quick refresher on timing

woodsnake

15 Year Member

Jan 16, 2007

1,352

15

69

Hicksville, NY

Mar 8, 2010

#1

• Mar 8, 2010

• #1

I was helping a friend work on his POS, and I couldn't remember the cause for backfire thru the intake/carb. The engine runs fine in park, but when you put it under a load, it back fires up thru the intake. I was thinking that since it hadn't run for over a year, it could just be sticky valves and bad gas.....

 

65FBE2

Member

Mar 8, 2007

283

0

17

Minnasnowta

Mar 8, 2010

#2

• Mar 8, 2010

• #2

If it is a timing issue it normal comes from not enough timing. Could be the points if it still has them. If it does, change them and set the dwell correctly then set the timing. 6 deg is the factory setting but 10-15 is what most sbf's like. Then check with a light to be sure that the advance is working correctly and that you have no more than 35 BTC max. If it still back fires check the the dist shaft for excess wear or play.
I'm old enough to have been working on these cars when they were only a few years old

 

D

D.Hearne

New Member

Sep 29, 2000

11,730

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0

south louisiana

Mar 9, 2010

#3

• Mar 9, 2010

• #3

In addition to what he listed, the accellerator pump could also be the culprit. If the diaphram is ruptured, not enough fuel getting squirted will cause a lean condition when you hit the gas. If it has points GET RID OF THEM, PRONTO. With all the electronic drop in modules out there today, there's no point in running points. Keep a set stored for a Nuclear war.

 

woodsnake

15 Year Member

Jan 16, 2007

1,352

15

69

Hicksville, NY

Mar 9, 2010

#4

• Mar 9, 2010

• #4

The car has electronic ignition, and fuel injection.
Maybe an intake manifold leak could be causing a lean condition?

 

D

D.Hearne

New Member

Sep 29, 2000

11,730

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south louisiana

Mar 10, 2010

#5

• Mar 10, 2010

• #5

If it did, you'd have a noticeable vacuum leak.

 

woodsnake

15 Year Member

Jan 16, 2007

1,352

15

69

Hicksville, NY

Mar 10, 2010

#6

• Mar 10, 2010

• #6

Can't hear anything untoward under the hood. Idles great, great throttle response, until you put in in gear....