benz_addict

@ 145k miles. I'm deciding whether or not to pull the motor out and replace all of them or go with more frequent oil changes?

Yacht Master

They look pretty good to me, can you take a better pic with more light?
Did you pop a piston on this one?

Oxygen

Your CL55 has 145,000 miles on it?!

GT-ER

They look good to me but you actually would need to measure their wear with a plastigauge and I'm also assuming they are still smooth.

benz_addict

Sure
The broken piston was #6.
The rod bearings I took out from through the oil pan are for #1, 5 and 6.
This is how they look under more light:

[




146,452 miles to be exact

Well that's good news. I'll check our their values too. I'm going to try to replace most of them as I can from under the the car without removing the engine.

GT-ER

If you run your finger nail through those sratches ( the ones on the surface that comes into contact with the crank ), can you feel anything? Does your finger nail hang up on it?

Even if you buy new bearing you still have to use a plastiguage to make sure the tolerances are good. Odds are you are safer using the old bearings than you are using new bearings if a plastigauge is not used.

_AMG_

Looks good to me.

WHTEVO

Looks like you had some dirt and oil contamination from the looks of it. Why not replace them all while you're in there? I've definitely seen worse. The first ones look like they are showing the copper. Not good.

Aaron

pearlpower

Considering 145k miles, looks good. Obvious signs of contaminants but expected @ that mileage. You can't keep everything clean forever.

Hellzno

is your motor still running well at that mileage? Are you just checking the bearings? or did something happen?

splinter

Unfortunately, more frequent oil changes won’t reverse to-date debris wear.
Owing to the substantial labor involved (and the telltale signs of FOD), I’d renew them as a matter of course.

The embedability properties of modern bearings is a given. Any untoward scoring on the crankshaft’s rod and main journals?
Factor that into your rebuilding decision.

reference

Exotic-metal55

They look ok to me too. I would make sure everything is clean and put it back together. Replacing the bearings , is still only a partial wear change. Be better then next time you decide to pull motor, to just rebuild or replace with low mileage motor.

Broken ring lands and valve issues seem to be the more common wear/abuse issues on these motors.

Quadcammer

why are you posting pictures of the back of the bearing shells?

some of those things are pretty scored.

I'd start fresh.

Anybody who suggest plastigauge has no business around a performance engine.


Edit: It seems like you enjoy tearing this thing apart while in the car. This is silly.

Pull it, refresh the bearings, rings, gaskets, etc.

Do it properly instead of slapping it together...using **** like plastigauge.

GT-ER

Funny since most MANUFACTURERS recommend plastigauge if you cannot use a bore gauge and micrometer. Try getting a bore gauge and micrometer in a partially disassebled engine. But I guess you just another one of those guys who only know how to throw money at situations.

Quadcammer

No. Changing rod bearings on a high mileage engine with the engine in the car is simply a band aid fix.

its not a matter of throwing money at it, its a matter of doing things properly. Like using a micrometer with the engine out of the car and the rods on your CLEAN work bench.

GT-ER

Unless I'm mistaken, his car didn't have bearing damage and those bearing do not look bad. So it isn't a band aid fix when there is nothing to fix.

I myself have used plastigauge various times on engines I've built and have NEVER had an engine failure after I built the engine ( I've had an engine blow up before but it was an engine that I never opened ) even after extended racing sessions and after many years of abuse. Again, nearly every MANUFACTURER is FINE with the use of plastigauge ( I've worked with Ford, Chevy, Nissan, VW, BMW and Honda and their factory service manuals were all fine with it, never worked with MB before but I doubt their engines are built by God. ). Who are you to say otherwise?

pearlpower

Absolutely nothing wrong with changing out rod bearings and using plastigauge. Though an engine rebuild is always the way to go, many people including myself have changed our rod bearings even as preventive maintenance. 944turbo's which have oiling issues is another example. I changed mine out every 20k miles and never had an issue. There are those that would argue rebuilding a motor is a waste and just buy a new motor. Point is, there are many ways to approach a situation and everyone has a difference in opinion. One does not negate another.

Quadcammer

Right, because the bearing clearance on most standard combos (i.e. stock crank and rods) is pretty good. But when the engine is on a stand, there is absolutely ZERO reason not to use a micrometer and calipers.

