Basically, you need to fabricate sheet metal to surround the engine to make it's outer shape conform to the VW engine compartment. You do this by taking a VW piece and modifying it. The rear shroud we used was a modified VW 36HP engine shroud. You take it to the 912 motor, and you see that you need to cut a little here, and add a little metal there, etc. One trick Richard found was these little stock 912 exhaust manifold covers. They bolt onto the top of the rear shroud and cover up the exhaust manifold as it exits the head. Very stock looking. In order to mount them though, you need to weld nuts to the back side of holes on the underside of the sheet metal, otherwise there's no place for the screws to get a bite.
The front shroud (behind the fan shroud over the joint between engine and transmission) was modified in a very similar way. Just find a VW piece that matches the contour of your Ghia body, and start modifying it to fit the engine. Use one that doesn't have the very large hole in it for the late doghouse style fan shroud.
On either side of the engine around the base of the intake manifolds are side covers. Richard and I are still a little out on the subject of whether or not we even need them. Technically, the engine compartment seal will rest on top of the valve cover itself, and it doesn't need the side cover. I have to imagine though that it keeps a little dirt from falling down where the valve cover sits on the head, and might keep the dirt outwhen you adjust the valves. Speaking of which, if you don't design your side covers correctly, they can really interfere with the removal of the valve covers when you want to adjust the valves. One nice benefit of having side covers is that it gives a place to bolt the front shroud to. If you don't have side covers, you'll need to rig up something custom to screw things together.
In the end, the really important thing is to make it look STOCK, like something the factory might have actually done. All of the engine sheet metal (except the fan shroud and bypass oil filter canister) was powder-coated a semi-gloss black, and it looks wonderful. When people look in the engine compartment and they know what they're looking at, invariably they'll ask "How did you make it fit? Why does this sheet metal fit both the engine and the body?!?" They can't even tell that the metal has been modified. And the real kicker is when people look in there and it looks so normal that they have no idea the basic engine might not be factory! They think it's just a VW engine with dual carbs. Then they see the large bypass oil filter, the breather can/oil filler, the throttle linkage on the backside of the fan shroud and the fuel pump on the wrong side of the distributor, and they do a double-take.
Lets see, throttle linkage. The Porsche used ball and socket joints and control rods to link the throttle cable to the engine, while the VW used a cable all the way from the pedal directly back to the carb. You need a way of mating the two systems together.
What I did was borrow from the Porsche solution for the 356/912 design. It’s a throttle linkage that goes from the transaxle bell crank to the fanshroud bell crank. We found one that had been worn at the transaxle end, and so cutting it up wouldn’t remove an otherwise fine piece from functional service. One end of the rod is threaded and has the correct throttle linkage ball joint to connect to the engine. On the other end it's basically a straight rod with a funny loop. In the middle, there is a gentle curve that was put there to allow the rod to operate AROUND another object. The rod can move back and forth, and the curve part of the rod moves around some immovable object that a straight rod would run into.
Why did I go to such trouble to get a rod with this special curve? Well, I mated the VW cable to the Porsche linkage underneath the car, just above the transmission and towards the drivers side of the car. The worn out loop on the throttle linkage rod was cut off leaving a bare, unthreaded rod. I've got two pictures of this rod HERE to help you understand what part was used and how it looks not. You cut the cable short so it ends right about directly over the transmission's side cover. You hook the rod to the ball on the throttle bell crank on the backside of the fan shroud. You line up the cable with the straight, non-threaded end of the rod and clamp the two together, making sure the carb linkage is in the "throttle off" position, and that the gas pedal is also in the "UP" and "throttle off" position. (Hint: exhaust system "barrel nuts" work great for this) This special rod curves around the transmission clutch throw out arm. It allows the throttle linkage and throw out arm to operate through full range of motion without interference. As you can see, in the end I’m using the throttle linkage in an almost identical way Porsche designed, except that the forward end doesn’t go to a bell crank, it just clamps to the cable.
Since you now have a rod passing through the front shroud instead of a cable, you’ll need to modify the shroud to allow easy passage. In my case, this meant moving and enlarging the stock cable hole.
Another thing Richard realized was that the pulling angle on the original throttle linkage was rather different than where the cable pulls from. The Porsche design pulled the bell crank on the back of the fan shroud at an angle that pointed to the ground, while the VW cable pulls in a more level plane, towards the front of the car. Because of the nature of the bell crank and how it was pulled, he reasoned that it may not allow full throttle to be achieved. He made up a new bell crank that put the upper ball joint in a different orientation, so there's a more natural movement. It removes any chance of the linkage not allowing full range of motion.
I've made up two very simple images describing the bellcrank and how it operates, and I've recently added two pictures. You can check them out by clicking HERE.
