View single post by Tim Murphy
 Posted: 07-17-2015 08:12 am
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Tim Murphy



Joined: 03-22-2005
Location: Huntington Beach , California USA
Posts: 96
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 I remember going thru something similar years ago. At the regular setting (8*BTDC?, don't have my manual handy) the idle was a bit lumpy with an occasional misfire. At around 30*BTDC, it increased in RPM's and smoothed out. Its just a trick the Engine Gods play on us mere mortals. The car is not drivable at that 32* setting, no power and possible engine damage.

Set your idle timing at the factory recommended setting. Since you are using a timing light, you can check the advance at higher RPMs. Max advance (about 17 additional degrees) is achieved at around 2,500 or more rpms. I think you will have to accept whatever the distributor gives you for the present.

The JH will never idle like a modern car, it is usually a bit rough in comparison. You will need to eventually balance the carbs. For the Zenith's there are a couple special tools (a airflow measurer,and special,long hex key for the carb needle value)to do properly. For now you can adjust the throttle to give you more rpms. A cold engine will idle about 100-200 rpms lower than a hot engine IME.

Congratulations on changing the timing belt and sprockets. That was always a "scary" job for me. Take care and good luck.