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R129 SL 72 AMG (M120 7-liter engine specs)

Re: R129 SL 72 AMG

There is much confusion about these engines around. Alot of figures are made by wild guessings and assumptions. Fueld by "experts" ...
According to the parts lists of amg, the 72 and 73 have the same bore and stroke. The 7.0 was available as lh and me engine. The 7.2 and later called 7.3 (with the same bore and stroke) only as me. As just written in the German exotenforum, the car there is not a 7.2 it's a 7.0 as written in the documents.
 
Re: R129 SL 72 AMG

The 7.0 has a 91 x 90,4 mm bore and stroke [7055.41 cc]
The 7,3 has a 91,5 x 92.4 mm bore and stroke [7290.96 cc]

The 7,0 (7055 cm3) had two versions. At first (regarding timeline ) the M120.980/981 E72. Producing 386 kW/525 PS and 740 Nm.
And second the M120.982/983 E70. Producing 365 kW/496 PS and 720 Nm.

I have some copies of Fahrzeugpapiere where the 7,0 engine has indeed the two kW (386 and 365) versions 'eingetragen'. While the displacement in those two versions is on both occasions 7055 cm3
 
Re: R129 SL 72 AMG

91mm bore x 92.4mm stroke would be 7211.50 cc, if they ever built one...

I found this info in my archives... not sure how accurate the info is:
============================================
6.0L (5,987cc) = 89.0 x 80.2 (stock SL600)
7.0L (6,947cc) = 90.0 x 91.0 (RENNtech SL70)
7.4L (7,414cc) = 91.0 x 95.0 (RENNtech SL74)



UPDATE FEB-2017: New info from this thread summarized below:

M120 Displacement -- Bore x Stroke:
===================================

6.0L (5,987cc) = 89.0 x 80.2 (stock SL600)
7.0L (7,055cc) = 91.0 x 90.4 (AMG SL70/SL72, LH+ME)
7.3L (7,291cc) = 91.5 x 92.4 (AMG SL73, ME only)
AMG Note 1: Some 7.0L were badged SL72, these are 7.0L engines with higher power output than the SL70 of same displacement.
AMG Note 2: Photos/decals indicate an AMG S72/SL72 was 7,055cc and 525ps/740Nm. See post #46 below.
AMG Note 3: AMG apparently only used 2 different crankshafts / stroke for the 7.x engines.

7.0L (6,947cc) = 90.0 x 91.0 (RENNtech SL70)
7.4L (7,414cc) = 91.0 x 95.0 (RENNtech SL74)
7.6L (7,XXXcc) = 9x.x x 9x.x (RENNtech custom one-off SL76 - Merc Enthusiast, March 2003, 497rwhp)
RENNtech note: RENNtech apparently used different / custom crankshafts, not AMG cranks.

6.9L (6,871cc) = 90.0 x 90.0 (Brabus 6.9, rated 509ps/705Nm or 540ps/715Nm)
7.3L (7,258cc) = 91.0 x 93.0 (Brabus 7.3, rated 530ps/754Nm or 582ps/772Nm)
7.4L (7,370cc) = 91.7 x 93.0 (Brabus 7.4S, rated 620ps/800Nm)

6.9L (6,898cc) = 89.0 x 92.4 (AMG CLK-GTR, Bosch HMS-6, 631ps)
7.3L (7,291cc) = 91.5 x 92.4 (AMG CLK-GTR, Bosch HMS-6, 664ps)
CLK GTR note: Engine block is not the same as production M120. (?)




:pc1:
 
Re: R129 SL 72 AMG

image97062.jpgimage97063.jpg

The left engine being a M120.980/981. The right M120.982/983.
980 and 982 for W/C140. 981 and 983 for R129.

That is what i read. If it is correct? I don't know.

I read more different displacement figures. Like 7010 and 7180 cm3.
11987034_906856009395296_777456219801810016_n.jpg12003350_1486256808366656_5687988302817434028_n.jpg

I rather trust an image that came from the AMG website, some years ago.

