Fuel system issues

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Nope.Where?Gotta spray and pray at least a couple times here before i think about vegas.mark
 
StrokerScamp said:
He's posted step by step what he did. He went to a steeper gear and started shootin ducks. That aint ignition. That's fuel. He even has said he fattened it up and it helped.
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I hear ya. Maybe the steeper gear was a coincidence? Extra fuel can help cover a ignition prob too. I hate to see a mystery problem, but it's how we learn.

Didn't mean to over-step my bounds on the full name mention. I shoulda kept out of that part... I was just thinking (yikes) if Mark's full name shouldn't be mentioned, you could get it edited out quicker.

I can't tell now, ignition or fuel. Oh btw, your distributor spinning to 8900 rpm w/o a breakup; A running engine will be harder on an ignition. Cylinder pressure for the most part, and also heat will cause a few ducks to be killed. (I'm 52 and that's the only way I ever heard those back fires described! lol!)

Keep us updated.
 
SpeedThrills said:
I hear ya. Maybe the steeper gear was a coincidence? Extra fuel can help cover a ignition prob too. I hate to see a mystery problem, but it's how we learn.

even before with the 3.91's, after the 3rd gear shift you can hear it... so it was there i just was not aware of the issue to the extent that i am now...


I can't tell now, ignition or fuel. Oh btw, your distributor spinning to 8900 rpm w/o a breakup; A running engine will be harder on an ignition. Cylinder pressure for the most part, and also heat will cause a few ducks to be killed. (I'm 52 and that's the only way I ever heard those back fires described! lol!)

well i ment it was spun on a dizzy machine to ensure there were no pickup signal issues.... and it sounds like mark is gonna set me up with a 6al so ign wont be an issue either...

Keep us updated.

of course!
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so ordered the new rail monday, wont be here till friday (coming from GA not NV)...

so i checked the needle and seats and they are both "H"'s... cant find a chart to reference that to... lol

also gonna jack the front end up a little and then set the floats... have been setting them at rest...
 
600 holley , red pump, 5/16 or 3/8 line , 5-7 lbs pressure on a slant 6 is plenty in my opinion. Set the floats so gas is just dribbling out of the sight holes with the engine idling. I dont think you need to jet it bigger than what it came with--if so maybe 2 or 3 sizes up

Is it idling weird? Have you thoroughly checked for vacuum leaks?


Try this -- go get a new cap and rotor. See if the high rpm crap goes away. Dont buy Oreilly Auto caps !!

I had that problem this year TWICE. It was the JUNK O'reilly dist caps. One lasted a couple months , one lasted a couple races. the center contact was burning out of them.
I stuck on an ACCEL cap and havent had any missing since.
 
496dart said:
600 holley , red pump, 5/16 or 3/8 line , 5-7 lbs pressure on a slant 6 is plenty in my opinion.

agreed

Set the floats so gas is just dribbling out of the sight holes with the engine idling.

were and re set today when i checked to see what size needle and seat i have in it... .110's by the way...

I dont think you need to jet it bigger than what it came with--if so maybe 2 or 3 sizes up

on the street it likes a 66 primary and on the track i was up to a 71 on the primary but just upped the secondaries to a 75 (from a 73) to make it more square...

Is it idling weird? Have you thoroughly checked for vacuum leaks?

idles like a champ @ 1000 with 30* timing...


Try this -- go get a new cap and rotor. See if the high rpm crap goes away. Dont buy Oreilly Auto caps !!

I had that problem this year TWICE. It was the JUNK O'reilly dist caps. One lasted a couple months , one lasted a couple races. the center contact was burning out of them.
I stuck on an ACCEL cap and havent had any missing since.
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cap and rotor are less than 10K miles old but i change them around there anyways...
 
496dart said:
Try this -- go get a new cap and rotor. See if the high rpm crap goes away. Dont buy Oreilly Auto caps !!

I had that problem this year TWICE. It was the JUNK O'reilly dist caps. One lasted a couple months , one lasted a couple races. the center contact was burning out of them.
I stuck on an ACCEL cap and havent had any missing since.
Click to expand...

BTW found good Standard Caps (CH410) with brass contacts and rotor echelin MO-3000 (extended tip rotor)

the .org guys agree these are the best we can get... so they are on order...
​
 
Its worth a try buddy --- like I said I had missing at 5000-5800 and it was the cap 2 different times. The outside contacts looked new but the center contact looked "burnt"
 
Having read the whole thread, I have to agree with Mad... It sounds more ignition related. Changes in the fuel system, if you're having ignition issues, will affect the ignition issues. You said it was spun up on a machine. IIRC, the slant is a gear driven distributor, off the cam. How's the distributor gear on yours? How much free play between the gear and the cam? Have you checked to see how much slop there's in the timing chain and dist drive system? Sounds to me like it's wandering at higher rpm.
 
moper said:
Having read the whole thread, I have to agree with Mad... It sounds more ignition related. Changes in the fuel system, if you're having ignition issues, will affect the ignition issues. You said it was spun up on a machine. IIRC, the slant is a gear driven distributor, off the cam. How's the distributor gear on yours? How much free play between the gear and the cam? Have you checked to see how much slop there's in the timing chain and dist drive system? Sounds to me like it's wandering at higher rpm.
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brand new gear on the dizzy, brand new roller timing chain from JP, as for clearance between the gears there is no way to check that... but my timing is very steady...
 
