477 BBC HIGH RPM MISFIRE
04-27-2009, 11:54 AM
#21
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Re: 477 BBC HIGH RPM MISFIRE
Originally Posted by bajaboat32
I have been fighting this for long enough... 477 BBC Dart pro 1 heads, Roller, 13:1, BG 400 pump (new), Quick Fuel 1050 Alch, MSD Distributor ignition.
Between the 1 -2 shift the car started popping slightly, steadily got worse. EGT was reading high. Put larger jet in carb. Kept getting worse as time went bye. Don't race alot so a few weeks go bye between attemts to cure. Thought it was a fuel delivery problem. Ordered new BG 400 pump and 4 port reg. Installed but no cure. Got up to almost 200 jets and still had hot EGT temps. Winter came a I said I'll see you next year.
Ordered new valve springs and installed. Went out today and problem still there. Any other things I am missing? I am probably looking over the problem so don't be afraid to mention some silly questions at this point.
Thanks in advance.
Between the 1 -2 shift the car started popping slightly, steadily got worse. EGT was reading high. Put larger jet in carb. Kept getting worse as time went bye. Don't race alot so a few weeks go bye between attemts to cure. Thought it was a fuel delivery problem. Ordered new BG 400 pump and 4 port reg. Installed but no cure. Got up to almost 200 jets and still had hot EGT temps. Winter came a I said I'll see you next year.
Ordered new valve springs and installed. Went out today and problem still there. Any other things I am missing? I am probably looking over the problem so don't be afraid to mention some silly questions at this point.
Thanks in advance.
04-27-2009, 12:10 PM
#22
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Join Date: Feb 2007
Location: Michigan
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Has the car always had a miss since you bought it? Have you added any new electrical extras to the car? See if you can find someone that has an MSD tester you can check the whole ignition system with out running the car and can eliminate components without buying unneeded parts. I went through a similar thing last year. Nearly pulled my hair out. Found out it was my 12 volt fan inside the car i would use when its hot out.
04-27-2009, 12:46 PM
#23
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Join Date: Nov 2006
Location: Quincy, IL.
Posts: 14
Some times you have to go back to the basics....
I was thinking the same thing. Go back to the ignition system, quit concentrating on valves or fuel delivery. Went down to the shop and popped the cap on the dist. and the center coil electrode is burnt flush with the bottom of the cap. The center tab on the rotor looks like it has been pretty hot also. Just got back from the parts store with new ones.
Won't be able to tell completely until we go back to the track this weekend but I think this may have had a little to do with the misfire problem. I will keep you posted and I truely thank you for all of the replies and direction that you all have supplied me with.
Steve
I was thinking the same thing. Go back to the ignition system, quit concentrating on valves or fuel delivery. Went down to the shop and popped the cap on the dist. and the center coil electrode is burnt flush with the bottom of the cap. The center tab on the rotor looks like it has been pretty hot also. Just got back from the parts store with new ones.
Won't be able to tell completely until we go back to the track this weekend but I think this may have had a little to do with the misfire problem. I will keep you posted and I truely thank you for all of the replies and direction that you all have supplied me with.
Steve
04-27-2009, 01:52 PM
#24
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Join Date: Sep 2007
Posts: 4,137
Try a different BOX!!! A friend had a 7AL3 that did that and they kept saying there was nothing wrong...we put it in my car and it did the exact same thing...hooked to the same wires as my box was hooked to. He got mad and bought a new box and the problem was solved. Hooked it to the same wires the other was hooked to. That was 7 years ago still no problems...it was a bad box...don't care what MSD said.