12002284_1486228591702811_5595188424318247972_n.jpg

And that says 7055 cm3.
 
Re: R129 SL 72 AMG

Copies of Fahrzeugpapiere. Left 7055 and 365 kW. Right 7055 and 386 kW.

Bilder_002.jpg200zqco.jpg

And here 7291 and 386 kW.

19.jpg

All these data, and some engine stickers like the one in my first post, made me convinced the M120 E70 and the M120 E72 are in fact the same engine. That is, if i stick to the figures. I mean, equal displacement but different kW and Nm.

First there was the E72, then the E70. And last the E73. Which in fact is a M297. And not a M120.

However, some documents and images still refer to M120.983 when the 7,3 engine is meant.
But that must be because the VIN leads to SL 600. And the 7,3 is at some later stage put in.

Confusing stuff. Like what about M120.990? I have seen that in SL 73 AMG car registration. And at the same time M120.983.

Like i said. Confusing.:D
 
Re: R129 SL 72 AMG

Confusing. Because i still do not know for certain, why the M120 E72 is called E72. Most likely is displacement. Like M120 E70 is 7055 cm3. Seems pretty accurate.

But 7,2 !! Where does that come from?

Maybe it deals in some sort of way with the W202 C 36 AMG. And the M104 E36 engine. The C 36 AMG was the first AMG model when being official Mercedes-Benz partner. The W202 C 36 was the top of the cheapest modelrange at the time. So why not call the top of the most expensive modelrange at the time - W/C140 and R129 - twice that figure? 2 x 36 = 72.

Or is it just my imagination running away with me? Great song. I prefer the Stones version.
 
Re: R129 SL 72 AMG

To my knowledge, AMG has only ever reported two different V12 R129 cars: (1) the SL 70 AMG at 7055 cubic cm (97.0 x 92.0); and (2) the SL 73 AMG at 7291 cubic cm (80.2 x 92.4). And those are the only two configurations they've ever reported for the M120 engine in any car, R129, C140, or W140 -- and they put them both in each chassis. Although curiously, when they report on the S73 -- "A Bold Giant" as they call it, they show the Displacement and Bore x Stroke as "Unknown." Go figure.

But everywhere else it's consistent -- the 70 designation is a 7055 cubic cm M120, and the 73 designation is a 7291 cubic cm M120.

maw
 

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Re: R129 SL 72 AMG

To my knowledge, AMG has only ever reported two different V12 R129 cars: (1) the SL 70 AMG at 7055 cubic cm (97.0 x 92.0); and (2) the SL 73 AMG at 7291 cubic cm (80.2 x 92.4).
MAW, where did you get those bore/stroke numbers? They add up to very different displacements via calculator, assuming (bore x stroke):

7055 cubic cm (97.0 x 92.0) = 8173 cc <-- damn, an 8.2L M120 would be badass!
7291 cubic cm (80.2 x 92.4) = 5601 cc

:blink:
 
Re: R129 SL 72 AMG

MAW, where did you get those bore/stroke numbers? They add up to very different displacements via calculator, assuming (bore x stroke):

7055 cubic cm (97.0 x 92.0) = 8173 cc <-- damn, an 8.2L M120 would be badass!
7291 cubic cm (80.2 x 92.4) = 5601 cc

:blink:

That same AMG 45 book... I knew you'd check the math, which is why I threw it up there.

But I'm not sure that's the right math. Multiplying two numbers produces a squared number. It takes multiplying three numbers to produce a cubic number. When I walk through AMG 45, multiplying bore x stroke NEVER nets the number they report for cubic displacement.

For example, on the E60 W124 car, they report a bore of 100.0, a stroke of 94.8, and a total displacement of 5956 cm3. And we all know 100 x 94.8 is 9480, not 5956. I think you need some other number. Isn't the bore a diameter number? That doesn't tell you the area of the cylinder circle, just the diameter of it.