Plastigauge is frankly bush league. If any major engine builders are using it, they are doing it on top of micrometers, not instead of.

Um yeah there is. How are you guaranteeing a clean working environment? The single biggest enemy for an engine builder is dirt.

While yes, it can be effective, its not the right way to do something.

Just like duct tape will usually keep a bumper attached to a car, a bolt is really the correct way to do it.

Especially on a high mile car that most likely need other work, and a bunch of other clearances checked

pearlpower

A bench offers no guarantees either, I have seen many so called professional mechanics with dirty shops all around. I would also say with good reason that 99% of all mechanics are subpar-being in the industry myself for 16 years. There is a difference between your hypothetical world and the real world. Again, a new engine is a far better choice than a used or rebuild, bench or not. You will NEVER get a rebuild to that of a new motor. Mics are dirty, hands are dirty, shop air is dirty, hose on the end of a cleaner is dirty, air in your nose, etc. Eventually you make do with what you have available and to the OP, he is probably pursuing the best path for him. I'm not going to judge him either way as I have no idea the circumstances of his life and available options and neither should anyone else.

I agree a bench is the best way should someone need to rebuild an old motor, but again, circumstances........

benz_addict

I can feel some scratches on the surface that comes in contact with the crank.

That's what I was thinking. I'm definitely leaning towards replacing them.

I know it's a pretty high mileage car. Especially how I beat the **** out of everyday

Pulls strong but I thought I heard some slight rod bearing noise so I thought I'd check them out. Turned out to be the timing chain though. Getting new timing chain installed, sliders and tensioner.

The crankshaft looks perfect. Can't see or feel anything on the CS rod. Just the bearings have some slight scratches I can feel with my nail. I'm going to replace them.

I guess for the mileage they look OK. But if any more broken ring lands issues or if It develops a valve issue then it's time to say good bye to this motor. But until then... After the number 6 piston replacement and new EC tune this thing runs like a BEAST

I don't know I thought I show both sides of the bearing and get some valued input from fellow mbworld members
Motor just got brand new head gaskets, valve cover gaskets, in process of getting new timing chain and also the heads were reconditioned. Thought I check the bearings
I'll be replacing them too. Believe me I'm a pretty **** when it comes down to a clean work place

GT-ER

If so then I'd replace them. It's really not a big deal but for the price of the bearings you can't go wrong. I Strongly suggest plastigauging though to make sure the new bearings are within tolerance. I know Oliverk only believes in buying all the tools AMG uses to build the engine but a micrometer and bore gauge is really not a NECESITY and will only incur in more unnecessary labor.

GT-ER

I tell you even more... when my brother and I started to build engines ( this was over a decade ago ) we really didn't know what we were getting into and would just slap all the parts together and let er rip.

You know what? We probably did over 10 engines like this and NOT ONCE did an engine fail ( except for some snapped rods and stuff but that has nothing to do with the engine build ). Not on the track, not on the street, and not after years of abuse.

Granted, I look back now and some of those engines would have definitely benefited from more care from us and I can see now the advantages of doing it right...but going so far as to say that a person that uses plastigauge has no business around a performance engine is just absurd.

Quadcammer

Its not absurd. You can do whatever the hell you want with your own junk, but just because you claim you didn't have any assembly related failures doesn't mean the engines ran particularly well or where gonna have a long life. As you mentioned, some of them broke (btw, snapped rod may have been from a spun rod bearing).

I'll say it again, plastigauge is bush league stuff. Maybe ok for a 350 small block, but I think its a very poor decision on any kind of close tolerance motor.

Now, you seem to think that the MB tools are useless. I think they are overpriced, but I also think they are useful.

GT-ER

I said useless? I have a micrometer and bore gauge at home...did I buy useless tools?

Also, a snapped rod with no bearing damage means it wasn't the bearings.

Again, if you want to fly over an AMG tech to build your engine that's up to you and your pocket...but we hardly own Formula 1 engines so I'll stick to what I know and has worked 100% of the time for years and on many builds.

Whatever man, bickering is useless when you obviously think I'm an idiot and nothing I can say will change that so to each their own. No point in continuing.

Benz_Addict, you already know my opinion. Hope it all comes out well.

sunil517

Also if you are going to reuse make sure they go back on in the same position on the cap and rod.