Need a good source for oversize pistons for M180, 230S

[Heckflosse]

I'm going to be rebuilding a M180 out of a 230 for my 66 230S.
This engine is an oil burner with low-ish compression, typical for something that's 60 years old with over 100,000 on it.
I haven't stripped it down yet, I'd like to know what's still available before I strip it and send it off for machining. I assume it's going to need the largest oversize pistons available because it is a burner.
The head on this engine has been completely redone; that's why I'm rebuilding it and not throwing it away.

So where can a guy buy new oversize pistons, rings, and bearings for this thing? I see gasket kits are still available.

[Benz Dr.]

I have a set of second version pistons but they would need to match your connecting rods.  24 mm piston pin with 3 ring pistons at 32.5 mm bore.

[parklandmb]

@Heckflosse

I have 2x 230s M180 engines in case you are interested.
I'm located 20min west of Edmonton not very far from you.

Sven

[Benz Dr.]

I have a set of second version pistons but they would need to match your connecting rods.  24 mm piston pin with 3 ring pistons at 32.5 mm bore.

Pistons are 82.5 not 32.5.

[Heckflosse]

Wow, that's interesting.

I truly appreciate the offer, and am learning a lot here. The biggest thing I'm learning is why there are none of these cars left on the roads anymore.

Now it seems I have to pull the engine apart just to determine the parts I may not be able to find. That's great. Mercedes really thought that through and like most European outfits, doesn't seem to understand the concept of interchangeable parts.

The funny thing is I have the same issue with repairing Swiss watches, you can't have enough of the wrong parts because every ebauche is different and they never standardized a thing, and even though they look the same, they aren't and nothing but the exact thing fits.

Ok: I will let you know once I tear it apart and have it laying all over the garage whether those pistons will work.
Right now I'm working on the other offer in this thread.

[Benz Dr.]

You can remove the cylinder head just to see the piston size. You may be able to see the serial number on your engine block which should give you your piston type. I say ''should'' because someone may have changed them.

[Cees Klumper]

... and with a borescope you don't even have to remove the head, only a spark plug ...

[Heckflosse]

Right; - I'm buying a borescope anyway.

The reason I was asking for biggest oversize is I'm assuming the cylinders will have to be bored, the engine was a serious oil burner and it's 60 years old, so I assume it has a ridge the size of the Grand Canyon in it. If it's anything like all the other Benz engines I've opened up, these things are all completely worn out by 100,000 miles. I was told this block has 80,000 on it; - yeah, my 250 was supposed to have 70,000 on it, and it looks more like 170,000.

The issue is the piston pins; - I wasn't aware that conrods or pins are different. I had hoped they'd be the same from 1965-1972 when they stopped building the 230. In order to figure that out, one has to strip the whole thing down. I don't imagine they printed part numbers on the tops of the pistons, and after 60 years of oil burning I doubt they'd be visible.

[stickandrudderman]

Interesting that you view Mercedes' constant improvements or refinements to their products as a negative.

[ja17]

These Mercedes six cylinder engines, when maintained properly, will last well over 200,000 miles. If the engine has less than 150K, compression and oil usage problems can usually be resolved by reconditioning the cylinder head. Considering the difference in cost of a total rebuild or just a valve job with new guides, valves and seals, you might not want to make the choice until you remove the head and inspect it. It is common to find some wear ridge at the cylinder tops, since Mercedes uses very hard rings.

[Heckflosse]

Well, I guess it's just my luck then.
 
I don't know how many people have told me that these cars are "bullet proof" and last forever. But I haven't had a good one yet. I keep hoping it's a fluke because I keep hearing how great Mercedes engineering was, and unfortunately I'm still waiting. I've owned a few Pontons that were also worn out and exhausted with around 100,000 on them, my last Heckflosse had a 110,000 known and it was completely worn out, so when this one came up and was supposed to be 70,000, I jumped at it, hoping finally to get a good one. Turns out it wasn't to be. So I wanted to solve that by rebuilding it and then finally being able to enjoy a good one for once.

The 230 I'm rebuilding has a refinished head. Valves, guides and seals were all done. It was also milled and is flat. Once the borescope gets here, I'll look inside and see where it went wrong. From what I understand from the guy who did the head, there wasn't much of a ridge visible, so it could just be the rings, I don't know yet. I've been told that the early 230 had issues with taper, they goofed it from the factory and they all used inordinate amounts of oil until it was corrected by a rebore and oversize pistons. It seems the older 220 was better and had less issues.

As for Mercedes' "constant improvement" style engineering, it has been nothing but a source of frustration, one can never have enough of the wrong part it seems. When you don't have the build sheets and you have to hunt for numbers is one thing, and then find to out your car is right in between two major design changes, it's enough to drive one to drink. I've lost count of how many times I've had to send stuff back and wait because mine was the version that it all changed on and yet according to Mercedes, it shouldn't have been.

