Con Rod Bearings. One hole or two ?

[alpina]

I hope you guys will be able to give me some advice. I am currently having the crankshaft and associated
Bearings replaced on an early 280SL.
The connecting rod bearings supplied have only one oil hole. Where the originals coming out have two.

Is it okay to use the bearings with one hole which obviously blocks one of the holes?
I have read posts on here from Benz Dr.  indicating this would be okay. As the original two holes caused
Excessive oil consumption.

So please put my mind at rest, and confirm it is okay for the guys doing the work to use the one hole bearings.
I need to know pretty quick, not to delay the work.

Best regards  DM.

[jpinet]

Hi,
The 127 engine (1965 230 SL) has shells with only one hole. I know 280 engine is somewhat different, but not that much. You could call Mike at Metric Motors  (818-712-9881) who specializes in rebuilding these engines and ask for his opinion.

[alpina]

Okay, so todays update. I have now spoken to two Mercedes Engine builders in the UK.
(Crewe engines ltd and Roger Edwards),  both say they would drill the extra hole to match the
Existing bearings, If they were building the engine.
So unless someone can provide a compelling reason not to drill the hole to match
The originals, this is what I guess we will do.  Matching the holes with what is coming out surly can’t be
Wrong, and I presume the safest option.
All opinions gratefully received.

DM

[ja17]

I have always matched the replacement set to the originals. I have literature to support this. You might want to check with Metrics also.

[Benz Dr.]

Don't drill the extra hole, is what Mike at Metrics told me. MB found that it wll make your engine use oil. Anything coming off of the crank will be enough to lube the cylinders.
Early 230SL's had gun drilled conecting rods and the pin bushings were lubed under pressure. The hole you have in your bearing is there for that application but on later engines the pin bushings are splash lubed so the center hole on the bearing isn't even needed.

[alpina]

Thanks for your confirmation. The question arose from reading the threads below. And comments for Benz Dr.
Who was told the info by Mike @ Metrics.

http://www.sl113.org/forums/index.php?topic=21652.0

http://www.sl113.org/forums/index.php?topic=15740.0

I think now we will be drilling the extra hole to match the originals.

[alpina]

Dan. I think I wrote my last reply before reading your last post. Surely there can
Be no adverse effects by matching the bearings that are being removed, or am I missing something here ?
Why would all the other advise be to replace like with like ?
Obviously I am no engineer, I just do not want to do anything that could cause damage further down the line.

[Benz Dr.]

If the extra hole/holes were supposed to be there, they would be made that way from the supplier. I've been called on this before and this time I know I'm right.

 Install them as is and you'll be OK.

[tel76]

On this occasion I agree with Dan, you can safely fit them, do NOT drill another hole.
Make sure when you fit the conrods/pistons into the block you position the oil hole to the THRUST side.

[Benz Dr.]

On this occasion I agree with Dan, you can safely fit them, do NOT drill another hole.
Make sure when you fit the conrods/pistons into the block you position the oil hole to the THRUST side.

That's not what I'm saying. You don't need to line up any holes or drill any new ones. The small notches on the connecting rod that locate the bearings go to the left or distributor side of the block but any oil holes drilled into the rod are of no importance. MB quit using them when they started replacing short blocks under waranty due to heavy oil consumption.

[tel76]

So are you saying that the plain shells could be fitted in the con-rods and not the cap ?

[Benz Dr.]

The rod bearings come with 6 shells that have holes in the center position in case you need them for gun drilled connecting rods and 6 shells that have no holes for the caps. No other holes are needed. 

[tel76]

The rod bearings come with 6 shells that have holes in the center position in case you need them for gun drilled connecting rods and 6 shells that have no holes for the caps. No other holes are needed. 

The latest con-rod bearings supplied for the 280sl are supplied with ONE oil hole and that hole is offset (NOT in the central position), when you fit the con-rod the said hole must be positioned facing the RHS/MANIFOLD side, this allows oil to be supplied to the thrust side of the piston.
As noted the plain ones are fitted to the caps.

[Benz Dr.]

I just built two different 280SL engines and niether of them had holes for oiling the thrust side. Some connecting rods have these holes on the manifold or thrust side; I've seen them; and some have two holes, or one for each side of the cylinder but none are actually needed.

 So, should I expect my rebuilds to blow up any time soon? 

[tel76]

Have a look at the picture at the top of this thread ,the picture of the new shell on the right is what is supplied with the offset hole for lubricating the thrust side, if you have fitted plain shells in your con-rods the recipient of those engines should be concerned.
This thread is going nowhere, you build your engines how you want to but please be careful not to pass on wrong information to members on this forum.

