Re: Kabooom... back fire thru carb
[Re: 452RT]
#441635
08/18/09 07:14 PM
08/18/09 07:14 PM
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Joined: Apr 2007
Posts: 3,746 Riverside, California
Lil Demon
master
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master
Joined: Apr 2007
Posts: 3,746
Riverside, California
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I was inside my car and it sounded like a M80. I was glad you figured it out. Hope you enjoyed your time up north here in the Great NW. I would like to make it down south next year and race some of you guys, maybe even Bill or Al.
Jim - you had better stick with me - Al's car is way out of our league.
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Re: Kabooom... back fire thru carb
[Re: 602heavy]
#441638
08/19/09 10:09 AM
08/19/09 10:09 AM
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Joined: Oct 2004
Posts: 8,165 Left Coast
BobR
master
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master
Joined: Oct 2004
Posts: 8,165
Left Coast
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Guess you got lucky , i sprayed a 300 shot pulling too much timing for the distributor , blew the throttle bades & boosters right off the carb mid track , set fire to the bulk head wiring & fried the hood , have since fitted a 'cap adapt'.
When spraying you should phase your rotor to what the timing will be on the spray or this is what can happen.
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Re: Kabooom... back fire thru carb
[Re: BobR]
#441639
08/19/09 10:20 AM
08/19/09 10:20 AM
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Joined: Jul 2005
Posts: 8,647 ELYRIA,OH
blownzoom440
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Joined: Jul 2005
Posts: 8,647
ELYRIA,OH
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Quote:
Quote:
Guess you got lucky , i sprayed a 300 shot pulling too much timing for the distributor , blew the throttle bades & boosters right off the carb mid track , set fire to the bulk head wiring & fried the hood , have since fitted a 'cap adapt'.
When spraying you should phase your rotor to what the timing will be on the spray or this is what can happen.
too pull too much timing wouldn't it have to be extream?a friend ran 50 NOS jet and ran 8* timing.[on a motorcycle]
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Re: Kabooom... back fire thru carb
[Re: blownzoom440]
#441640
08/19/09 12:44 PM
08/19/09 12:44 PM
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Joined: Oct 2004
Posts: 8,165 Left Coast
BobR
master
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master
Joined: Oct 2004
Posts: 8,165
Left Coast
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Quote:
Quote:
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Guess you got lucky , i sprayed a 300 shot pulling too much timing for the distributor , blew the throttle bades & boosters right off the carb mid track , set fire to the bulk head wiring & fried the hood , have since fitted a 'cap adapt'.
When spraying you should phase your rotor to what the timing will be on the spray or this is what can happen.
too pull too much timing wouldn't it have to be extream?a friend ran 50 NOS jet and ran 8* timing.[on a motorcycle]
If the rotor is phased improperly when the timing changes it can be close to another cylinder's cap lug. The coil fires into the wrong cylinder and kaboom!
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Re: Kabooom... back fire thru carb
[Re: BobR]
#441644
08/19/09 08:05 PM
08/19/09 08:05 PM
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Joined: Dec 2008
Posts: 1,200 UK
602heavy
pro stock
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pro stock
Joined: Dec 2008
Posts: 1,200
UK
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Quote:
Quote:
Guess you got lucky , i sprayed a 300 shot pulling too much timing for the distributor , blew the throttle bades & boosters right off the carb mid track , set fire to the bulk head wiring & fried the hood , have since fitted a 'cap adapt'.
When spraying you should phase your rotor to what the timing will be on the spray or this is what can happen.
Yea i know , was only pulling 13* on a stock cap which should be good for around 20* of retard (MSD), since then have gone for a larger cap with two piece rotar , no problems since , cylinder pressure can be a killer.
It's difficult to phase a stock cap pulling 13* of retard to fire right where the rotor meets the cap terminal , with high cylinder pressures the rotor will prefer the easiest route , hence the next cylinder whilst the intake valve is still open , either a crank trigger or adapt a cap is the easiest way to avoid this happening , had to modify the valve cover to fit the 'adapt a cap'.
Last edited by 602heavy; 08/19/09 08:16 PM.
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Re: Kabooom... back fire thru carb
[Re: S/ST 3040]
#441646
08/19/09 08:39 PM
08/19/09 08:39 PM
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Joined: Dec 2008
Posts: 1,200 UK
602heavy
pro stock
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pro stock
Joined: Dec 2008
Posts: 1,200
UK
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I don't see how a crank trigger alone would solve an out of phase rotor. It signals the MSD box, MSD delays spark but, rotor still has to be oriented correctly for the retarded spark.
