Re: Plug Reading Please
[Re: chryco]
#1381292
02/04/13 02:22 PM
02/04/13 02:22 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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Post another picture of a different spark plug, preferrably # 7, with the backside of the ground strap to the camera   It looks like it is rich to me, I always jet the motor up two sizes first, before leaning it down. Do that and look at the time slip 1/4 MPH, if the car slows down then try jetting it down one size leaner at a time than it is in these pictures until starts to slow the MPH down again  If adding two jet siezes makes it faster keep jetting it up until it slows down the MPH in the 1/4 If you can't get it rich enough with the jetting to slow the car down, look at the fuel supply side of the fuel system, needles and seat sizes, fuel filter size, fuel pump and line sizes, pickup and delivery side lines  BTW, what fuel and compression as well as what spark plug brand and part number are these pictures of?
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Plug Reading Please
[Re: Cab_Burge]
#1381293
02/04/13 08:31 PM
02/04/13 08:31 PM
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Joined: Jan 2003
Posts: 2,152
Fancy Farm Ky
wyoming
top fuel
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top fuel
Joined: Jan 2003
Posts: 2,152
Fancy Farm Ky
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If you really want to read a plug, need to not be looking at it after several passes, need to cut ignition at end of the run, coast down to pit turn off and pull plug and look at it then, if you idle back to the pits, you'll be looking at your idle mixture. What kind of ignition are you running? Even though all the new hi power ignitions are great, they make plug reading harder, they fire plugs so well, you can be a little rich and look lean. Best ways to adjust mixture with the good ignition boxes is to either buy one of the new wide band O2's, or make passes changing mixture and jet for best MPH. Thats my opinion anyway, you can still use the ground strap to check if your timing and heat range is correct, but tougher to tell on jetting. Plug magnifiers help, but still can be fooled by new hi power ignition.
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Re: Plug Reading Please
[Re: wyoming]
#1381294
02/05/13 10:07 AM
02/05/13 10:07 AM
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Joined: Jan 2005
Posts: 866
Winnipeg ,Mb. CA.
chryco
OP
super stock
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OP
super stock
Joined: Jan 2005
Posts: 866
Winnipeg ,Mb. CA.
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Quote:
If you really want to read a plug, need to not be looking at it after several passes, need to cut ignition at end of the run, coast down to pit turn off and pull plug and look at it then, if you idle back to the pits, you'll be looking at your idle mixture. What kind of ignition are you running? Even though all the new hi power ignitions are great, they make plug reading harder, they fire plugs so well, you can be a little rich and look lean. Best ways to adjust mixture with the good ignition boxes is to either buy one of the new wide band O2's, or make passes changing mixture and jet for best MPH. Thats my opinion anyway, you can still use the ground strap to check if your timing and heat range is correct, but tougher to tell on jetting. Plug magnifiers help, but still can be fooled by new hi power ignition.
Totaly agree on all points .I have an MSD 7AL w/ MSD Blaster coil . I have a thread in here somewhere regarding my fuel system issues I`ve experienced (car has only 12 passes so far). My dyno numbers didn`t jive with what my MPH / E.T. should be. (down 150hp or so). Generally from what you and Cab mentioned I am on the lean side .I`ve gone through the basics and found my line pressure too low by mfgr`s specs (BG400) at 8.5 - 9 # should be 18 - 20 # - fixed. My 10 micron filter between the tank and pump , now a 100 mic - fixed.
My Gary Williams 1050 is square jetted at 90 as it left the RBRE dyno making peak HP/Torq. Also has slosh tubes in the secondary bowl. I`m running -12AN to the filter , then right into the pump, and -10AN to the BG 4port reg and -8AN 4-6" to the carb. Not sure whether to up size my lines from the pump to the carb one - AN or not ? I think the problem was the filter and line pres.
Thoughts ?
Thx All !
chryco
Gas is fer washin' parts ....Alky`s fer drinkin' ...Nitro`s fer Racin'!
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Re: Plug Reading Please
[Re: chryco]
#1381295
02/05/13 10:49 AM
02/05/13 10:49 AM
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Joined: Jul 2010
Posts: 1,491
Oologah, Oklahoma
Big Squeeze
pro stock
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pro stock
Joined: Jul 2010
Posts: 1,491
Oologah, Oklahoma
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IMHO, the only reason to look at plugs is to make sure they all look the same (equal fuel distribution) and to make sure it's not detonating...otherwise, it's a waste of time.... Like already mentioned, tuning for best mph tells you what you need to know...and trying to put the timing mark in the bend is a waste of time...all you have to do is run as little timing as you can and still run the best trap speed..  And Chryco, I hate to be the barer of bad news, but I'd venture to say that your motor makes what it's supposed to make and Barton's Dyno is 100-150hp happy, just like Andy F's and the one Cab was using...
If you can't handle the truth, you're living a lie.......
