Waking the Dead
A humorous tale of resurrecting the heart – and as it turns out, the soul – of a deceased 300CE
Article and Photography Rod Diridon Jr.
I have a friend – for the sake of this tale, we’ll call him “Dave” – who is the grim reaper of fine automobiles. If the cars from Stuttgart could talk amongst themselves, the name Dave would be whispered in hushed tones as if he were a demon to avoid summoning. As a high-tech executive with a juris doctorate, Dave is an intelligent, cultured, charming guy with a shocking wake of automotive carnage trailing behind him. He has destroyed four cars in recent memory, two of them with a silver star on the hood.
Dave is the reason I first came to appreciate Mercedes engineering. When we were housemates years ago, he traded me a well-worn 190E with a cracked exhaust valve for a month’s rent. With a mild restoration and a rebuilt head, the robust little four-banger jumped back to life and I drove the car for almost a decade. We joked as I helped him pick a replacement, a beautiful black-on-black 1990 300CE, that I’d eventually end up owning it after Dave had done his magic. That day came four months ago when he started up the Benz and pulled forward over a parking block, knocking a hole in the oil pan. Of course, oil pressure warning lights are of no concern for a harbinger of automotive death like Dave. The engine seized a few miles later.
When I received the call that the car was mine – this time in trade for a few cases of good wine – I was at first ambivalent. Rebuilding the motor in a 23-year-old, depreciated German marque is not a winning financial proposition. But, the 300CE had been well maintained by Bay Area Motor Works of Campbell, California, and the car had solid original paint, a supple interior and even the factory radio. And, it has such beautiful lines that I couldn’t resist.
Plus, I had an ace up my sleeve. My friends and I race a Mercedes in the 24 Hours of LeMons series and have come into a number of spare W201 and W124 chassis and inline-6 motors over the years – albeit in varying states of disrepair. The thought of Frankensteining an engine together from a bunch of useless cores seemed a good way to reverse some of Dave’s bad car-karma.
The first step was assessing the damage. The crank wouldn’t turn by hand, but how bad was it really? It was bad. Very bad. It was so bad that the aluminum main bearings had fused to their journals, destroying the crankshaft and gouging large grooves in the saddles as they spun. While the scored bearing seats and blue discolored metal relegated the crankcase to the junk pile, the oil pickup’s debris screen had done its job, sparing a recently rebuilt top end from any ill effects.
Fortunately the M104 doner block, complete with valves and pistons, was in perfect shape. Not only had the old timing chain stretched, but the bolt holding the guide sprocket had stripped.Pistons for the early M104 block that was used have four cutouts on top to accommodate the engines’s 24-valve design.
So, with a solid top end, I set about stripping two core engines – an M103 and early M104 – to scavenge the best parts from each. A word of warning: If you’re going to disassemble an engine, it’s important to recognize what an efficiently packed system of parts they are when together. Even with a fairly spacious garage, two workbenches and four large tables, there wasn’t a bare spot remaining after all three engines were stripped and cleaned.
It was a pleasant surprise to find that the cores had decent interchangeability and proved to be incredibly durable. The crankshafts for the 3-liter M103/104 engines were identical, which left two acceptable donors. While I chose to replace the bearings and rings with an abundance of caution, those too were the same and in fine “runable” condition.
Running in the 24 Hours of LeMons for years had left Diridon with a stockpile of spares, including several inline-6 engines in various states of repair; Here’s a lineup of identical donor crankshafts for the 3-liter M103/104 engine.
The main differences were in the blocks and the pistons. The early M104 block had oil squirters installed to cool the bottom of the pistons. And, it required four cutouts on the top of each piston to accommodate the 24-valve design. Fortunately, the block, pistons and rods from the donor M104 were in perfect shape. As a factory performance upgrade, the later mill had a windage tray that would avoid the crankcase pressure-induced main-seal leakage we experienced in our M103 racecar.
With plenty of photographs taken for reference through the project’s course, I thought the hard part was behind me. I was wrong. Surprisingly, the most difficult part of the build was finding the correct consumable parts. It turns out that few people choose to rebuild these engines, opting instead for low-mileage salvage-yard replacements or assembly-line rebuilds from Mercedes-Benz classic specialists.
The factory’s color coding on bearings and rings had long since worn off. With some sleuthing, we found that ours were yellow. The coolant jacket seal for the a/c-compressor stand was redesigned from a bonded aluminum-and-rubber piece to a metal compression gasket, which looked funny, but seems to have done its job. There is no kit to order when rebuilding one of these engines, so many of the parts – from rod bearings to o-rings – must be individually purchased. And of course, Mercedes factory parts are a bit pricey, $100 per cylinder for piston rings, for example.
