The evolution of my 32-Valve SEC...

 

 

For months, the SEC was parked in closed storage in Pasadena, California.  I just didn't have the time nor a solid plan on what to do with the car.  The original engine had long since been removed in place of a 6.0L engine built by Barry Taylor.  The subsequent demise of Barry Taylor's engine, transmission, and exhaust system rendered the car eventually useless.  I pulled the entire setup from my car myself and parked the car in storage.

The delimma...I had several choices open to me.  Here's what I had on the table:

   1.  Just sell/part out the car, be done with it and buy a brand new 2001 Mercedes-Benz CL55

   2.  Buy a brand new stock engine and transmission and reinstall it back into the car at a tune of nearly $8000

   3.  Buy a brand new 6.0L block from RENNtech or MKB at a cost of $15,950 for JUST the engine, another $2,000 for the transmission, plus $3500 for labor and towing            = $21,450 minimum

   4.  Talk to AMG and get a 6.0L block from them in Germany at the tune of $10,000

   5.  Sit and twiddle my thumbs and keep driving my other cars....

After much thought and discussion, I decided that no matter what option I went with, I MYSELF would personally perform all the labor on my car.  I didn't care what RENNtech, Brabus, or any of the other tuners had to say nor what reputation they had, after the long ordeal with my SEC, considering how cosmetically perfect as it is, NO ONE was going to be allowed to touch this car any more except me, myself, and I with my own bare hands.  Not to mention, I really have as much necessary knowledge about the car as any of these other clowns.  That said, another thought as well, "...how can one acheive good hp, update the car, but NOT give up the day-to-day reliability and servicability that Mercedes designed into the car to begin with?"  DEFINATELY not by going to any of the tuners as they produce one-off engines that only THEY can service.  After my first ordeal with the 6.0L M117.967 engine, I steered away from this.  I also couldn't justify spending $8,000 on a stock motor and transmission.   It was almost cheaper to just buy another SEC!  At least I'd have a whole other car.

I had a conversation with my friend, David Cole regarding the installation of a newer MB motor into the SEC.  The thought of the project seemed complex especially since I didn't know of anyone else personally that performed such a feat.  Also, since the SEC used the Bosch CIS-E fuel injection system, the ONLY MB with a newer motor that would be most compatible was the M119.960 engine.  This engine also used Bosch CIS-E but was ONLY available from 1990-1992 in the R129 500SL convertible.  Also, I needed EVERYTHING; not just the motor, rather, the intake, sensors, harness, plugs, caps, electronics including all computers, relays, etc.  I started passively looking...slowly....then more concentrated but had little luck...

One day my friend, Bobby Mukkamala pointed out that there was a wrecked 1992 500SL near New York City.  I was able to contact the owner of the wreck and found out that his mechanic was an MB tech who did work on the side.  Well, this MB tech's personal car was a 1985 500SEC.  He wanted to implant this 500SL motor into his car.  With that in mind, the motor and all electronics, harnesses, computers, exhaust manifolds, intake, sensors, EVERYTHING was pulled complete and intact from the wrecked 500SL.  Afterwards, the tech changed his mind and decided just to sell it all.  Enter my good friend, Max Moussalli.  Max, who resides in New York, gratiously offered to examine the engine, ancilliary items, and speak to the owner regarding what I had in mind.  In the meantime, the thought of transplanting an M119 engine into the SEC was REALLY growing on me....

 

What are the inherent advantages of the M119 5.0L 32-valve V8 vs. the old 5.6L M117.96x V8?

old air box from M117 (left) vs. nice, modern air box from M119 (right)  

Technical Modifications and Innovations from Engine M117.967/968
            Engine Block

● Newly-developed gaskets are made of an asbestos-free material

● Helicoil threaded inserts, M12x30, are used for the cylinder head bolts.  The right and left outer threads have an inclination of 5◦

● Holes are drilled in the crankshaft main bearing webs to prevent oil foaming

● Lateral oil return bores for larger volume of return oil are installed.  There is a connector with an opening to the cylinder head for air injection.  The cylinder head bolt pattern has been modified

                Cylinder Heads

            ● Heater supply pipe from the left cylinder head through the intake manifold flange.  The lengthwise oil gallery in the cylinder head is closed in the rear with a threaded plug.  Core holes

                    are covered with sheet metal plates.  Valve cover gaskets in the semicircular slots have an overlap to the outside

                ● 4-valve, aluminum cylinder head with 2 overhead camshafts   Inlet valve:  14° inclination      Exhaust valve:  23° inclination

                ● Roof-shaped combustion chamber each with 2 intake and 2 exhaust valves

                ● Valve seat bores:               Intake:  39.10 mm                Exhaust:  34.10 mm

            ● Valve tappet bores (35mm diameter) with oil pockets for the hydraulic lifters

                ● Spark plugs located in the center of the combustion chamber

                ● Flat ring sealed spark plugs, thread:  M14 x 1.25

                ● Spark plug bores without lower water drain holes are sealed from above

                ● A lengthwise air injection duct with branching passages to the exhaust valves

                ● The threads for the exhaust manifold screws are surrounded with engine coolant through a system of drilled holes.  These holes are sealed from the outside with steel balls

            

