Replace Piston Rings While Motor is Disassembled? - Page 2 - PeachParts Mercedes-Benz Forum

leathermang · #16 02-29-2016, 06:11 PM

As to Country of Origin not making a difference....
I have never seen instructions for an American auto engine which called for measuring the piston which is to go into THAT bore and then boring to provide the proper fit...
but that is what is called for in the FSM for our engines...

Dan Stokes · #17 02-29-2016, 06:38 PM

Leathermang makes a good point about pre-lubing before start-up. These engines cannot be primed with a drill or similar arrangement as the oil pump is chain driven off the crank. I built a pressure lube system out of a pressure cooker and it works great. I posted on it, I think in my build thread but it might have been in a separate post. Might be worth a look.

If you're close enough I'd be happy to have you swing by and I'll lend it to you.

Dan

pragmatic · #18 02-29-2016, 10:00 PM

Thanks all. The car isn't rusted out, but isn't a pristine example either. It certainly doesn't make sense to drop 3 grand on an engine rebuild when the whole car cost me half that. That said, I intend to use it and want it sorted properly.

I'm down in Athens GA, so a bit too far to pick up the pressure cooker rig. I still have Red Line assembly lube from my last build, so I'll use it liberally on the cam and bearings. It will sit before initial startup, so I was thinking I'd also add a tablespoon or so of oil in the cylinders via the injector holes before tightening them down and firing her up.

Bad idea?

Since we're on the break-in topic, what is the favorite procedure here? On turbo cars I've usually done the 20-30 minute varied RPM run on dino oil with a bit of healthy acceleration and coasting, followed by a change of oil and filter, then some relatively aggressive driving while keeping it away from redline and out of too much boost.

That has worked well for me in the past, but didn't know if there were tricks here.

leathermang · #19 02-29-2016, 10:05 PM

You have hit the right points on break in from my point of view.. many do not realize the coasting is needed also...harder to do with auto trans....
Good idea on the teaspoon of oil .

You should research which OIL FILTER should be used on a newly worked on engine...
from the FSM....

" During the first inspection (800-1000 miles ) the initial operation oil filter element (1) should be replaced by the combination filter element (2).... ""

The initial operation filter has no metal shield around it.

'' Attention ... On this engine, install only the combination filter element (b) part no 617 184 01 25 with the larger main flow filter component ( dimension " b" =56mm)""

that is the distance from the bottom of the filter to the start of the metal canister over the pleats.

ROLLGUY · #20 02-29-2016, 11:12 PM

If you decide to just replace the rear seal, and not pull the pistons, it is possible to replace the rear seal without removing the crank (as others have said). I posted a thread on it a couple years ago. Here it is: Rear Crankshaft Rope Seal Replacement Without Removing Crank

dieseldiehard · #21 03-01-2016, 01:14 AM

I was just calculating the miles on my '87 300D which I got in 2005 as a lien sale, it was missing the head after a shop owner let a scrapper carry it off while the owner was procrastinating on whether to repair it or not. It had overheated on an uphill stretch in the Summer on the highway from San Jose over to the coast. The shop it wound up at was a generic auto shop not a MB shop at all. The PO was a CPA and could count well but never did any maintenance on the car, when the car finally overheated it was probably something he couldn't understand. It had no rust and although was garaged most if its life it was showing fading on the top and hood so it wasn't a a beauty but quite a potential beast in my book. So I bought the car for what the shop was owed for their labor ($475) and had it towed back to a friend's shop.
I located a head (#14 and don't cringe it is a good one!), had it rebuilt and at that time in the planning stages my friend insisted strongly that I replace the rings. The cross hatching looked good and the pistons were good, no chips in them from any metal to metal stuff, so I cleaned the ring grooves myself and being truly a novice on the re-ringing job my friend Martti called in a machinist who removed the lip on the cylinders while the engine was still in the car and he stuffed the pistons for me using assy lube and a neat tool then we rolled in a new timing chain and timed it with the factory light tool.

