390 pinging
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Lead Driver
Joined: Oct 2004
Posts: 8,062
Likes: 35
From: Central Oregon
390 pinging
I have a 66 F-100 4x4 with a 67 GT 390, engine is stock with elderbrock carb and Cyclone headers. Yesterday I drve it 20 miles to the next town and 20 miles back, when I started out she was running good, but after about 10-12 miles she started pinging when I pushed, even lightly on the gas. Same in the ahternoon on the way home, I did stop after about 18 miles on the way home for about 15 mins. and she did not ping as I was leaving until I had driven about 2 miles then she started pinging agin. Timing is set at 10 degrees and the dist. is new. I run only 92 octane fuel. Any ideas would be good to here.
Post Fiend
Joined: Jan 2003
Posts: 8,600
Likes: 4
From: Iowa
Pull timing a little bit at a time until it stops. At least then you'll be relatively safe to run it.
Pull a few spark plugs and look at them. If they're white, it's running too lean and that could be contributing to your problem. They should be light tan colored. If they're white and have little specks of metal on them, you're running real lean and causing damage.
If it is running lean, you'll need to richen up the carburetor until the plugs read light tan.
Also, with a new distributor, you never know what advance springs you'll get. So the timing curve may not be optimal. You might want to go grab the springs from the original distributor and see if that fixes it.
Pull a few spark plugs and look at them. If they're white, it's running too lean and that could be contributing to your problem. They should be light tan colored. If they're white and have little specks of metal on them, you're running real lean and causing damage.
If it is running lean, you'll need to richen up the carburetor until the plugs read light tan.
Also, with a new distributor, you never know what advance springs you'll get. So the timing curve may not be optimal. You might want to go grab the springs from the original distributor and see if that fixes it.
Last edited by rusty70f100; Sep 30, 2006 at 04:35 PM.
Elder User
Joined: Mar 2004
Posts: 747
Likes: 0
From: Klamath Falls OR
Before you do anything, what is your total timing on that engine? 10* initial is fine but what is your total? You should be able to run on mid grade fuel as well. Unless if its 11 to 1 then run super. I would start at 34* total and work your way up. JMO
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