Sunday, June 10, 2018

Mercedes 300 SLR: Interior and chassis

The chassis sure has some idiosyncrasies. Enormous inboard front drum brakes require driveshafts to connect them to the wheels, but can be bigger than the wheels would allow. They also reduce unsprung weight substantially. Cooling, however, might not have been ideal as the radiator is immediately in front of the drums.

The view from the rear highlights just how far over the engine is tipped. One would expect this would be needed with a typical prewar long stroke motor, but the motor was apparently square at 78 x 78 mm, having been expanded from the oversquare (76 x 68.8 mm) 2.5 litre GP engine.

I mentioned the driver having to straddle the clutch housing; the driveshaft runs under the seat and between the left side inboard rear drum and the lower swing axle control arm.

The transmission was at the rear under the gas tank, and appears to include a mechanical fuel pump driven off the back of it. As this is likely the location of the remote starter motor in the race version, one could expect the transmission input shaft to reach all the way to here.

Interior shots show the pedal arrangement on either side of the tunnel, with a partition designed to keep the passenger's left foot off the throttle. Or maybe the brake ... Uhlenhaut had a reputation for being somewhat fearless, and some race cars of that period did have a central throttle.

High, wide sills cover the tubular frame through the cockpit area, as in the 300 SL, and are the reason for the gull wing doors. De Lorean went for gull wing doors, too, but in that case the chassis, consisting of a Lotus-designed backbone system, did not make them essential.

The interior, as befits a car built for the director of engineering of Mercedes Banz, is snug but well trimmed in red and plaid. The plaid is surprising. Was Uhlenhaut of Scottish descent, perhaps? He was born in London, and his father appears to have been posted there by a German bank, but Wikipedia says his wife, Hilda Brice, was English, not Scottish.

The next bits will be tricky as the 'birdcage' chassis is not well modeled forward of the cockpit, and the floor pan is slightly twisted in  this location where it is not strengthened by the 3D superstructure. Glue and clamps will be required to get the cockpit to sit flat and to pull the frame straight. Stay tuned!

Saturday, June 2, 2018

Mercedes 300 SLR: Planning

As a way of further avoiding dealing with the Auto Union, and as followup to the successful 190 SL and 300 SL builds, I decided to tackle the 300 SLR.


First off, the kit I obtained was a gift set, which also includes a kit of the newer Mercedes SLS AMG and some paint and glue. The box is enormous, and the bits had been thrashing about in there for some time, so there was some damage to more delicate components -- in particular, one of the rear hubs, molded in one piece with the chassis floor, had snapped off. However, it was cheaper on eBay than kits of the 300 SLR alone, with the extra kit of the SLS as a bonus, so worth it. (I have also ordered a similar kit of the BMW 507 and i8, also cheaper than a kit of just the 507, which is what I really wanted).

Second, the SLR may appear to differ only slightly from the SL, but make no mistake: this is a completely different car. The GP-derived straight 8, with two cams and desmodromic actuation of the valves, is leaned way over on its right side, where the sedan-derived six in the SL is leaned over to the driver's side.

The driveshaft runs under the driver's seat to the rear-mounted transmission, and forces the driver to straddle the clutch casing. The final drive is a swing axle with inboard drum brakes; there are also inboard drum brakes at the front, necessitating front driveshafts even in the absence of FWD. What a complex beast, with a mix of state-of-the-art and just plain old-fashioned choices that required lots of fine-tuning to get it right. Mercedes kept building swing axles until the demise of the so-called W108 series in 1972, and while they were a special low-pivot design intended to minimise the usual problems with a swing axle, it highlights how the company could be traditional in many ways.

Tuesday, May 29, 2018

Mercedes 190 SL: Complete (#7 for 2018)

This 1960 Revell kit, in 1/25 but with a bilingual English/German instruction sheet typical of Revell's 1/24 offerings, had a number of quirks that made it a challenge. All parts, including tires, were molded from red plastic; the body was a multi-piece design that had to be assembled after paint; detail was fairly poor. Except for a strip of 0.010" acetate, there were no clear parts, and no decals. Nonetheless it was an interesting build and one that will sit well next to my other vintage Mercedes Benzes. Photos were taken before the taillamps and front turn signals were installed; as with my Tamiya 300 SL, I am going to leave the bumpers off.