So using Area = pi x Diameter can get you the area of the cylinder circle. Multiplying that by the stroke can get you the volume of that cylinder. Multiplying that by the number of cylinders will get you total displacement. I've confirmed that math on the E60 M119 engine -- each cylinder has a volume of roughly 7.44, which multiplied by 8 cylinders (V8) gets you roughly 5,956 cm3. I'd expect that math to hold for the V12s as well.

Here you go... http://www.onlineconversion.com/object_volume_cylinder_tank.htm

maw
 
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Re: R129 SL 72 AMG

Sorry, I should have provided the formula - and you are correct, btw:

(((bore/2) squared) x pi) x stroke x number of cylinders x 0.001 = cc


Example with 91.5 bore x 92.4 stroke:
91.5/2 = 45.75
45.75 x 45.75 = 2093.0625
2093.0625 x 3.14159 = 6,575.544219375
6,575.544219375 x 92.4 = 607,580.28587025
607,580.28587025 x 12 = 7,290,963.430443
7,290,963.430443 x 0.001 = 7,290.963430443

7,290.963430443 rounds to 7291 cc (about 7.3L).

:matrix:
 
Re: R129 SL 72 AMG

I will post some more details later from the office.

Bore of 7.0 is 91mm
Bore of 7.2/7.3 is 91.5mm

7.0 was available as lh and me engine
7.2/7.3 only me

The often seen 7.2 badge is listed in the 7.3 parts list as well there is a special 7.2 intake manifold cover used for some models delivered to Brunei.

In the 7.0 lh and me are different type of cams installed.
All versions use the same head gaskets.

The differentiation of 7.2 and 7.3 was due to the fact that a 7.3 was officially available in the SL chassis, the 7.2 was the unofficial version available for different chassis such as also w and c 140 before the official sl73 was introduced.

Here some pages of the official parts list
 

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Re: R129 SL 72 AMG

Sorry, I should have provided the formula - and you are correct, btw:

(((bore/2) squared) x pi) x stroke x number of cylinders x 0.001 = cc


Example with 91.5 bore x 92.4 stroke:
91.5/2 = 45.75
45.75 x 45.75 = 2093.0625
2093.0625 x 3.14159 = 6,575.544219375
6,575.544219375 x 92.4 = 607,580.28587025
607,580.28587025 x 12 = 7,290,963.430443
7,290,963.430443 x 0.001 = 7,290.963430443

7,290.963430443 rounds to 7291 cc (about 7.3L).

:matrix:

Math aside, it still doesn't make sense that the 73 has such a smaller reported bore than the 70, when the strokes are roughly the same and they both have 12 cylinders. Part of the reason for my confusion on some of this, is the inconsistencies in AMG's own reporting of this stuff.

The 80.2 x 92.4 reported for the SL73 was apparently a typo or just plain wrong. For the CL73 and the CLK GTR 7.3 car, both with 7291 cubic cm, they report 91.5 x 92.4, as GSXR indicates. Which calls me to question the 97.0 x 92.0 they report for the 70 series cars. It just can't be true -- math doesn't lie. Pun intended.

As I look at the way these numbers are reported in the various models, I'd bet the SL70 was a 90.0 x 92.4. That is, the "80.2" was a typo, and reported for the wrong model. There was a second V12 CLK GTR 6.9 car, which had 6898 cubic cm, 89.0 x 92.4. That tells me ALL of the V12s had a 92.4 stroke, and only the bore diameter changed, which makes some business manufacturing sense (same block). The CLK GTR 6.9 had an 89.0 bore; the SL, CL and S 70 cars had a 90.0 bore; and the CLK GTR, SL, CL and S 73 cars had a 91.5 bore.

Are there pistons to support a bore between 90.0 and 91.5 in your "unofficial" parts lists? I think that's the only way you get an AMG V12 72 car. A 91.0 bore would get you 7212 cubic cm.

maw
 
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Re: R129 SL 72 AMG

When calculating the displacement i use the formula 0.785 (¼ pi ) x bore x bore x the number of cylinders x stroke = (roughly) displacement.

