2.0 stock(ish) rebuild, Initial carb jetting Options

[AE354803]

Since this is my first major project on the 912, I figured I would make a project thread since I'll have lots of questions.


The back story:

Car is a 67 912 with a 2.0 914 type IV, Weber 40 IDFs, bosch .050 dist installed. Transmission is original 912 with 914 gears 3,4,5 installed, newly rebuilt (synchros, selector forks, etc.) 73 911 front end suspension/brakes/steering, dual zone master cylinder, ER polybronze all around.

I've been investigating a loud, clanking noise for the past few months. The noise happens regardless of engine/oil temperature or pressure. It is present below ~3000 rpm and then disappears entirely above 3000 rpm. When the noise is gone the engine sounds great. While this noise was present I have driven the car from San Diego to San Francisco and back, as well as San Bernardino and a few other trips, so I think I've put on approx. 2500 miles (it's been present and slowly getting worse (as best I remember) since I purchased the car (June 2012)).

The noise has bugged me but I always figured since everything ran fine that maybe this is just characteristic of this engine. However I stopped driving the car a few months ago because the more I ruled out what it wasn't the more I worried about what it was and it's eventual catastrophic failure stranding me and destroying the engine.

Seems to be coming from the center of the case. I've gone through the valve train and replaced a stripped stud, installed new adjusters and made sure everything was wearing and fitting properly (which it was).

After this did not fix the issue I decided that before something destroys itself and everything around it I would remove and rebuild the 2.0 so that I wouldn't have to worry in the future. I wasn't using the car just because of the noise and the gut feeling that it was a time bomb. I suspect an issue with a main or rod bearing (possibly multiple) or excess piston slop, maybe a deteriorated piston skirt.



The Project:

1. Remove and rebuild to mostly stock the 2.0 type 4.
I have Weber 40 IDF's, GA 2.0 heads, WebCam Hydraulic+Carb grind w/ WebCam hydraulic lifters (turns out to be some ), Bosch .050 distributor (will most likely install Petronix or other electronic points)
Turns out that I had low compression bus pistons, some unknown cam, the cam to cam gear mounting bolts were too long and machined the base and also half of the cam thrust bearing was missing. The crankshaft timing gear was no longer a press fit and could be removed by hand, the crankshaft itself had material missing due to the slop.


2. Rebuild specifics:

New (used) stock oil pump
Rebuild heads [new SS exhaust valves, guides and retainers, heads cut to accept new cylinders without gaskets]
new gaskets/bearings/rings throughout,
EMW 96 mm cylinders and KB 96 mm pistons
new reground crankshaft and gearstack,
494 webcam and mechanical lifters w/ double thrust bearings and new cam gear
Petronix electronic points and rebuild dist.
Static balanced rods (0.1 grams) pistons (1 gram)
New Sachs pressure plate
New motor mounts and heavier mount bar to frame mounts (1/4" steel plate)
Install engine to exhaust header flange supports (engine did not have them)
CB Performance rotary fuel pump
Cut to length pushrods and solid rocker arm spacers


3. Have a set of EMW bus headers that I will add heating tins to and install with a new header and muffler. Not until after the engine is back in and running.

4. Fix small issues found along the way (so far fix bumper mounting alignment and rear engine bar mounts need to have a steel tube installed w/ bolt through to remove play and prevent further wear.)


This is my list for now, I am expecting it to grow, thanks in advance for any help.

Andy