Add to that the arrogance of the dealerships, "It's not the car's fault, it's yours". Right; nobody should drive them, they look great in a garage holding down a concrete pad. Yeah, it's been fun and I don't know why I keep buying these things, as I said, I keep hoping I'll find out what it is that makes these things so great. The nice thing I guess, is I no longer have to deal with Mercedes because they have absolutely nothing for my car anymore. In fact, they told me not even to bring it to them for service, they wouldn't know what to do with it.

Honestly, I have yet to see a Mercedes Benz car that has held out more than 100,000 miles here in Alberta. Even the modern ones don't get there without a serious amount of work, my father had 2 modern ones after he retired that were constantly in for warranty work, the weirdest things kept breaking. He spent more time walking then driving those cars. He ended up buying a Toyota which solved his problems. I have that car as my daily now and it has well over 160,000 on it and isn't missing a beat.

 The vintage ones weren't that great either it seems; - I don't know what it is, it could be a combination of incredible distances done at highway speeds, mostly done in the extreme cold, lousy service and maintenance, bad oils, bad gas, owner indifference, who knows, but the survivors that haven't completely rusted out were absolutely worn out by 100,000 miles.

[Benz Dr.]

Right; - I'm buying a borescope anyway.

The reason I was asking for biggest oversize is I'm assuming the cylinders will have to be bored, the engine was a serious oil burner and it's 60 years old, so I assume it has a ridge the size of the Grand Canyon in it. If it's anything like all the other Benz engines I've opened up, these things are all completely worn out by 100,000 miles. I was told this block has 80,000 on it; - yeah, my 250 was supposed to have 70,000 on it, and it looks more like 170,000.

The issue is the piston pins; - I wasn't aware that conrods or pins are different. I had hoped they'd be the same from 1965-1972 when they stopped building the 230. In order to figure that out, one has to strip the whole thing down. I don't imagine they printed part numbers on the tops of the pistons, and after 60 years of oil burning I doubt they'd be visible.

Cylinder bore size will be stamped into the top of the piston - if you can see it, which will be very difficult with a bore scope. Any carbon deposits will obscure that rather fine printing.

[Heckflosse]

Cylinder bore size will be stamped into the top of the piston - if you can see it, which will be very difficult with a bore scope. Any carbon deposits will obscure that rather fine printing.

That's what I thought; Either way, it looks like I'm going to have to tear it down. Running the serial numbers didn't help either, it seems there is no solid record of what was produced when.

I'll let you know what I find, it will be interesting considering that these things should be so tough and last so long.

[rwmastel]

Running the serial numbers didn't help either, it seems there is no solid record of what was produced when.

I call BS on that one.  The VIN and engine number (serial numbers are for computers) are critical to getting the right parts.  Did you get the recent Pagoda World?

But, as we all know, parts wear so you have to take things apart to find their actual condition, see if they've already been replaced or modified, and learn what you really need to do to make things right.  You might already have max oversized pistons!
Then what?  You can't make assumptions, especially on a car you have no history with.  I'm starting down that

[Heckflosse]

I call BS on that one.  The VIN and engine number (serial numbers are for computers) are critical to getting the right parts.  Did you get the recent Pagoda World?

But, as we all know, parts wear so you have to take things apart to find their actual condition, see if they've already been replaced or modified, and learn what you really need to do to make things right.  You might already have max oversized pistons!
Then what?  You can't make assumptions, especially on a car you have no history with.  I'm starting down that

Which is what I will end up doing before I buy anything. I just wanted to know if the over sizes were available, that's all. No point even taking it apart unless parts are available. However, it would be typical German, strip it apart to find out what you need, only to be told, "Ausverkauft, Nicht mehr Lieferbar". Then I have an interesting disposal problem I didn't have before and am no further ahead.

As for the numbers, someone somewhere has to have an engine serial number decoder that should be able to give the date of manufacture, at least one would think. I know the block will fit, and I was told it was from a car from the same period, but whatever date coding I see on the block doesn't make sense, it shows it to be a 1972 block. With American cars, if there was a replacement block installed, the serial number would indicate it, along with the year code, plant code, and then in some cases down to the shift and model of car it was installed in. I was hoping that Mercedes would be that advanced, but so far haven't seen it. To my knowledge, no such coding exists with Mercedes. All I have is the stamped in numbers, the little plate is gone. So if I'm wrong, I'd appreciate someone letting me know where I can find that info. I can decode the serial number of the car well enough, just the componentry is difficult. And, I don't have the pink build card for my car, that went missing ages ago. So tracking the inevitable line changes that were done on the assembly line is now a crap shoot. It can never be a "matching numbers" car.

The 230 engine was stripped and the head replaced. Pistons are stock, I know the guy who did the head work, and he said it's all stock. It burned when he got it, and it burned after he did the head work, so to correct the burning issue, it will probably need oversize, I have yet to see an oil burning engine that didn't, when the bore and taper are redone it will need a new set of oversize pistons. To think it's just rings needing replacement is foolhardy, what causes rings to fail? Excessive clearance caused by wear, detonation, all of that.