It also got new crank seals and the front cover was OK and not fatigued or leaking, thats always of concern on early 603's. It started but hardly ran - I was afraid I had made a very bad dicision to pour time and money into this car but I drove it down to the dealer where they had the pleasure of replacing the entire exhaust and removing the Nasty Trap Oxidizer under the factory campaign, the very things that contributed to its demise in the first place (besides a crapped up radiator!).

Mileage at the time I got it running was 262K and now its 297K (I have to calculate from the new speedometer now on it to get the right mileage, - see the Blue Bomb on my photo album.
The car runs strong, it starts with a flick of the key and shifts perfectly thanks to a rebuilt transmission I salvaged off my wife's 87 when she totalled it

Its a very good commuter vehicle and I enjoy SUV drivers trying to pass me who make their tires squeal on curvy mountainous roads (hey, its not may fault they don't know how to drive!).

If I had to do it again I would do it just the same but if you have the money and aren't in a hurry you may want to consider putting new liners in the block. That leads to a complete rebuild but I guess you have to have a love affair to invest in one of these cars nowdays to justify that.
Now that I think about it, I surely spent more than a full engine rebuild on the suspension (OE Sport suspension, body panels and not to mention the new radiator, water pump, rebuilt IP etc.) so that puts me squarely in the car lover category but with a little money left to throw at my other cars

DDH

dieseldiehard · #22 03-01-2016, 01:25 AM

Quote:

Originally Posted by leathermang

You have hit the right points on break in from my point of view.. many do not realize the coasting is needed also...harder to do with auto trans....
Good idea on the teaspoon of oil .

You should research which OIL FILTER should be used on a newly worked on engine...
from the FSM....

" During the first inspection (800-1000 miles ) the initial operation oil filter element (1) should be replaced by the combination filter element (2).... ""

The initial operation filter has no metal shield around it.

'' Attention ... On this engine, install only the combination filter element (b) part no 617 184 01 25 with the larger main flow filter component ( dimension " b" =56mm)""

that is the distance from the bottom of the filter to the start of the metal canister over the pleats.

Hmmm, I never knew there was a special filter for breaking in an engine. But please remind folks to use regular dino oil in the break in, for a diesel I would use 15W40, you don't use synthetic for a break in.

After my rebuild the engine sounded like it was going to Hell in a handbasket with all the rattling, it was nailing to the highest order. Was told to live with it and it would go away, which it did but it took a couple oil changes before it quieted down and now it just purrs. I wonder why? is that normal after a rebuilt head, new gasket (Victor Reinz) new rings, rebuilt IP - whatever else is there that wears in ?

leathermang · #23 03-01-2016, 01:40 AM

Quote:

Originally Posted by dieseldiehard

Hmmm, I never knew there was a special filter for breaking in an engine. But please remind folks to use regular dino oil in the break in, for a diesel I would use 15W40, you don't use synthetic for a break in.

After my rebuild the engine sounded like it was going to Hell in a handbasket with all the rattling, it was nailing to the highest order. Was told to live with it and it would go away, which it did but it took a couple oil changes before it quieted down and now it just purrs. I wonder why? is that normal after a rebuilt head, new gasket (Victor Reinz) new rings, rebuilt IP - whatever else is there that wears in ?

