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
Rod Bearing Defects
As I was taking all of my detailed measurements, I discovered that the rod bearings, which are Brazilian made, contained two manufacturing defects. The first defect was a bearing that was "crooked" and didn't sit in the rod cap saddle properly:
The second defect was a bearing that was too long - one side of it rose above one mating surface:
When this cap was bolted to the rod, the visible gap shows how much space there is after the bearing makes contact with its other half:
And, once the rod bolts are torqued down, it causes bearing distortion that can easily be measured. The following two pictures show the diameter inside the bearing (at locations 90 degrees from each other) as measured with a caliper - NOT the most precise way to measure internal bores - but the 0.006" difference clearly isn't acceptable.
I have a new set of higher quality "German" bearings on order which, hopefully, will prove to be more precise.
