Re: rough idle/acceraltion

Posted by Ralph Holland on May 13, 1997 at 15:53:43

In Reply to: rough idle/acceraltion
posted by Ken Bigham on May 11, 1997 at 20:33:41

I have found that if you do not mill the intake and exhaust as an assembly, you will develop leaks.Also tighten the manifold from the center nuts outward, alternating on each sequence.Also retourque after bringing the engine back up to normal operating temperature.
We had similiar problems on 3 or four Model As that we restored in Honolulu and this seemed to work every time.
: I'm hoping someone out there has a suggestion to help me with a problem i'm having.
: My engine has recently been rebuilt. 30 over all the ususal
: balanced, adjustable tappet, hardened valve seats etc.
: My problem is that I have been unable to get the motor to run
: smoothly. It starts easily, but requires that the fuels mixture
: be turned open 3-4 full turns. At that stage it will run and
: accelerate well. Any less and the engine, bucks and will
: not accelerate.
: The timing is correct as far as I can see. I have tried 2
: Zenith carbs and 1 x aftermarket carb which runs the best of the three. I've checked the fuel flow which is adequate
: and have even blocked off the windshield wiper vacum.
: The engine just seems to be running like it has a vacum leak.
: The manifold was milled and there were no apparent cracks.
: I've also retightened the manifold...all to no avail.
: I really think it is carb or intake manifold related.
: On the road the car runs o k,does not overheat etc...
: but just will not run at idle. The air screw on the carb is currently 1/8 open. Opening the screw kills the motor.
: I know that the engine is very tight..spec wise, and maybe this will improve after breakin...
: I appreciate any help or advice.
: Thanks in advance.
: Ken

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