I am rebuilding a 1985 300d turbo engine. I am on the last piston right now and while looking at the oil ring with my kids magnifying glass I think I spotted a difference in the profile top or bottom? None of the oil rings were marked top side as was the other rings, and visually I could see no difference before being magnified. How critical is this? They are Goetz rings. Please tell me I dont have to remove the other four pistons and check. I want to do it right. Thanks

There typically is a difference between top and bottom... they are designed to allow pressure from above to press them out towards the bore...
If you are going to have to check them now is better than after you put it all together and find it did make a huge difference....
Does the FSM specify anything with regards to this ?

the folded envelope that the rings came in show different profile ring schematics and orientations for top. None match the oil ring exactly as did the other rings. The mercedes shop manual on cd refers to the part as a chamfered oil ring. There appears to be a chamfer on both sides. Again, I need a magnafying glass to see the difference, but one side appears to have a smaller legdge. -
-

They come in bag/pouch for each ring...they print ring id pictures on each pouch, or there is an instruction sheet in the box.

The top and second rings must be installed with 'TOP' facing up because the edge of the ring has a specific taper and bevel on the inside.... I don't remember the oil ring having TOP marked on them.

Any multi piece oil ring has no up or down...a single piece ring with expander, might have.

Do you still have all the packaging and pouches the rings came in ?


.

__________________
[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

Yes I have packages. as I described. It is a multi piece (2) oil ring. Looking at it more withe a magnifier I can see Goe etched in one side but not top.

FSM = Factory Stop Manual

One problem with both the CD and the paper copy is that sometimes important information is accidentally placed in other sections... almost as a side note... they assume the reader knows some things which were standard operating procedure either at that time or in the Mercedes shops... but may not be familiar to the normal American mechanic...

Instal with 'GOE' up if it is on the upper/lower ring surface..

Is this a two rail face with gold colored expander with plastic/colored ends on the expander type ?

.



.

__________________
[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."