1972-1989 MB'sIron blockvs.Aluminum V8!
 

There is an article that I've read,that
an iron block V8 can go to 300mi.w/proper
maintenance. R&T says,there are two
knowledgeable persons who knows MB.respectivley.
Steve Marx and Rod Cunha.
Both agreed the iron block V-8's are
axeptionally long lived.1972-1989 V-8's
are just unburstable.Around 350,000 before
bottom end overhaul isn't unreallistic said
Cunha.The top end is often good for 180-240,000mi.
And from Marx,I have some customers w/ at least
300,000 mi.on their cars and the engines haven't
even needed a valve job.R&T MARCH 1994 pgs.106-
111.My question is,are the iron block V8's
more durable than the newer aluminum V8's?
If so,in what respect?I'm very curious.
Anybody?

MB stopped building the cast iron V-8 blocks in 1980!! The aluminum blocks starting in 1981(USA) haven't had any real bottom end problems at all. In fact the oil consumption on these engines due to bottom end problems are non-existent.

I agree totally.

The bottom end of either motor has no end. I have a current customer with 650k on the bottom of his 91 420SEL.

We did a valve job at 380k due to upper rail failure (our first work for this customer who drives to us from Jacksonville - 85 miles). Unfortunately at the time we thought the car had 180k on it as the speedo had been changed (so we didn't change the lower rails). At 490k the lower right chain rail wore through and the chain went again. At 600k we put VG oil seals on it as it was using some oil (its never used a quart between 3k oil changes except as the seals wore). This customer drives 90k a year but takes very good care.

When we did the job at 490k the customer was skeptical that he could get another 100k out of the bottom end. He has gotten at least 160k more and still going strong. It had almost no cylinder ridge at the time it was last apart.

Were the heads also iron on the iron-block v8's?

Never!! Only diesel cars upto the OM601 series had cast iron cylinder heads.

I can breathe now!
 

Whew!What a relief.Now I know my car will
last for a while.Thanks gentlemen.:)

I think all MB gasoline engine heads since the 50s were aluminum.

Sixto
91 300SE
81 300SD

So are you all saying that a V8 would definately last longer than a 4-cyl? Or will a well kept 4-Cyl last a long time without a major overhaul

Christian

97 C200
89 300TE
00 ML430 (sold)

That's like asking "how long is a piece of string?"

Depends. There is some thought that the need for a four-banger to rev to make power would mean earlier wear. There is also thought that due to their smaller displacement, they are higher stressed and therefore wear out earlier.

I'm not familiar with the smaller displcement four-cylinder engines found in the C-Class, as they were not offered here. Is your engine an M111 DOHC family member? If so, you've happened onto a good engine.

I have several friends with very many miles on their M111, and the engines are proving to be very strong. The following are things that will extend the life of any engine:

1. Change the oil and filter often.
2. Use synthetic oil, especially if you live where temperatures get cold.
3. Be very gentle on your engine after a cold start. Wait for the engine to warm (not just until coolant is at 80) completely before high revving or loading it up.
4. Don't drive like Tommie on rally-day.
5. Keep things like fuel filters and air filters fresh.

By following these practices, I've had several M102 (early 8V 190E four cylinder) engines still strong at 400,000 kilometers (250K-miles).

Most MB engines, whether 4, 6, or 8 cylinders, will outlast the automatic tranny it's bolted to.

Cylinder liner
 

Another thing that confused me is in another
article,it says that the newer alumimum block,
is that the cylinder is coated w/ silica,that it doesn't need a cylinder liner.Its scary b/c the
early BMW alum.V8 are coated w/nikasil something
are troublesome.
:eek:

Actually the cylinder walls are not coated in either case. The technique is called hypoeutectic cooling/casting. The concept is to disolve as much silicon dioxide (sand/glass) in the matrix of aluminum. As I recall this was about 17%. The amount that can be held in solution varies the freezing point and changes the amount that can be disolved. By controlling the freeze an artificially high level of SiO2 is held disolved. What this all means is that even though the whole thing is 17% the first part to freeze is about 35% and the last about 8%. Sort of the opposite of drinking frosen kool-aid. The first to melt is real sweet and the last is real weak.

Anyway the cylinder bores are made to freeze out first and they are very rich in the SiO2. This is very high for only a small depth.

After three step boring with ever finer cut. The honing is intended to polish out all mechanical deformation. After looking like glass (it is 35%) a siliconizing procedure is done. This sounds like its adding something, but it actually involves leather swabs dipped in an acid etch being drug through in a honing like procedure that removes the aluminum on the surface. This leaves a surface that IS glass and wears like it.

And friction is decreased!Shoot!
No wonder why theyre so expensive.
Thanks Steve.

Steve,

What kind of shape your customer's car with 650k on it? I'm guessing that it must look very tired regardless of how well you try and maintain it (interior wear, etc.). I'd love to see a pictures cars like this with so many miles on them.

Actually we had 4 126 SELs here yesterday (and a couple 126SDs). One of them was the car in question. It looks as good as any of the rest of them better than most as it is a 91 model. The upholsery has probably seen less Florida sun than many cars. We are exceptionally busy right now but I'll see if I can take some pictures today.

With that kind of mileage, I'm suprised its a 1991. I'd love to see it.

Steve, what year did the V8's get "better" with stronger cam shafts, etc.? Was it 1989? or 88? Were there any other changes? I keep hearing about this and wonder if it really pays to try and find a car with the later, updated engine components.

(I've had a few 420SEL's and the 88 has some minor revisions, the 86 and 87 were virtually identical.)

the engine in the C200 is a M111, with the 4 DOHC. Do u know if its the last generation of that series motor? or is does the w203 have the same motor just modified?

