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Discussion Starter #1
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.

Regards,
BillGear

1966 Mustang Coupe, 302 custom roller cam, holley 650dp,http://www.289mustang.com
http://www.289mustang.com/images/vmfcar.jpg
<P ID="edit"><FONT SIZE=-1>Edited by Billgear on 03/28/01 10:39 PM (server time).</FONT></P>
 

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What kind of distributor are you running? Do you have a vacuum advance? I think 32 is not enough. Should be more like 38 total. Check out the excellent article at FORDMUSCLE.COM. Look in the archives for "Timing Is Everything." Post again with more questions if you need.

65 FB "J" 302 lots of mods. 94 GT K&N only.
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You should be able to run on pump gas with that compression. I've got 10.5:1 in my 302 and I have no problems with 92 octane and 14 initial and 39 total. At what rpm are you getting the total advance? You might try and put in a little heavier spring.

I was having a similiar problem with my 351W, but I've got over 11.5 compression. I was talking with the folk at century performance and they said that running a stick shift I'm going to have a little pinging. They told me to keep the rpm up a little bit.

Rob
Member: Slightly Modified
66 coupe 302
66 fastback 351W
 

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Bill,
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 range....you get there pretty fast anyway...*G*

Pat
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I would try richening up at the rpm that it pings... Probably by using a lower number "window" type power valve (if Holley equipped)... May try going up on the jet sizes a couple of numbers and see if that helps.

Required tools for operating a Vintage Mustang:
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Discussion Starter #7
I'm not sure about the CR stock block, stock pistons, heads milled to 54cc. I don't think octane ia a issue? My plugs look
like they are new, they have about 1200 miles on them. I have a air/fuel meter, it indicates that i'm a little on the rich side. I
would rather be a little rich. The car is a 5 speed, it will do it
in any gear, it's harder to tell in 1st or 2nd (not there very long). I'm concerned with damaging the alum heads more then anything. I will try the firmer advance spring in the duraspark.

1966 Mustang Coupe, 302 custom roller cam, holley 650dp,http://www.289mustang.com
http://www.289mustang.com/images/vmfcar.jpg
 

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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...

Pat
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Discussion Starter #9
The temp has been staying right at 180, I have a fan shroud and new fan clutch. These did seem to help, the outside temp
hasn't gone over 80 though!


1966 Mustang Coupe, 302 custom roller cam, holley 650dp,http://www.289mustang.com
http://www.289mustang.com/images/vmfcar.jpg
 
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yo need to know how much timing is coming in. But your right...It does sound like there's too much timing in ti at that RPM level...

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1970 Fastback, 4V 351C, various colors with black interior
 

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I had the identical problem with my Ranchero. That motor made 10.5:1 compression from the factory. After I had it bored .030 over(429 big block, heh) it would clatter on 93 octane pump gas when I romped on it. I had to run booster or lead additive to keep it from doing that or back my timing way down. I experimented around with the advance springs on my distributor but it never made the clatter go away.

Your timing is way low but I'm assuming you've retarded it to try and prevent the clatter. That has to be holding back your power. I'm surprised it doesn't spit back through the carb on you when you try and crank it. I have a bit more cam in my 289 than yours but I have to run 18 and 38 timing. If I lower my initial much it will catch the carb on fire from the spit back. My advance is all in by 2500 but it still seems a bit slow. I'm considering going to total timing and just running a 20 degree crank retard.



You can see my 65 fastback at: http://hottarod.stangnet.com/
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