Engine questions

[mattr_914]

Okay, I spent the day with some 914 guys today and we went over my 67 912 engine. We found a few things (some simple, some not).

1) The distributor is an 050, with the wrong cap. Whats the best readily available distributor for a 67 with weber 40s?

2) Is the mark on the engine pully for TDC? Or is it for the "correct" (factory) timing?

3) What is the factory timing?

4) What is the factory dwell?

5) The most difficult. On my #4 cylinder (furthest from the trans on the passenger side) its not firing. Its getting a strong spark, valves are adjusted reasonably well, and the plug is relativly new. Im thinking its either a stuck valve or its carb related. When the car is idling and I take off the plug wire the idle drops SLIGHTLY. Then when I put a rag over the stack on just this cylinder during idle the idle doesnt change note. When I put a rag over #3 the idle drops a LITTLE. Is this idle circuitry? These are weber 40 IDFs, remember. They look relativly new, but looks can be decieving.

Any help is appreciated. Thanks!

[914Ghost]

Matt!
These 912 engines aren't too mysterious. Basically identical in tuning procedure to a 914.
1) distributor- the 050 parts are still available you just have to ask at you local VW shop. OR! Call Will Pringle @ CSP. He can sell you a Duance Spencer book too,, to guide you on your way.
And you 050 if in good shape is one of the best distributors out there for your 912- as good as or better than the original stuff.
2) The notch on the pulley is TDC. I set my timing at roughly 4-6deg before TDC static. With on 050 or 022 should give about 37deg total advance. Your timing may need to be a couple degrees different depending on compression, engine tune, gas, how / where you drive etc,
My easy rule of thumb is you want ALL the advance your distributor will allow (within factory specs) and may need to back off a little if it pings.
3) Factory timing is roughly what I mentioned above. You should set it using an adjustable timing light, and I think the 050 should have about 39 deg @ 3300 rpm total. Or if set static - about 4 deg advanced. Most of our distributors are 30-40 years old now, so, those are the numers, but you need to set the thing where it works best for you.
4) Dwell is set at 50deg +/- 3 deg.
5) Cylinders are numbered thusly-
Drivers frt (3) Pass frt (1)
drivers rear(4) Pass Rear (2)
Thats a birds eye view looking down on top of the car, front being UP on your screen. So by your description your talking about #2.
Good thinking though, always check valves first, cuz' its a waste of time if they're off. So, if valves are set-my thinking is that since Webers have a solid shaft that both throttle plates work off of, and at IDLE one shows air flow and one doesn't- it's just possible that the throttle shaft could have a tweak in it? So the one with "no flow" is shut, and the other throat has air flow?
I wouldn't worry too much, does the car run okay?
I've found some cylinders wil act like they do more work than others- especially at idle. You car may run perfect and you still may have one cylinder that hardly fires at idle. Take the plugs out and "read" them. If they look like you have a good mixture, then you're probably okay- balancing and idle aside, sometimes the end product is what matters.
Does it idle pretty much smooth? - Good!
Does it run strong and pretty much smooth? - Good!
Shut that engine lid and drive!
Bob O