Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: steves sl on July 25, 2018, 20:22:29

Title: Piston Numbers
Post by: steves sl on July 25, 2018, 20:22:29

I have an early 1965 230sl. The engine has been in a crate for 5 years. The Pistons have the following numbers stamped in the top........8297.....SPoo4 ........158/024.....plus the arrow pointing to the front. I am hoping that someone can tell me what I have, only good news please.

Title: Re: Piston Numbers
Post by: Benz Dr. on July 25, 2018, 20:38:36

I'm going to say that you have 82.97 mm pistons which I think should be standard. I think the other numbers are production reference and not so important. Pistons should be 4 ring 24 mm pins and possibly gun drilled for pin lubrication.

Title: Re: Piston Numbers
Post by: drmb on July 26, 2018, 10:39:48

82.97 refers to 1.00 oversize,standard size is 82.00 for a 230sl engine.
The sp0.04mm is the clearance required between cylinder bore and piston skirt when reboring cylinder bore.

Title: Re: Piston Numbers
Post by: Benz Dr. on July 26, 2018, 15:12:51

Quote from: drmb on July 26, 2018, 10:39:48

82.97 refers to 1.00 oversize,standard size is 82.00 for a 230sl engine.
The sp0.04mm is the clearance required between cylinder bore and piston skirt when reboring cylinder bore.

Sounds right to me.

Title: Re: Piston Numbers
Post by: steves sl on July 26, 2018, 21:12:12

Thanks for the info guys. If the engine has to be bored again, how difficult will it be purchase new piston and rings? Engine #127.981-10-005407, only good news please.

Title: Re: Piston Numbers
Post by: Shvegel on July 27, 2018, 02:44:32

I am afraid you are already at 2nd oversize.  I thought it was odd the first oversize was 1mm out when they usually go by halves.  82mm, 82,5mm, 83mm.