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
Prepare the Camshaft Assembly
I had a few minutes to spare, so I decided it was time to put the camshaft gear onto the camshaft. The alignment procedure is: with the timing mark on the cam gear pointed up, the lobe farthest away should point down. (The timing mark is a little dot at the base of a tooth just past the 12:00 position.)
Because I'm going to run an oil pump that's a little larger than stock, the bolt holes in the cam gear need to be recessed a little bit. This, in conjunction with the heads of the bolts being machined down a little bit, should provide adequate clearance between the bolt heads and the oil pump. I used a little thread locker on the bolts, too:
Place the cam in the engine and put the oil pump in place. The oil pump is a gear displacement pump - as the two meshing gears turn, oil is trapped in the space between the teeth and the outside wall. In this picture, the cam rotates counter-clockwise and the oil pump gear on the left has a shaft with a flat tab that goes into the slot on the end of the camshaft. The hole that is visible on the side of the pump is the pickup or suction side - the oil goes into the pump here (it can't get through the center of the pump, because of tight tolerances where the two gear mesh there is no room for the oil to get through), is transported in the space between the gear teeth along the perimeter of the pump, and to the other side where it gets pushed (now under pressure) to the oil filter:
And, good news, the heads of the bolts do clear the pump:
But, bad news... the other side of the bolts don't clear the case!
A little careful grinding is needed to "shorten" the bolts and then some good deburring with a wire wheel to make sure there are no little metal shards that will eventually fall off and make their way though the engine.
Success! The bolts are now short enough for the camshaft to spin in the engine case:
