385sbc timing question

Old 05-21-2007, 07:36 AM
  #11  
sp2816
Senior Member
MASTER BUILDER
 
Join Date: May 2003
Location: Owingsville, Ky
Posts: 157
Default

chev78 wrote:
my question is this when i go to time the car it doesnt want to idle under about50 degrees and when i do back the timing down to around 34-36 (with the vacumm advance unhooked) it starts to run poorly and backfires through the carb wehn you hit the throttle.any ideas on what it could be.
I have used the method described about setting the distributor for start up. I set the balancer to 20 degrees and then set the distributor in and then after it is running adjust the timing with the light. But I have verified where TDC is at with a dial indicator before the head was installed.
From the post above, it sounds like he was using a light and couldn't get it to run correctly at 36 degrees, so if you manually set it at 20-35 degrees it would still run poorly unless it is a bad timing light. It could be the timing light (I would try a different light), not on #1 plug wire (not likely), TDC marks are incorrect for the balancer and pointer (I always verify this), and the camshaft timing to be incorrect (I have found the 0 mark on the crank gear to be stamped incorrectly and the dowel pin hole to be off. A guy had installed his cam "straight up", but it would not run the ET's expected. He had me degree his camshaft, and I found that it was 12 degrees advanced. The timing set was in error)
As bjuice stated if the timing set is correct, setting the cam in straight up in a street car you will not tell much of a difference in hp. In degreeing the camshaft, most of the time you are verifying that the pieces weren't built on a "hang over" Monday or on a "get out of here" Friday.
Other things that can cause the rought idle and popping through the carburator could be valves adjusted too tight or the carburator itself. I have found so many carburator problems corrected themselves by just verifying the timing, plugs, and wires.
It sounds like it is sluggish from the timing.

Just some information from my misfortunes,
Bill M
sp2816 is offline  
Old 05-21-2007, 09:42 AM
  #12  
chev78
Junior Member
SHOW GUEST
Thread Starter
 
Join Date: Jan 2006
Posts: 5
Default

i'll give it a try and let you all know.
thanks for all the advice!!!!
chev78 is offline  
Old 05-21-2007, 04:16 PM
  #13  
chev78
Junior Member
SHOW GUEST
Thread Starter
 
Join Date: Jan 2006
Posts: 5
Default

thanks for all the advice guys this site is second to none when it comes to technical advice.i got the car timed (36) degrees and running smooth.i really have no explanation why it was reading in the 50 and 60,s before.the only thing i changed was isolating the 1 wire from the rest when i attached the pickup for the light it might have been picking up some pulses from the number 3 wire even though i'm running taylor 8.8mm wires.i also had the leads that go to the battery for the light hooked to my dodge diesel battery which runs dual 12 volts because the battery for my nova is in the trunk.do you think the dual batteries affected the light i wouldnt think it would cause its still 12 volts.when i timed it tonight i ran the positive lead down to the starter and the ground to the frame and it worked fine.anyways it sounds great i cant wait to get it on the road and strip!!!!

thanks again to all who responded you guys are all a bunch of stand up guys!!!!
chev78 is offline  
Old 05-21-2007, 05:43 PM
  #14  
sp2816
Senior Member
MASTER BUILDER
 
Join Date: May 2003
Location: Owingsville, Ky
Posts: 157
Default

Glad that you got it running and timed.

I think that what happened is that the timing light was not grounded to the car that you were timing. That caused a differential voltage on the light.


Bill
sp2816 is offline  
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -