I was scanning through one of the threads on the BmW 2oo2 FAQ website and came across this image some time ago and saved it to my desk top. I figure this must have been some time shortly after AlpinA sold the car (1975/1976?). No front spoiler but still had the Gr. 2 AlpinA front wings. Still has the aluminum windshield retainer clips the car had late in its life from AlpinA as well as what appears to be the Scheel 3o3N (light blue ) same as it had in its final days in the black with green/blue AlpinA stripe livery. Rear wings had been changed to the wide "CSL esque" with openings for coolers/radiators (in this car's case it was oil coolers).
Friday, January 30, 2015
Monday, January 26, 2015
Most folks out there have read this article more than once, for a short article it is I think very informative as it describes the fundamental operation of the SCHNITZER 20,4 16 valve, fuel injected (slide throttle) racing engine. Dave Foley, the author of the article is a friend of mine and was the one who sold me the NOS SCHNITZER "Rallye" head kit in addition to conducting the PPI on my behalf of the BMW ALPINA Grp. 2 race car. The following is the text of that article......as a side note, I am happy to report that the car mentioned in this article is still alive and well and being restored at a "secret" location here in the United States. At some point I am sure that the owner will let me post some images of his project.
by David Foley
European Car August, 1995
Schnitzer '02: Rebuilding a Legendary Twin Cam Motor
by David Foley
European Car August, 1995
To the less informed U.S. fan of BMWs, "AC Schnitzer" means little more than a line of aerodynamic components, wheels and engine goodies. In Europe, the Schnitzer name is highly respected and is well known for its association with BMW's racing heritage.
The Schnitzer brothers, located in Freilassing, West Germany, were dedicated to getting the most out of four-cylinder BMW motors. Josef Schnitzer, the oldest brother, had a brief stint with the factory motorsports team, aiding in the design of their racing motors. In ] 972, after about a year with the factory, Josef returned to the family business, concentrating on his own design of twin-cam power, based around the standard four-cylinder block. Unlike the factory twin-cam motors of the day, Schnitzer's engine had the intake and exhaust placed on the same sides as the production fourcylinder engines. Much of Schnitzer's success came in l 973 with Formula Two open-wheel cars.
Schnitzer twin-cam motors were used in the 2002 chassis for both rallying and road racing. The Weber-carbed rally motors produced approximately 225 bhp. For road racing, the injected motors developed around 275 bhp. These were installed early on in the same attitude as the production engines, canted 170 to the side.
The car featured here is an early Group 2 car, prepared in Germany by Schnitzer The engine is fed fuel by a Kugelfischer mechanical injection pump driven off the front of the crank in the same fashion as the road-going 2002tii. Unlike the tii, this pump has no limiter or automatic cold running enrichment device. Cold starting takes two people-one to hold the difficult to get to enrichment lever and the other to hit the starter.
Air metering is performed by an aluminum slide throttle encased in a magnesium casting complete with detachable magnesium trumpets. The slide plate glides across about 120 tiny roller bearings on one side and Teflon(g) strips on the other. At first, the use of two different sliding surfaces seems odd but not when you realize that the injectors are located upstream of the slide so that at partial throttle the injector spray is hitting the plate, causing slight pooling of fuel at idle and low speeds. I Having the Teflon strips on the pooling sides keeps the lubricated roller bearings cleaner. You can actually hear the tapping noise of the injectors hitting the slide plate at idle. Neat! Wide open, the fuel\air mixture has no throttle plates or shafts to impede its flow through the intake tract.
As the cylinder head and cam carrier was in two parts, the head was always cast in aluminum, but the cam carrier was cast both in aluminum and magnesium. There were early and late versions of the cylinder head\cam carrier assembly design changes in strengthening ribs and oil return valleys being the main differences. Also, the newer style heads were beefed up for use with turbocharging (more in a moment).
As with most twin-cam motors of today, the camshafts ride on split bearings directly on the aluminum of the cam carrier. Cam and bucket lubrication is by hollow core cams fed by the first of five split bearings. l his first bearing also serves as the thrust bearing for the cam. Pressurized oil in the cam cores is then distributed to each bearing and cam lobe through small brass oil jets. A duplex roller chain, similar to the standard production engines but longer, drives the twin cams by their standard cam gears. Here is seen a distinct difference between the factory and Schnitzer. The factory motors used a series of helical gears off the crank and cams to drive everything. Valve adjustment on the Schnitzer motors is both tedious and time consuming, since the adjusting caps can only be exchanged by removing each camshaft. This is the same method used to adjust clearances on the M1 BMW. Combustion chamber shape is that of the efficient "pentroof" design, resulting in a compression ratio of 11.5:1.
