1981 SL timing chain

[corbitt]

Not knowing the history of my 1981 380SL timing chain, it seems prudent to replace it. The car has 80K miles. It is discouraging to know that MB stopped producing the 1981 single chain. What is the typical US price to replace the single chain and the cost to convert the engine to a double chain?

The lifespan of a single chain is 30-50K miles. What is the lifespan of the double chain? I know that conversion to a double chain costs more, but is it perhaps a better long-term value? Thank you. You people are smart!

[Frank Reiner]

To convert to a double row chain, as you likely know, involves disassembly of the front of the engine; all pulleys, the crankshaft hub, accessories, water pump, timing cover, and five sprockets & the chain.
Even though MB may no longer supply the single row chain, it can be obtained on the aftermarket. At an average use of 2000 miles/year, regular 25 year replacement of the single row chain, and the tensioner, is certain to be the practical approach.

[Graham]

Frank's math is fine IF the chain does not fail.

Actually, those metal chains don't fail that easily. It could be the plastic guides that fail first, likely causing the chain to jump. Weak tensioner could presumably also allow enough slack to allow chain to jump.

Result is often disastrous and engine has to be replaced.

You might go over to the Benzworld R/C107 forum. This has been discussed there many times. Here is one report:
https://www.benzworld.org/threads/1985-380-sl-timing-chain-failure.1644228/

I don't have any good suggestions Maybe if teh car is pristine, it may be worth having it converted to double chain. Or maybe install a different engine.

[hercules]

The chain stretches, the top gears wear out, the tensioner backs off (poor design), chain jumps, extra stress of valves hitting pistons may pop chain.
All engines were double row chains, untill new engineers thought the old guys did not know what they were doing and of course money talks.
Twelve hr. job.
If before engine breaks replace chain,top gears,tensioner,ck.guide rails as best as poss.
at 50,000miles change over to double row chain at least by 90,000 miles.
Use good quality oils.

[Sugar Bear]

Are you certain yours is still a single row? At 80k if it is converted you could probably subtract 30k from when it was replaced reducing it 50k on a double row and your still good for many miles.

If it is single row at least replace it ASAP with an aftermarket single row to protect the engine.

Good luck!!!