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Tuning question, it's pinging

1039 Views 10 Replies 7 Participants Last post by  Hottarod
I have a modified 302 with AFR heads and performance cam. I'm running 12 degrees intitial with 32 total on
my timing. the car is about 9.8-1 compresion, and I run 92 octane gas. I intalled light springs in my distibutor to get my timing to come in quick (read that this was a good thing). My car will ping if a bog
it down like 2k in 5th gear and then floor it. It doesn't ping once the RPM's have gone over about 3K.
Do I need to install some heavier springs in my distributor advance to keep the timing from advancing so quick? I'm going to get it dyno tuned soon, I want to get it close to optimize my dyno time. Any idea's
would be appreciated. I'm not running any vacuum advance.


1966 Mustang Coupe, 302 custom roller cam, holley 650dp,
<P ID="edit"><FONT SIZE=-1>Edited by Billgear on 03/28/01 10:39 PM (server time).</FONT></P>
1 - 2 of 11 Posts
Are you dead-sure about the CR...I mean, did you quantify all volumes and compute mathematically?

Of the face of it, you should be OK with that CR and 92 octane......but, the combination of 5th gear (is that OD or do you have a six speed?) and a relatively low numerical rear gear jack up the cylinder pressures during your maneuver and put you into pre-ignition or detonation....
Have you read your plugs....? Have you tried a colder plug? Have you richened the jets in the carb? Have you quantified at what throttle position detonation occurs first?

Yeah, slow down that advance curve into the 3K get there pretty fast anyway...*G*

So, you're not noticing any spots or glazing on your plugs....hmmm...the pinging must not be progressing into something more lethal then...

How have your engine temps been lately?...IIRC, you fixed a cooling related problem recently......usually, if you get the rattles, the temp climbs up....

Personally, I think it's just the advance coming in too quickly...

I have the reverse problem on my D-coder...the vacuum advance doesn't drop off quickly enough when I burp the throttle while at freeway speeds, a couple of blips and the rattle disappears...likely a sticky advance plate...

1 - 2 of 11 Posts
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