            Connecting Rods

            ● Forged connecting rods with a lengthwise bore (4mm diameter) for oil spray cooling of the pistons

           

            Pistons

            ● Cast aluminum pistons with iron-coated running surfaces

                ● Flat piston crown with 4 identical valve recesses

                ● Piston cooling by oil spray through the connecting rod bore

                ● All piston rings are chrome-plated

           

            Vibration Damper

            ● Newly adapted harmonic frequency

                ● 45° before TDC mark is stamped on the circumference as an assembly mark.  When the no. 1 piston is at 45° before TDC, each camshaft can be turned by hand without any valves colliding

                  with pistons.  Therefore, in this position, heads can be installed without valves touching pistons

                ● In place of the steel pin for the TDC transmitter, a recessed dove tail key is inserted at 25° BTDC

               

                Ring Gear

            ● 2 magnets are now installed on two segments of the ring gear.  This allows the position sensor to distinguish the two cylinder banks (1 to 4 and 5 to 8)

               

               Oil Pan

            ● The aluminum oil pan with bolted on sheet metal lower pan is sealed to the crankcase with a gasket as before.  The bolted-on oil baffles prevent foaming of the engine oil returning through

                  the return passages

               

                Camshafts

            ● Two camshaft timing adjusters hydraulically/mechanically rotate the intake camshafts relative to the driving camshaft sprocket by 20° of crankshaft angle in the advanced position and back

                    to the retarded position.  The adjustment is controlled electromagnetically through the CIS-E control unit

                ● The adjustment time of 1 second is dependent on the engine oil pressure at the camshaft adjusters and the temperature and viscosity of the oil

                ● The camshaft position indicator on the camshaft sprocket sends the camshaft rpm signal from the camshaft position sensor as an input parameter for the ignition control unit.  The angle of

                    rotation for the camshaft advancement is limited by circumferential stops between the camshaft sprocket and the flanged hub.  A spiral cone spring prevents gear play from causing

                    noise during cranking

                ● Adjustment points are as follows:

                    0 to between 1000-2000rpm                          retarded                 improved idle, improved cylinder

                                                                                                                                scavenging, reduced valve overlap

   Between 1000-2000rpm to 4700rpm            advanced               increased torque, reduced waste of

                                                                                                                                Intake charge

               Above 4700rpm                                                retarded                 intake valves open and close later,  

                                                                                                                                Improved volumetric efficiency

    Engine shut-off                                                  retarded                 -

 

 

There are several more advantages:

1.  The EZL ignition control unit now has knock sensors on either side of the engine block.  The ignition unit has FULL control of the ignition system on the engine.  Also, with all the talk of superchargers, turbos, etc., this engine is a MUCH better choice to supercharge vs. the old M117 aluminum block.  The reference resister is now built right into the EZL unit as well.

2.  The super beefy 722.370 4-speed automatic transmission found in W140 S-Class sedans with V8 and V12 engines (i.e. S500/S600) was considered.  Of course, it would be modified with extra clutches, a tuned valve body and ultra-precise spacing tolerances between the packs for perfect shift.  The unit was built to handle 450+ hp.  Also, this unit comes with 5 friction discs as standard right from Mercedes-Benz.

3.  Since the 500SL had a 2.65 rear end, the 3.07 on the car right now would be a much better match for the torque characteristics of this engine than the M117.

4.  The transmission has a high-pressure switch in it.  Under hard throttle, when engine speeds hit the redline, the transmission sends a signal to the EZL ignition control unit signalling the unit to retard ignition for 400 milliseconds to provide a lightening fast shift.  Way cool!

5.  Oil spray cooling of each individual piston is awesome.  This is similar to what MB does on their diesel engines for cooler operating temperatures and much longer life.

6.  More modern serpintine poly-V belt drive is much nicer and more reliable than the old single V-belt design of the M117.

7.  Boy is the M117 engine ugly compared to this one...The 4-cam, 32-Valve heads with dual distributors mounted on the front of each head really was a mass improvement over prior.

8.  The valvetrain was much improved with hardened valve seats and stronger valves.  The old valve guide problems of the M117 was reduced immesely.

9.  And MOST important of all, this engine, without cat (on the 500SL), the M119 made 333hp, 339ft. lbs. of torque with 10:1 compression, 91 octane fuel AND gets 18mpg city/23mpg hwy.  BONE STOCK.  No changes, no maintenance headaches, no fuel problems, anyone can service it, ALL factory Mercedes-Benz parts.  Why reinvent the wheel?!

Now, I considered a few more issues....  this engine is very similar to the 500E/E500 motor.  That car did 0-60 in the mid 5's to 6.0 second range.  The 500SL was rated around 6.1-6.2 second range as well.  Keep in mind that the SL weighs nearly 200lbs. MORE than the W126 SEC, has cats, 2nd gear start, and a 2.65 gear ratio.  My car has NO cats,  large bore exhaust, a beefy transmission, 1st gear start, AND a 3.07 limited-slip differential.  When coupled with the large 275/35ZR18, there was simply no reason to not expect the SEC to be in the mid-5 second range for the 0-60 figure.  Once again, all with a BONE STOCK ENGINE!  But how hard is such a conversion?  WILL IT FIT?!  Time for some massive homework....

 

 <- BACK                                                           NEXT PAGE ->