If 7.2 = 7.3 why does 7055 then have two kW versions? Like i showed on car registration papers.

Like here.

a.jpg

And in this car document even AMG M120 7.2 is named when refering to 7055 cc and 386 kW.

Naamloos.jpg
 
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Re: R129 SL 72 AMG

Naamloos.jpg
Naamloos.jpgNaamloos.jpg

All 92,4 mm stroke.

By my math, a 90 bore would be for a 7.0; a 91 bore would be for a 7.2 -- assuming both had a stroke of 92.4, which seems a fairly safe assumption.

This could indeed make sense. That 92,4 crankshaft comes from the dieselengines. Proven reliability with higher torque. And with higher rev engines like the M104.941.

Naamloos.jpg

91 bore and 92,4 stroke. 3606 cc. Multiply makes 7212.

Is the M120 E72 twice a M104 E36?

If so, what about the car registration papers then?
I still read 7055 and 365 kW and 7055 and 386 kW. I still read M120 7.2 in one of those car documents.
 
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Re: R129 SL 72 AMG

I can't solve your puzzle, but engine management could produce different output from the same displacement. AMG has numerous examples of the same engine with different output. When I'm back to the book, I'll provide a couple. I also cannot comment on the papers.

Cheers,

maw
 
Re: R129 SL 72 AMG

I can't solve your puzzle, but engine management could produce different output from the same displacement. AMG has numerous examples of the same engine with different output. When I'm back to the book, I'll provide a couple.
Yes - different engine management, different camshafts, different head porting, different compression ratios... etc, etc.

The important thing, IMO, is the actual bore & stroke numbers. There seem to be an awful lot of different numbers which seems odd to me. The M119 only has 2 crankshafts available (MB 94.8, and Brabus 100, AFAIK) and the bore varied from 100-102mm depending on the tuner. Were there really that many custom cranks produced for the M120?

90.4
91.0
92.0
92.4
95.0

I think MAW is on to something where there were probably only 2 different cranks from AMG, with varying bore diameters. Harder to say what RENNtech or other tuners did. Magazine articles say RENNtech had a "custom billet 95mm crankshaft", which would help solve the mystery, if true.

:detective:
 
Re: R129 SL 72 AMG

I think there were only two AMG variants -- 70 and 73. The CLK GTR cars I looked at for reference only, as they were a different block. But I found it not a coincidence that they all used a 92.4 stroke. So I think you only had 2 different bore sizes from them, 90.0 and 91.5. Consistency with the M119 points to an internal policy -- you have to keep some limits on the science projects.

Might they have toyed with a 92 bore and deemed it too risky? Sure. Might someone have taken a 90 bore and fiddled with it? Sure. Might an aftermarket tuner have done something that they could sell but that might fail under pressure? Sure.

But I think only 2 passed MB AMG's tests -- the 70 and the 73. And those tests, the discretion and care and engineering budget they entail, is the only thing worth buying for my money.

And for all we know, what's in the system as a 72 is what was BADGED the 73, just like today's 6.3's are nothing more than a marketer's pipe dream.

Cheers,

maw
 
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Re: R129 SL 72 AMG

That's what I've said further up already. There's the 7.0 an& 7.2/3.
Bore on the 7.0 is 91mm,on the 7.2/3 91.5mm.
Since I had to work on two of these engines I have the complete parts list from AMG with all specific part numbers. The crank of the 7.0 is different in stroke than the 7.2/3. Further are the rods of the 7.2/3 made out of titanium alloy.
7.0s are rated 496hp
7.2/3 are rated 525hp, for the royal family of Brunei was a special version with 565hp made.

To make a correct statement about the installed version it is absolutely mandatory to get the amg engine number stamped in on the side of the block. There you will find also find a clear identification of the engine capacity.
 
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Re: R129 SL 72 AMG

So, if all 7.2/3 have the same 91.5mm bore and 92.4mm stroke, the displacement is 7291cc, which I could consider 7.3L. Odd that AMG considered this a "72".

