Building the Ultimate Porsche 935

[Icon Modeler]

Introdution

I introduced this project to Automotive Forums a while back and have made some progress on it. I felt the desire to back up a bit and share with everyone a little more back ground on myself and how the project came about. As well as my thoughts about the project. The previous post is of the body master that will be used to make all the new body parts. I hope you will enjoy watching this WIP as much as I will enjoy telling you about it.

http://www.automotiveforums.com/vbul...d.php?t=550626

Building the Ultimate Porsche 935

About The Builder

Years ago, as a young kid I built my first Tamiya 1/12 scale Porsche 935. What a fantastic kit it is. I was a mere 13 years old when it was first released for sale in the U.S. I had already been building plastic models for 7 or 8 years and had already made the decision that car models where all that I was interested in building, and even then, only Tamiya car models. You see I was heavily influenced as a young lad by one Dale W. King as to the type and quality of model I should choose. While my interest now and then go far beyond the mark of Porsche. The same was not as apparent to me then as it is now of my close friend Mr. King. In 1979 Tamiya released a 1/24 scale version of the 935 Moby Dick. I was 15 and thought then, what a great model that would be as a 1/12 scale. It would be a prize to have in any collection. I continued to build models into my young adulthood but had found that I did not build as much as I did as a youngster. I found that I was just as happy to stay involved by collecting kits. In 1990 I took a job that saw me move my home half way across the country. It was during this time that I seamed to completely forget all about models and model building. It was not a decision I thought about, it just happened.

Skip forward now 11 years. I had moved back to the Golden State I was from a couple of years before. I had still not returned to building or collecting until I went to visit a friend who owns a model shop that I had worked in as a 14 year old. He was also an employee of the shop when I worked there and has since gone on to owning it. We talked of old times and he started telling me of all the great kits I had missed over the years. Needless to say I have returned to my childhood hobby. Up till now I have spent the last few years collecting the kits I missed out on. Ebay is to thank for that. Ebay is also responsible for a huge flat spot in my wallet!!!! As I got reacquainted with the hobby I was also introduced to Tamiyacon by my old friend Dale King in 2002. Well a couple of years ago I started thinking of kits that I wanted to build. I also put together a list of cars that I wanted in my collection for witch there may or may not be kits available for. At or near the top of my list was the phenomenal Porsche 935 “Moby Dick”. It was at Tamiyacon 2004 that I made the decision to build a 1/12 scale “Moby Dick” to enter into the next years competition. Well it never made it to the ’05 Tamiyacon, but I’m still working on it and the following pages are some insight into my thought process as I create what I hope to be worthy of a Tamiyacon award. You must bear in mind that 1/12 scale is my scale of choice. However 1/12 scale is not the only scale that I collect. I have upwards of 400 pieces in my 1/20 scale F1 collection as well as a stout 1/24 scale collection that includes over 100 956 & 962 Porsche’s all with different livery’s.


About The Subject

Moby was a wonderful beast created by Norbert Singer. It was the car Porsche would use to completely extort the rules in what was know then as Group 5 sports cars. In December of 1976, the then governing body of Group 5, the CSI, meet in Paris France to discuss rule changes for the upcoming season. Of the rule changes put forth the ones of greatest significance where; 1) That the bulkhead separating the engine from the cockpit could be moved 20cm into the cockpit area; 2) That the body structure could be removed for and aft of the main cockpit for and aft bulkheads; 3) That the floor could be removed and raised to the bottom of the existing door sill height. These rule changes where written with the intent of leveling the field so to speak between the rear engine Porsche and the front engine BMW. However Norbert Singer and his design team where to brilliantly exploit all these rule changes to there fullest over the course of the next two years. Singer used the 935/77 to push the rear bulkhead forward into the cockpit to allow more room for the intercooler. Later that same year Singer would create the 935 “Baby”. This car would push the envelope farther by replacing the front and rear chassis structure of the car with a lighter tubular alloy substructure. Last Singer’s team would create the “Moby Dick”. A design that would encompass all three of the changed rules into one package that would leave little more then the front windscreen pillars, roof and rain gutters from the original 911 body shell. The design was so clever, by doing so Singer was able to lower the central portion of the chassis by nearly 3 inches. You see there was nothing in the rules that stated how the three structures, for, aft & central, where to be orientated to each other. By lowering the main cabin of the car this produced a lower center of gravity as well as less frontal area for better aerodynamics. The front suspension was nearly unbolted and reattached from the 935/77 car. The rear suspension was a different store though. Because they where now using the tubular structure they could make further changes to the rear suspension geometry. They where also no longer going to use the stock rear suspension trailing arms and in their stead use fabricated one piece alloy units. Other changes made where, the use of the new 3.2 liter four valve engine, with water cooled heads and twin KKK turbo chargers. Singer’s team had decided to retain the trustworthy 930 gearbox. However with a stroke of geniuses they had cleverly mounted the unit upside down thus lining the output flanges of the gearbox up better to the now high wheel hubs.