I've heard that these Mercedes blocks are so "hard' and don't wear out. Hmmm....yeah. Two that I looked at a couple of months ago had a ridge the thickness of a fingernail. I'm assuming this will be the same. It'll all depend on how much the machine shop has to mill out to correct the taper. Apparently these things can't be sleeved either, although I don't know why not, but it could be that the walls are too thin and it would be too close to water. 

So I'll bore scope the 230 I have and see what's going on, and while I'm at it, I'll do the 250 that's still in the car. I'm interested to see what caused my "dead" hole, no doubt something else that should never happen and no one here has seen before.

[rwmastel]

As for the numbers, someone somewhere has to have an engine serial number decoder that should be able to give the date of manufacture, at least one would think.
.....
So tracking the inevitable line changes that were done on the assembly line is now a crap shoot.

MB doesn't care about dates, they care about the sequential numbering of the chassis and the engine.  They record "Part 501 replaced by part 502 at engine number 0123".  (Example numbering, obviously.)

[ja17]

I would dare say that most of our thousands of members in this group have a much better experience with the longevity and durability of Mercedes engines. Fortunately my 55 years experience of driving, repairing these engines and cars has been much more positive also. There is no doubt that the cost of ownership and dependability of a modern Toyota is one of the best. I'm sure finding parts for a 50 year old Toyota can be difficult also, (if you can still find a 50 year old Toyota still on the road). It seems that you are getting a lot of fragmented information from too many different sources. There is a lot of wrong information out there on the internet. 230 or 250 engines can both be easily sleeved. A good parts man should be able to look up the correct parts needed, by using the engine number and vin number. Of course, there is always the chance someone has been into the engine before and used some wrong parts. Parts availability, price  and location information, of original parts, can be easily accessed by a good parts manager. NLA (no longer available) parts is rare and sometimes only temporary until new supplies are procured by Mercedes. Many high quality aftermarket parts can also be sourced. Experience of the assembler, accuracy of any machining, quality of parts and correct assembly procedures are critical to the success of a rebuild. You have come to the right group, we can help you. Don't take on too many broad assumptions from wrong sources.

[Heckflosse]

Thanks, I appreciate that, it's good to know. Good to hear sleeving is still an option in case pistons are not accessible.

It's tough to remain positive when everything I've tried so far has either not worked, or I've walked into a dead end. Yes, I'm used to North American collector cars which are much easier to source parts for, even if there are none available in Canada. I had the misfortune of liking and restoring Buicks, I really appreciated their engineering and they had some of the best quality control going, - for an American mass produced car. But like Mercedes, there was absolutely nothing left for parts for anything older than 10 years old, it all had to be imported from the US. I was thinking Mercedes parts would be similar, and 20 years ago this stuff was easy to find, but it seems that all the sources I used to know are long gone.

I won't even go into a 50 year old Toyota. They were a bad joke back then. But they learned and improved, while Mercedes was at the top and has declined. I do like the older vintage Mercedes cars, my family owned a lot of them back in the day, both over there and here in North America.

I'm really surprised that no one seemed to overhaul these things when they started to get tired, they just ran them to complete failure. With a lot of American cars I restored, some of them were on their 2nd or 3rd rebuild, and were salvageable without too much work. Most of what I've seen in 6 cylinder Mercedes so far is in need of some pretty severe machining.

Please excuse my frustration; I've got 3 engines in my garage that are boat anchors, (at least they were free or really cheap) one in the car, one on an engine stand, and the other one out back because it's total scrap, and am possibly going to look at one more in the next week or so. Hopefully it's good and still useable. I've walked away from 2 more, and all of them I've seen so far have the same issues, they're all suffering from the same thing, advanced old age and total exhaustion. I guess being close to 60 years old has something to do with it.

[Heckflosse]

Just bore-scoped out both engines, the 230 I intend to rebuild, and the 250 that's in the car.

The 230 has a definite ridge, so it's likely rings, meaning a re-bore is probably going to be in order. But there were no other surprises. The walls are pretty glazed, there's no evidence of a cross-hatch or anything which is to be expected. There isn't a lot of carbon except in the #2, that's a wet burner, the rest are not terrible. The previous owner told it too had no compression left, so there's no point in tossing it in, it will need a total rebuild and right now it's the likely candidate.

The 250 shows rust pitting in the walls, and there might have been a valve strike on the #3. There's a lot of rust in the #4, and there might be a head gasket leak. I can pretty much see where the pistons were stopped for an awfully long time. And yes, there's a nice ridge on this one too, it's also completely worn out.

On the plus side, the carbs appear to be working fine. The plugs are all a uniform brown, no longer black or rich. So I re-gapped them to .035 (it has electronic ignition on it now) and took it for a drive. The car pulls like an ox, it's actually a pleasure, it just doesn't like to lope along at 30-40 mph, it surges with the major miss that it still has. I was able to knock the idle down a hair, it's probably 1200-1300 rpm now. So the cam was a definite improvement, and I think I have the carbs pretty much dialed in; so I think I've gone about as far with this motor as I can right now.

Next week I go look at another donor motor, hopefully it's still good. If I can get a year or two out of it, that would be nice, that would allow me to save the money up and do the rebuild in phases, because I assume it won't be cheap.