We don't get any four cylinder W203 cars here, :mad: so I have no idea if they are M111 mills or not, but I would assume they are. The M112 V-6's were carried over.

Oh ok....still I think your philosophy of drive em till 400 k is good....still it takes FOREVER to get there and in the meantime if ur like me, you would like to be updating to the latest model..still it think maybe sometimes there would be better things to spend money on other than cars even though im a mercedes diehard...


Christian

89 300TE
97 C200

My experience has shown all the 2 valve V8s to have similar wear characteristics. Notable changes were in the valve guide oil seal style - the last change I know of came in 83-84 (before 420), the valve guides/valve stem diameter - came with the aluminum motors - 1980-81.

I looked up cam numbers and they have been the same since the 420 came out except in the european version where the number currently in use for US models changes. The US numbers are 117 051 08 01 and 09 01; these numbers chnge to 20 01 and 21 01 after engine number 965: 048805.

Most changes to the car were cosmetic/trim from 86-91 although the car did enter onboard diagnostics in 1988. The A/C controlled the aux fans and was smarter from 88.

Its probably more important to find a nice example of any of those years than to get a particular one. I would go for after 88- though as a start.

Look at it this way:

1998 C230 new, Canada, $43,000. Worth 4 years later, $28,000.

Depreciation charge: $15,000. Average mileage 100,000.

Cost per km: $0.15.

Projected price of 15 year old C230 with 375,000 kilometers: $7000. Depreciation: $36,000 (here a 15 year old high-mile 190E sells for about $7000. I sold my very-high mile 190E 2.3 for $9500. This analysis of course has no accounting for inflation along the way.)

Cost per km: $0.09.

Factor in interest opportunity costs on new cars, (even people who pay cash give up interest income) huge initial depreciation charges, and even with the high repair/service costs associated with a 10+ year old car, and it's much cheaper to keep driving.

I have no need to drive the "latest" model, and the only reason I bought my C230 brand new was a desire to own an MB right from the showroom floor. I wanted at least one that would get the care I lavish on cars right from kilometer one.

Steve,

Regarding your findings:
Do you know if this was the case for the 560? I thought in '89 or so they started using a cam that wasn't so "soft". Perhaps, they did and didn't change the part # (??)

Good info!
Thanks,

The US does get the W203 chassis with 4 cylinder. The new compact coupe!! W203.747 has the M111.981 engine.

Doesn't the US C240 also have an M111?

Sixto
91 300SE
81 300SD

Well, that is interesting. There was a cam change on the 117.968 motor at 027352.

What is really interesting is that the replacement cam 117 051 26 11 and 117 051 27 11 (replaces 18 11 and 19 11) are to be installed with new number 116 055 15 01 (rocker arms) to replace 116 055 11 01 (whitch changed at the same chassis break). Early rockers failed regularly before 100k. They took cams with them. I always wondered if we would be doing rockers again on these cars; maybe not.

Looks like I'll be checking part numbers on the cams when I pop the valve covers off the 560.

No. It's not an inline 4-valve-per-cylinder DOHC design. It's the newer 2.6L M112 family 3-valve-per-cylinder SOHC engine in V-6 form.

It's turning about to be a great engine, but I'm a tad disappointed at the C240 performance. It has 18hp more than my C230, but at the track this summer, my C230 automatic ran pretty much exactly the same acceleration times as an 01 C240 automatic. Mid 8's 0-60 and mid 16's 1/4's. I imagine the manny-tranny C240 might be quicker.

I would strongly consider a new W203 SEDAN (sorry about missing the Coupe) if they offered the 2.7L inline-five turbodiesel. Auto-mags agree that it's the real jewel in the C-Class line. Unreal fuel economy combined with stump-pulling torque. Our stupid low-grade diesel precludes us from getting it here.:mad:

I learn something new everyday. Thanks.

Sixto
91 300SE
81 300SD

So Steve what you are saying is that rocker arms changed later in the 117.968 run along with the harder cam that wasn't prone to lobe problems (??) Was that in '86?

Thanks,

The change was made at engine 968: 027352. That means the 27352nd engine. They started in late 85, I guess. I don't know where that engine number fell. Looking back at our shop history of 560SEL chassis numbers the earliest I found was in the 200000 range and was an 86. The first 27000 might have all been euro cars.

Actually I was confusing chassis number with engine number. Using the data card for a few different cars I found that a chassis number ending with 322258 had a motor number 27839 which is a few higher than the change point. This car was an 87.

Interseting.... sounds like something GM did back in the '60's on some of their muscle cars. "Does my 442 have a nodular iron crank, forged or???" Sometimes the only way to tell was look for the # on the part in question.

Thanks!

manny are you not reading what is being told you.What it meens is that the cast iron blocks last almost forever.

Then,why did MB turn to aluminum? :confused:

Michael,
Have you read that?

Having read through all these posts with very interesting info.
I am a bit puzzled. I have seen quite a few M117's with totally worn out engines loosing compression due to worn out cylinder walls and burning oil like crazy and nothing is metnioned about that. These were W126 380SEL's and 420SEL's up into the last year early 90's models. What exactely, if any, are the differences in the production of the blocks for the aluminum M117's and the later M119's? Do both have silicon liners/sleeves or is that just the M119 and the M117 were merely honed, no liners? I was under the impression that the M119 is by far the better engine and not only in the performance department.
Thanks for the info in advance.
F.J.

manny there are more things in heaven and earth than------------- Happy holidays.Michael Rybikowsky