Reference

I have a verity of reference photos, some from the various books that I’ve collected over the years as well as Internet sites. I have also received a large amount of reference from a good friend that I know only threw the internet in Italy. His name is Dr. Edgardo Azzollini and without his reference pictures this project would be much harder to accomplish. The majority of my reference pictures however where taken by myself and a few friends, Dale King, Scott Truesdell & Charles Fox at the Monterey Historic vintage car races in 2004. I had also found a web site called Hudson Historics. They restore vintage racecars for current day vintage competition and had just finished the restoration of the Moby that was at Monterey in ‘04. There are plenty of useful pictures of the car on their web site documenting the restoration work. These photos proved invaluable reference for the chassis. The Moby that was at the Historics in 2004 was not the factory car, but it was one of two cars that were built by Reinhold Joest with factory help and the use of factory blue prints. The two car built by Joest differ slightly from the factory car in that they cut a bit more of the original sheet metal out from under the body shell to make way for the new tubular chassis.


Thought Process

Because we were only able to photograph the car full assembled it has been hard to come by in depth info on the chassis construction, specifically the rear suspension mounting points. I had to make certain educated deductions as to how they had come to the design of the Moby chassis.

A few things we do know about the chassis and have been documented above are the tubular chassis front to back and the lowering of the cockpit area of the chassis. By deductive reasoning I concluded that the rear suspension mounting points must have been raised back up to or near original height or it would have had a negative effect on the handling of the car as a whole. I also concluded that they must have raised the front lower wishbone mounting points just as they did the rear suspension points because of the handling issue. In addition they would have left the front shock towers in the new lowered position and used shorter struts otherwise the struts would have protruded threw the tops of the fenders and we all know that this was not the case. The rear shock mounts I would imagine are moved back up along with the rest of the rear suspension mounts but, because I’m not convinsed of this I will wait to make a final decision on this until I get a little deeper into the build. The last and probably the most logical conclusion was that the engine relative to the body is the same so that is to say the engine is now 3 inches lower just as the body is. The fact that they inverted the gearbox is a good indication that the engine is now lower.


Building The Chassis

To build my version of Moby I will start with a Tamiya chassis that I salvaged from a 935 I built as a youth. This will give me all the stock suspension mounting point information needed as well as allow me to establish the ride height of the original 935 so that I can accurately lower the model 3 scale inches (1/4 actual inches).

To start, I made a flat Chassis plate to build off of. This allows me to fixture the chassis at the original ride height, including the front lower wishbone mounting points, the steering rack and pinion mounts and the rear suspension trailing arm mounting points. Then I lower the Tamiya chassis on the chassis plate and fixture the front shock tower mounting points along with the engine mounting points. Once I have the pick up points established I then rework the mounts that hold the chassis so that they can now hold the body at the new lowered position. The body will need to be removable so that I can build the chassis and then reinstall the body over the chassis to check for clearance and fit of the roll cage relative to the body. There will be many times that body will go on and come off to make sure that the chassis construction will fit under the skin.


Pictures:

Chassis Plate:









Fixturing The Chassis:




























Enjoy,

Icon Modeler

[robrex]

What the???
This is going to be incredible!!!!!!!!!!

[Risko]

That looks very interesting, I´ll follow your topic

[mikkod]

Wow...i will stay tuned for this....

[Decs0105]

Ohh.. this is going to be interesting

[Robi J]

Hmmmm, I love this kind of approach...

Roberto

[Raikkobin]

I bought the re-issue as soon as it was available and it's been collecting dust ever since. I think it's the "I'll build it, if you do" syndrome kit. C'mon, make some progress so I do!!!! Pleeeeeease!!!

[willimo]

Um.... WOW! If this keeps up, it's going to be amazing.

[WasteGas]

Wow! Talk about a whole new approach to building. I'll be following this closely.

[mike@af]

I look forward to following this build. I eagerly await more updates.

[Icon Modeler]

Building the Ultimate Porsche 935

Update #1





06/18/06

Thanks everyone for your interest and comments. The main reason I choose to start this thread was in the hope that it would keep me motivated to see this project to the end. Your comments and feedback should serve to do that for me, so by all means please do not hold back. Any comments suggestions are welcome.

WasteGas made an interesting comment that I would like to touch on. He said “Wow! Talk about a whole new approach to building……..” This approach is not all that different to how the factory may have originally approached building the real car. In the first photo from a book titled Porsche Racing Cars of the 70’s by Paul Frere.



You can clearly see two standoff fixture tubes that are bolted to a surface plate under the car and are locating the rear pickup point of the lower wishbone. My primary occupation is race car fabrication, 1/1 scale and this is exactly how I would of built the full size car. The only difference that I can see is that the factory would have had the benefit of design drawings. I only can refer to photos. My point is that this may seam like a wild approach in the modeling world but it is a very widely used method in the full sized world.

