[QUOTE]Originally posted by suginami
[B] The early M104 used the old mechanical CIS-E fuel injection, and the 3.2 liter in the 1992 300SE was an LH system, used only for this one year.

The 92 and 93 300SEs are identical, both using the same ignition components. Although the nomenclature was not adopted until later both used the hot film air mass meter. You may be right that the 93 124 represented an evolution in engine controls.

Does anyone know what the factory estimated B10 and B50 life of the M104 engine is? That would be good way to settle this.

I always hear that MBs are engineered to go 300k but that could just be marketing blabber. What are the true engineering estimates for B10 and B50?

[QUOTE]Originally posted by deanyel
[B]I am pretty certain that 1993 300SE's use the same HFM system that other 1993 W124's use (3.2 or 2.8).

I could be wrong, but I don't think so.

I cross-checked this with MBUSA's webpage, and it also shows that 1993 300SE's went to HFM....

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

What does B10 and B50 stand for?

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

My '93 300SE is most definitely a HFM system. I was given a basic lesson on this system by my mechanic when my AMM failed about a year ago. My car only has 65K and I expect at least another 100k of reliable service from her.

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2002 500SL(Black/Black)
1992 300SE(Black/Black)
1992 190E 2.3(White/Navy)
1999 VW Jetta TDI(Pearl Green)
1986 SAAB 900 Base 3 door(White)
1983 Porsche 911SC(Chiffon)
1977 VW Scirocco(DiamondSilver)

B10 is the engineering term for predicted engine life from the manufacturer. It's usually used in reference to diesel engines but I believe it applies to gas as well. The 10 stands for the mileage or gallons fuel burned at which 10% of the engines produced will have catastrophic failure.

B50 is the same concept except the it is the point at which 50% of the engines produced fail.

These numbers are usually the result of extended testing.

Example: The B10 life for a 6.0 liter Powerstroke in a Ford F-250 is 300k miles. Thus, 10% of the enigines will have failed or required a rebuild by 300k miles.

This may or may not help but here goes. I take care of a 1987 260E(M103) for a friend, who is the original owner. The current odometer reading is 438,XXX miles. I did a valve job w/new guides, camshaft, rocker arms, tappets and a timing chain at 275K. The bottom end is all original. In fact the oil pan has never been off. It burns a quart of oil every 4,000 miles. I've used a variety of motor oils including Castrol, Pennzoil, Quaker State, Valvoline, etc. and I always use an OE filter. I change the oil and filter every 5,000 miles(instead of 7,500). The engine runs as smooth now as it did new. Since this post deals with an ENGINE question I won't list all the other things that I've replaced under the hood. The M103 and M104 short-blocks are quite similar so it's fair to expect the same durability. Also, the M120 V-12 uses an M104 cylinder head on the right side as well. Just my $.02.

438,000 miles is very impressive.

At minimum, with similar care and oil changes, we should be able to expect at least this much on an M104.

On another note, two years ago I was at my Mercedes mechanic's shop, and he had a 1992 400E with 44x,xxx miles on it.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

The only difference between LH and HFM systems is the type of air flow sensor (LH= Luft Hotwire, or just "hotwire" to most folks vs HFM= Hot film, unsure where the "M" fits in. Management? Dunno for sure.) Neither of these can in any way compensate for unmetered air leaks, ie leaks downstream of the mass airflow sensor. Not even to this day can this be detected and compensated for.

The statement regarding the ignition system being integrated into the fuel injection control module is incorrect, this did not take place until after the HFM system was discontinued. The next system, the Bosch ME1 system, finally integrated the ignition system to the fuel injection system.

I would also state that as far as idle speed compensation, although the LH and HFM systems began to integrate electronic accelarators (EA) that it is no simple matter to adjust the idle speed on the CIS cars either (electronic idle control valves are not adjustable).

Gilly

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Hi suginami, thanks. Yes, 438,XXX is impressive, but I should mention that I've replaced quite a few things on this car in the past. Two water pumps, three front flex discs, one differential, both fuel pumps, one fuel distributor, all the injectors, two alternators, one radiator, complete exhaust system, shocks and struts, all steering linkage, two windshields (due to pitting), A/C compressor and hoses(although the evaporator is original), rear wheel bearings, and countless assorted filters, door checks, window regulators, switches, etc! I figure the cost in parts nearly equals the price of another car, but my friend has gotten three cars worth of service for the price of two. What amazes me the most is that the little 2.6L M103 has seen thousands of highway miles between New Jersey and Florida at 3,500-4,000 RPM for hours on end! The car is still a daily driver and we're hoping to reach 500K.

Good. It shouldn't be too long until he does reach 500K.

Please tell us when it does.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

I think that on a properly maintened MB engine, the last thing in the car to go would be the engine, especially the bottom end. The bigger concern would be the accessories in the car such as A/C and accessories on the engine such as water pump, control systems, etc. I don't think that an engine with proper maintenance would suffer from internal mechanical failures too often.

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Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
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