Clamping of the cylinder head to the block is taken care of by the stud and nut method, which is more effective than the standard bolts. Magnesium is the metal of choice for both the valve cover and upper front timming cover.
Pistons are of the skirted variety and have fairly low domes and shallow eyebrow cuts for sufficient piston-to-valve clearance. The low domes allow for good, even flame propagation at the ignition point. Schnitzer used two different rod lengths in its motors and also two different metals, depending on if the motor was normally aspirated or not. Turbo motors received the steel 148mm ccnter-to-center length rods, while the early atmospheric motors had 143mm titanium rods. It is interesting that both Schnitzer and the factory had problems with titanium rods early in their development. A change in actual design, it seems, was needed along with the use of the then exotic metal.
Lubrication for this particular motor is provided by a three-stage dry sump pump mounted on the lower exhaust side of the engine. Cool oil is supplied to the pump by a four-gallon tank mounted in the passenger side rear seat area. Pressurized oil is sent by the gilmer belt-driven pump via large radisized curved -10 Aeroquip line to a remote-mounted Fram racing filter and then into the engine through a very modified standard filter mount. Particular attention was paid to oil flow, both to the motor and inside it.
Excessive oil is helped off the crank and into the pan by a handmade windage tray assembly whose center piece is secured on pedestal-style mounts secured to the main cap studs. The outer one-piece tray is sandwich-mounted between the oil pan and the block. Both the windage tray assembly and oil pan with special scavenge pickups were fabricated using pieces of the original as a guide.
The car's owner approached me several years ago about the possibility of reconstructing his original Schnitzer motor, which had grenaded on its first outing. After having made numerous attempts through different repair shops to no avail, I was contacted again to evaluate the situation and devise a plan to get the car back to its original state.
As is usual in these cases, the prognosis is always worse than first imagined. It was concluded that a new cylinder head\cam carrier assembly was needed since the original was not even usable as a boat anchor. Being as rare as these engines are, you can imagine what it would take to find a "new" head. Five of these new cylinder head kits were imported into the country back in the '80s, and l had two of them. This car got one of them, so I now had a solid base to build from.
The agreed upon overall plan with this car and motor was to build the engine to stay together and keep the car in its "it has character" condition. What this meant was a lot of money was going into the motor and its life supporting systems, so there would not be much left over for a fancy spit shine.
With these marching orders to follow, the engine was built with an emphasis on reliability. Pistons were made using a Mahle racing piston from another Schnitzer motor as a sample. I incorporated modern ring, pin and material technology to this design. This resulted in a narrow, good for highrpm use, 1mm top ring and special skirt design to allow much tighter pistonto-cylinder wall clearances than called for by older forged pistons made in this country.
Since this was a later style head and was new-in-the crate, many of the bosses for the ancillaries needed machining for our intended installation. Schnitzer used these motors in several different configurations such as the upright and canted mountings. The motors were installed in the upright position for Formula Two cars and also the 1.4-liter turbo version of the 2002. In 1977, Schnitzer successfully campaigned a 1.4 turbo version of the twin cam, which put out over 386 bhp. This was an incredible car and motor! It won the German Championship in 1977, defeating the twin turbo Porsches of the time!
Along with the special engine, the Schnitzer brothers performed their magic on the car itself, especially the suspension. Originally the car was equipped with 13x13 rear wheels and 10x13 fronts. To accommodate these massive wheels, the front and rear suspension pick-up points had to be moved inward. In the rear, the half shafts were shortened, and the shock mounting points were totally refabricated and reinforced. At the front, standard diameter springs were used, while at the rear special 2.5-in. coilovers did the job. Presently, Ronal three-piece 8x13 and 9x 13 wheels, shod with Mickey Thompson road race tires, are used.
Brakes are vented discs up front and solid discs at the rear. Calipers are Porsche all around. A unique water cooling system is used along with ducted air to cool the front discs. The rear brakes are cooled by the vertical vents fabricated into the front of the rear flares. To keep the rear differential temps in check, a belt-driven pump transfers oil to a front-mounted cooler.