Most people have have more important things going in their lives than to sit down and read the MB FSM's front to rear... When I arrived on this forum and embarrassed myself a couple of times giving standard mechanicing advice from 50 years of non MB engines I decided since I had the paper manuals I would just read them. Not that I remember all that stuff.. or understood all of it then or now... but some things were surprises and I do remember them... this filter deal was one of them... MB is so OCD in a basic way that appeals to my inner core.
NEVER USE SYNTHETIC OIL FOR BREAK IN PERIODS... the other word for ' BREAK IN ' is WEAR IN .... those friction items in contact with each other are supposed to WEAR... that is why one of them is designed SOFTER than the other one... I would do tens of thousands of miles and multiple oil and filter changes before switching to synthetic... no use rushing that process... too important for long engine service life.
I would be pretty upset if I was told just to live with noises like you describe... as I equate some noises to Something is Wrong....
I am glad you were able to wait it out and that they seem to have been correct in their advice..... would raise my blood pressure though... I have no idea what the cause of those might have been...

dieseldiehard · #24 03-01-2016, 11:32 PM

I remember reading the 123 Factory manual on brakes, was shocked to learn the factory recommends using a special brake pad to recondition rotor surfaces, in the boondocks or third world countries I suppose. They make (made?) them out of some sort of highly abrasive material (sandpaper grit?).
Clever, huh?

leathermang · #25 03-01-2016, 11:38 PM

LOL, Like I said... OCD in the best way....
totally different rules if you want to do it right...

BillGrissom · #26 03-03-2016, 12:22 PM

A slight data point. My 1985's engine had ~250 psig in all cylinders (recall) at ~300K miles. It needed the block heater and several glows to fire on 30-40 F mornings. At 330K, the engine seized w/ much bore scars and chunks missing from several piston ring grooves. My 1984's engine has one cyl ~340 psig (recall) and the others ~400 psig at unknown mileage (cluster from PickNPull). It has no block heater and starts on the coldest days.

Typically, rings wear faster than bores since less surface area. You might get another 100K as is before cold starts get hard and more blow-by. The sleeves aren't hard to change (I did), but requires machine shop work (I haven't done yet).

Clemson88 · #27 03-03-2016, 01:23 PM

Quote:

Originally Posted by leathermang

As to Country of Origin not making a difference....
I have never seen instructions for an American auto engine which called for measuring the piston which is to go into THAT bore and then boring to provide the proper fit...
but that is what is called for in the FSM for our engines...

I hung around a Napa machine shop in Harriman, TN with my brother in law back in the seventies. Every sleeve that he ever put in an engine was bored according to the diameter of each the piston. The piston were attached to the exact rod of the piston they replaced before being balanced. I doubt American auto manufactures need to tell anyone about sizing each cylinder to it's hole.

He did the same for thirty-over and sixty-over bores too.

leathermang · #28 03-03-2016, 02:14 PM

Quote:

Originally Posted by Clemson88

I hung around a Napa machine shop in Harriman, TN with my brother in law back in the seventies. Every sleeve that he ever put in an engine was bored according to the diameter of each the piston. The piston were attached to the exact rod of the piston they replaced before being balanced. I doubt American auto manufactures need to tell anyone about sizing each cylinder to it's hole.

He did the same for thirty-over and sixty-over bores too.

The fact that your brother in law was doing that has nothing to do with what I said.. I said I have never seen instructions for an American engine which called for measuring each piston and boring to fit That piston to that bore... ...

Dan Stokes · #29 03-03-2016, 02:27 PM

Actually, 'Mang, that's SOP in any decent American machine shop. I took auto machine in college (Ferris in Big Rapids, MI) and we certainly were taught that - in fact, it was DRILLED into us - "Don't bore an engine until the new pistons are in your hand!" Measure each and bore/hone to fit.

Don't assume that American machine shops are run by knuckle-draggers, though, of course, some are. You have to be fussy about who is doing your work, but that applies to lawyers, doctors, hair dressers, etc.

Dan

leathermang · #30 03-03-2016, 02:39 PM

When you went in the 50's, 60's, or 70's and bought a remanufactured GASOLINE engine short block... which was the most economical thing to do... I promise you they were not matching up individual pistons to individual holes.... they got as close as they could on average... and had a 100k miles warranty....The block had had some standard things done to it like Vatting... which is often skipped these days... surfacing and line boring... all set up on an assembly line... they were good engines at a good price...which they could do because they were not individually matching pistons to their respective holes...

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