1981 380SL Timing chain replacement

[Gilliac]

I am a fair mechanic but mostly American V-8s. I have a 1981 380SL that has the dreaded single row timing chain. The chain was replaced at about 40K (before I owned it) and now at 80K it is time to do it again.

I found a video on YouTube but it was for a double row chain (https://www.youtube.com/watch?v=7DQdGlSLMLM)

Is there any difference in the procedure for a single row chain?

I plan to do the chain, three guides, and the tensioner. Besides a new fan clutch and valve cover gaskets, do I need to do any thing else?

Thanks for the help

Gil

[Benz Dr.]

I would also do the oiler kits.

The single row chain is more difficult to change that the dual row. It has a way of slipping off the gears while being fed through the chain case. If this happens you will find out what grief is all about. Gears may also be worn.

[christopher@rywelski.com]

I just completed a single row chain replacement on my '83 380SL. It too was (reportedly) replaced by the previous owner but as he couldn't supply any proof, I took it upon myself to tackle this job. I'm not an experienced mechanic and it was (one of) the most difficult that I've done to date. Although it references a "double row", this YouTube video was instrumental in helping. https://youtu.be/7DQdGlSLMLM

As with any job, it's always good to know what parts you'll need prior to starting and the video opens with a complete overview.

As Benz Dr. suggested, I too replaced the oil filler tubes, valve gaskets, belts and generally cleaned up the alternator, power steering pump and related brackets.

The "double row" appears much easier as it can be purchased with "circlips". All the "single row" replacement chains come with a "master plate" and "master link"...which need to be properly peened. I'd purchased a (relatively) inexpensive chain riveter off Amazon, and it was a complete PoS. After a number of different (failed) methods, I wound up paying a mechanic (took :02 minutes with his specialized MB die/chain riveter) to join the master link. Simply, I didn't trust my abilities with this part because simply, if the link isn't properly peened, then the chain will break apart.

The only other advice I would offer is to be extremely careful with removing wire from the distributor to the ignition module. The distributor had to be removed to get to the pin holding in one of the rails and the wire was so old and brittle it fell apart in my hands..but in the process, likely damaged my distributor. The pickups inside the distributor are quite delicate. Simply, after replacing the guides and chain, I had to battle finding out why it wouldn't turn over and it came down to the distributor.

I've been benefitted greatly by contributors herein (thank you all)...so hope my perspective helps...I'll keep an eye on this thread to see if there's anything further that I can offer.

[corbitt]

I am not much of a mechanic, but isn't it cost-effective to replace the single timing chain with the more reliable double? I am just curious, for when this becomes necessary for my 1981 380SL. Corbitt

[rocky raccoon]

corbitt; Not in terms of "cost effectiveness". To backfit a double-row chain to an early 380SL is about a $6k job since it requires engine out or at least a front end dismantle. If I had a single-row engine, I think I would prefer to simply plan a preventive chain replacement every 50 to 60k miles at a cost of less than $1k..

Note: '84 and '85 380SL had factory dual row chains.

[Gilliac]

Guys, thanks for the advice. I am going to spend next week trying to get this done - new single row chain, upper guides, tensioner and plastic oilers.

One last question, since I will have to remove the alternator for access to the guide pin, has anyone replaced the MB unit with a Delco CS130? Living in Louisiana (it's HOT!!) I want to add dual electric fans and I don't think the stock alternator will cut it.

[rocky raccoon]

Please get back to us with a status. Thanks.