If someone wanted to determine if they had the original chain they could inspect it to see if it has a master link. When the engine is assembled at the factory the front is open.. so they put on a chain with no master link.... seldom would it get rebuilt later in that style.... so ' no master link' pretty much means original chain.

I think it dangerous to use motorcycle chains and sprockets as the way we conceptualize our chain and the wear characteristics. While some motorcycles had enclosed chains and good oiling systems... most did not...and the quality of the sprockets may not be in keeping with what MB puts on their high dollar engines. This is also a double roller chain.. side pressures and load spread would be very different...
If you compare 10,000 mile increments on the engine... the most relative wear will occur in the first 10,000 miles.... compared to for instance the time from 190,000 to 200,000. I do not remember what increment they use.. but this concept is straight from the Factory Shop Manual ( Surprise,Surprise .. for those of you that know me )....
New chains and ' touch feely' peripherals are so cheap compared to the damage done by a lockup ( typically bending valves and potentially breaking pistons ) that I would think it prudent to change out the stuff somewhere in the 200,000 to 250,000 mile range.

can you elaborate on 'open'? How is the front originally installed?

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Wanted to update this thread as I refueled for the 1st time since the repair.

The good - the car clearly drives better - there is less lag between hitting the throttle and feeling acceleration, and less of a lurch after lifting off of the throttle. Also, when going down a hill with no throttle, but at mid-high rpm, the enigne doesn't have a particular grumble I had noticed but not thought much about.

The bad - 20.7 mpg. I thought I was getting better mileage b/c I was getting 70 miles per 1/4 mark on the gauge, but the last quarter fell pretty quick - this is a slight improvement, but obviously not where I had hoped to be.....

I did have a fuel leak for a few miles from a return line that had slipped off the injector, and I neeed to do some suspension work, but I don't think this accounts for the 6-8 mpg I was hoping to recover.

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Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

Thats no good, I would start with the easy stuff, brake dragging, spedo error, leaking fuel from the "usual' places and then timing. 20.7 mpg is supper bad. Good hunting

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Thanks Stevo,

I have already checked brake dragging, speedo calibration, and fuel lines.....there is some fuel weeping from the first injector, and the third injector is moist on top.

Still, it's not a puddle of fuel, so I doubt that that is responsible for the super bad mileage......

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Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

Hummm, the only thing left I can think of, which will cause poor milage is "reverse slipstream syndrome". Only effects red cars which drive mostly in an east, west direction. Or the calculator you've been using was submerged in a flood.

Seriously, since the thread is kinda old, you might summarize the things you have done and perhaps someone can come up with an idea. Around here where theres not allot of freeway driving 240Ds usually get 30+MPG.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Is it true that the pulley on the front of the crankshaft, and the balancer, have to come off in order to replace the long chain rail? I think I read somewhere that the pin holding the rail is behind the balancer.

Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

So far I have adjused the valves, replaced the soft brake lines and checked to make sure the calipers are not grabbing. I have tested the odo to make sure it is measuring properly, I have replaced fuel lines that were moist, including the braided return lines, I have installed a 5* offset key to remove some of the chain stretch, I have replaced the air filter, and front shocks.

Still a problem:

The DS tie rod has a little crack and the PS tie rod ends wiggle. There is a sproingy clunk when I turn the wheel with the car not moving and a bit of a chunk sound over some bumps.

The control arms seem ok, but the DS wheel hub has soe play in it, and the PS wheel has play that appears to be due to the tie rod ends being loose (they wiggle with the wheel)

So I am wondering if the suspension issues are related to the low milage.

As I said earlier, there is some fuel weep from 2 of the 4 injectors.....I may try to resolve that this weekend - I have some spare crush washers.

__________________

Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

Zeke, I have done this twice. You will get many opinions but 8 deg of stretch is way excessive. When I did my "85 300TD I had 8 deg of stretch on a motor with 275K.The tensioner rail looked OK and I left it. Put in a new tensioner but could have put in just a new spring if I could have found one. The guide rail was cracked clear thru and ready to fly apart and kill the engine!! Jeez, got lucky! The rail comes out with a series of metric bolts and washers from ace hardware. I rolled in the chain with my wife's help. 10 minute job. You must not let the chain slip on the sprocket! I have a very careful wife. I put the master link in with my german crimping tool in 5 minutes and you can't tell my crimp from the factory crimps. Hand peening seems an absurd risk for a tool you can resell here on this site. The biggest job is not the chain and tensioner. It's taking out the thermostat hosing, new coolant, new short hose etc which you should do while you're in there. BTW, the car runs and starts much better, mpg is up 1-2 mpg and noticeable increase in power but I put in flow balanced injectors at the same time so everything contributed I guess. Don't worry about the lower chain. It's bathed in oil when it's running. Keep your oil clean. Dirty oil is what wears out chains.

Thanks Hugh,

Looks like I will be doing this job a bit later this year - first I will be replacing my injectors.

I am a bit scared about the difficulty of replacing the rails, etc...and the crimping - guess I will break down and get the german tool.....

__________________

Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

My Indy said 1.5 hours for rolling out chain. He only work on Mercedes.

He charges $75 per hour. I don't know if this is going rate or not.

Chain and link bout $160 at Phils. So for me it would cost $250-$300 labor and parts.

I guess add an hour to adjust valves and you are well over $300.

I've done timing chains but never rolled one out.

I would need a "sexxie blonde" to assist as you are supposed to need a "helper".

This is not a job I'd want to do but many here have this on this site.

Roy (whunter) says only use IWIS (OEM chain and master link).

Phil sells them.

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1982 300SD

Can I ask you how you calculate your fuel mileage?

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1982 240D auto
1978 300CD auto
1985 300D auto
1983 300TD auto
1984 Porsche 944 5 speed
1973 Opel GT 1900 4 speed
1967 Chevy C30 350 Sm420
1973 Mustang Grande Convertible 302 C4
1981 VW Pickup 1.6D Turbo 5 speed
1983 Rabbit 1.6D Factory Turbo 5 speed
Plus parts vehicles...

If you can get your chain replaced and valves adjusted for total parts and labor cost of under $400 bucks, go for it. That's dirt cheap.

What about the guides?

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Question Authority before it Questions you.

Maybe some chain experts here can help with this question. Last time I adjusted valves(maybe a year and a half ago) just for kicks I pushed on the chain with my index finger just below and to the right of the cam sprocket to see if there was any play there, there wasn't any. Next,I grabbed the top of the chain at the top of the cam sprocket with two fingers and tried to move the chain in a horizontal plane. I was able to move the chain in a horizontal plane. Is this normal to be able to move a chain horizontally on top of the sprocket. There's no mechanical science involved here, just an observation.

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1981 240d
Newport,RI

while your that far into your engine, it's a good time to check for chain stretch. rotate the engine (clockwise) to TDC, check the marks on cam sprocket and bearing tower, if over 3 or 4 degrees consider new chain; not a terrible job. As to your question the difference in verticle lift between an old chain and a new one is noticed most after you change it; mine was slapping the inside of the valve cover and sounded really bad. It was actually a great warning signal. Many Blessings.
84 300td
85 300td