Vacuum Controllers 1971 Z

[JimmyZ1971]

I have started a restoration project on a 1971 Z that has not been on the road since 1989. Trying to keep as original as possible and trying to source some parts and answers. Finally got it started but running very rough and refuses to idle even after warming for 15+ minutes. Have replaced rotor, dist. cap and points, fuel filter, fuel pump, plugs, spark wires, oil, etc. Adjusted timing but I wonder if it might be a vacuum problem. Have replaced majority of hoses but having trouble finding vacuum controllers. Where can I find them and would these controllers be the cause of the rough running or should look elsewhere? First restoration project from this sort of condition. Thanks for your advice.

[Walter Moore]

Vacuum controllers??

The only devices hooked to the manifold that use vacuum on the 71 are the vacuum advance on the distributor, the power brake booster, the EGR valve, and the "throttle opener" if it is still installed. (An emissions control device that sits on top of the intake manifold and causes the throttle to close more slowly when you lift your foot from high engine speed.)

There is nothing under the dash that is vacuum controlled on the early cars.

How slow are you trying to run the car at idle? Did you rebuild the engine?

I didn't see any reference to adjusting the carburetors. Have you tried to set them up? Were they rebuilt?

I asked all of those questions, because starting up an engine from scratch is an intimidating challenge, and ultimately you will have to check everything. If it at least starts, and will stay running at some speed, you can dial in everything else eventually.

[Carl Beck]

If you started it up without first cleaning the gas tank and lines - you'll suck varnish into the fuel rail and carb.'s as well. If you didn't clean the carb's and float bowls everything in them will be "sticky" as well.

FWIW,

Carl B.

[JimmyZ1971]

Thanks for the quick replies. I did drain and "flush" the fuel lines with fuel line cleaner, placed new fuel and filters before starting BUT I have not yet rebuilt or cleaned the carbs besides spray carb cleaner where I could reach. I haven't rebuilt the engine yet. I can't let the RPM's drop below ~750 rpm or it bogs out..it will not idle and it runs rough with lots of engine vibration on anything below about 1200 RPM. No backfires even when with higher revs. The car has a pretty incomplete history with some new parts, alot of original and others that have been "rigged" together so I am looking for advice on where to start. It seems like the best thing to do is to assume nothing has been done right and start with a carb rebuild and synchronization. Thanks for you help, Carl and Walter, and I look forward to talking in the future.

James

[Mn_Z_Man]

order of trouble shooting.

1. valve timing (timing chain stretch)- and valve lash adjsutment

2. ignition timing and parts

3. check compression and vacuum- correct testing of BOTH is invaluable for diagnosing mechanical problems

4. fuel supply

5. carb adjustment

Assuming you have SU carbs, the fine folks at Ztherapy.com are the first stop. The sell a video that is very useful to getting the SU's set up properly.

Eric

[Daniel]

Hey Jimmy, I've got parts and knowledge call me 704.533.2253 Daniel ( in Charlotte)