Follow along as I build a high performance 914 engine
- Begin tear down
- Long-block to short-block
- Split the case
- Take apart the crank assembly
- Remove the oil pressure relief valve
- Clean up the fan shroud
- Remove secondary oil relief valve
- Replace oil galley plugs
- Clean case halves
- Machine oil pressure sending unit mount
- Measure piston ring gaps
- Dry assembly (TDC & crank end-play measurements)
- Electromotive ignition sensor mounting
- New TDC mark on fan
- Case clearance for connecting rods
- Prepare the camshaft
- Crankshaft assembly and rod clearance
- Rod bearing defects
- New heads arrive!
- Rebuild the alternator for $8
- Modify engine tin
- Setting up to measure valve geometry
- Installing rocker studs
- Measuring pushrod length and valve travel
- Evaluate valve-piston clearance
- Making custom pushrods
- Lapping cylinders to heads
- Modifying windage tray
- Final crank assembly
- Short-block assembly
- Installing pistons in cylinders
- Long-block assembly
- Installing sheet metal
- Distributor drive cover & CHT sensors
- Installing exhaust manifolds
- Modifying Bursch muffler
- Installing transmission
- Rebuilding carburetors
- Fitting velocity stacks
- Building cable throttle linkage
- Making oil pressure
- First start & initial tune
- Preparing for engine installation
- Engine installation
- CHT gauge
- Throttle linkage
- First drive
- On the dyno
Modifying Engine Tin
Well, after too long a hiatus, I finally got to spend a little bit of time on my engine over the 4th of July weekend. I mocked up one side of the engine (cylinders 1 & 2) - first putting the crank and cam in the case halves, then grinding my cylinder shims a little bit for proper clearance around the head studs:
After sliding my cylinders in place and setting one of the new heads on top, I was able to put the "engine tin" - the metal shrouding that directs air over the cylinders and head - in place to see how it would fit:
My new heads have the spark plug locations modified, so I will have to "move" the original spark plug access holes. To mark where the location should be, I was able to put a Sharpie marker in the spark plug hole to mark the tin:
Here I've marked up both locations (see my little cross hairs?):
After using a center punch, I was able to drill holes with a step-drill (which works great for sheetmetal, by the way). Probably most people would use a hole saw for this step, but I don't have one that size - but do have a knock-out punch that is the right size.
A knock-out punch is a little die and anvil set with a bolt going through. First you make the holes in your sheetmetal the right size for the bolt (3/4" in this case), then you slide the one piece over the bolt, put the bolt through the hole, and finally, thread the other part onto the bolt. After a little turning, you have a clean, round hole!
Both holes are made in their new locations:
And now it's time to weld up the old holes! I used the knockout slugs from the new holes and some random washers I had laying around.
