Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: balder on February 24, 2021, 21:54:41

Title: 230SL 1966 engine rebuilt help needed
Post by: balder on February 24, 2021, 21:54:41

Hi all,

I am rebuilding my 230SL 1966 engine and have a few questions:

1. When opened the engine, piston 1 was burnt (see photo). What can be the reason for that? Other 5 pistons are OK. Bad material or..?
2. The pistons are 83mm, 25mm pin, 3 rings. Can I replace them with mid 3 rings piston or even early 4 rings pistons? I must then replace conrods as well? Is 180 030 71 18 part no for this late 83mm piston?
3. What is the standard size of conrod and crankshaft bearings? 47mm and 59 mm respectively? Anyone knows part no for these?

Thanks a lot for help.
Srba 

Title: Re: 230SL 1966 engine rebuilt help needed
Post by: Sead on February 25, 2021, 07:33:52

I sent you email...
or contact me +387 61 528 220

Title: Re: 230SL 1966 engine rebuilt help needed
Post by: Harry on February 25, 2021, 23:57:41

Just finished my rebuild of same engine.  The Classic Center was super helpful with these types of questions.  I’d be happy to help as well.

Title: Re: 230SL 1966 engine rebuilt help needed
Post by: balder on February 26, 2021, 07:50:45

Thanks, guys.

I am a bit concerned about piston burn, have no clue how this might happen. If it's bad material structure, should I replace all 6 pistons?

Srba

Title: Re: 230SL 1966 engine rebuilt help needed
Post by: mnahon on February 26, 2021, 09:57:20

Looks to me like that cylinder was running too lean, also indicated by the color relative to the one next to it.

Title: Re: 230SL 1966 engine rebuilt help needed
Post by: ja17 on February 28, 2021, 02:19:35

Yes, running too lean, spark plug much too hot or inhalation of foreign debris (any engine nuts or bolts missing)?

Title: Re: 230SL 1966 engine rebuilt help needed
Post by: balder on March 01, 2021, 19:08:38

Thanks a lot, Joe & Meyer.

No debris was found in cylinder, so I guess it was running too lean for some time. Need to check injection pump and nozzle. I assume this didn't happen instantly, more likely it was more gradual process?
Do you have any experience on con rod for this cylinder? It looks intact, could higher temperature make any structural not visible damage?

Srba

Title: Re: 230SL 1966 engine rebuilt help needed
Post by: Benz Dr. on March 01, 2021, 20:33:20

The whole engine should be gone through and since shards of metal circulated everywhere, all of the crank bearings with oil pump should be replaced. I'm not sure what the red stuff is on the top of the block but I would take a light cut off of the parting surface to true it up. I would also inspect the intake manifold to make sure that it's not warped. It's possible that you had a major vacuum leak.

Title: Re: 230SL 1966 engine rebuilt help needed
Post by: balder on March 02, 2021, 22:34:35

Will do all checks above. Red thing is a silicone sealer someone put on earlier, nothing serious.

Big thanks for your help and support.
Srba

Title: Re: 230SL 1966 engine rebuilt help needed
Post by: Esmo on March 10, 2021, 13:16:26

The Piston you have described is a generation 3 and yes 180 030 71 18 is the correct part number for the 83mm 3 ring 25mm bolt. I understand you cannot replace with a Generation 1 or 2 .