Then there comes the clutch arrangement. There are at least three setups that have been known to work. When I first got the engine, it was using a non-modified 356 A/B flywheel, a stock 180MM VW sprung center clutch disc, a stock late VW throw out bearing and guide tube, and a Kennedy 1700lb pressure plate. The great majority of 356's were 6V, and so their flywheels are also 6V with the appropriate ring gear. To use the 6V flywheel in the 12V transmission, you need to run a 6V starter. You can buy a special starter support bushing that allows the use of the 6V starter in a 12V transmission, but it's very thin and I found that you wear them out with some frequency. There was another problem I ran into where every once in a while the starter gear wouldn't engage the flywheel correctly, and would instead impact the side of the flywheel. Very loud, bad and annoying noise, and after enough of these it actually hurt the teeth of the flywheel. There was talk that it was caused by people running 6V starters on a 12V system, and the 6V solenoid was pushing out the starter gear too quickly. If this is the case, you can replace your 6V solenoid with a 12V version, leaving the rest of the starter running on 6V. I did this but it didn't help in my case.
Eventually, running a 6V starter on 12V might cause wear, but there are people in the 356 community who routinely do this and have run such setups for dozens of thousand miles and many years. The 6V starter spins quite quickly, it's a nice brawny reassuring sound.
To allow the Kennedy pressure plate to fit over the VW guide tube, we had to remove the T/O bearing mating surface ring from the pressure plate, such that the throw out bearing rested directly on the three arms of the pressure plate.
Eventually the clutch started to slip after about 10,000 miles because I had too much power for the small clutch and pressure plate, so I started investigating alternatives. One solution I learned about goes something like this: apparently you can use a 200MM 356C/SC or Super-90 flywheel and machine it to fit the VW 200MM diaphragm pressure plate (not the coil spring type) and the matching VW clutch disc can be used.
This is an expensive alternative though, the machining, surfacing and balancing is considerable and the whole thing will easily run you several hundred dollars ($400-$700). When you're done, you're still stuck with a 6V flywheel, and the minor headaches associated with it. One benefit is that replacing the VW pressure plate and clutch disc is cheaper than the Porsche equivalent. Of course if you’re running a 6V car, you’d have a matching starter and flywheel.
Eventually, Richard learned of a different setup that turned out to work well for both his double cab bus and my Ghia. You use a stock 912 pressure plate, flywheel and 200MM clutch disc, you get a 12V ring gear flywheel, all without requiring machining of any of the above mentioned parts. It's also expensive, but cost competitive with the other solution I spoke of above.
Unfortunately you need to have a transmission that uses a throw out bearing guide tube to run the 912 parts. According to the catalogs, VW first introduced the guide tube in 1971. For those people running ’68 and older cars, your best bet may be to run the 356 pre-guide tube clutch components. This includes both options I spoke of above, the Kennedy pressure plate/pre T-6 356 flywheel setup and the 200MM late 356 flywheel modified for the VW P-plate. It should be noted that when I pulled my clutch disc after 10K miles, it wasn’t worn particularly badly, or contaminated with oil, etc. Even when properly adjusted, it was slipping because the pressure plate simply didn’t have the strength to grip the clutch disc. If your engine is going to be particularly strong, you may consider trying a stronger pressure plate like a 2100lb model.
Two other options for earlier cars who wish to run the 912 setup: You can have a swing axle transmission built into a late IRS case with the guide tube mount in place. This will add to the cost of the total project, but it will give you the opportunity of choosing your ring/pinion and gear ratios, and you’ll have the peace of mind that comes with a fine rebuilt transmission. The other option would be to drill and tap the case to accept a guide tube. You’ll likely have to have someone skilled in aluminum welding to build up the area so there will be a place to drill into, and so it will have a flat surface to support the guide tube. Again, this does drive up the cost, as the welding will be done on a bare case and will require re-assembly.
For those running IRS in their ’69 and ’70 cars, you can install a later transmission case with a guide tube, or follow the procedures above for the pre ’68 cars.
The reason you need a guide tube for the late 356 or 912 clutch parts is because of the way the two surfaces mate when you push in the clutch pedal. The early design used two fairly large flat surfaces as the contact face. The T/O bearing didn’t ride on a guide tube, and moved up and down slightly with the throw out arm as it travels through it’s arc. If the two surfaces didn’t mate together perfectly, it wasn’t a problem because it had a large enough surface area. The late design has a radius rather than a flat contact face on the T/O bearing. If it didn’t run on the guide tube it wouldn’t interface correctly with the pressure plate. You’d run the considerable risk of having the T/O bearing get caught on the spinning pressure plate, tearing everything apart in one explosive moment.
To convert over to the Porsche style pressure plate though, you need to run a Porsche throw out bearing. Early transmissions (‘61-’70) have the appropriate throw out arm to support the Porsche T/O bearing, but as mentioned above they don’t have the guide tube. They changed the T/O bearing style in 1970, and went to a different style T/O bearing cross shaft arm. So for those who have a '71 transmission (and part of '72) you can install the early style cross shaft and you're in fine shape. For those after the mid-year change in '72 (like me, unfortunately) you get kinda screwed. In '72, they gave the clutch arm a thicker shaft, and the early cross shaft just swims in the huge cross shaft hole in these late transmissions. So what’s the best solution? Use a 1971 or early 1972 transmission and run the early type shaft.