Unless they actually built some with 91.0mm bore & 92.4mm stroke, which would work out to 7211cc as mentioned earlier in the thread.

:scratchchin:
 
Re: R129 SL 72 AMG

Yes. Only info to this is that all 72 stuff is listed in the 73 list and it's only cosmetics like the 7.2 engine badge or a specific Brunei 7.2 intake manifold cover.
 
Re: R129 SL 72 AMG

Funny, below is a quote from the AMG Private Lounge...

"Dear AMG Private Lounge members,

For today’s Throwback Thursday we go back to 1999. Just before the turn of the century, Mercedes-AMG presented the SL 73 AMG, undoubtedly the leader in the small, exclusive segment of open super sports car. With a performance output of 386 kW, the vehicle accelerated from 0 to 100 km/h in just 4.8 seconds.

Even today the AMG 7.3 liter V12 engine continues to impress: a stroke of 80.2 millimeters and a cylinder bore of 92.4 milimeteres delivering a volume of 7,291 cubic centimeters. But despite its emphasis on speed, the SL 73 AMG stunned customers with its litheness and – of course – its typical Mercedes-Benz style sporting AMG styling at the front, sides and rear, plus the 18-inch lightweight alloy AMG wheels.

Let it also be noted that to this very day, the SL was the only vehicle among competitors of its era to be equipped with an automatically extending roll bar that offered open-air driving with optimal safety.

Enjoy our selection of SL 73 AMG bliss!

Best regards,
Your AMG Private Lounge Team
"

At least they're consistent...

I think we've beaten this horse to death.

maw
 
Re: R129 SL 72 AMG

I still have my doubts. Because i have collected information on two cars, that have both the E72 sticker as well as the 7055 cc in the car documentation. And one even a stamped 7.2 engine number.

38794384030_large.jpg38794384034_large.jpg38794384031_large.jpg

This car by the way.

http://www.cardomain.com/ride/3879438/1995-mercedes-benz-s-class/photo-gallery/

And the other is the white one from Tino Zovko.

0213683466014.jpgIMG_1682-500x500.JPG

To me a match of car registration documents and details on the engine, prove that a 7,2 liter is a 7055 cc.
 
Re: R129 SL 72 AMG

Yes, and if the donor car is available, there should be AMG decals on the car somewhere indicating the displacement, power rating, etc. If it's really a 7.2L, I'm sure someone here would want it.

:pc1:
 
Re: R129 SL 72 AMG

Hi all,

Am trying to figure out whether this is a SL70 or 72.

Also, seems like car left Daimler as a SL600 and was customized by AMG Japan (is there one there)?

Would appreciate any thoughts.
 

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Re: R129 SL 72 AMG

Another image that relates 7055 ccm displacement to AMG 7.2.

a.jpg

And it probably is this car from 1995. Since i found it here. http://www.nakamuraengineering.com/entry_machine/ 5th row from above. Most right. Adding that to reading nakamuraengineering in the first image. One and one makes two. Right?

S600C 7.2 AMG 1995.jpg

Or is this circumstantial evidence?

Second, click other makes for several maintenance reports of a Hammer C124. Where here i read there were 29 Hammer Coupes made. http://www.nakamuraengineering.com/report/the-other/other-makes/20081115-10611/ First line:

AMGファクトリー 世界限定29台  6.0ハンマー CEワイドボデー

translated into: AMG factory world limited 29 units 6.0 hammer CE wide body.

Mostly i read 12. Just like here.

35bdnhi.jpg
 
Re: R129 SL 72 AMG

Thanks for the info everyone! I updated my summary back in post #4.

:thankyou:
 
Re: R129 SL 72 AMG

And then there is this Lotec 90 x 92.2 mm = 7038 ccm according to this Fahrzeugbrief. With also 348 kW at 5200 tpm.
Naamloos.jpg
 
Re: R129 SL 72 AMG

Brabus 6.9 = 90 x 90 mm.
Brabus 7.3 = 91 x 93 mm
Some of the cc's are not matching from other sources. I wonder which are correct.

