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Author
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Topic: Pinging caused by too efficient ignition & lean mixture ?
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Pierre
Gearhead Posts: 366
From: France
Registered: Apr 2002
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posted 11-01-2002 02:48 PM
   
I am experiencing some rapid knocking in the engine under medium or heavy acceleration and even at steady speeds above 2500-3000 RPM. The engine still has plenty of power but runs rough when that happens. It was not doing that when I had standard ignition, it became noticeable with the addition of MSD6A (gained good power too) and bad after I installed the MSD SS blaster coil. I, then, had 14 ��static advance + 6��vaccum+ 24��centrifugal (44��total, octane = 98). I reduced timing to 8��+ 6��vaccum + 24 centrifugal (38 total) and the intensity of the knocking was reduced but will not fully go away even if I unplug the vaccum advance ! The MSD guys are saying that this is due to a lean condition in the mixture (carb = 600 Holley DP with stock settings, engine = 302 middly built-up with large alum heads and 214/[email protected]). 1- Does that make sense to you guys ?
2 - Will my new 750 Vac Sec Holley (standard jet setting) run richer and fix this ?
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Moneymaker
Administrator Posts: 19751
From: Lyons, IL, USA
Registered: May 99
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posted 11-01-2002 03:00 PM
Yes I concur that it is too lean. Either richen up the 600 or instlall the 750.  ------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
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V8 Thumper
Gearhead Posts: 3529
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 11-03-2002 05:44 AM
What temp does your motor run at? I agree that it sounds lean ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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Pierre
Gearhead Posts: 366
From: France
Registered: Apr 2002
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posted 11-04-2002 04:25 AM
quote:
Originally posted by V8 Thumper:
What temp does your motor run at? I agree that it sounds lean
Around 185-190 at most (mesured a little while back), I did not mesure the actual temperature since then but the gauge seems to be in the same location. If a lean condition raises the temp, I did not notice it.
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V8 Thumper
Gearhead Posts: 3529
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 11-04-2002 08:35 AM
185-190 is just right IMO. I've heard those 'motor marbles'  start comming around at 220+, I was just curious. I still agree with Alex, sounds lean. Does it stumble anywhere in the rpm range?I total my motor out at 36*, 44* is a bit much IMO ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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Pierre
Gearhead Posts: 366
From: France
Registered: Apr 2002
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posted 11-04-2002 09:16 AM
quote:
Originally posted by V8 Thumper:
185-190 is just right IMO. I've heard those 'motor marbles' start comming around at 220+, I was just curious. I still agree with Alex, sounds lean. Does it stumble anywhere in the rpm range?I total my motor out at 36*, 44* is a bit much IMO
No particular stumble (that my very short experience is capable to feel since I have never driven a perfectly tuned Mustang)
This fast "knocking" (best way to describe it) seems to appear randomly at various range mostly under medium/heavy accelerations
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indyphil
Gearhead Posts: 877
From: Lafayette, IN, USA
Registered: Jul 2002
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posted 11-04-2002 09:52 AM
You didnt say what compression ratio your motor is at, but I would agree it is probably a lean condition and some agressive timing more than anything. Check the plugs for the lean condition and experiment with richer settings and you may pick up even more power!
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Pierre
Gearhead Posts: 366
From: France
Registered: Apr 2002
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posted 11-04-2002 10:01 AM
quote:
Originally posted by indyphil:
You didnt say what compression ratio your motor is at, but I would agree it is probably a lean condition and some agressive timing more than anything. Check the plugs for the lean condition and experiment with richer settings and you may pick up even more power!
9.2/1 which isn't too bad. I checked the plugs & they seemed OK but MSD tech support told me that it may not show if the condition is temporary.
I am going to install the 750 carb & test it (as soon as it stops raining here  ) and as usual will let you guys know Thanks to all of you
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RonnieT
Gearhead Posts: 637
From: Port Allen, La. 70767
Registered: Jun 99
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posted 11-04-2002 07:21 PM
Pierre, What spark plug are you running? With the MSD system your plugs may be too hot causing some preignition. You may try a step or two colder plug and see if it helps out. I read somewhere that Platinum plugs run even hotter than regular plugs, so if you are using the platinums try a set of regular plugs. ------------------
Ronnie
69 mach1 351W-4V engineless at the time!
70 Torino GT 351C-4v with a "shaker"
Mustangs and More Member #23
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Pierre
Gearhead Posts: 366
From: France
Registered: Apr 2002
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posted 11-05-2002 04:56 AM
quote:
Originally posted by RonnieT:
Pierre, What spark plug are you running? With the MSD system your plugs may be too hot causing some preignition. You may try a step or two colder plug and see if it helps out. I read somewhere that Platinum plugs run even hotter than regular plugs, so if you are using the platinums try a set of regular plugs.
Plugs are basic Champion brand RC10YC, is this a cold or hot one !? I can never remember !!
