3200cc Mighty Mouse
Page 5
In all, we dry assembled the engine a total of three times before all the clearancing was finished. During this time we had to remove a little material off the rod caps, as well as slightly enlarging the notches we added on the piston skirts, which are similar to those on stock Corvair cylinders. With clearancing complete, the parts are thoroughly cleaned and balanced and final assembly begins. When it comes to the cylinder heads, they've been modified quite a bit up to this point, but they are also cut for larger 94-mm cylinders (stock bore is 87mm or 3.437-in.).
The stock exhaust tubes are removed and modified to receive 1-1/2-in. exhaust tubes and flanges along with retainer tabs that fasten to the outside of the head beneath the rocker area. The heads are also modified to receive Manton heavy-duty valve springs and chrome moly retainers.
Above, left to right shows the clearance notches on the Cima and stock Corvair cylinders. As you slide the cylinders into the engine case you'll also notice that the center cylinders, #4 and #3, will encounter interference between the cooling fins. To remedy this, we ground the cooling fins slightly on a belt surfacer to provide adequate clearance between the center and end cylinders. You can begin to see at this point that there's a lot of tedious hand work involved with making a larger displacement Corvair engine.
We also learned that there was not enough clearance between the rod caps and the case halves, therefore we needed to remove a little material off them by hand. After everything begins to move freely, and there's no interference between the rods and cylinders, all the parts get balanced once and for all, and the final assembly procedure begins.
Above, left, cylinder head modifications include the addition of HD dual valve springs and chrome moly retainers, as well as opening up combustion chambers for the 94mm cylinders. In the picture above, right, the stock exhaust tubes are removed and 1-1/2-in. exhaust tubes and flanges are added, with retainer tabs that fasten to the underside of the head.