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Re: Plug Reading Please
[Re: Crizila]
#1381296
02/05/13 11:20 AM
02/05/13 11:20 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Your fuel system sounds fine.... you might have to go with a larger N/S on the carb(maybe)... on the O2.. they work fine ONCE you get your WOT figured out.. there isnt any magic number you should shoot for.. but once you find your best MPH then you can take a O2 reading so you can get back to that number easy if you change the jetting around... remember that MPH is the HP... ET is chassis 
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Re: Plug Reading Please
[Re: MR_P_BODY]
#1381297
02/05/13 02:11 PM
02/05/13 02:11 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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WOW. This guy just wanted a spark plug read? It does sound like he doesn't have a supply problem. Plenty of pump, line size/ filtration is good. Assuming he is running appropriate sized needle&seats. Bottom line of course is what the guage is reading at the end of the run. Not true that you can only read a plug properly if shutting off at the end of a run - at least on the heat range side. I've learned a little bit on plug reading after recently melting off a few ground straps.  The line of "demarcation" ( eyeball measurement for proper plug heat range ) on a ground strap will remain and be easily readible after returning to the pits - unless you are WAY rich at idle or the pits are located in another state.  Also the sharp edges on the electrode and ground strap are a good heat range indicator and will remain readible. Reading the plugs for a ball park AF ratio WILL be affected with any amount of idle time, especially if you are rich at idle, which in many cases is the case with big cams. So, IMHO, you can still read plug heat range with some idle time, but not A/F ratio. Plug reading is not a waste of time - any time.
Fastest 300
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Re: Plug Reading Please
[Re: chryco]
#1381298
02/05/13 02:43 PM
02/05/13 02:43 PM
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Joined: Jun 2003
Posts: 9,225
Charleston
sixpackgut
Drag Week Mod Champion
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Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
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Quote:
Quote:
If you really want to read a plug, need to not be looking at it after several passes, need to cut ignition at end of the run, coast down to pit turn off and pull plug and look at it then, if you idle back to the pits, you'll be looking at your idle mixture. What kind of ignition are you running? Even though all the new hi power ignitions are great, they make plug reading harder, they fire plugs so well, you can be a little rich and look lean. Best ways to adjust mixture with the good ignition boxes is to either buy one of the new wide band O2's, or make passes changing mixture and jet for best MPH. Thats my opinion anyway, you can still use the ground strap to check if your timing and heat range is correct, but tougher to tell on jetting. Plug magnifiers help, but still can be fooled by new hi power ignition.
Totaly agree on all points .I have an MSD 7AL w/ MSD Blaster coil . I have a thread in here somewhere regarding my fuel system issues I`ve experienced (car has only 12 passes so far). My dyno numbers didn`t jive with what my MPH / E.T. should be. (down 150hp or so). Generally from what you and Cab mentioned I am on the lean side .I`ve gone through the basics and found my line pressure too low by mfgr`s specs (BG400) at 8.5 - 9 # should be 18 - 20 # - fixed. My 10 micron filter between the tank and pump , now a 100 mic - fixed.
My Gary Williams 1050 is square jetted at 90 as it left the RBRE dyno making peak HP/Torq. Also has slosh tubes in the secondary bowl. I`m running -12AN to the filter , then right into the pump, and -10AN to the BG 4port reg and -8AN 4-6" to the carb. Not sure whether to up size my lines from the pump to the carb one - AN or not ? I think the problem was the filter and line pres.
Thoughts ?
Thx All !
chryco
18-20 lbs?
I run 5 lbs of fuel pressure to 2 edelbrock carbs and run 140 mph in the 1/4 and it never drops below 5.
I agree with big squeeze, jet up till you get best MPH and just make sure all plugs look the same.
with no carbon on the base ring I would say your plug looks lean
Gen 3 power 6.22@110, 9.85@135
Follow @g3hemiswap on instagram
performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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Re: Plug Reading Please
[Re: Dunnuck Racing]
#1381300
02/05/13 03:37 PM
02/05/13 03:37 PM
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Joined: Jun 2003
Posts: 9,225
Charleston
sixpackgut
Drag Week Mod Champion
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Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
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Quote:
The BG 400 has a built in bypass system. It gets set to approximately20 psi,then that pressure is regulated down near the carburetors .
Holley like 6-7 psi,Carter's are lower 5-6 usually.
Keith
Oh, didn't know that. My bad
Gen 3 power 6.22@110, 9.85@135
Follow @g3hemiswap on instagram
performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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Re: Plug Reading Please
[Re: sixpackgut]
#1381301
02/05/13 04:37 PM
02/05/13 04:37 PM
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Joined: Nov 2009
Posts: 3,410
Belpre,Ohio
CHAPPER
master
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master
Joined: Nov 2009
Posts: 3,410
Belpre,Ohio
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Rob,,I think 90 jets sound a little lean to me. Are you using power valves?
If you like drag racing, support your local track.
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Re: Plug Reading Please
[Re: VernMotor]
#1381304
02/05/13 06:32 PM
02/05/13 06:32 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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If he sees a pressure drop it can be a multiple of things... including a venting problem... I set my pressure at 7 at idle... and I dont care if I see a .5 psi reduction but I dont want to see any more than that.. at that point it can be vent or pump... if its holding pressure but seems to run lean then look at N/S... a 1050 comes with a .120 but in some cases a .130 will work nicely (I should say it could be vent, pump OR filter... so guys dont run a large enough filter for the flow)
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