Mercedes-Benz Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
Well first of all I would like to say hello to all being that this is my first post. Here is my problem I have a 79 300SD that started knocking real bad. I am a mechanic but never have worked on diesels. A friend that was a diesel tech in the navy for 20 years helped me narrow it down to a con rod bearing. I don't want to rebuild it because I don't have the time to do so. I need a long block or complete engine. I live in San Diego CA and need to find some one that has one. Any help would be great! Thanks again
 

·
Registered
Joined
·
6,118 Posts
Are you sure its not a injector pouring diesel into the cylinder? Crack each injector line and when you find the bad cylinder, swap the injector out to a different cylinder and see if the noise changes.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #4
Ok I will check that out. My friend that worked on the diesels had me crack the lines on each injector intell the knock went away. I got to cyl 1 and the knock went away mostly when I released the line. I pulled the lower oil pan but there was no play in con rod 1. Thanks for the reply
 

·
Registered
Joined
·
5 Posts
Discussion Starter #6
When I release the psi at the injector the knock go's away 70%. I can still hear a small bit of knocking. When it first happened I was driving up a steep grade going to work and all of a sudden I lost a lot of power then it came back up.. odd. Once I got to work and in the parking lot I could hear the knocking noise loudly. At highway speeds the knocking go's away 80%. I figured spun con rod bearing since the car was not smoking badly like a bad injector would do and go's away at highway speeds. Even now the car has great power which also leads me to believe a bearing fail not a fuel delivery problem.
 

·
Registered
Joined
·
2,653 Posts
I have driven an OM617 with rod knock that didn't sound as loud on the freeway compared to when it was clanking away while at idle. It very well might be that there is something else going on internally.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #8
Yea it's toast I did the injector swap tonight.. no change. Thanks a bunch guys for the replys. A sad end to a beautifull car might just have to scrap it. Hard to find parts for that car for some reason. Thanks again all
 

·
Registered
Joined
·
626 Posts
Find a good machine shop, pull the engine & work with them to rebuild it. Its not that expensive if you dis-assemble & reassemble the engine yourself & very doable if you have transportation, as the vehicle will be out of action for the duration. Depending on the shop you use, you may be able to negotiate a deal with them to tear down & reassemble it for you yet still get by for less than the cost of a complete long block from a rebuilder.
 

·
Registered
Joined
·
2,653 Posts
There are engines out there. W116's are great cars, if the rest of the car is in good shape it's well worth putting an engine into it. Since you're in San Diego, I think you can get engines from Ecology. Ask around or even post a wanted ad in the forum I am sure you will get some bites. Call Sun Valley Auto Dismantlers and see what they have up in Sun Valley on the north end of LA, it's a bit of a hike but it's doable.
 

·
Registered
Joined
·
2,653 Posts
Yes it will fit. The engines are essentially the same. In terms of output the OM617 motors in later cars had more power. Yours is only 110hp (new) and the later engines were 125hp (new).

I can't say exactly how the throttle linkages will fit but you can probably swap what you need off the old motor.
 
1 - 12 of 12 Posts
About this Discussion
11 Replies
4 Participants
diametricalbenz
Mercedes-Benz Forum
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!
Full Forum Listing
Top