Manifold replacement

[Edwardjohnsr]

Well, I finished installing my new manifolds at last. Unfortunately when I tryed to start the car when I finished, it was a disaster. It would hardly start, I had to keep reving it to get it to run, it would backfire, it ran like a bucking horse and finally coughed and died. I waited a while, tryed again, same story. What did I screw up?

[Heart Of Texas]

Well, I finished installing my new manifolds at last. Unfortunately when I tryed to start the car when I finished, it was a disaster. It would hardly start, I had to keep reving it to get it to run, it would backfire, it ran like a bucking horse and finally coughed and died. I waited a while, tryed again, same story. What did I screw up?Edward:

Installation of new manifolds is hard to diagnose...

Stepdown engine:
if you installed a Twin H to replace a single barrel carb installation... there are a variety of things that could cause the symptoms you list...

1. Make sure that the gaskets you installed are all seated and that the manifold mounting bolts are all tightened to spec.

2. Vacume lines to the manifold in place and sealed

3. Carburators installed with proper gaskets and tightened appropriately.

4. Linkage installed and adjusted correctly.

5. Fuel to the carburators...

6. Did you disturb the ingnition? If so what was disturbed and did it get restored to the proper condition...

Go to this URL for a few pointers in mechanical installation and adjustment of a Twin H.... http://members.aol.com/stepdown53/TWINHADJUSTMENT10001.htm

Twin H linkage.. albeit a hydramatic... at the bellcrank same as standard otherwise http://members.aol.com/stepdown53/images/TwinHlinkage.jpeg

Only real way to balance the Twin H carbs...

http://members.aol.com/sanjuana/Incoming/UniSync.pdf

Quoted from my website:

The key to a proper adjustment of a Twin H set up (http://members.aol.com/stepdown53/TWINHADJUSTMENT10001.htm) depends on several factors. The most important of which is that the system does not leak vacuum. This means the intake manifold is not leaking nor is the individual carburetors. A quick test to determine if the engine intake or carburetors are leaking can be performed with a vacuum gauge. Connect the vacuum gauge to the vacuum intake port on the intake manifold. The correct reading for a properly running Twin H car at seal level will be approximately 18 -22 inches of vacuum. A complete vacuum check of the engine should be completed (http://members.aol.com/stepdown53/VacumeGaugeTestingHudsonStepdownMaintenance.htm) and all other discrepancies corrected PRIOR to adjusting the carburetors. (A MOTORS or similar manual will provide you with pictorial and written explanation of how to run a vacuum check and interrupt your findings)

Assuming the vacuum check is complete you are ready to adjust the TWIN H carb set up (http://members.aol.com/stepdown53/TWINHADJUSTMENT10001.htm).

To complete the adjustments shown in the mechanical procedures manual you will need a UNISYNC carburetor balance tool.

Hope this helps!!!:rolleyes: