Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #61  
Old 10-24-2013, 10:10 AM
Stretch's Avatar
...like a shield of steel
 
Join Date: Sep 2009
Location: Somewhere in the Netherlands
Posts: 14,461
Quote:
Originally Posted by 97 SL320 View Post
...
Remove material from the green areas _TOWARDS_ the crown, don't increase the diameter.

...
Quote:
Originally Posted by 1project2many View Post
...

What 97 SL320 is referring to is the factory's balancing method. It's a single cut to save time and money. If you look at the difference in thickness of the pin boss between that machined area and the portion toward the center of the piston, it appears substantial. I wouldn't be afraid to continue the factory operation. I would still try to identify where the differences are between pistons before metal removal.

...
Here's a quick sketch showing why cutting into the green line area can't be done for long



Apologies for the lack of ISO standard drawing practices!



^^^ This rough sketch shows a quarter cross section of the piston - I hope it is understandable...

Attached Thumbnails
Engine builders' advice req'd - removable piston weights?-sketch-m102-piston-cross-section.jpg  
__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
Reply With Quote
  #62  
Old 10-24-2013, 10:23 AM
Stretch's Avatar
...like a shield of steel
 
Join Date: Sep 2009
Location: Somewhere in the Netherlands
Posts: 14,461
Quote:
Originally Posted by benedict View Post
You are not the first! My parents s420 was destroyed because the chain jumped a tooth on startup from an incorrectly fitted tensioner by an Indy.

What type of tensioner was it? The ratchet type that requires activation once it's installed or the hydraulic type. Please give us the heads up.
It is the bayonette / ratchet type. You are meant to push the tensioner all the way through the outer casing - fit the outer casing - and then AND ONLY THEN(!) fit the tensioner and the spring and the end cap...

http://www.peachparts.com/shopforum/tech-help/341121-achtung-das-schweinhund-baby-benz-thread-5.html

Help my M102 is a whinger!

I've been told that a similar set up exists on diesel engines of the same period.

These tensioners are not just a spring like the OM617a tensioners and not like the hydraulic OM617 / OM616 non turbo tensioners that should be filled with engine oil prior to refitting...

...I know I've kind of bitten myself on the arse for all of this extra work but I do feel I've had enough punishment for a RTFM blip - I've been sold a 2.0 litre head that won't fit my 1.8 litre engine and that seller is being a cock asking for more money for a second hand 1.8 litre one that will probably be as just as bad as the 2.0 litre one he sold me "by accident" with pitted valve surfaces and worn guides etc etc <= so I have little confidence in him. This is a shame I've bought loads of stuff from him previously but have never tried to send anything back. He's lost a good customer.

The cost of head refurbishment here in Holland is going to be between 500 and 700 euros from a reputable place. In fact there's only this "good place"near to me - I don't know of any cow boys!

Anyway now chasing down a "brand new" Carlson head that should be good - bought via paypal so I should have a bit of protection (perhaps) but that bugger doesn't seem to have sent it yet...

...and of course the piston nightmare continues with a different seller (first time used) who has sent me a set of pistons that are incompatible with each other.

This is called banging your head against a brick wall.
__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
Reply With Quote
  #63  
Old 10-24-2013, 11:21 AM
Registered User
 
Join Date: Jan 2013
Location: Lakes Region, NH
Posts: 179
Quote:
^^^ This rough sketch shows a quarter cross section of the piston - I hope it is understandable...
Ahhh. Crystal clear now.
__________________
When life gives you lemmings... make lemmingade.
Reply With Quote
  #64  
Old 10-24-2013, 09:11 PM
Registered User
 
Join Date: Jan 2012
Posts: 7,515
Are you able to post pics of each piston? ( are the casting numbers / general shape the same on all? )

Got it on the 4 mm thickness of material.

I'd do a few things here:

It would be a good idea to cover the outer skirts with tape during grinding. Be sure to weigh the piston pre / post tape then calculate your target weight, don't try to remember it as target with tape will be more than desired bare piston.

Make sure of piston weights.

On the heavy ones, remove the casting boss on the left side of your last pic.

Increase the OD of my green cut but only in an area that does not enter or reduce the profile of the skirt ( the red area ) This can be done by hand with a die grinder. The center of the red area is what keeps the piston from rocking left to right, as you travel towards the pin the loads are taken up by each end of the red area. The pin area does nothing for front to rear location.

Remember you only need to get within 10 G not 0 if enough material to remove can't be found.
Reply With Quote
  #65  
Old 10-25-2013, 11:02 AM
Stretch's Avatar
...like a shield of steel
 
Join Date: Sep 2009
Location: Somewhere in the Netherlands
Posts: 14,461
Piston pictures

Going from left to right in this picture

614 grams, 617 grams and 633 grams - these are weights with the pins and the rings fitted



In this picture the line continues showing 617 grams, 633 grams and 634 grams (weight values refer to with pins and rings fitted)



So using a bit of a crap method I shoved my digital caliper in as far as it would go and made some measurements of the wrist pin boss area of the pistons



Measurements shown in next post due to number of attachment restrictions...
Attached Thumbnails
Engine builders' advice req'd - removable piston weights?-nural-pistons-614-617-633-examples.jpg   Engine builders' advice req'd - removable piston weights?-nural-pistons-617-633-634-exacples.jpg   Engine builders' advice req'd - removable piston weights?-nural-piston-measuring-wrist-pin-boss.jpg  
__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
Reply With Quote
  #66  
Old 10-25-2013, 11:07 AM
Stretch's Avatar
...like a shield of steel
 
Join Date: Sep 2009
Location: Somewhere in the Netherlands
Posts: 14,461
Nural piston measurements

This method is a bit changeable you can get slightly different results with a bit of wriggling but I think is shows where a lot of the extra weight probably is...