In my experience new doesnt mean good.
You can rotate the see if there's any play in the dist. drive gear by trying to rotate the shaft back and forth with the engine off (be careful if you have the lightweight advance springs in there...the advance plate moving isnt slop, obviously...lol). Any more than a few degrees is too much.
But the best way is to rotate the crank clockwise until the timing mark is at the "0" mark. Then stop and go counterclockwise VERY slowly (helps if the plugs are out). Watch the rotor. As soon as the rotor moves, look where the mark is on the timing tab. How many degrees does the crank move before the rotor moves? That is the best way to check for slop in the chain and drive gear/cam. The max amount it could move is twice that figure. I've seen some of the new cheaper chains allow as much as 4-5° on the crank with less than 1000 miles. I wish they made tensioners for all engines...lol.
 
110's should have no problem for fuel flowing into that carb.... I think you have a sound fuel system. Pressure and flow with what you have.
As far as I can tell, you should only be needing somewhere in the range of 370-400CFM to cover the combo, And your well over that for supply and demand....
If it dose turn out to be Ignition.... Hope you havent lost too much of you base tune up with all the change's....
 
moper said:
In my experience new doesnt mean good.
You can rotate the see if there's any play in the dist. drive gear by trying to rotate the shaft back and forth with the engine off (be careful if you have the lightweight advance springs in there...the advance plate moving isnt slop, obviously...lol). Any more than a few degrees is too much.
But the best way is to rotate the crank clockwise until the timing mark is at the "0" mark. Then stop and go counterclockwise VERY slowly (helps if the plugs are out). Watch the rotor. As soon as the rotor moves, look where the mark is on the timing tab. How many degrees does the crank move before the rotor moves? That is the best way to check for slop in the chain and drive gear/cam. The max amount it could move is twice that figure. I've seen some of the new cheaper chains allow as much as 4-5° on the crank with less than 1000 miles. I wish they made tensioners for all engines...lol.
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no i agree new dosn't mean good lol... but this isn't an autozone set either... (it did get alot of slop in 6k miles!) this is a billet peice out of assuie land... best you can get for the slant....

racerhog said:
110's should have no problem for fuel flowing into that carb.... I think you have a sound fuel system. Pressure and flow with what you have.
As far as I can tell, you should only be needing somewhere in the range of 370-400CFM to cover the combo, And your well over that for supply and demand....
If it dose turn out to be Ignition.... Hope you havent lost too much of you base tune up with all the change's....
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base tune hasn't changed at all... lol... just added new parts... new fuel rail will be here friday... cap and rotor by the end of next week!
 
By "fuel rail" you mean the dual feed fuel line ?? Reading back-- i think so.

the dual inlet fuel line--whatever brand--for the 4160 or 4150 carb is PLENTY big for a 225 slant 6.


i bet you a beer thats NOT your issue ,as long as your carb is clean and you have 5 psi fuel pressure at wot , you dont have a fuel issue.
 
..........Change ur spark plugs...........i had the same issue years back.........a MSD will probably cure it........wires r next, ur almost there anyways.....kim........no, i dont think u have money 2 burn, just trying 2 help get there......
 
SpeedThrills said:
Have you checked fuel volume yet?
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I'd also second this. Get a clean 5gal bucket, mark it into 5ths, and flow the pump thru the fuel log into the bucket. Use a stopwatch to see how many seconds it takes to pump 1 gal.
 
moper said:
Gotcha. Just keep updating. I'm curious what you find.
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hey we learn as we go!

496dart said:
By "fuel rail" you mean the dual feed fuel line ?? Reading back-- i think so.

the dual inlet fuel line--whatever brand--for the 4160 or 4150 carb is PLENTY big for a 225 slant 6.

when i first drilled it out it was as small as 1/4" so i would say thats a big problem...

i bet you a beer thats NOT your issue ,as long as your carb is clean and you have 5 psi fuel pressure at wot , you dont have a fuel issue.
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dont drink beer but i know the carb is clean and have 5 so ignition is next lol...

SpeedThrills said:
Have you checked fuel volume yet?
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exact pump just came off an 11 sec slant car...

oldkimmer said:
..........Change ur spark plugs...........i had the same issue years back.........a MSD will probably cure it........wires r next, ur almost there anyways.....kim........no, i dont think u have money 2 burn, just trying 2 help get there......
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running autolite 65 plugs (street hemi) with the washers off per slant rules, gapped at .037... have new 8.5mm 500ohm wires...

and i know your being helpfull, but i sure wish i had money to burn... could help alot of people...
 
805moparkid, try this out. I just fixed this issue with my Demon this weekend, I put it on a chassis dyno, and the dyno man said it sounded like it was in the rev limitter. I have a MSD Digital 6 box. The rev limit was set at 6500, but was breaking up at 5900. Set it past 8000 and the car pulled to 6500 clean on dyno and gained 50 HP at wheels with no engine tuning at all! Check your chip! Car went from 111 MPH limit on dyno to 119 MPH!!
Chuck
 
moparmanestock said:
805moparkid, try this out. I just fixed this issue with my Demon this weekend, I put it on a chassis dyno, and the dyno man said it sounded like it was in the rev limitter. I have a MSD Digital 6 box. The rev limit was set at 6500, but was breaking up at 5900. Set it past 8000 and the car pulled to 6500 clean on dyno and gained 50 HP at wheels with no engine tuning at all! Check your chip! Car went from 111 MPH limit on dyno to 119 MPH!!
Chuck
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dont have an MSD box yet or any limiter... but thats really weird...
 
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