477 BBC HIGH RPM MISFIRE
04-27-2009, 05:20 AM
#12
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Originally Posted by bajaboat32
I have 8 to 9 lbs of fuel pressure. When I started changing jets, The EGT did not change or got worse. I am i at 1335 degrees and only running 1/8 mile.
tell me more about the carbs your trying ? 1335 is likely the cause of it, thats very high. How about a vacuum leak ?
04-27-2009, 05:47 AM
#13
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No. It is not even clean in the water anymore. I just talked to the engine builder to verify the springs I put on. I purchased this car turn key. I don't know exactly what cam is in it. I matched up the springs and purchased a set of K-Motions. He told me he was not a fan of them but he would pull the sheets and make sure the ones I had are o.k.
The carb is a Quick Fuel Alch 1050 Dominator. He also said I may have it too rich and the heat is from the fuel burning outside the exhaust ports now and giving me false readings on my EGT. The problem is that I can still build heat fairly easy and I do not have a lean out valve. I have checked for vacuum leaks and I do run a belt drive vacuum pump.
The carb is a Quick Fuel Alch 1050 Dominator. He also said I may have it too rich and the heat is from the fuel burning outside the exhaust ports now and giving me false readings on my EGT. The problem is that I can still build heat fairly easy and I do not have a lean out valve. I have checked for vacuum leaks and I do run a belt drive vacuum pump.
04-27-2009, 06:58 AM
#14
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Go down to 6 1/2 or 7psi. Change the jets back to 180 squared, and try it.
At 8 or 9 psi your possibly misting fuel into your plastic vent in your bowl. With a BG 400 it can maintain 6 1/2 psi. 200 jets are way to big in my opinion.
Go down to 6 1/2 or 7psi. Change the jets back to 180 squared, and try it.
At 8 or 9 psi your possibly misting fuel into your plastic vent in your bowl. With a BG 400 it can maintain 6 1/2 psi. 200 jets are way to big in my opinion.
Go down to 6 1/2 or 7psi. Change the jets back to 180 squared, and try it.
04-27-2009, 07:30 AM
#15
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[quote="bajaboat32"]
The carb is a Quick Fuel Alch 1050 Dominator. He also said I may have it too rich and the heat is from the fuel burning outside the exhaust ports now and giving me false readings on my EGT. The problem is that I can still build heat fairly easy and I do not have a lean out valve. [quote]
The quick fuel alky carbs are a far cry from a good one, they are a weird deal to get right. Back the jet way off (180 like dparker said) and see what it does if that egt goes down you know, if it goes down some keep going with it. Remember egts arent "perfect" but once ya figure them out you can keep tuning to them. Where are you idle screws set at ?
If you have the wrong springs (springs for 750 lift cam 770) it could cause a issue like this also.
The carb is a Quick Fuel Alch 1050 Dominator. He also said I may have it too rich and the heat is from the fuel burning outside the exhaust ports now and giving me false readings on my EGT. The problem is that I can still build heat fairly easy and I do not have a lean out valve. [quote]
The quick fuel alky carbs are a far cry from a good one, they are a weird deal to get right. Back the jet way off (180 like dparker said) and see what it does if that egt goes down you know, if it goes down some keep going with it. Remember egts arent "perfect" but once ya figure them out you can keep tuning to them. Where are you idle screws set at ?
If you have the wrong springs (springs for 750 lift cam 770) it could cause a issue like this also.
04-27-2009, 07:44 AM
#16
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Good point guys.
Yesterday I started out at 164 front 176 rears. Car was bad. Popping very bad. EGT was High. I went to 180 front 188 rears. Car was better, Still popping. Did not make a full pass. Got out of it and EGT was 1129. So I went to 192 square, Still popping bad and EGT was 1330.
Yesterday I started out at 164 front 176 rears. Car was bad. Popping very bad. EGT was High. I went to 180 front 188 rears. Car was better, Still popping. Did not make a full pass. Got out of it and EGT was 1129. So I went to 192 square, Still popping bad and EGT was 1330.
04-27-2009, 08:21 AM
#18
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Originally Posted by bajaboat32
Good point guys.
Yesterday I started out at 164 front 176 rears. Car was bad. Popping very bad. EGT was High. I went to 180 front 188 rears. Car was better, Still popping. Did not make a full pass. Got out of it and EGT was 1129. So I went to 192 square, Still popping bad and EGT was 1330.
Yesterday I started out at 164 front 176 rears. Car was bad. Popping very bad. EGT was High. I went to 180 front 188 rears. Car was better, Still popping. Did not make a full pass. Got out of it and EGT was 1129. So I went to 192 square, Still popping bad and EGT was 1330.