Observation:

As I stated previously I stopped building for a number of years and so far the biggest obstacle that I come up against is the fact that I now ware glasses and find myself really struggling to see the really small details. Getting old sucks!!!! I guess a visit to the eye doctor is in the near future!!!

Progress Report:

The next step will be to fix the body to the fixture plate. I have chosen to use the Tamiya 934 body for this build. I believe that it lends itself better because of the more natural 930 style rear fender shape behind the door and below the rear quarter window. This more natural shape will lend itself better to attaching the new rear fenders. The second photo from a publication called "Porsche 935, The Story of a Champion Long Distance Race Car" by Sapphire Publications Ltd. shows Moby undressed in the work shop. It allows us to see just how little of the original body is left.



I located the chassis to the fixture plate by using the holes in the chassis that the body screws too. Sense these pieces where used to locate the stock chassis we will use them again to locate the body because they already give us the proper height relationship to the chassis. To fixture the body location I started by scribing a line on the fixture plate at the front edge of the pieces that located the chassis. Next I carefully busted the pieces loose and reattached them so that they are lined up with the scribe line at the front and so that they are now the same width as the chassis. I can now attach the body to the fixture plate. But this is only a means to get to the next step. Now that I have the body located successfully relative to the chassis I now must make new mounts that will hold the body at the same location and allow me to install the chassis pieces as well. I did so by making two mounts that are on the very outside of the lower door sill. These are the last of the fixture points (I think) and now the real fun will begin!!


More Thoughts:

One more of the very important changes made by Norbert Singer, I forgot to mention was, to move the driver from the left side of the car to the right side. This was done so that the driver would be closer to the Apex of the corner. The thought was that most European circuits are run in a clockwise manner and by moving the driver to the right it would allow him to better see and hit the apex of the corner. I also believe this would improve the handling of the car by moving the driver’s weight to the inside of those clockwise corners.


Right Hand Drive:

This poses a couple of challenging obstacles, one being the front bulkhead and the other being the dash board. Now that we have the body successfully screwed in place the next step is to dissect the chassis into the pieces we will use for the Moby chassis. Basically this consists of only the sides that make up the inner door sills and the front and rear inner fenders. Also the front bulkhead and rear package tray. As stated the front bulkhead will be the first major challenge. I used the area local to ware the steering wheel goes threw and scratched the rest. I also started looking at what mods needed to be made to the dash while waiting for glue to dry. I also installed the rear package tray. This gives me a more complete (four sides at least) chassis. After more research I found that there is much more of the original front bulkhead used than I had first thought and will require a little reconstruction of a portion of the front inner fenders. The rear package tray will also require plenty of mods to more accurately duplicate the Moby.
































Enjoy,

Icon Modeler

P.S. Sorry for the crap crop job on some of the pictures I’m new to Photoshop and in order to get the pictures below 80K to post I had to do some rather tight cropping.

[RallyFanatic]

Excellent, a very professional approach to building this model.
Just out of interest, what work do you do in the racing business?
(I've just finished designing the powertrain for a Formula Student team)

[Icon Modeler]

Originally Posted by RallyFanatic

Excellent, a very professional approach to building this model.
Just out of interest, what work do you do in the racing business?
(I've just finished designing the powertrain for a Formula Student team)

Thanks for the nice comment. I thought I would get more response to my update. Maybe I need to get more done and update less often??? just the right hand drive front bulkhead took me 10 hour to complete. It is slow going for me as I don't have a dedicated model building spot at home yet. I'm working on it though and should have a nice spot carved out in a few months.

You name it and I've probably done it. Not tooting my horn, it's just that I've worked in alot of forms of motor racing. Everything from CART/IRL with Robby Gordon and Patrick Racing to Endurance Sports cars with Tom Walkinshaw and Nissan to Offroad Racing with Terrible Herbst Motorsports and again, Robby Gordon to restoration of classic Porsche cars from the Panamerican road rallies of the 50's. Some people look at my carrier and think there must be a problem with me because I don't stay in one place too long. They're right, I get board fast, so I move around alot. Plus I don't spend alot of time putting up with BS. I look at my carrier and see alot of experiance. Right now I'm working for the afor mentioned Terrible Herbst Motorsports, they race Offroad race trucks. I started my carrier in the dirt and will probably finish it thier as well.

Icon Modeler

[mikemechanic]

Wow. I missed the second update so no comment from me. I didnt know what to say when you first posted as I did not fully understand what you were doing. Now that I see the update I get the jig set-up a little more. Your work is very clean and very professional, the kind of thing that I strive for but usually end up rushing things at the end. Please keep up with the clean work and whatever updates you make I will be watching. I don't always comment because I have no words to describe my feelings.
Mike.

[88Porsche944]

I am very impressed with the build. I'd like to see updates as often as possible. My primary interest is in motorsports, 1:1 cars and modeling. Porsche's specifially all era's past and present, although I do have to say I wish Porsche would have factory backing, as they did back in the day.

Please keep us updated as often as possible.


Trevor