming from.

snapped_bolt

jt20 · #**115** 07-19-2016, 05:34 PM

not the bushing, the bolt that goes through the front of the timer and attaches the timer to the shaft.

Im not really suggesting that it is the culprit. just another thing on my mind I immediately jump to because I was traumatized by that event.

got any 2x4 around? its a great way to find knocking noises. Just pry on different spots with the engine running... no back torture required!

snapped_bolt · #**116** 07-20-2016, 09:37 PM

After removing the cam sprocket, the idler sprocket and pin, the upper timing chain guide and pin, the vacuum pump, I was ready to remove the timing device. I removed the bolt, and fabricated sprocket tool #3 to rotate around the timing device to pull the chain away from the sprocket so the timing device can be removed. But tool #3 stopped at about 3 o'clock-
That #@%!! chain retainer, the bolt that comes in from the side of the block to keep the chain from hopping off the timing device sprocket, was stopping the progress with the incredibly hi-tech tool #3 from rolling the chain off. I removed the bolt; I was unable to find information on setting the bolt depth/torque; for certain I won't run it in so far this time, perhaps a cut washer would provide the additional clearance needed. The bolt has tracks from the chain cutting into it; whatever metal is there is of a "sacrificial" nature, not case-hardened tool steel. The cuts from the chain are so recent that they were clean- no black oil deposits. The cut wasn't there a couple of weeks ago when I removed it at first.

Anybody know if there is a way to set these? Mercedes makes a tool to remove the chain; it has got to be an awfully thin sheet of metal to pass by the bolt. I am just using "Sprocket Tool #3", which is just a piece of HDPE water jug that will slip around between the timing chain and sprocket. Unless the bolt is in the way; the HDPE is too flexible as it is being rotated around the sprocket, and runs into the bolt.

Any good ideas appreciated!

Thanks!

snapped_bolt

jt20 · #**117** 07-20-2016, 09:51 PM

you are so lucky I like you.

wild guess:

you did not put the bolt back on with a crush washer.

(okay, maybe not so 'wild' ... been there, took me forever to fig'r out)

jt20 · #**118** 07-20-2016, 09:53 PM

it is a surprisingly soft bolt. I was worried my chain was ruined when I saw that!

snapped_bolt · #**119** 07-20-2016, 09:58 PM

I did use the original crush washer...and it was quite crushed. I also found 2 o-rings on the bolt.
I don't know if I have a crush washer that size- it looks thinned by never having been replaced, but tightened repeatedly to stop a leak.
I was going to add a cut washer just to back off the bolt tip from the chain.

snapped_bolt

jt20 · #**120** 07-20-2016, 10:02 PM

I made a timing chain tool out of thin sheet metal... must have been around a 1/16 or or less.

fits right in. But I remove the bolt these days... I have had enough battles.

the machines will always win.