Author Topic: Baseline timing for Edelbrock headed combo...  (Read 3307 times)

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chilly460

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Baseline timing for Edelbrock headed combo...
« on: May 16, 2013, 11:17:41 AM »
I've done some reading online about timing for combos using Edelbrock heads, just wanted to see if there is as consensus on where to start. 

Combo is:
750dp
Performer RPM
Performer 60059 heads with no chamber work
Comp 270H installed 4* advanced as suggested by comp 224*/.519 on 110lsa
1 3/4" FPA Tri-Y
9.5:1 nominal CR
3.00 rear T10tranny in '63 Marauder, going to 3.50s soon

No plans to put it on any type of dyno, so was going to set it up with 16* initial, 36* total in around 2500rpm.  Does this sound about right for the combo with these heads?

Joe-jdc

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Re: Baseline timing for Edelbrock headed combo...
« Reply #1 on: May 16, 2013, 07:03:30 PM »
  I would static time it at 14* intital for start and break in procedures.   After you double check everything, I would suggest 36-38* total @~2800 rpm.   Joe-JDC.

chilly460

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Re: Baseline timing for Edelbrock headed combo...
« Reply #2 on: May 16, 2013, 07:26:18 PM »
Sounds good, thank you

plovett

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Re: Baseline timing for Edelbrock headed combo...
« Reply #3 on: May 17, 2013, 01:20:57 AM »
x2.  I got best power with 37 degrees total timing with the unmachined chamber Edelbrock heads.  So 36-38 total is right there.  It can vary depending on the compression ratio and the octane of the fuel, but it I think 36-38 is spot on for most combinations.   Low compression ratio and high octane want's more ignition timing and vice versa.

paulie


chilly460

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Re: Baseline timing for Edelbrock headed combo...
« Reply #4 on: May 17, 2013, 05:44:41 AM »
I can get 93oct here in VA, so will try it at 38*

chilly460

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Re: Baseline timing for Edelbrock headed combo...
« Reply #5 on: May 19, 2013, 05:33:42 PM »
Alright, had to make up a pointer because of the old damper/new timing cover mismatch.  It was tuned by ear to this point, and not really run hard. 

It was at 13/33*, ran it up to 16/36*.  I didn't feel like throwing another bushing in it to give more advance, and figure with the heavy car/small cam/tall gear it can use a conservative tune. 

When running before, it did have a definite surge to it when going 3/4 throttle and getting up over 3500rpm, that is now gone.  I thought it was going to be carb, but wanted to get timing squared away.  Happy to find the "surging" was timing related, but surprised that just 3* would cause it.  Timing is in at 2700rpm, so it's been at full advance when this occurs. 

Going to start on the carb now, setup the idle mixture and that's it to this point....runs ok but can definitely use some tuning.