It won't , if using a crank trigger a normal cap will suffice , just need to phase rotor/cap terminal with trigger.
Did'nt think i needed a long winded post to explain it , sorry.
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Re: Kabooom... back fire thru carb
[Re: S/ST 3040]
#441648
08/19/09 09:02 PM
08/19/09 09:02 PM
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Joined: Dec 2008
Posts: 1,200 UK
602heavy
pro stock
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pro stock
Joined: Dec 2008
Posts: 1,200
UK
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Quote:
I'm no electrical or nitrous whiz but, if the problem with intake explosions were directly related to the nitrous, which I assume is when you retard the timing, I'd think you'd want to phase the rotor whereever the ignition was most retarded.
Correct , the rotor needs to be phased @ the point of highest cylinder pressure , which would be full retard , the adapt a cap allows the rotor to be phased up to around 20* of retard , more can be pulled but then the rotor is starting to get away from the cap terminal , although a lot more than 20* can be pulled & still be safe.
Last edited by 602heavy; 08/19/09 09:05 PM.
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Re: Kabooom... back fire thru carb
[Re: Bill_G]
#441650
08/20/09 01:17 PM
08/20/09 01:17 PM
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Joined: Nov 2004
Posts: 6,890 North Alabama
Monte_Smith
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master
Joined: Nov 2004
Posts: 6,890
North Alabama
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Just went through this with a friend we put the spring loaded pressure relief valve on his SM tunnel ram, get one of these it will save you money in the long run! Bill
This is a waste of money. A serious nitrous backfire will blow the carbs off and take the top off a tunnel ram. What good is a few quarter sized holes going to do to prevent that.
The fact that he sprayed the nitrous into a non running engine is not an issue. Simple fix, pull the coil wire, open the carb and spin it over a few times, problem gone. Nitrous is not the problem, nor is it dangerous. Improper use and lack of knowledge is the problem or danger. Nitrous gets a bad rap for most of the problems that are self inflicted. A leaky solenoid is not a problem either, unless the bottle is left on, which it should NEVER be, if the car is not running, or you don't have a ball valve. If you don't know much about nitrous, get some help from someone who does.
Monte
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Re: Kabooom... back fire thru carb
[Re: Monte_Smith]
#441651
08/20/09 02:01 PM
08/20/09 02:01 PM
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Joined: Jan 2003
Posts: 13,363 Marion, South Carolina [><]
an8sec70cuda
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 13,363
Marion, South Carolina [><]
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Destroyed a set of split dominators, the hood scoop, windshield, and cracked a sheetmetal tunnelram a couple years ago due to a nitrous backfire. NOT pretty. It was noone's fault but the driver. He's been racing nitrous cars for nearly 30 years, but after a long day of frustrating testing, he wasn't thinking clearly. The hood scoop must have been 60 feet up in the air and landed 50 feet behind the car. 700+ miles from home, we leak tested the motor, borrowed another set of splits, JB welded the intake back together (after beating it back into shape w/ a hammer and 2x4 ), patched the scoop and windshield, and we were ready to race the next day. That intake had burst panels, but like Monte said, they don't do much if it's gonna sneeze. CHIP
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 18 spline 4 speed, Dana 60 '71 Demon, 340, low gear 904, 8.75 '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: Kabooom... back fire thru carb
[Re: an8sec70cuda]
#441652
08/20/09 02:13 PM
08/20/09 02:13 PM
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Joined: Jan 2003
Posts: 8,022 Tulsa OK
Bad340fish
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master
Joined: Jan 2003
Posts: 8,022
Tulsa OK
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I saw an Impalla with a Tunnel Ram pop both carbs off on the starting line, the only thing that kept them on was the fuel lines. Intake manifold went all over the place(cast)
68 Barracuda Formula S 340
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Re: Kabooom... back fire thru carb
[Re: Bad340fish]
#441654
08/20/09 03:12 PM
08/20/09 03:12 PM
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Joined: Jan 2004
Posts: 550 Ma
Voluster
mopar
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mopar
Joined: Jan 2004
Posts: 550
Ma
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Like Monte said it was not the nitrous that cause the problem it was user error. Seen it happen a few times and some nice carbs ruined. but again it was user error if you ever inject nitrous in a none running engine. you have to pull the coil wire and spin it over and it will be fine Rookie mistake just go play the lottery cause you got very lucky it didn't do any other damage
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