A little piece of trivia: Mercedes diesel tolerances are so tight that Mercedes specs cylinder number 1 differently than the other 3 or 4. They do this because number 1 runs slightly cooler than the rest.
Thanks, Tom Hargrave www.kegkits.com 256-656-1924 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Peter Frederick Sent: Wednesday, December 13, 2006 5:25 PM To: Mercedes Discussion List Subject: Re: [MBZ] 1972 220D Marshal: Concerning rebuilds and factory engines on the W115 -- MB had quite a few problems with pre-mature wear on that engine, and factory originals are prone to excessive cylinder wear. A miss-match between piston, sleeve, and ring types will also do the same thing on rebuilds. My friend remembers them being replaced a lot under warranty (or rebuilt with high nickel sleeves and different pistons) -- and today one with 150,000 original miles may be a smoker. Terrible head cracking problems during the 60's as well, during which time his father stopped using MB diesels in his taxi business. MB was eventually forced to give extended warranties on heads by the German government. Something about taking the head design away from the actual producer because it was cheaper, then changing it, somewhat less than successfully. I agree that rebuilds done in the US can be horrible -- if not done to MB tolerances, you can end up with one burning a quart of oil in 200 miles within 10,000 miles of rebuild! Some are so sloppy the rings never seat -- my brother and I got one like that to replace his 617 with a broken crank (again, a crappy rebuild -- orange silicone slopped all over the oil filter housing gasket, a big slug sat on the #2 main oil hole --- you can guess the result). That replacement engine had a ring ridge almost 0.015" deep! Bore was 0.005" larger than the piston, pistons had extruded ring lands, crank was ground to the nearest SAE dimension SMALLER than the minimum metric size allowed, was only smooth and shiny where ti ran on the bearings, valve were way beyond terminal wear, and the valve guides were all 0.005" or more oversize. I don't think it ran long, I'm quite surprised it ever started. I don't remember what the bearing clearance was on the crank when we got the engine, but I think it was 0.005" or more. We rebuilt it properly (after much discussion about valve guide clearance at the machine shop), and it's been running for six years now -- starts instantly no matter how cold it gets, very little black smoke and never uses oil between changes. Has 45 lbs oil pressure at idle hot unless you just pulled off the interstate! Peter _______________________________________ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
