SAVING THE IMMORTAL - Mercedes-Benz 300D OM606 1982

This spring's Tuning Car Show's Young Builder class was won by Iiro Sorvali with his W123 Mercedes-Benz. How a once scrapyard-ready Merc transformed into this wet dream with an OM606 turbo engine, is indeed a story to behold.

In 2011 Iiro Sorvali had put on his shopping pants and was looking for a W123. One of his school mates happened to have a W123 300D sitting idle, and when Iiro heard of this, he didn't so much as blink when he'd already promised to buy said car. During the test drive he came upon the realisation, that he had never driven a car that was in such a poor condition. He bought it anyways, since he's a man of his word. After the car arrived home Iiro started to examine it thoroughly, and found out that it was pretty much rotten. The welding project took six months, since the only place that didn't need patching was the right side rear door.
Long days spent on welding makes a man think of weird things, and this time the quality time between a man and a machine birthed the idea of an engine swap. The original five-cylinder OM617 isn't known for its immense power reserves, and it's not tunable either. An organ donor was found soon, and the engine to be installed was an OM606. This engine is 3.0 litre inline-six DOHC, and Iiro spiced it up with a Turbobandit turbocharger. The exhaust manifold is made by Iiro himself, and it's manufactured so, that all the tubes are the same length before they attach to the collector. A large intercooler, a Griffin radiator, 3.5” stainless steel exhaust and a Turbobandit wastegate aid in producing a reliable +400hp all day long. The tiny oil cooler in the front is for the transmission, and the engine oil cooler is located in the fender.
The powertrain, especially the differential and drive shafts would not be able to handle so much power, so Iiro had to do some upgrading there as well. The organ donor car had a five speed electronically controlled transmission, so that was installed in the W123. OF-Gear's Arduino based transmission controller can be used to control pretty much everything, and the accompanied display show's used boost pressure, transmission temperature, speed, revs, etc. Searching for the right rear differential he found out that someone had used BMW's differential for a similar project. Iiro decided to up the ante, and fitted a BMW E34 530 V8's full rear axle in place. As you might imagine, it's not a plug and play installation, so some connection points had to be altered, and the suspension had to be custom made. Many a sceptic visited the garage during the project, and deemed it impossible, but lo and behold, thar she blows! The American Racing Torque Thrust alloys have been a dream of Iiro since he was six years old, so when he found a car he could put them on, he didn't even think of any other wheel choices.
Iiro bought this Raid steering wheel before the car was even in his possession, and he refurbished it to its former glory. The gauge cluster is from a W126 S-series, and it's electronic where the W123's cluster is mechanic. The first drive with this current engine was adventurous, to say the least: the throttle linkage got stuck behind the oil filter housing, wide open throttle. There were no rear brake lines installed at this point, the automatic transmission switched bigger gears all the time and there was no main switch installed yet. Luckily Iiro managed to stop the car and turn it off from the engine bay.
For three months Iiro spent all his spare time prepping the car for painting. The hood and the front fenders were soda blasted, and the car was cut and sanded by hand. For the paint job itself Iiro built a painting booth from boards and construction plastic wrap. Brilliant Blue paint, borrowed from an E-series was sprayed on the car three times, since the first two times had some issues with boiling paint. Practice makes perfect, however. The side vinyls Iiro designed by himself with AutoCAD, and printed them out. Finding tuning parts for a W123 is not an easy job, but finally Iiro found a shop in Poland that manufactured an AMG replica spoiler for him. The reflector panel between the tail lights is extremely rare, but Iiro lucked out, and found a brand new Sacex manufactured panel from a Mercedes enthusiast. The panel is tinted, so he coated the tail lights in candy red to match.
The stock seats aren't very supportive, so it was time to upgrade them as well. Iiro's cousin happened to have a Subaru WRX STi seat hanging around. Soon Iiro found himself doing brackets for said seat, so he had to buy it. He bought another seat without upholstery soon after, and started to search for someone who would upholster the seats. Sami Neuvonen sourced some genuine Mercedes MB-Tex faux leather, which was used in the original seats as well, and created this amazing looking upholstery. The fabric in the middle was chosen so, that it would match the door cards and the dashboard. The seats were finished on a wednesday, and on the following day Iiro put the car on a trailer and travelled to Helsinki, so the project was finished pretty much in time, which seems to be rare when it comes to show cars. The purpose of this project was to practice doing different sorts of things without help from outsiders, except when absolutely necessary. Iiro won his class in Tuning Car Show, and we're pretty sure this isn't his last notable project.



Mercedes-Benz 300D Sedan 1982


OM606 turbo engine, cleaned cylinder head, stiffer valve springs by KM-Cams, DIY exhaust manifold, Turbobandit TB60-3 turbocharger, Turbobandit 60mm wastegate, Dieselmeken manufactured feed pump with 7.5mm elements and pressure dependent feed adjustment


S210 300 turbodiesel's stock 722.6 five-speed electrical gearbox, OF-Gear gearbox controller, option for steering wheel paddles, DIY prop shaft made of 2.5” cardan tube, BMW E34 530 V8 LSD and drive shafts


GAZ adjustable dampers and cut springs in the front, GAZ adjustable coil springs in the rear, BMW E34 rear axle


W126 300SE calipers and 300mm cooled disc brakes in the front, E34 stock calipers and 300mm uncooled disc brakes in the rear


American Racing Torque Thrust 2 wheels, 17x8” ET25 in the front, 17x9.5” ET46 in the rear


Nankang NS2 Sport 225/45-17 and 245/40-17


AMG replica rear spoiler, side vinyls, front grille painted balck, red tail lights, front light surroundings painted black, Sacex reflector panel between tail lights


Raid wooden steering wheel, Subaru Impreza front seats upholstered to match the original interior


2x4” Blaupunkts made in West Germany sitting on the parcel shelf (just filling the holes, there's no headunit)


400hp and +600Nm (stock 88hp and 172Nm)


A better intake manifold, electric fuel transfer pump, polyurethane bushings, paddle shifters


Everybody who helped during this project, a special thanks to Simo for painting the car, and to Vuoksen Ruuvi ja Autotarvike for always listening to my problems