I made a few modifications. The stock tires, tall skinny Firestone Phoenix 6.40-13 units molded with the rims in red plastic, were replaced with wider Goodyear Polyglas tires of about the same height. Not period correct for a 1957 model, but a likely upgrade that an enthusiastic owner might have made, even if this particular set (from the AMT parts pack) are probably larger than might have been specified. I also skipped the hubcaps, going for the steel rim look instead. The new tires are taller and I had to lower the suspension to maintain a half-decent stance; still the ride height is probably stock.

Body assembly required gluing on the right side body panel (two fenders and a door), then attaching front and rear panels with holes for hood and trunk, then the left side panel, all over the completed chassis. A challenge! Revell's VW van is also put together this way, as are a number of other older kits.

The windshield, which consisted of a strip of 0.010" acetate within a frame and chrome surround, got turned into a cut-down roadster screen without a frame, I also ditched the hardtop roof and installed a soft top cover from the parts bin.

Engine detail is poor and I added a distributor to try to smarten it up. The valve cover looks like no Mercedes valve cover I have ever seen, and the carbs are wrong -- it should have a pair of double-barrel sidedraft units from Stromberg, where the kit has what looks like a pair of single barrel units (or a single double-barrel unit). Mercedes was always fairly conservative about adopting new ideas, and while the cylinder head had 4 inlet ports, it looks from online photos like the #2 and #3 exhaust ports were siamesed. That being said, aluminum overhead cam heads were standard going back to the immediate post-war era, if not earlier, so

Neither the hood nor trunk lid, both of which open, are particularly good fits,  although the mounting approach is nice.

I know this review sounds negative so far, but it is an interesting build of a forgotten classic. Making it into a slightly customised roadster was a fun exercise. Everyone has focused on the 300 SL, especially the Gullwing, but the 190 SL was an important part of the mix as it took basic sedan bits and added better carburation and a stylish body, all at a reasonable price.

Part of the size difference is due to different scales, but the 190 was quite small. I'm not sure what's next; this build eliminates a long-standing WIP but there are plenty more on the shelf. Stay tuned.

Thursday, May 24, 2018

Mercedes 190 SL: Final assembly

This vintage Revell kit, which has been a WIP for over 2 years, has a lot of challenges, starting with a body made up of 9 different parts, and continuing with a poor level of detail under the hood. (See my post in January 2016 for more information about the kit).

Poor engine detail is only slightly mitigated by an aftermarket distributor. I worked as an apprentice mechanic at the local Mercedes dealer in 1975 and 1976, at which time there were still a few cars running around with this engine from the Pontoon sedan of the 1950's; the valve cover looks like no Mercedes engine I have ever seen. At least the boss for the distributor is in the right place.

Nonetheless it will be an interesting addition to the SL collection even if it is 1:25 and the Tamiya 300 SL is 1:24. (The picture dates to July 2016). Other SL's on the shelf include a resin version of the 1952 Le Mans winner, and the 300 SLR Uhlenhaut monster.

My immediate challenge is whether to use the scrawny 6.40 X 13 tires (molded, like the rest of the kit, in red styrene) or to find something a little more assertive that will fit from the parts bin. Then I will need some kind of cover for the soft top storage area as I do not intend to put on the hardtop. Stay tuned!

Sunday, May 13, 2018

1956 Chrysler 300B: Complete (#6 for 2018)

Time to go cruising! I seem to have gone off on a Barge tangent lately. The 354 Hemi in the 300B will overwhelm the Stovebolt 6 in the Belair, but the Hornet's 308 might put up a fight until the disadvantages of a flathead show up at higher revs.

A moderate custom this time: suspension lowered about 2.5" at scale, and steel wheels with Racemaster slicks in the rear. The lovely little baby Moon caps are turned aluminum from the aftermarket.

