4/11/2020 I bought this car about ten years ago. The radio in the car was the German transistorized replica. The original was in a box. Well after ten years I decided to open the box and see if it works. The original speaker was in the box too. The speaker is on the right. At the back is the power amplifier and the front is the AM/FM tuner.
The buttons worked, changed the frequency, but the knob on the right didn't work. So I opened it up. The knob shaft goes to a worm gear. To the right of that is a clutch, the gray thing. A little tightening of the adjustment screw fixed it. You can tell this was all hand soldered. Just a bunch of resistors, capacitors, filters and of course, vacuum tubes. It takes about 30-45 seconds for the radio to warm up.
I cleaned the buttons. The black paint on the back of the face was flaking off. So I carefully took the paint off then repainted the black.
Not too bad for 62 years old.
Here is the radio working.
1958 190sl Mercedes restoration
4/22/2020 I got bored of welding and grinding so I decided to take apart the engine. Before I did, I put the starter back on it and did a compression test of each cylinder. 120, 90, 105, 100 Not very good. It should be 150+. So it definately needs to be rebuilt. Below, right is with the head removed. The stock cylinders are 85.00mm bore. All four were measured to be 86.00mm. Available pistons and rings are 85, 85.5, 86.0 and 86.5mm. So if the cylinders are OK as is, and only need to be honed, then I can use 86mm pistons and rings. If it needs to be bored, then it will be 86.5 and it won't be able to be bored again.
The engine is a single overhead cam with an aluminum head. Below left is the head, top side, cam shaft and rocker arms. The right picture is the bottom side. The stock head thickness is 85.00mm. I measured it to be 85mm so it has never been cut, which is nice. It can only be cut by 0.1mm.
I started looking into see if the engine was original. Based on the 190sl Group books I have, the original engine had side covers on each side of the block. This engine was used untill chassis number 8501731. My chassis number is 8501233. The car was build on 4/28/1958. This engine change was on 7/7/1958, after my car was built. So the engine is not original to the car. The previous of the car bought a spec sheet from Mercedes. The original engine number was 121 921 85 01 277. The engine number is 101 920 000 752. The original 190sl engine had the oil drain plug on the passenger side of the oil pan. On 9/4/1958 they moved the drain plug to the driver side of the oil pan. Mine is on the passenger side. So this tells me that the engine was from a car built between 7/7/1958 and 9/4/1958.
4/25/2020 I flipped the block over and removed the oil pan. I then removed the oil pump, disconnected the connecting rods and removed the main bearing bolts.
I then removed the crankshaft
I then put the block on its side and pulled out the pistons. As you can see, a ring on each of the center two pistons was broken. On those two, the very top of the cylinder walls was rough so they may have broken removing the pistons. They are going to be replaced anyways. The pistons and the cylinder walls look pretty good so hopefully this means honing the cylinders and just replacing the rings. I measured all the bearing locations on the crankshaft. They were all standard dimensions so the crankshaft has never been turned.
4/24/2020 I bought a valve spring compressor and removed all the valves and springs. The intake valves look great, exhaust not so. The valve guides are another replaceable item but they look good too.