The first driving event was coming quick, so actual testing consisted of more than a few runs up and down a deserted stretch of road. Fuel mixture, ignition timing and oil pressure were all checked and adjusted. When everything looked good, the car was loaded up and my friend Eddy and I were on our way on a nonstop ride to Sebring, Florida. We made it there about two hours before tech! I really don't think the owner thought we were going to make it since I was up all night for three nights before the event getting the car finished. Sound familiar?
Well, the car ran great and got better at the second event in Atlanta, after an ignition glitch was resolved. At Daytona, the car sort of kissed the wall a bit too passionately but has since been repaired and is currently touring the southern HSR circuit.
So what does one do now as an encore to the Schnitzer 1 (4 valve? The next project is a genuine factory CSL with the m49\2 twin-cam 24-valve, full flares, wings and all the other factory goodies.
Sounds like another story!
Friday, January 23, 2015
Sunday, January 18, 2015
Top image is of the AlpinA Gr. 2 car interior from 1974. It is a scan so the quality of the image isn't great. You can make out the gas pedal with what looks like "stripes" running up and down the face. This was a race part offered by AlpinA back in the day - you will see this in both AlpinA "werks" race cars (2oo2, CSL) as well as 32o's ..... as well as any other racers that wanted to utilize this system. The pedal itself is cast aluminum. The base is machined aluminum and fastens directly to the sheet metal floor. There is a small fabricated steel piece that attaches to the pedal and allows the throttle cable to attach (sometime ask me what "McGyver" procedure I used to get the secondary lock nut attached = partially obscured by the steel.....). A fabricated bracket attaches to the transmission tunnel and holds the throttle cable. The throttle cable feeds through the fire wall and then attaches to the slide throttle manifold. At some point the location of the bracket on the throttle pedal was changed and so a secondary set of holes had been drilled. I sent this up to Hamlin Fabrication to have the holes filled back in - very difficult to tell where they were - Roger does incredible work. This piece can get wrapped up and put away until it is ready to go back in the car. One job down, about another thousand to do.
Wednesday, January 14, 2015
The top image is a scan of an original AlpinA document (schematic diagram) of the dry sump pump arrangement with engine, tanks and flow chart. I "loosely" translated the German for those who read English only and then superimposed the flow arrows. Inside the pump of course are toothed gear sets clearanced for petroleum and most synthetic oils. In the 6 and 12 hour races that my car ran in you would want a 3 stage system like this to have a chance at keeping the car in the race. Many thanks to my friend Rikard for the AlpinA schematic. Pictured is the pump, drive belts, pump drive gear (large), crank drive gear (small), bracket w/bushing (attaches to pump and block), aluminum bracket (attaches pump to block). The pump has to mounted in a completely rigid position perpindicular to the crank.
Monday, January 12, 2015
Just before my son headed back to school from Winter break I had him snap some photo's for me with his fancy pants Nikon digital camera. This is the new spoiler. As you may recall I repaired the original AlpinA part, then made a mold and then pulled two new parts. I gave the original owner of the AlpinA spoiler back his original part plus one of the new ones. I had the new parts done in epoxy resin in a natural color. Gel coat I think looks better, however it gets painted in any event AND I think is a bit more fragile when it comes to rock/stone damage that is inherent on a front spoiler. Probably half a dozen one or the other really. You need to have the spoiler in order to properly fit-up the fenders, everything needs to fit together. I did a little bit of layout of the brake duct openings...sans Sharpie. The brake duct openings are a slightly different shape on the "Langnese" car (white/red) than the 1975 "ALPINA" car (Black). These are laid out the way the 1975 ALPINA car had them. No cutting for sure until 1) I make a final decision on the paint for the car and 2) they are measured at least five more times
Saturday, January 10, 2015
A great pic of a MOTOR - NORD (sohc) BmW M10 valve cover. As far as I know, Motor-Nord is still in existence today. Back in the good-old-days they were a major supplier of BmW, AlpinA, Schrick and Schnitzer racing parts. I have a very comprehensive catalogue from them from 1974 that offered ALL of the various AlpinA hp/race bits for BmW 2oo2's and 3.o Series cars ..... including a 4 valve AlpinA racing motor (which was the AlpinA "engine" with Schnitzer cylinder head used in my car during the 1974/5 season). This is a great piece and thanks to my friend Niklas for sharing it with me.