Moebius kits are very well detailed and will reward an experienced builder, while being easy for a beginner -- everything fits, and the instruction sheet is all pretty clear. That being said, there is some flash and mold part lines are visible. This is unfortunate for new molds. I've got their '69 F100 with a six that I am looking forward to building, as well as another Hudson.

Moebius kits have lots of underhood detail not found in other American kits: transmission dipstick, fender-mounted vacuum tank with hoses leading to manifold and brake booster; heater hoses; detailed decals for air filter housings and power steering reservoir, among others. Detail extends to the chassis where a proper steering box can be found, actually connecting through the firewall to the steering column. 

The 300B is far more elegant than the brutish Three Hundred, and doesn't exhibit the huge fins found on the 300C and subsequent 'Letter' cars. The grille is especially nice, and could even have come from Pininfarina or Scaglietti.

Of course both cars are enooormous by today's standards. And while I haven't driven either, I have driven other barges from the mid-'60s. The word flotation comes to mind ...

So was it therapeutic? Yes, in that it was possible to get something done quick. However, it's not show quality; 'quick' still means 'sloppy' to a certain extent. Back to the more complex stuff next.

Stay tuned!

1956 Chrysler 300B: chassis and interior

In keeping with the therapeutic value, I decided to keep it simple and build it out of the box, with the exception of tires and wheels, and getting the stance right. I also went for a non-standard two-tone paint job which caused some problems.

The suspension has been lowered about 2.5" at scale. Front and rear rims come from the parts bin, probably from a Parts by Parks pack or something similar. The baby moons are turned aluminum bits from Parts by Parks, while the Racemaster slicks are from one of the AMT parts packs. The front tires are from the kit; I may switch to blackwalls before final assembly.

The engine is well detailed, with a transmission dipstick, breather tube, fuel lines joining the carbs and a crude-looking throttle linkage. There will be a vacuum tank with hoses leading to the manifold and brake booster, and a set of heater hoses.

The interior is box stock, although I used a darker shade of tan than specified for the leather seats. A lot of nice detail here, but the steering wheel sits too low and would prevent the driver getting in or out. This is a kit problem as the column lines up with the hole in the floor as it should.

Overall I am pleased with it, even if the paint could have been better. Final assembly next. Stay tuned!

Sunday, May 6, 2018

1956 Chrysler 300B: Initial planning

Suffering as I do from a bad case of ADD, and needing a break from the mental effort involved in the highly customised S600/2000 and resin Type C, I decided to tackle Moebius' fine 300B. I've got a '69 300 (from Johan) and one of Moebius' Hudsons, so this will fit right into the Barge category.

In order for it to work as therapy, I'll build it out of box, except for two-tone paint, lowered suspension and (possibly) new tires and rims. And with the distributor in the back, and plug wires running under covers to the plugs in the hemi head, I won't even need to bother wiring it up.

All my stalled projects have one thing in common: the engine and drivetrain are quickly complete, but I get stuck on the bodywork. So I decided to start with the bodywork on this one.

So the first problem arose when Tamiya's white primer started pooling and making little pockets of no coverage, just like there was a lot of solvent or grease on the body in spite of a careful wash in dish soap and thorough rinsing and drying. I cleaned it all up with isopropanol, and went straight to the top coat for the roof, Tamiya TS-7 Racing White.

This also acted funny, but added coats seem to have leveled out. Still it needed a lot of careful sanding between coats before taping the roof up to put on the lower body colour. I am trying to avoid excessive paint build-up or sanding because the very fine Chrysler script on the fenders and hood will quickly disappear otherwise, even though I covered it in Bare Metal Foil prior to painting.

As soon as the white is hard enough, I'll tape it up and paint the lower body using Tamiya AS19, Intermediate US Navy Blue. I like these military colours as they are very '50s; the downside is they are slightly matte. A bit of polishing and some clear usually fixes that. Meanwhile the engine and chassis are coming together, with the only major problem (I hope) being figuring out how to lower the front end.

So was this restful and therapeutic? Not really ...