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Pierre
Gearhead Posts: 366
From: France
Registered: Apr 2002
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posted 11-05-2002 05:01 AM
.......... & I gapped them at 0.050 (approx)if that comes in the equation
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V8 Thumper
Gearhead Posts: 3529
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 11-05-2002 08:47 AM
quote:
Originally posted by Pierre:
.......... & I gapped them at 0.050 (approx)if that comes in the equation
eee-gad
(this I learned from Alex) .035-.040 MAX!!! Any greater than that, you run the risk of the electrode cross-firing to the head rather than the ground strap. That may in fact be contributing to your problem
------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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Pierre
Gearhead Posts: 366
From: France
Registered: Apr 2002
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posted 11-05-2002 10:40 AM
quote:
Originally posted by V8 Thumper:
eee-gad (this I learned from Alex) .035-.040 MAX!!! Any greater than that, you run the risk of the electrode cross-firing to the head rather than the ground strap. That may in fact be contributing to your problem
I've been getting different feed-back on that particular issue but since my motor has a problem I'll reduce that to be on the safe side
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SteveLaRiviere
Administrator Posts: 33988
From: Saco, Maine
Registered: May 99
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posted 11-07-2002 08:16 AM
quote:
Originally posted by Pierre:
Plugs are basic Champion brand RC10YC, is this a cold or hot one !? I can never remember !!
Champions are the worse plugs made. Get Autolites.
------------------
'70 Mustang Mach 1 - '72 Mustang Sprint - '94 F-150
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V8 Thumper
Gearhead Posts: 3529
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 11-07-2002 08:23 AM
quote:
Originally posted by SteveLaRiviere:
Champions are the worse plugs made. Get Autolites.
Agreed 110%. Pierre, we don't mean to pick on you, but I wouldn't run Champions in my lawnmower ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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Pierre
Gearhead Posts: 366
From: France
Registered: Apr 2002
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posted 11-08-2002 09:53 AM
What autolite reference # do you recommend for edel perf aluminium heads ?
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V8 Thumper
Gearhead Posts: 3529
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 11-08-2002 10:01 AM
Do you have any literature on those heads? I just browsed Edelbrock's site for tech info, they do not list spark plug recommendations not online, at least. I bet if you were to email tech support they'd probably get back to you within 24 hours ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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Pierre
Gearhead Posts: 366
From: France
Registered: Apr 2002
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posted 11-08-2002 10:19 AM
Just did a few test: installed the original ignition back, timing at 35��max (at 3K) and it still knocked 
So I installed my new 750 with yellow spring and it sounds back to normal (very confusing)..........but it just started pooring again here so road test will be for another time !!
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Pierre
Gearhead Posts: 366
From: France
Registered: Apr 2002
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posted 11-08-2002 10:21 AM
quote:
Originally posted by V8 Thumper:
Do you have any literature on those heads? I just browsed Edelbrock's site for tech info, they do not list spark plug recommendations not online, at least. I bet if you were to email tech support they'd probably get back to you within 24 hours
I'll do that I am sure they can cross references over
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bluestreek
Gearhead Posts: 1332
From: Athens,GA
Registered: Jul 2001
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posted 11-08-2002 10:52 AM
Trick Flow and AFR both recommends Autolite 3924 or Champion RC9YC as a starting point. Edelbrock recommends RC12YC. Dan ------------------
1966 Mustang Coupe: Custom glass hood and BIG scoop sits atop a 289 stroked to 331 c.i., Steel crank and girdle, 5.4 H-beams, Forged slugs, ported TFS alum. heads, ported Stealth 8020 intake, CompCams Xtreme Solid Roller, Holley 750 HP, long tubes, 4speed, 9" 3.50 posi, BFG Drag radials..
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Pierre
Gearhead Posts: 366
From: France
Registered: Apr 2002
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posted 11-09-2002 03:00 AM
quote:
Originally posted by bluestreek:
Trick Flow and AFR both recommends Autolite 3924 or Champion RC9YC as a starting point. Edelbrock recommends RC12YC. Dan
On the 6025 edel head instruction sheet they say RC9YC to RC14YC (I think the lower the number the colder the plug but I am not sure)
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bluestreek
Gearhead Posts: 1332
From: Athens,GA
Registered: Jul 2001
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posted 11-09-2002 11:47 AM
I'm using the Autolite 3924 in my 10.5:1 Trick flow stroker. No pinging problems at all. ------------------
1966 Mustang Coupe: Custom glass hood and BIG scoop sits atop a 289 stroked to 331 c.i., Steel crank and girdle, 5.4 H-beams, Forged slugs, ported TFS alum. heads, ported Stealth 8020 intake, CompCams Xtreme Solid Roller, Holley 750 HP, long tubes, 4speed, 9" 3.50 posi, BFG Drag radials..
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Pierre
Gearhead Posts: 366
From: France
Registered: Apr 2002
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posted 11-09-2002 12:02 PM
OK went out for a test drive with the 750 and problem is fixed. Either the 600 was too lean or it was catching air (it was a loaner that had seen better days).
Could'nt really floor it (its been raining for days here) but seems like the lite vaccum spring makes a huge difference (Alex was right again !)
As for the plugs I am going out to get some I am just hoping they don't sell them 10$ a piece here 
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Moneymaker
Administrator Posts: 19751
From: Lyons, IL, USA
Registered: May 99
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posted 11-09-2002 12:03 PM
Autolite plug gapped at no more than .035 ------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
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