Attached Thumbnails
Engine builders' advice req'd - removable piston weights?-nural-piston-613-grams-pin-rings.jpg   Engine builders' advice req'd - removable piston weights?-nural-piston-617-grams-pin-rings.jpg   Engine builders' advice req'd - removable piston weights?-nural-piston-633-grams-pin-rings.jpg   Engine builders' advice req'd - removable piston weights?-nural-piston-634-grams-pin-rings.jpg  
__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
Reply With Quote
  #67  
Old 10-25-2013, 11:12 AM
Stretch's Avatar
...like a shield of steel
 
Join Date: Sep 2009
Location: Somewhere in the Netherlands
Posts: 14,461
Muhammad and mountains

Whilst it looks like a some metal removal might get me closer to the desired weight of the lighter pistons...

...how about going the other way and adding weight to the lighter ones?

Could a steel bolt with a countersunk head bolted to the skirt be an option? (I think I remember hearing about large lumps of metal being bolted to pistons in ship engines...)
__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
Reply With Quote
  #68  
Old 10-25-2013, 11:46 AM
Simpler=Better's Avatar
Ham Shanker
 
Join Date: May 2008
Location: Baltimore, MD
Posts: 2,544
Unless you're welding on aluminum it will come off later. Drilling & tapping is asking for a crack in a few miles.

If you can't get Nural on the phone I'd grind down the heavy ones
__________________
$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment
Reply With Quote
  #69  
Old 10-25-2013, 11:53 AM
Stretch's Avatar
...like a shield of steel
 
Join Date: Sep 2009
Location: Somewhere in the Netherlands
Posts: 14,461
Quote:
Originally Posted by Simpler=Better View Post
...
If you can't get Nural on the phone I'd grind down the heavy ones
That seems to be the plan at the moment. I'm a bit concerned about this uncharted territory though - give me a gear box and bearings and I'm a happy man but metal removal with a proxon multi tool...
__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
Reply With Quote
  #70  
Old 10-25-2013, 06:10 PM
Registered User
 
Join Date: Jan 2012
Posts: 7,515
You only need to find 9 to 10 G from the heavy ones.

Working the areas I recommended won't reduce strength, just be sure not to leave any sharp internal corners as this leads to cracking.

Got an old piston to practice on?

Before cutting, you could always mark the piston and post a pic to make sure we are talking about the same areas.
Reply With Quote
  #71  
Old 10-26-2013, 11:47 AM
Stretch's Avatar
...like a shield of steel
 
Join Date: Sep 2009
Location: Somewhere in the Netherlands
Posts: 14,461
Oh for a milling machine - my kingdom for a milling machine...

...bor-or-or-or-or-or-ing...

I've managed to remove 6 grams from one half side of the heaviest piston so far. Most of this material was removed from places that are easy to access.

On Monday I'll see if I can get hold of a milling cutter with about a 6mm diameter to get down into the depths to hoik out a bit more - then I'll start on the other side of the piston...

I have found that those multi-colured stones on sticks that get sold with those mulit-tool machines are kind of OK but the best results come from the little bands of sand paper that you fit on the expanding rubber bungs on sticks.

Ignore the brushes in the picture below - the sand paper things are the bits I mean

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
Reply With Quote
  #72  
Old 10-26-2013, 11:55 AM
vstech's Avatar
DD MOD, HVAC,MCP,Mac,GMAC
 
Join Date: Mar 2006
Location: Mount Holly, NC
Posts: 26,389
for aluminum, I use wide flute milling bits. the sandpaper, and close flute bits clog up too quickly...
__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
Reply With Quote
  #73  
Old 10-26-2013, 12:08 PM
Stretch's Avatar
...like a shield of steel
 
Join Date: Sep 2009
Location: Somewhere in the Netherlands
Posts: 14,461
Quote:
Originally Posted by vstech View Post
for aluminum, I use wide flute milling bits. the sandpaper, and close flute bits clog up too quickly...
The sand paper has been really good actually. I think it is about 80 grit on one of those little rolls and you can remove about 0.5 grams of material with a single piece. It seems to wear away more than clogging - which is exactly what those little grinding stones do.

The sand paper method is definitely arsing about though - a milling machine is the thing to have - no doubt. This dremmel / proxon multi-tool method is almost inadequate. It is t-e-d-i-o-u-s
__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
Reply With Quote
  #74  
Old 10-26-2013, 01:37 PM
Registered User
 
Join Date: Jan 2012
Posts: 7,515
Before you go any farther, post some pics.
Reply With Quote
  #75  
Old 10-26-2013, 03:30 PM
Stretch's Avatar
...like a shield of steel
 
Join Date: Sep 2009
Location: Somewhere in the Netherlands
Posts: 14,461
Work in progress

Quote:
Originally Posted by 97 SL320 View Post
Before you go any farther, post some pics.
Well bear in mind it is a work in progress - I'll be smoothing out the bottom parts once they are a tad deeper...

...that sounds a bit strange...

...anyway here's before



Attached Thumbnails
Engine builders' advice req'd - removable piston weights?-nural-piston-destruction1.jpg  

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 12:43 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page