Author Topic: Fresh engine tune up procedure question  (Read 1537 times)

Offline Chuck Step-a-side

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Fresh engine tune up procedure question
« on: December 29, 2019, 10:06:14 AM »
I have a 1984 Chevy Stepside with a freshly installed early model crate motor (1977) and Edelbrock 4 bbl carb. When tuning up the motor do you first set the timing and then adjust the carburetor fuel mixture and idle or adjust the carburetor fuel mixture and idle first and then timing? Thanks, Chuck

Offline bd

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Re: Fresh engine tune up procedure question
« Reply #1 on: December 29, 2019, 10:43:11 AM »
Adjust ignition timing, then idle RPM, then idle mixture. 

Disconnect the distributor vacuum advance and cap the vacuum line.  Set the ignition base timing.  Reconnect the distributor vacuum advance.  Work back-and-forth between idle RPM and idle mixture until the engine idles smoothest at the specified idle RPM.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Chuck Step-a-side

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Re: Fresh engine tune up procedure question
« Reply #2 on: December 29, 2019, 11:21:30 AM »

Db Thank you!!


Offline 75gmck25

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Re: Fresh engine tune up procedure question
« Reply #3 on: April 19, 2020, 09:59:49 AM »
When checking base timing, set the idle down as low as possible to ensure you aren't getting any mechanical advance.  After verifying base timing,  rev it up to see how fast the mechanical comes in and how high it goes.  Most stock SBCs run well with about 8-12 degrees base timing, and they might take even more.  The mechanical usually adds 18-20 degrees.

Bruce