As best I can figure, you should be able to make up bushings for the cross shaft to take up the gap made by running the early shaft, or you can do what we did and MAKE a new shaft. What I did was I purchased two new shafts, one early (with the appropriate T/O bearing cradle arms) and one late (with the appropriate large shaft diameter). I cut the early one apart, separated the arms from the shaft and had the shaft holes in them machined to fit onto the larger shaft. Then I ground off the welds to pop the arms off the bigger shaft, and slid the early style arms on the late style shaft. After getting everything oriented correctly, we welded it up and reinstalled in the case. You can see some pictures of this new shaft HERE. In order to keep the T/O bearing on the cross shaft, I used early VW T/O bearing clips. They were designed to go into a hole in the VW T/O bearing pivots. The Porsche T/O bearing doesn't have such holes, so you need to drill them into the pivots on both sides of the T/O bearing. You'll see these holes in the pictures of the throw out bearing below, drilled into the sides of the T/O bearing pivots.
You need an appropriate guide tube. You could fabricate one from scratch, or you could do what we did - modify one that's close. We secured one from a Porsche wrecking yard that fits - well, we're not sure, but we think it fits 911, 912, and perhaps some others. What's key is that it fits the t/o bearing and is of an appropriate length. The donor part we got has two mounting ears, but the VW transaxle we were mounting it to - a '73 - has three ears. One ear was close enough to use with only a slight re-sizing of the hole, but to secure the tube to the other two mounts, we had to provide some ears. To do that, we cut a hole in a piece of stout scrap steel which fit onto a machined face on the back side of the tube. We then cut out the shape of our desired ears, and welded it together. We then had the correct number of mounting ears. Some pictures of our T/O bearing guide tube can be seen HERE, please remember that we made this piece to be functional and not aesthetically pleasing. If you're using a case that never had a guide tube, you can do much the same thing, but you must provide a secure mounting place for the tube, so it won't fatigue crack and fail in service. Early Porsche guys have the same problem, and they solve it by doing some aluminum welding onto the transaxle case like I mentioned earlier. Richard has seen it done without this welding, with merely holes and spacers, but thinks such a solution would be short-lived and expensive to remedy when it fails.
Also, the T/O bearings come in a variety of different depths. You need to measure how much clutch travel and free play you'll need and what T/O bearing will fit the bill. You do this by measuring from the mounting flange on the engine to the T/O bearing mating surface on the pressure plate while it’s mounted to flywheel on the engine. Then using a flat bar laid across the mounting flange on the transmission you measure the depth from the flange to the face of the T/O bearing. You need a throw out bearing that is short enough to fit between it’s own cradle in the cross shaft (in the “clutch disengaged” position) and the pressure plate when the engine is mounted up, plus about 6MM of extra space to allow for the clutch disc to wear through it’s life.
I found that for my setup, I needed the shortest T/O bearing style, (which I think was a 356B model) that way when the clutch pedal is up the T/O bearing is NOT touching the fingers of the pressure plate. There was one other model (the next longest one) that Richard recalls would have just barely fit, but when the clutch disc wears down it would close the gap between the T/O bearing and pressure plate. At that point it would be just like any of the longer T/O bearings and would always touch the pressure plate, slightly releasing the clutch. Bad. I have some pictures of the T/O bearing if they prove to be at all helpfull, I'm not sure if the number stampings are usefull or not. Click HERE to view the pictures. The bearing is made out of a rough casting, please excuse me if these numbers aren't accurate: F41018-5 and 501481
The thickness of my bearing (measured from it's mating surface back to it's pivots that ride in the throw out arm's cradle) is 28MM. Also, and I'm sure it's not really necessary, but I have some pictures of the bearing, throw out arm and guide tube all together. You can take a look if you're still having trouble visuallizing anything by clicking HERE.
Almost there, but not quite. I found out that in order to use the 912 flywheel you need to run the VW self-supporting Auto-stick starter. This was fine by me, the specs show that the auto-stick starter is stronger, it's cheaper than the standard starter if you buy it from Pep Boys, and you never need to worry about replacing your starter bushing again. The problem with the standard starter is that is has a large collar below the gear covering a spring inside the starter. When the starter engages, this collar follows the gear out and jams into the flywheel teeth. The auto-stick starter doesn't use this collar at all.
Even then, the 912 flywheel sticks a little deeper into the bell housing of the transmission than the stock VW flywheel. This requires that you make a shim for the starter motor or the teeth will never fully disengage. It's fairly easy to do, and since you're running the self supporting starter you don't need to worry about reducing your starter support by pulling it out a little bit. You can see a picture of the shim by clicking HERE, it's simply cut from aluminum stock, and measures 5MM thick.
Also, I found that I had been forced to clearance the inside of my bell housing to allow the 912 flywheel to fit. A big pain in the butt, but it's not difficult work.
