Re: Please help me read my spark plug
[Re: jbeintherockies]
#2710292
10/27/19 01:24 AM
10/27/19 01:24 AM
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Joined: Aug 2003
Posts: 43,190 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,190
Bend,OR USA
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The porclyn is NOT chipping off, it is chemical deposits from combustion that you are seeing chipping off What type of heads (aluminum or iron)and compression are you running? You might want to try a #65 plug in your motor to see if that hotter plug will burn hot enough to prevent those deposits
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Please help me read my spark plug
[Re: Sniper]
#2710388
10/27/19 02:34 PM
10/27/19 02:34 PM
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Joined: May 2011
Posts: 220 Aurora, CO
jbeintherockies
OP
enthusiast
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OP
enthusiast
Joined: May 2011
Posts: 220
Aurora, CO
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Hello, I have been using Exxon/Mobil Synergy Supreme premium gasoline mixed with about 5 gallons of Sunoco 260 (100 octane). https://www.exxon.com/en/synergy-supreme-plushttps://www.sunocoracefuels.com/fuel/260-gtAdding the 260 really helps with fuel boil. About the car, '68 Barracuda FB Formula S, 3.91's, 5 speed manual, DLI ported X heads, M1 intake, holley carb, mech roller cam (about 248@50), about 9.7:1 compression ratio, bored and stroked to about 386ci. Timing is 22 degrees initial, 37 total all in at 2500. Vacuum advance adds about 8 degrees of advance. This engine likes a lot of advance, meaning I could probably go with a little more initial and total (2-3 degrees). Maybe it wants more timing to burn off some of the deposits? Cab's suggestion of a hotter plug is interesting; I could give it a try and listen carefully for ping/rattle. If you need any additional info, please ask. What pump gas are you guys running in your cruisers with carbs?
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Re: Please help me read my spark plug
[Re: jbeintherockies]
#2710479
10/27/19 09:29 PM
10/27/19 09:29 PM
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Joined: Aug 2003
Posts: 43,190 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,190
Bend,OR USA
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The race fuel is making the deposits on your plugs, at that compression ratio and any altitude above 4500 you don't need any fuel additive or race fuels Based on how much total timing your running I'm assuming your above 5000 FT altitude, correct? On your deal I would change to the #65 Autolites with no other tuning changes other than dropping the race gas to your tank I use to help several NHRA stock class racers that ran 340 motors, one ended up setting the E/SA record that stood for two years, later on he held the C/SA record with a Challenger I sold him that he made into a 340 6 pack T/A clone car, that car was a rocket ship None of those Stocker motors, 1970 4 barrel, 1970 six pack and the1971 340 four barrel motors like more than 33 degree total at the track or on the engine dyno under 4000 Ft altitude in SO CA IHTHs
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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