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
Valve-Piston Clearance
With my adustible pushrods in place, I can now get an idea for how close the valves will get to the pistons when everything moves together.
With the head off and a piston installed, it was a perfect oportunity to check the deck height:
It's measuring up at 0.022" which will give me a static compression ratio of about 9:1.
Now, I borrowed some of the boys' Playdough and put it on top of the piston. After putting the head and valve train back on, I turned the engine over a few times - relieve that I didn't feel any hard stops! Here's my Playdough after taking the head back off:
I was thrilled to discover that I have plenty of valve clearance! The exhaust valve didn't even touch the Playdough, and the intake valve only made a small indentation. Here's a cross section to show how much clearance there is:
