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
First Dry Assembly
Now that the case halves are clean:
And I'm happy with the way they fit together:
It's time to do some test assembly and get some measurements.
For this, I'll use my "special engine assembly table" - really it's just a table with a wood top that I've drilled holes in so the head studs can pass through. I used this table for my 944 engine and it worked superbly! Anyhow, here's the #3 / #4 case half on the table:
The new bearings fit nicely on the new crank, and it fits nicely into the case:
Put the other case half in place and tighten the 6 through bolts:
The crank spins as nice as can be! Silky smooth! So, I bolted the flywheel in place, put a dial indicator on it and was able to measure the crank end play (which was 0.047"). There are three shims that go between the flywheel and the thrust bearing (rear most crank bearing) - by getting the right size shims, I can bring the end play into spec.
Next, I put one piston and rod together and put it in the #1 cylinder spot. After sliding a cylinder over it, I was able to use my new homemade tool - a dial indicator mount that I'll use to measure deck height and TDC (top dead center - or the very top of the piston's travel before it starts moving back down):
By turning the flywheel slowly, I can watch the needle on the dial indicator and find the exact top of the piston's travel. (This same tool will be used to measure the deck height (the distance from the top of the piston to the top of the cylinder). It looks like I'll need spacers 0.146" thick between the case and the bottom of the cylinders to achieve a 0.040" deck height.)
It's interesting to note that when the piston is at true TDC, the mark on the flywheel is lined up here: (I assume it should line up with the split between the cases... I will measure TDC for all cylinders to verify the crank was ground properly.)
It is even more interesting to note that the timing mark on the impeller fan is considerably off location - perhaps as much as 5 or 10 degrees! (I will, of course, be putting a new TDC mark on that...)
