Timing chain - Page 2 - PeachParts Mercedes-Benz Forum

kbannister · #16 07-23-2006, 07:35 AM

Milt...

The two "c" clips are used to secure the master link to the chain. Insert the master link through the firewall side of the chain, add one of the link plates in the middle of the chain then the outer plate. Secure the c clips to the outside of the link. Be CARFULL not
to drop one of them.

Tomguy · #17 07-23-2006, 11:59 AM

Those "C" clips are for permanent use, AFAIK. If you think about it, that part of the chain (outside the outer links) does not move at ALL. If you're paranoid you can crimp the chain if you have the tool, but I trust those C clips just fine.

Dog, I don't think that large "Nut" is supposed to be removed, but I can't say for certian. I reused my old tensioner because it worked fine - I can't say if they're all reusable but I wouldn't see why not. And like I said, I left mine tight the entire time. I suppose if you aren't careful it COULD pull the cam backwards, but that's only if you don't have the chain on the front edge of it.

milterino · #18 07-23-2006, 10:57 PM

Once again, thanks for your imput. I feel better now about using the "C" they sent with the chain. Milt.

milterino · #19 08-18-2006, 12:55 AM

Well, I have finally got my new timing chain in. With the help of Tomguy's DIY article the installation went relatively smoothly. Of possible interest to others. I lost one of those tiny C clips down into the engine and was lucky to be able to find it with a magnet. From then on I greased the clip with heavy grease and this facilitated working with those tiny things. Instead of vise grips I bought (3] 2" C clamps at Walmart. I ground a slot on the fixed end of the clamps and matched the slot to the sprocket holes. This worked pretty well. Had to remove the battery and battery tray in order to rotate sprocket in 90 degree increments. The C.D. says that there are 181 links in the timing chain. This is a typo, there are 81. Had a tough time breaking loose the bolts on the pulley. Found that a 2 1/2" pipe wrench would hold the hub enough to permit breaking the bolts loose. I did use the inside coupler from the old chain as the outside coupler when attaching the old chain to the new chain. After feeding the old chain thru I attached the ends of the new chain using the tight fitting coupler that they enclosed in the package. Large pliars supplied sufficient pressure to seat the coupler.
The reading for my old chain was 12 degree ATDC. The reading for the new chain was something like 7 degree ATDC. I did not change the guiderails but intend to next.
Now, the problem is that it is running hot. It used to run consistently at close to 175 degrees on the highway. It is now running at about 10 degrees higher on the highway and another 10 or 15 degrees higher than that in town. The timing at 2500 rpm is 28 BTDC and at 3300 rpm it is 33 degrees BTDC. This seems to be what close to what the C.D. calls for.
My question is is there anything that would occurr in a timing chain change that would cause my heating problem. Once again, thanks to Tomguy for that DIY article. Milt.

Lostyankee · #20 08-18-2006, 01:30 AM

Posting dates are getting a bit wierd but in case someone else is about to do this:
http://dieselgiant.com/replacetimingchain.htm
I'd still want two sets of hands doing this job, one guy holds the chain while the other spins the engine.
Have you checked the guides and tensionar?
Keep plenty of clean rags around to stuff in the 'holes' that are just waiting for you to drop some small metal part ... I like magnets & rags for insurance.
With 12 degrees I bet someone adjusted the dist (I believe it was posted as a gasser).
The cost of guides and tensioner is = to doing the job over again if you catch it before CATO.

milterino · #21 08-18-2006, 12:15 PM

Yankee, I intend to replace the three top guiderails. they are the plastic variety. I can get to these without taking off the timing cover. Engine is 117.986. Hadn't considered the tensioner but perhaps will. The 12 degrees ATDC I referred to was the relationship between the camshaft-tower mark and the pointer-damper mark. You mentioned the timing. Are you suggesting that a tooth was skipped at some time. As Tom mentioned, a tooth on the sprocket (10 degrees) is equal to 20 degrees on the crankshaft. That would have throw things all out of kilter wouldn't it? The car never operated like it had any problems and it doesn't now except for the heating. The reason I changed the timing chain was that it was old and I occasionally heard clattering noises up there. I mentioned the spark timing as I had heard that if timing was too advanced it would cause an engine to run hot. Still puzzled. Am wondering if it is a coincidental failure in some part of the cooling system. I thought I might start by taking out the thermostat. that should be fairly easy. Any other suggestions welcome. Milt.