[Benz Dr.]

Have a look at the picture at the top of this thread ,the picture of the new shell on the right is what is supplied with the offset hole for lubricating the thrust side, if you have fitted plain shells in your con-rods the recipient of those engines should be concerned.
This thread is going nowhere, you build your engines how you want to but please be careful not to pass on wrong information to members on this forum.

Really? It's one thing for you to disagree with me but it's a whole other thing to say to me and everyone on this site that I'm passing on wrong information and apparently, by your tone; I'm doing it on purpose. What possible motive could I have in doing that? Trust me, being right, or thinking I am, isn't close to enough reason to even respond. However, inferring that I'm a fraud crosses the line.........
 
I can be as wrong as anyone around here and I'd be the first one to admit it too. If I'm not sure I say, '' I'm not sure....'' If I'm fairly sure I say, I believe, or I think this or that about a certain subject, and if I know I'm right about something, and I'm certain about it, I say so. In this rare and partiular case, I'm sure about it.

I buy a certain amount of engine parts from Metric Motors in CA. They build about 300 engines per year; I believe all of them are MB. When this question arose some time ago I asked Mike ( the owner ) how to deal with this issue. This is what he told me: ( I asked his permission to quote )

“ NOTE: THESE BEARINGS SUPPLIED ARE AN UPDATED/SUB TO VERSION. OIL HOLES IN ROD BEARING WILL NOT ALIGN WITH THOSE IN ROD... THE HOLES ARE IRRELEVANT. NO PASS THROUGH OIL HOLE IS REQUIRED. AS MOST 130 TYPE RODS HAVE NO OIL HOLES ANYWAY. RUN AS SUPPLIED.”

 For the record – This comes from old Germans that were working these vehicles back in the day. Mercedes was having trouble with oil consumption on the M130 engine types partly due to too much oil squirting from the rod to the cylinder wall. So in 1971 they omitted the holes in the rod to alleviate such. We have flipped the bearing around to do the same for over 25 years without any consequence. In fact it’s only an improvement. ''

 
 If Metric Motors is wrong, then I'm also wrong and all of the rebuilt engines done in this manner are apparently junk. Will your engine fail if you use the holes in the rod? I doubt it, but when an enlighted view from an expert comes along does it not behoove a serious student of these cars to pay attention?


 

[tel76]

It was not my intention to continue with this tread but I will address two allegations you have made.
1 - The comments that I have made were NOT suggesting that you are a fraud, you have read something in my reply that was not there.
2 - The comment from Metric Motors !MOST 130 TYPE RODS HAVE NO OIL HOLES ! In all the engines I have done I have never seen any 280sl/130 con-rods with no holes and also all the bearings that have been supplied by MB had the one oil hole that lined up perfectly with the one in the con-rod.
One other item worth noting is the last engine I overhauled (late last year) was out of a 1970 280sl, this car had a Mercedes replacement short block fitted in 1973/4, when I stripped the engine the con-rods had one hole fitted and the holes in the shells matched perfectly,  before you say it could have been old stock,( which it was not) it was the latest block fitted with the inserts for the longer bolts, I also sent you a picture of it and at the time you said you had never seen such a block.
If Mercedes advocated plain shells in the con-rod end or any other modification then they would have issued a technical bulletin to that effect, I have never seen or read any such bulletin.

[stickandrudderman]

Here's an 130 engine we're stripping at the moment.
There are things that are most definitely wrong in this picture:


I'll let Tel 76 and Dan fight it out as to what exactly is wrong!

[mbzse]

.../...There are things that are most definitely wrong in this picture.../...

Oooh, I know, I know!  [eagerly waving hand]   /hans

[Benz Dr.]

I think the plain shell bearing might be located in the wrong place ( have to check in the manuals ) and they didn't blank off the holes the con rods.

   

[Benz Dr.]

And it looks like the con rods were installed backwards.

[ja17]

Yes, plain shell in the wrong place and connecting rods in backwards, good observations Dan!

[Benz Dr.]

In other words.......... a complete CF.

[stickandrudderman]

And here's how the cylinders look after only a few thousand miles.

It's lucky we've picked this up early as this engine was heading for a very premature demise.

[Benz Dr.]

There's a posibility that it was over heated or that the cylinders were running hot. Do the score lines run all the way to the top edge of the cylinder or only as high as the top ring? It's hard to see in the shadows.