230SL New Pistons v Con Rods

[Esmo]

The background to my question is my 1967 Uk car chassis no 113 042 22 018131 , original engine number 127 981 22 005232 had a replacement engine / short block exchange fitted by the local Mercedes main dealer in 1978. The car had been maintained by the same garage and had developed a knock the invoice states short block exchange £704 in the parts charged for. The invoice does not list pistons or con rods but does list gaskets etc.totalling £1100 including labour. The new number stated Mercedes Benz United Kingdom Ltd Replacement engine 127 981 22  12971 . After starting an engine bay  tidy up one thing led to another and the local independent garage discovered a scored cylinder . The old pistons are 82.5 (82.46) 4 ring . The SLS site is showing 4 ring as first generation yet the car is a late SL230 , I understand only third generation pistons are available and the main MB parts department quoted me for 127 030 02 18      I subsequently bought a set of same 83mm 127 030 02 18. My main question is will I need to source a new set of con rods ( mine appear to be not stamped with the part number) hope someone can help

[mbzse]

.../... con rods ( mine appear to be not stamped with the part number).../...

Hmm, really. I was under the impression that all M-B connnecting rods had the part No visible

[Esmo]

Just to clarify is the con rod the same for all SL230 generation pistons , Thanks

[Sead]

Just to clarify is the con rod the same for all SL230 generation pistons , Thanks

NO.
Last - 3th. piston gen. requires last con rod version, which is 1080302320. See pic.
Sent u PM.
Sead

[Esmo]

Thanks Sead ,  I’ve been reading every thing I can about the 3 Generations of pistons for the SL230 but  still need input from the forum . Is it possible that back in 1978 MB supplied a short block exchange that included generation 1 pistons and rods , this would explain why 4 ring pistons 82.5 mm were fitted to my late model SL 230 ? . I have since purchased a set of 127 030 02 18 83mm 3 ring are these 2nd generation, if so Do I need to find a set of con rods 127 030 26 20 . The car is currently locked down at my re builders and I’m trying to gain as much info to give to the engine shop.

[stickandrudderman]

You need to be very careful as there are different wrist pin diameters, different compression heights and different con-rod lengths.
You'll need to compare the new pistons with the old to determine if you can use your con-rods.

[MikeSimon]

I am not sure if there are any "aftermarket" rods out there for SLs, but Mercedes con-rods have always been forged. Some aftermarket rods are castings.