Hey everyone, this is my first post on the forum. I've got an L20B (long block with W58 head) and FS5W71B 5-speed tranny that I bought off another forum member and I'm running into some problems trying to resurrect it. It hasn't run in 7 or 8 years. My plan is to eventually swap it for the L16 in my '72 521. My goal is just to get enough power to make my truck highway capable.
Here's what I've done so far and where I'm at:
+ I got the motor with 5 speed transmission on a test stand and hooked up my 521's starter and radiator to it. I also added a mechanical oil pressure gauge and a tachometer. The whole thing is wired to an extra ignition switch I have.
+ I checked valve lash and the 4 exhaust valves were too loose so I tightened the clearances to cold specs
+ I found TDC (cylinder one exhaust valve at 2 and intake valve at 10) and verified that valve timing is good. The dash is right in the middle of the v-notch
+ With TDC identified, I opened up the distributer, noted the position of the rotor, and I connected the spark plug wires in 1-3-4-2 order
+ I replaced worn out vacuum lines and capped the vacuum line that would go to the carbon canister. I also capped the brake booster vacuum line.
+ I jumped the red idle cut solenoid wire to the blue choke heat wire and connected this to ignition power. When I turn on the ignition I hear the idle cut solenoid click, so i think I should be getting fuel to the idle circuit.
+ I primed the fuel pump and turned the thing over to verify the pump works properly. The fuel return line is also clear.
Here's my problem: The engine fired up but the RPMs were very high. It rev'd to ~3300 rpms. I got some penetrating oil into all the moving parts on the carburetor and loosened up the sticky vacuum diaphragm. The engine never calmed down, and at 3k rpm my timing gun showed it was at ~5 degrees before TDC. The photo below shows where the distributer was rotated to:
I thought maybe the valves could be open too far, so I checked those. The choke seems open the right amount:
And I checked to make sure the primary and secondary throttle valves are closed. It's hard to get the camera to focus on them but here are photos:
Rotating the distributer CCW to retard the timing brings the fast idle RPM down to ~2000 where I think it's supposed to be, but it never calms down to warm slow idle RPMs. Here's where its at now:
The oil pressure is also a little high at 55 psi. Hopefully that will go down once the engine can idle normally. Initially the motor blew lots of blue smoke, but a new oil filter, new oil, and more running time cleared that up mostly.
I didn't want to just start turning idle mixture and speed screws without a strategy. Am I missing something? How can I get this thing straightened out?
There are other problems to address like oil leaking from the valve cover and water leaking from the water pump near the pulley during test runs. I replaced the cover gasket, but I need to clean up the old mess to verify that its fixed.
Also I want to get some general guidance: My original plan was to get this motor running properly before taking it apart for a basic rebuild and cleaning. Nothing major, just new gaskets and piston rings, and checking innards. I am also considering swapping the Hitachi carb for a Fitech fuel injection setup like Peter Spackman's. Another possibility is a Weber redline 32/36. Should I give up on the Hitachi and move forward with the rebuild, or get the thing working first?
My L16 runs perfectly, so I'm in no rush to swap in this L20B.
Since this is my first post, and I know folks will ask, here's my truck