Putting Humpty Dumpty back together again was a fairly straightforward process. Torque specs and build processes were provided in factory manuals and online. Having worked on an Italian V-8 recently, I found the intuitive German engineering was a blessing. The trickiest part of the rebuild was the cam timing, which involved setting the crank at TDC (top dead center) and using holes in the back of the cam sprockets as guides to determine where the timing chain should be set and locked into place.
While the instructions seemed simple enough, nightmares of folding over 24 expensive German valves admittedly led me to ask friends and journeyman mechanics William Sverdlov and James Osborn to lend their expertise. They not only found that the timing chain had stretched, but the bolt holding the guide sprocket in place was stripped and was working its way loose. After some effort to locate a left-hand thread insert, the sprocket was secured and a new chain installed, guaranteeing the Benz would get its full dose of advance.
After finally locating a left-hand thread insert, we were back in business.
With the engine out of the car, I took the opportunity to add a few extra touches. The most visible parts on these engines are the valve cover and air cleaner. So, the tattered factory finish was stripped and replaced with powder coating by the guys at Spray Technology here in Santa Clara, California, with beautiful results. As a precaution, the 150K-mile transmission and torque converter were also rebuilt. The folks at MB Exchange Transmissions based in nearby Fremont picked up the tranny at my house and returned it in shiny, almost-new condition a few days later. And, with plenty of room in the engine bay to move around, some proactive repairs on the notoriously crispy engine wiring harness were cheap insurance for a durable rid
Having the engine out of the car for the rebuild meant I could tackle some pressing cosmetic issues as well; here’s a composite shot of the valve cover before and after a powder coating makeover.
Then, with the engine purring and properly broken in, the car suddenly seemed to lose its will to live. First, the brick in its half-year-old catalytic converter started to break apart with chunks rattling down into the resonator. The main driveshaft support bearing began to howl, moan and clunk. Next, a nuance with the 1990-’92 emissions-testing process for the 300CE made it very challenging to get a smog certificate.
Time for the heart transplant at last. After the hunt for elusive parts, dealing with tricky valve-timing and frustrating issues with the timing chain, the completely rebuilt M104 engine in Rod Diridon Jr.’s workshop, ready to install in the refreshed 300CE.
The rebuilt engine, transplanted back into the black 300 CE’s rewired engine bay. At first, all seemed well ... but then the car appeared to lose its will to live.
Scratching my head with bemusement, I consulted one of our team members with experience messing about in boats, Captain Daniel von Beerman of the SS Geldgrube (known in other circles as Dan Beerman, whose boat is named the SS Money Pit). He told me about an old tale having to do with avoiding the wrath of Poseidon after refurbishing a boat. Every remnant of the vessel’s old name has to be removed and a new moniker bestowed. In my haste, I had not yet removed Dave’s old personalized license plates and installed the shiny new placards from the DMV!
Realizing that the ghost of Dave the Destroyer had to be exorcised to appease the car gods before the poor little 300CE could function properly, Rod Diridon Jr. enlisted the services of Captain von Beerman of the SS Geldgrube to oversee the ritual of removing the car’s bad karma. Here, von Beerman pours consecrated champagne onto the possessed vehicle through the skirts of a ruined piston.
I enlisted Captain von Beerman to oversee the ritual. We installed a new set of plates and, as an offering to the car gods, he poured champagne through the skirts of a broken piston and onto the bow of the vessel. Now rechristened as “Lucky,” the formidable little Benz made its way back from Death’s Door and has run without complaint ever since.
Today I can say the 300CE lives up to its reputation as a beautiful touring car. The solid feel and fit of the W124 remain while the pillarless doorframe and sleek design have withstood the aesthetic test of time. “Lucky” is truly a joy to drive and one of my favorites to wear the Mercedes badge.
The little black 1990 300CE has behaved like a perfect angel ever since.
As for “Dave,” he has since destroyed a high-end Hyundai Equus loaner car and his nanny totaled his family’s Prius. He recently bought a low-mileage Mercedes S500 that promptly dropped its transmission. And if you were wondering about Dave … while he’s like a brother to me, rest assured that no, he won’t be allowed behind the wheel of the 300CE. I love you, Dave, but I’m sorry: With all this little tri-star car has been through, it deserves a few more years on the street-side of the junkyard fence.