How to Rebuild a Mercedes-Benz V12

vinuneuro · #1 02-17-2007, 11:46 PM

Just in case you always wanted to know how to go about doing it, here's how it's done. The pictures speak for themselves.

http://community.forenshop.net/forum...opic=3378&st=0

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X5Jones · #2 02-17-2007, 11:55 PM

Ouch!

As abused as it is that engine is one masterpiece of engineering!

xnsf · #3 02-17-2007, 11:59 PM

wow...that's something i never thought of...

asawadude · #4 02-18-2007, 12:23 AM

Burned pistons, scored cylinder liners, that engine was toast. I'm surprised they rebuilt it instead of getting a remanufactured short or long block.

vinuneuro · #5 02-18-2007, 02:58 AM

Remanufactured short block?$?$? You need a new short block when there's a rod sticking out the side of your block or when you spin a main bearing bad enough to chew the block too. His problem was not really that bad. Remachine or replace the sleeves, new pistons + rings, new main/rod bearings and he was good to go. What I don't understand was why he went through the trouble of tearing down the engine and then reused those pistons

.

Did anyone else notice the flat tappets (instead of rocker arms) ? Very cool for an engine that old..

Also note that you do not want your engine to look like this when you open it up. If it's stained like this, you know the oil intervals were waay too long:

asawadude · #6 02-18-2007, 06:04 AM

Quote:

Originally Posted by vinuneuro

Remanufactured short block?$?$? You need a new short block when there's a rod sticking out the side of your block or when you spin a main bearing bad enough to chew the block too. His problem was not really that bad. Remachine or replace the sleeves, new pistons + rings, new main/rod bearings and he was good to go. What I don't understand was why he went through the trouble of tearing down the engine and then reused those pistons

.

My point exactly. Along with reusing the pistons, it doesn't look like he resleeved the cylinders either. I didn't see any pictures of new sleeves installed. Did you?

There's 2 reasons for not resleeve. No money or the cylinder liners cannot be resleeved, similar to the M52 engine issue. I don't know much about MB V12 engines. If you say the liners can be replaced, I believe you.

vinuneuro · #7 02-18-2007, 12:41 PM

Those scratches in those sleeves really aren't that bad..not enough to catch a finger nail. What looks bad is the nick out of the corner of the piston and corresponding distortion of the top end of the sleeve. If that wasn't there, he'd easily be able to rebore and/or just hone the sleeves and be set.

Looking at pictures and translating later on in the thread, it looks like he rehoned the block and got some used pistons (and hopefully new rings). The guy seems like he knows what he's doing, so I'm sure he did things logically..we just won't know without translating many of the pages.