Fuel system issues

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SpeedThrills said:
"Enquiring minds need to know." Waz up?
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ordered the new summit rail but it is also only 1/4" holes in the flair and 5/15 on the inlet to the rail... but as some have said im leaning away from that being my problem... i mean ive talked to a could of guys with hot 440's running the same rail un modded so im looking to play with ignition now...

i have a mopar electronic out having my curve put in it and then i will install it, MSD street fire box, blue streak cap and long tip rotor...
 
ok so i got the MSD street Fire box in

also installed a different home rebuilt dizzy with my curve...

then i got the Blue Streak Cap with brass contacts and rotor...

set the limiter at 6200 and went for a drive....

well its doing the same thing @ around 5600 and up...
 
racerhog said:
Recheck the valve spring tension......
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yea i have over 10K miles on the springs, almost 100 passes, and a stuck valve event so i think they might be done for...

but going to try and get them pulled and tested in the AM and see where were at...
 
Maybe i over read this but did you say your only using 30deg total ign timing? shouldnt you be about 36Deg min? ive also had similar issue before on a 340 with the carb i kept jetting up and the prob never got better just stayed the same with a miss at 6500 rpm but i did everything but lean it down some and when i did it was a new beast and revd clean to 7200rpm.
 
CHEATHAM said:
Maybe i over read this but did you say your only using 30deg total ign timing? shouldnt you be about 36Deg min? ive also had similar issue before on a 340 with the carb i kept jetting up and the prob never got better just stayed the same with a miss at 6500 rpm but i did everything but lean it down some and when i did it was a new beast and revd clean to 7200rpm.
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the slant racers say max of 30... i havn't got to try to bump it up yet to see if it likes it or not...

but i just jet up at the track till it slowed down... first couple runs of the night are always jet changes... so its not to fat is thats what your trying to say...
 
805moparkid said:
the slant racers say max of 30... i havn't got to try to bump it up yet to see if it likes it or not...

but i just jet up at the track till it slowed down... first couple runs of the night are always jet changes... so its not to fat is thats what your trying to say...
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yep thats it on the fat side, i would try to go back to your baseline setup and lean it out a couple of jet sizes, i would deff try more timing, it is a 4 cycle engine no matter how many cylnders it should take more than 30 deg unless your using boost or nitrous, in some cases add more jet and add some timing to add some power . if your fattend up the carb then id try more timing if it dont clear it up then id jet it the other way lean it out.
 
CHEATHAM said:
yep thats it on the fat side, i would try to go back to your baseline setup and lean it out a couple of jet sizes, i would deff try more timing, it is a 4 cycle engine no matter how many cylnders it should take more than 30 deg unless your using boost or nitrous, in some cases add more jet and add some timing to add some power . if your fattend up the carb then id try more timing if it dont clear it up then id jet it the other way lean it out.
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you miss read my post... i jet up till it slows down and then back off one... so its where it should be...
 
You're just not going to check that fuel volume, huh? :banghead: The pump might be off of a 11 second slant, but if your system is restricted, it doesn't matter if you use a Top Fuel pump.
 
SpeedThrills said:
You're just not going to check that fuel volume, huh? :banghead: The pump might be off of a 11 second slant, but if your system is restricted, it doesn't matter if you use a Top Fuel pump.
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i dont know how there could be a restriction... brand new 3/8's pick up with new sock, new 3/8" line that i blew out before install...
 
805moparkid said:
i dont know how there could be a restriction... brand new 3/8's pick up with new sock, new 3/8" line that i blew out before install...
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It's good info to have, whether it's the problem or not. It's on the list of things you check when you have high rpm "duck shootin".
My experience with weak valve springs is that the car will nose over. Never had one backfire because of it. But that's just my experience.
 
SpeedThrills said:
It's good info to have, whether it's the problem or not. It's on the list of things you check when you have high rpm "duck shootin".
My experience with weak valve springs is that the car will nose over. Never had one backfire because of it. But that's just my experience.
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well i will check it... but the car did not back fire out the carb... just misfire out the headers...
 
805moparkid said:
well i will check it... but the car did not back fire out the carb... just misfire out the headers...
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That's what it will do when there isn't enough fuel volume, backfire out the exhaust, that is. It's a lean misfire. (If it's not an ignition problem, that would actually be a rich misfire.)
I never said it would backfire out the carb. It won't backfire out of the carb at high rpm's.
I don't want to make too big a deal out of the fuel volume thing. It's just something that should be checked when chasing high rpm backfires out of the exhaust.
High rpm exhaust backfires are generally a lean condition or an ignition problem.
If you have good volume, maybe there's some debris in the carb?
Have you checked all of the grounds on the ignition?
Is the ignition getting proper voltage?
An ignition problem could show rich-looking plugs.
Engine to chassis grounds good?

I didn't re-read the whole thread. Don't remember what you've done.
 
SpeedThrills said:
That's what it will do when there isn't enough fuel volume, backfire out the exhaust, that is. It's a lean misfire. (If it's not an ignition problem, that would actually be a rich misfire.)
I never said it would backfire out the carb. It won't backfire out of the carb at high rpm's.

thats good cuz that would be very bad lol

I don't want to make too big a deal out of the fuel volume thing. It's just something that should be checked when chasing high rpm backfires out of the exhaust.

well im glad your bringing it up as i need to get into the habit of correct diag now... this is a new issue for me to learn on...

High rpm exhaust backfires are generally a lean condition or an ignition problem.

full MSD ignition now with no gains...

If you have good volume, maybe there's some debris in the carb?

i clean it everytime we go to the track (carb cleaner down all the air bleeds, check jets before install)

Have you checked all of the grounds on the ignition?

with the petronix kit it just went onto the coil so nothing there to mess up lol... on new set up with MSD its grounded on the bolt that also grounds the motor to the chassis and vis versa... i have my negative cable on the block, and then a strap from the block to the fire wall with clean contacts...

Is the ignition getting proper voltage?

by-passed the ballast with petronix, and now have the MSD hooked right to the starter relay stud

An ignition problem could show rich-looking plugs.

one (only pulled on so far) looked a little fat when i was pulling valve springs to check tension... but that was after trying to get the timing right and idling for quite a awhile so unfair reading...

Engine to chassis grounds good?

above

I didn't re-read the whole thread. Don't remember what you've done.
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so new springs/retainers are on there way, should have them wensday and installed by the latest this weekend... i will then check the fuel volume then to...
 
I had a miss at 5500, 5600 out the exhaust and it was the black wire from the alt.going thru the bulkhead making bad contact. solved that by doing the mad electrical fix.
 
If there's debris in the carb, you're very unlikely to get it out by spraying while assembled.
A clogged air bleed would make it rich. Any problem making it lean will be anywhere from the fuel inlet to the discharge nozzle(s).

Electrical gremlins can be tricky, so don't write off that possibility just yet.

Hang in, you'll get it.
 
ok so the springs are in! just need to get the rear brakes fixed and i can test...
 
805moparkid said:
well originally i was running it with the air cleaner, once i slowed down while jetting up i took it off and got another jet in it... but this was way back now... 14.7 range
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Did it bust up with the cleaner on. Look at that monster scoop. I bet the air is stoopid on top of the carb. Maybe try a stub stack on top.
 
daredevil said:
Did it bust up with the cleaner on. Look at that monster scoop. I bet the air is stoopid on top of the carb. Maybe try a stub stack on top.
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yea it does it with air cleaner on or off...

it started with the gear change...
 
like i said in the other topic of your's. TOSS OUT THAT RED PUMP. every one's telling you it's a lead condition. that pump can't no way supply enough fuel for your engine, it's a street pump.
 
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