Tracy Crook wrote:

Anderson Ed wrote:

I happened to be thumbing thru Racing Beats Technical Catalog last night
and notice their recommendations for ignition timing.  For 86-89 13Bs
using the stock (crank angle sensor) ignition they recommend 5 ATC at
700 rpm.  If using an older electronic distributor (pre 86) they
recommend setting it at 23 BTC at 5000 rpm.  This is because several of
the pre-86 electronic distributors had different advance curves but all
are fully advanced by 5000 rpm.

I mis understood Tracy's timing recommendations and at the time I had my
prop off had set the timing for 30 BTC at 5000 rpm (instead of
static-stop).  Since I did not want to reset timing with the prop
spinning full bore and did not want to undo all the spinner screws and
prop bolts to remove it, once I recognized my mistake I simply set it
back to 23 BTC at static which is clearly not correct.  Based on the
Racing beat recommendation it looks like I should be able to set it to 5
ATC at 700 rpm and be close. I don't mind (too much) being near a prop
spinning at only 350-500 rpm. Any reason why I should not use the 5 ATC
at 700rpm setting. Tracy? Any comments??

Ed Anderson

This will get you close.  The ignition advance curve of my controller
approximates a centrifugal advance but not exactly.  Timing at 5000 is still
the best way to go.   Its a pain I know but removing the prop makes it a lot
nicer.

I don't like to idle my engine down that low because the backlash in the
drive makes it thrash too much.  There is not enough flywheel weight in the
system to work smoothly at 700 rpm.  At least thats the way it is for me.
How does yours sound at 700 Ed?

 
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