Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - weird timing issue
View Single Post
  #22 (permalink)  
Old 01-22-2013, 01:03 PM
cobalt327's Avatar
cobalt327 cobalt327 is offline
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Posts: 5,031
Wiki Edits: 1616

Thanks: 128
Thanked 616 Times in 565 Posts
Originally Posted by bowtie44s View Post
I have the small block cam retarded 4 degrees, the big block is straight up. I haven't messed with the small block for a while. I am adjusting initial timing. I don't know when the mechanical advance starts but i would assume after 750rpm. I have the vacuum advance unhooked and when i slow the timing much below 60 it starts idling rough and will die.
So it idles w/60 degrees BTDC and then the mechanical advance adds to that? Yikes!!

As long as you've confirmed TDC, firing order, etc. like you have, unless the carb is way out of tune/faulty/"modified", there's no way it should need anywhere near that kind of timing. So I'd start w/the carb:

As long as the carb is working right and not too far from factory specs, I'd start by baselining the transfer slots of whatever carb you're using. Then use initial advance and idle bypass air to get it to idle w/o the primary throttle blades being open too far. This can be done in several ways depending on the carb; a Holley can use the secondary throttle shaft adjustment screw to tip them open a little. If bad enough (although this is rare) holes can be drilled in the primary blades, but that's only as a last resort.
Reply With Quote