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Building a Pre-Add BRM

10837 Views 81 Replies 18 Participants Last post by  Rail Racer
The combination of an apparent high level of interest in Mac Pinches Pre-Add bdies as decribed in "News" and the recent arrival of some of Mac's new laser cut chassis has prompted me to start another project along side the W154/Patto chassis that is ongoing.

Thinking that there might be some interest in this project, I am going to document it in photos and (hopefully) brief text as it progress.

These will be a series of "real time" progress reports, not a "how to" since what I describe in one post may well be reversed in the next when I discover that it didn't work! I'll try to keep a rough log of time and cost.

The bits and pieces:

In no particular order: the body molding, driver, vac-formed screen and metal castings for the steering wheel, exhausts and filler cap (all part of the body kit) There are actually two chassis in the picture - on the lower right the laser cut chassis as supplied and spread about the middle, the parts after cutting and removal of the webs. The rear axle carriers/rear motor mount are "stuck" together. The fit of the parts is so good that the assembly is stable without soldering! Also in the picture is a guide and guide shaft bearing. One of the first things that I do with any commercial chassis is to try and figure out what guide shaft fits the hole. This is of particular interest for laser cut steel chassis because my experience is that these holes can oly be enlarged with some difficulty, the steel being very hard. In this case, the TSRF guide made for conversion of plastic chassis is a perfect fit and, on preliminary examination, to be short enough so that it will not extend beyond the front of the car (important for some rules)

Now let's do the numbers: A quick Google search yielded:

LOA: 158"
Width 56"
Height 35"
WB 98"
Wheels and tires: 5.25 X 18 front, 7.00 X 17 rear

If I believe my digital caliper, the wheelbase is spot on and the length is very close (perhaps 0.10" too short, but, the body that Mac has modeled differs from the one pictured on the site so I'm going to call it perfect!

A listing of tire dimensions for Dunlop Vintage Series tires yields:

7.00 X 17 30.2" diameter
5.50 X 18 30.1" and 5.00 X 19 29.6" so I'm calling 5.25 X 18 as 29.7"

This translates into 0.94" rear tires and , rounded to /100s, the same at the front.

Quick dimension check: The distace from the center of the rear axle carrier to the bottom of the chassis is about 0.288" If we subtract that from the radius of the proposed rear tire, 0.47", we are left with 0.18", plenty of room to add a weight pan and still meet a 0.125" ground clearance rule.

Second check - height is listed @ 35" or 1.1" in 1/32 scale. Knowing the axle height we can then check the body to see where the axle would be to give us that height in the finished car - and it turns out to be exacltly where Mac has placed the top of the rear axle slots!

Little worry (postponed until the initial chassis assembly is done and a motor fitted) - the fit between the top of the motor and the dash is the limiting factor for positioning the body on the chassis and, at first glance, it is a problem. The decision will be: can enough be ground off the bottom of the dash to accomodate the motor or will the dimensions dictate a front motor placement (and, in the latter case, isn't it nice that the chassis kit includes twoadditional motor mounts!)

An issue which has arisen long before its time: decoration: I am not really enamored of the peculiar diseased liver green that was chosen for these cars! (I recognize that there may have been budget constraints but did they really have to use paint left over from the redecoration of the railway station loos?) Any suggestions as to alternate correct liveries will be appreciated. I reserve the right to assign the car to Ecurie Martini and since this organization (long predating the red, white and blue "Martini" sponsorships) is a Belgian/American consortium, I'll paint it yellow!

Time so far, hands on and on the net, about 2 hours - parts @ current exchange, about $50

Next steps: chassis assembly, motor, axles & gears

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"Duck Egg" and "Sky Type S" are actually the same color. Sky is the official designation, Duck Egg the fitter's designation because everyone could see the green tinge.
Ex RAF stocks were cheap and a number of cars used it until about 1960. Actually, I find it rather attractive.
The only BRM Dark green I remember chasing down was called "Brunswick". This particular color has more variants than you can immagine. Some 20 years ago, i got a chip from the manufacture of the paint BRM was using(long story, friends in ECRA....) That particular green was one i matched by taking Floquil's Brunswick and adding a little Dark Blue. Floquil's is a railroad color and a little to gray.


Yes, as I indicated, the "Ex-RAF" color is listed as "sky type S" or "Duck Egg" in the catalogs. Everyone makes it. My favorite is Humbrol, they are a little anal about getting the color right. Going into more detail is a kind of a pain...In the US the humbrol military colors are difficult to find. And in Britiain, I assume that things like Floquil are tough to come by.

Anyway, Sky is easy. Besides the BRM, Moss used it on a variety of their cars. Including those wire wheel equipped Lotus 19s!

It is mixing up the "BRG" that causes the problems. The short version is that there IS NO SUCH COLOR! Lots of things got called BRG. In BRM's case, the supplier listed it as "Brunswick" green. And the chips I aquired match no known BRG any hobby company has produced.

Hi John

The Forum guys invited a couple of us infidels from the colonies to join. Something unexplained!
I was an ECRA and BSCRA member for decades, but never made a race in England. But I find kindred spirits in the old sod. Even in the UAE!


I assume that there has been a meaning shift to the term! Most of the ex-pat english and irish I talk to in person use the term all the time with no connotation at all. Hmmm.
Course, I have teased Alan Smith of not sounding "properly british" as well.

EM talked about the 61/2 cars. It may amuse you that we race our resurrected 1/24 cars from that period every year at Vegas.
My oldest/first used a Strombecker Merc body(and the second a Lancia), but those both disappeared due to Air Force Movers mis-laying the footlocker they were in in 61! However, recently, I aquired fairly good original bodies, and I have all the pieces to resurrect New copies. I am pretty excited about this. Don is the guy who actually directed me to FINDING them.

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