Lostyankee · #22 08-19-2006, 02:17 AM

I'm not a gasser expert.
One tooth should = 20* & crash pistons into valves. Some believe this happens at shut off and the 'backlash' jumps a tooth. Then you have at least bent valves and at worst most of the goodies from the crank up.
I have seen gassers that had the timing adjusted to compensate for chain stretch. Now that you have a good chain and maybe compensated dist. adjustment, you may need to adjust the timing (dist.) back to origional spec.
Some posters like to drill a few small holes in the thermostat to allways allow some flow in diesel beasties. Is your aux. electric fan working?

milterino · #23 08-19-2006, 01:00 PM

The auxiliary fan does operate when the motor heat gets high. I don't think I understand the timing process. Is the centrifugal timing dependent on what I will call the idle timing? For instance suppose that my idle timing was set at 8*btdc and the centrifugal timing for this car at 3300 rpm was 33* btdc. If I advanced the idle timing to 12*btdc would the centrifugal timing at 3300rpm be 4* higher or 37*btdc? Or are they independent of each other ie changing idle timing by swiveling the distributor has no effect on the high rpm centrifugal timing. Milt.

Tomguy · #24 08-19-2006, 01:43 PM

Changing the idle timing changes the advance timing as well - since that is dependent upon the initial position of the distributor. You should set idle, then verify timing at speed - if they don't match, then your mechanical advance is probably worn or possibly stuck. The springs do stretch out and lose their original tension properties after 30 years! It's more time than miles with this one I believe.

You still have 7° of stretch AFTER putting the new chain on? Do those top rails ASAP! I kept my old rails (the original metal ones) and only had about 1-2° of stretch, down from my initial 12. Also, keep in mind that chain drives the distributor, if it's stretched, replacing it will change your timing.

milterino · #25 08-19-2006, 10:38 PM

O.K. Thanks for the help. Now I am going to start switching parts with my donor car to try and isolate the heating problem. Milt.

milterino · #26 12-04-2006, 11:42 PM

The rest of the story. As it turns out the mechanic tells me my timing was allright so I did it correctly after all. Of interest is that coincidentally with changing the timing chain the tempeture gage sensor in the block and the fuel distributor went goofy so it was doubly perplexing to try and figure what was going wrong. Had to take it to a mechanic to get it cured. He said that he adjusted the fuel distributor as well as he could but it still is not running correctly. The rich mixture has been eliminated as the plugs are not sooting up like they were and the mileage seems to be what it was before the fuel distributor went goofy however the cold starting and the warm starting are definitely worse than before. Are these fuel distributors that sensitive that it takes a PHD in Mercedes to adjust them? Along these lines I bought a fuel pressure gage at Harbor Freight for $10. It says it goes up to 100 PSI but also says doesn"t work on K jetronic. The system pressure on my car says 5.5 athmospheres or times 14.7 lbs comes to about 80 lbs. If I can get the right fittings I am going to try it on my car (outside) to see what happens. What do you think? Another question, I seperated the gas feed tube from the injector and turned the motor over at battery speed and no fuel came out. When you do this should fuel come out of a fuel injected system. I have had no experience with a fuel injected motor except this one. Milt.

milterino · #27 12-05-2006, 12:06 AM

In article 19 I said the C.D. was wrong about the number of links in the timeing chain. I was wrong, the C.D. was correct. Milt.