a question on timing and performance
Thread Starter
Instructor
Joined: Oct 2006
Posts: 181
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From: Des moines Iowa
a question on timing and performance
I have a 290hp chevy crate engine with a edelbrock 600cfm. I bought the car with this engine and am trying to get it running correctly. It seems to have a off idle hesitation and it feels like its surging. Watching it idle the tach surges a few rpms. It sounds like it has a bigger cam than it does. at 800 rpm. at idle. I am in the process of getting the total timing set. However I have to get a dial back light this weekend. i used my standard light just to see where the initial timing is set at. It shows 8 degrees BTDC. It seems like it should be higher than that maybe 10 or 12?? Could this be causing it to hesitate and surge?
Instructor
Joined: Mar 2003
Posts: 217
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From: Buffalo MO
I would agree on wanting the base timing a bit higher. I like the 10-12 mark. Just make sure your total doesnt go more than 34.
And ensure your balancer is correct (not slipped and so forth) to get an accurate reading. Otherwise all your work is in vain. I have been bit by that one..... ouch!
You might check the swing of your advance? Weights, springs and such. The movement of your advance (centrifical and vac). Make sure your total is achieved at a desirable rpm. And the wires on the pickup coil are in good shape. You can pull a little vacuum on the advance at an idle, just enough to move the pickup, and see if your hesitation arrives. If you do, it could be a loose wire on the pickup coil.
And ensure your balancer is correct (not slipped and so forth) to get an accurate reading. Otherwise all your work is in vain. I have been bit by that one..... ouch!
You might check the swing of your advance? Weights, springs and such. The movement of your advance (centrifical and vac). Make sure your total is achieved at a desirable rpm. And the wires on the pickup coil are in good shape. You can pull a little vacuum on the advance at an idle, just enough to move the pickup, and see if your hesitation arrives. If you do, it could be a loose wire on the pickup coil.
Advanced
Joined: Jan 2007
Posts: 96
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From: Sandnes Norway
And ensure your balancer is correct (not slipped and so forth) to get an accurate reading. Otherwise all your work is in vain. I have been bit by that one..... ouch!
How can the balancer slip? Thought this was on a spline?
How can the balancer slip? Thought this was on a spline?
Pro
Joined: Oct 2006
Posts: 564
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From: London
outer ring metal then a ring of rubber then the an inside ring of metal,if the rubber is shot the outer ring of the balancer slips,and gives a false reading.
Last edited by Mikes*Corvettes; May 26, 2007 at 05:47 PM.
