I got a coupe this July, a 1994 S 500. Its name is Chimera, which means it’s not an authentic preservation example and I’m going to mix some style on it. The wheels are one of those elements, the original wheels for the Chimera are 16″ 8-loch, which are really too small for the coupe, so I’m going to install different AMG wheels on both sides.
When I got the Chimera, it had the 18″ 5-loch modified by the previous owner, which have been the official coupe wheels since MY1995. Unfortunately the Chimera was produced in December 1993, which was MY1994, and the 5-loch period did not match .Although being completely original wasn’t the goal with the Chimera, I wasn’t planning on traveling through time, so I decided to go with larger than 16″ AMG wheels. Two rims made it to the finals.
The earliest AMG wheels for 140 are code 797, 8.5X18 ET 44 255/45. Manufactured by BBS, it is generally known as the Aero II, or Design 4, and has been available as a factory option since February 1992. This rim is only available on the S-class sedan and coupe.
Code 799, 8.5X18 ET 47 255/45, was also launched in August 1993, made by O.Z, generally known as Monoblock II or Design 3. This rim is more common and is only available in silver from the factory. The release of Monoblock II is only 4 months earlier than Chimera’s birth, but it’s qualified.
I acquired 2 sets of Aero II in 2020 and 2021. I didn’t need the second set, but I was buying AMG mufflers from a 600 SEL and the seller asked for them to be sold in a bundle, so I was forced to get the second set. I originally planned to use these wheels on Ruby, but then I decided they were more suitable for pre-facelift, the wheels have a kind of pre-merger violence, and the facelift body is too gentle. As I said, if you need to spray the center piece, the factory only provides pearl black, but Chimera can mix other things, so we will spray the center piece Tourmaline Green.
The code 779 body-color centerpiece is also available from June 1992 to October 1993, but only offered with199 Black Pearl.
Monoblock II has not entered my field of vision for a long time, the style is relatively generic and “plain”. I acquired a set in April this year. It had been restored, looked good, and the asking price was reasonable, so even though I didn’t have any cars that needed it, I kept it. I had been tracking a 1998 S 500 in 269 Tourmaline Green for a long time and thought it would look good with a Monoblock II in the same color. I later gave up on that car because it had all the same options as the Bianca and it was a serious duplication.
Now that the idea of the wheels was carried over, I decided to spray paint the center Tourmaline. Here’s a picture that gives a good idea of what it should look like.
I couldn’t really decide which one to put on the car, so decided to restore both to spec first. I wish I could take both and mount them on both sides as I or anyone would never be able to see the wheels on both sides at the same time so there would be nothing embarrassing about it. I had these images running through my head for a long time, and I decided to put the Aero on the left and the Monoblocks on the right.
I roughly decided how the job would go: the Aero would need to be completely redone, which meant disassembly, individually repairing the outer ring, fasteners and painting the center piece. The Monoblock had been refinished previously so it only needed the green paint for center. Both rims will be painted together, before that we working on the Aero’s parts restoration.
I checked out two Aero sets and was pleasantly surprised to find that the “unnecessary” second set was better for restoration. Both sets were restored, but the first set was completely spray painted silver and I didn’t want to strip the paint off 80 screws. Although the second set has also been repaired, the screws have been removed to avoid overspray. I disassembled the rim and found that the nuts on the inside were severely rusted, which was not good news and I had no idea how to repair the screws and nuts. They have a BBS stamp and I can’t replace them with replacements, and at the same time these screws are destined to come into constant contact with water – even though I never drive on water, car washes are unavoidable. I don’t think zinc plating is a sufficient solution.
I contacted several suppliers and listened to different solutions and eventually I was convinced to chrome plate the fasteners, there is a general lack of confidence in galvanizing. Chrome plating would make the screws extra shiny beyond the factory standard, but I didn’t receive a suitable solution. The compromise is not unacceptable for the Chimera, in fact I would have liked the screws to be brighter which would have made them more visible. The screws are a very important decoration, and if they are also painted green, the whole wheel will be boring.
Re-tightening the screws involves another topic. If the paint on the center piece is too thick, it may be peeled off by the flange. This set was once spray painted silver and I had no idea what kind of material it was, so I threw the center piece into paint stripper to create a thinner film of paint. Regarding the paint, I ordered PPG D894, which is PPG’s mid-range paint, I haven’t tried it myself, but it works great on my friend’s Porsche 986. In the past I mostly used PPG D8122, which is a top-grade ceramic varnish. Its advantage is high hardness, but its disadvantages are also. This varnish is not easy to polish and puts a burden on maintenance, so I would rather go with a softer varnish that is easier to maintain.
The outer ring was immediately sent to a professional shop that I’m familiar with for polishing and I’ve been very pleased with their past work. I sent a few original photos for reference – it’s really hard to find the right gloss these days, so they did. As for the Monoblock, I don’t think the gloss is quite right, but since it’s already been fixed, maybe there’s no need to repeat it. They were sanded and masked, waiting to be painted with Aero.
The construction period was extended. The first thing to go in place is the paint, then the outer ring. With paint arrived, we can paint, but the authorities are holding the “One Belt, One Road” conference, leaders of many countries came to Beijing 200 kilometers away. We were informed to stop all operations that may cause pollution to provide a blue sky. Ironically, during the three days that the conference was held, the air quality was very poor. The AQI was as high as 180 at one time and dropped to 20 immediately after the conference. No industry needs to be responsible for this. I have to say, God knows the undesirable guy is coming. We were stuck on painting for 3-4 days, during which time I had time to carefully sand every corner.
The painting strategy is to mask the outside and paint the inside first , then cover the inside and paint the outside. This can effectively avoid overspray. I couldn’t find a clear cutoff on the Monoblock, so everything except the polished ring was painted. Both rims only have clearcoat on outer surface to avoid future cracking. Primer first, then a thin layer of color coat, with the clear coat being thicker. Even though I wiped down all surfaces with degreaser, the once refinished Monoblocks outer ring appears to have been contaminated with some kind of oily passivating fluid, which prevented the clearcoat from adhering effectively.
At the same time, paint rim holes is also a matter of knowledge. It is necessary to reduce the thickness of the paint film while ensuring coverage, otherwise it may be scratched by the lug nut, and then the peeling of the paint will be continuously amplified. Only the outside has clear coat, this is to prevent the coat cracking from the inside and spreading to the outside during installation. Therefore, the inside and outside need to be masked separately during being painted. I’m very happy with the results, Tourmaline is an outstanding colour.
Too sad one bolt didn’t come back! The supplier is too careless because all the nuts and bolts are stick together when plating, except one end only fasten a nut. I wonder why their employee didn’t report this as long as he’s not blind, but nobody noticed. As they said, there are blasting, polishing and plating, it’s a long tour but no one noticed. The shop owner insisted they plated all I sent. I had a feeling such thing could happaned so took pictures of all 80 before I send out, my testimony is valid. After 5 hours, they found the bolt. As of 4.5 hours in, the owner, she claims they have absolutely nothing missing as it never happened.
My displeasure about the delay in painting is because we planned to let the painted Aero centerpiece sit for a few days to completely dry. Anyway I didn’t receive all bolts at once. A few days later I started installing the bolts, and I felt like I was getting a little nervous. Everything was perfect up to this point, but tightening was full of uncertainty, even though we had made the safest plan: fix the outer side to tighten the nut inside to prevent the flange rotating and damaging the paint. As for the inside, the flange of the nut is fixed to the polished aluminum ring, so there is no need to worry about any damage to thering. There are a number of things that require extra attention, if you look closely at the pre-restoration photo, you’ll see that the valves and the AMG wordmark are on the same side, in fact they should opposite each other. It took about 2 hours to install and torque all the bolts.
The ET of the two wheels differs by 3 mm, they share the same lug nut. Interestingly, this part was used not only on AMG wheels, but also on the 6-loch that was later widely used, so there was no need to worry about accessory availability. These screws are no longer available from MB aftersales so I have to get them redone. Collecting these screws was a surprise and I discovered how lacking I was in them! I can’t wait to put the old lug nuts on the assembled wheels! I only found 9 from stock and 1 was rough so ordered 12 extra. Placing the 5 shiny rather than green lug nuts in the middle is absolutely necessary, they provide a huge contrast and add detail to the rim. At the same time the Monoblocks are ready with almost no additional work. Since the passivation layer on the outer ring wouldn’t allow paint to adhere, I cut away all the clear coat there.
The unpleasant experience with BBS bolts made me decide not to send out parts that needed counting. For lug nuts, I pickled, copper-plated, and zinc plated them myself. Instead of previous regualr zinc plating, I added copper plating and a final polish, which made the screws shine. We also plate several times longer to increase corrosion resistance. It takes at least a week from sending to receiving, it only took me 4 hours. While I’m not sure how long it will last, it’s better than losing it.
The results are stunning! AMG wheels require so much detail, right down to the alignment of the center star. I can’t imagine what would happen if this job were completely delegated to a wheel shop. So even though this is just one part, it deserves its own article.
Soon after collecting enough valves I will take the wheels to the tire shop and install the Michelin Pilot Sport 5 that I installed on the 5-loch not too long ago, can’t wait to see how they look!