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Discussion Starter #1 (Edited)
hello everyone

I'm rebuilding an M112 engine for an SLK 320 ( my first Benz engine). Before I buy the conrod bearings, it's asking for A COLOR that is supposed to be on the back of the conrod bearing but it's not. I've looked at the service manual and it does not even show where the color codes would be if I were to replace the conrods altogether.

I already have the color codes for the main bearings...just need the conrod bearings.

Any help would be appreciated.

Juan
Fast Lane Automotive
 

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Seeing as we are an SLK only forum and your post relates
to a mid 60's 300SE (?), I'm moving this to Off Topic from R170 Gen Disc. Someone may still be able to help you though.
 

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Hi,

I always understood you need to Mic the Bearing Cap Bores and the Crank Journals in order to get the correct Shells ;)

It might pay you to Email a few MB Specialised Engine Building firms to confirm ;)

HTH, Cheers Dave
 

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Discussion Starter #5
Ok, so I've mic'd the conrod bores and journals, but unlike the crank that gives out the color codes of the diameters in the service manual, I can't seem to find the color designations or diameters for the conrods. Any ideas?

Dave, Do you know of any MB engine rebuilders I can contact?

Juan
 

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Hi,

Bearing in mind I live in NW Scotland, UK, I wouldn't have a clue who you should ask in USA, try phoning Kleeman, ask who, (if not themselves), builds Engines for them, or try Google etc "Mercedes Performance Engine Builder".

This is a very strange scenario .............

If you are just freshening an Engine, are there no part numbers or size ID on the existing Shells ?

If the shells are damaged, then there will be machining work at very least needed, in which case the Machine Shop would ordinarily supply the Shells !!

Or of course you could go back to basics and use good old fashioned "Plasti Gauge" to check bearing clearances ............

HTH, Cheers Dave
 

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Unfamiliar with the internals of these engines please excuse me if I am wrong.

Engines that I have rebuilt have standard size shells or +010 or 020 or 030 or 040 dependent on crank grind. Is it a case that you are just putting in new shells or are you also having the crank ground which would seem the logical way to go as presumably you are rebuilding due to wear. If the latter take the rods with you to the machine shop and ask them to supply suitable shells.
 

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Hi,

Like many Car Manufacturers there are also different Rod and Main Cap / Block over / undersize "gradings" ............

So not only do the Shells have to match the Crank Journals, they must also match the Line Bore in the Block (Mains), and the Bore in the Con Rod (Big Ends) ..........

Hope this clarifies ;)

Cheers Dave
 

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Discussion Starter #9
I was going to just by the standard aftermarket shells... and I've done several engine rebuilds on other cars. I rebuilt a Hyundai 2.7 engine once that had the same deal with bearings that were coded for the mains and rods and was clearly in the service manual on how to deal with it.

I measured the rod bores and journals and will talk to a Benz shop...see what they say.

Thanks!
Juan
 
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