BBF timing question

[Crusader]

Got a BBF question for ya. My motor is .030 over, mild cam, single plane intake and a holley 850 DP carb. The ignition is a DUI 7000 HEI dizzy, timing set to 28 degrees at 3,000 rpm.....basically a tad over stock motor.


I'm pushing about 4,800rpms WOT with an A impy. I know theres more in the motor. I've heard that BBF motors love 30-32 degrees total timing. Besides R & Ring motor with a chebby.....do you thinking bumping up the timing to 30-32 degrees might help gain a few more RPM? I won't do anything to the motor until Friday.....but am researching the issue now.

 

[duanehydro]

Yes, absolutely. 28 ain't enough....

 

[duanehydro]

hell, we ran 32 degrees with marty's 871 blown 460... :smile16:

 

[Crusader]

Yes, absolutely. 28 ain't enough....

Okay, cool. when I set it to 30-32, the darn thing barely wanted to crank..... the starter was fresh too.

 

[Disturbed]

Interrupt the ignition power with a toggle switch.  Get it cranking then, flip the switch.  Or, go all fancy and get a start retard box. 

 

[duanehydro]

:huh: are you sure the balancer hasn't slipped? or the marks are correct?

 

[Disturbed]

Also, is the distributor locked out?

 

[duanehydro]

Or the advance mechanism frozen? Most aftermarket dist. have 20* advance, so initial timing @12*= 32* total, if working properly. If it only has, say 10* advance, initial would have to be 20*, possibly causing the hard crank situation. What is the timing at idle? think.gif

 

[Patchman]

That don't sound right! think.gif

 

[Crusader]

I initially set the timing to 10 degrees at idle...and at 3000 rpm it was at 28 degrees. I think DUI set the dwell at 24 degrees... so wouldn't I have 34 degree total timing?

The dizzy is not locked out.

The balancer is keyed and I marked 10 degrees with a sharpy.

 

[Patchman]

Is it mechanical advance or vacuum? :smile21:

 

[Crusader]

mechanical.

 

[Patchman]

You know, I spin an a at 4700. What heads do you have on it? :smile21:

 

[Crusader]

I have D0VE-C heads. They have not been worked on and the emissions bump is still there

 

[Patchman]

Then you have more compression than me, so I think more timing should help. :smile30:

 

[Crusader]

Then you have more compression than me, so I think more timing should help. :smile30:

Oh okay. Thanks man.

I'm picking up a new timing light today and will work on it this weekend.

Thanks!