I had seen a Brabus 6.9L as 6,866cc (unknown bore/stroke). The one above shows 6,871 (which matches 90x90 bore/stroke). This may simply be a rounding error; if the value of pi is only 3.14 the maths work out to 6867cc (4cc less than if 3.14159 is used for pi).

For the 7.3... looks like the same thing. Pi at 3.14 = 7255cc, pi at 3.14159 = 7258cc.

Thanks for the info, I will update my notes!

:thankyou1:
 
Re: R129 SL 72 AMG

Good afternoon Gentlemen,

I'll start by confessing I'm a bit of an imposter. I don't actually own a 500E, though I've been lucky enough to drive and admire one which belonged to a good friend of mine. That car was very recently sold to Rowan Atkinson of Mr Bean fame.

I'm here because I found this thread whilst searching Google for info on the SL73 AMG.

I've just purchased a Sultan of Brunei RHD SL73 AMG with very low miles. The car was sourced in Brunei and is currently on a boat heading toward these shores. It's been sitting unloved for a long time and will need work to get it up and running again.

For weeks now I've been researching these cars and their history. I've never come across a car which has so much conflicting information. The story around the Sultans cars make it all the more complex but also all the more interesting!

Your research regarding the engines is fascinating. Until now everything I've read tells me the SL70 was the 'base' model and the 72 and 73 were effectively the same car with a badge change around 1995.


Does anyone have information relating to how many of these cars were made? I've read a total of 85, of which 35 were SL72 and 50 were SL73. But the info on here re the engines would seem to blow that theory apart.

To confuse matters even more, the Sultan of Brunei cars are sometimes referred to as SL730 and have a more powerful engine fitted (565bhp). Are these included within the numbers above?

The Sultan apparently ordered somewhere between 25 and 52 SL73's/SL730's with the more powerful engine, but I only know of two and another two which are called Argento and have been butchered with nasty Honda concept car bodywork. All of these are RHD.

Personally I don't think the numbers are correct. I believe the confusion comes about as he owned between 25 and 52 Mercedes with that specific engine, not all of which are SL73's. Certainly he ordered ten S Class estates with this engine.

Would love to hear any other info you guys can provide.

Thanks,

Chris
 
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Re: R129 SL 72 AMG

Confusing and conflicting information? Or do more versions exist that i know of?

Up till now i thought a 7055 ccm M120 AMG engine comes in 2 versions. A 7.2 LH version with 386 kW. Called M120 E 72.
And a 7.0 ME version with 365 kW. Called M120 E 70.
Check my posts and images above.

But these two examples below show otherwise.

LH M120 7055 ccm with 4 speed auto transmission* but with 365 kW.

CIMG3480.jpg

CIMG3483.jpg

ME M120 7055 ccm with 5 speed auto transmission but with 386 kW.

ch1_7256.JPG

a.jpg

* confirmed by AMG Aftersales that M120 LH versions go with 4 speed auto transmission whereas M120 ME versions go with 5 speed auto transmission.
 
Re: R129 SL 72 AMG

And then there is this case for me, where i am still not 100 % certain of. Is the above image a ME version? And the second one a LH version?

Since that information is by which i pull my conclusions. Together with the information whether a certain vehicle, that i try to get the specifications from, has a 4 or 5 speed auto transmission.

image98940.jpg

image98939.jpg
 
Re: R129 SL 72 AMG

And then there is this case for me, where i am still not 100 % certain of. Is the above image a ME version? And the second one a LH version?

Since that information is by which i pull my conclusions. Together with the information whether a certain vehicle, that i try to get the specifications from, has a 4 or 5 speed auto transmission.
Yes, the top engine must have ME since it has coil packs, the bottom engine must be LH... the M120 never used any systems besides ME (coil pack) and LH (distributors), AFAIK.

:strawberry:
 

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