Fine Tuning a 360 Magnum with a Brawler "Double Pumper"

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So once again my float needle got stuck, this time on the primary side. Now I can’t really tell if it’s a dirty fuel issue or if the fuel pump is going bad and is punching out wonky pressures. I did look at the pressure gauge at the carb and it is staying consistent at 5psi so seems like a coin toss now.

I guess a cheaper way to determine if it’s fuel or the pump is by getting another fuel filter and putting it in?

I did just change out the pump assembly in the tank as the pump I had had a bad sender so the gauge didn’t work (surprise surprise), but the pump assembly I had for the v6 did. It’s possible that there was some junk in the pump housing that I didn’t spray out but I find it odd that I had no issues yesterday but today it stuck open twice. Both days on the same tank of gas too.
 
jmanhoff said:
I’m currently at Walmart where they have 93 for $2.99 a gallon, how they get it that low is beyond me. Probably will start coming here from now on to full this thing up. The gas station I go to that has cheap 87 has 3.69/gal 93
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Damn. That’s a great price. I hope out here in the west our prices go down. I think we are still around the 4 buck mark for premium.

A great deal of that is my state is regressive so the fuel taxes are high.

Somehow they need pay for buses
 
Newbomb Turk said:
Damn. That’s a great price. I hope out here in the west our prices go down. I think we are still around the 4 buck mark for premium.

A great deal of that is my state is regressive so the fuel taxes are high.

Somehow they need pay for buses
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I think we can all agree that $4/gal for premium is better than $7, I live in northern VA and around 2020-2021 that’s how much I remember seeing it in some places. I used to drive around my dads 2500 Cummins because diesel was cheaper enough where it actually made sense to drive it around lol
 
Instead of introducing more idle bypass air by drilling the primary throttle blades, if you only need a slight change, now is when you can go back and crack the secondary open slightly. Remember I told you early on to close them down and tune the primary? Hopefully you did that, and now you can add some air with em. After you do go back through the idle mixture screw tuning process. BTW your idle mixture screws should be between 3/4 turn out and 1-1/2 turn out from lightly bottomed. That’s the “preferred” range.
 
TT5.9mag said:
Instead of introducing more idle bypass air by drilling the primary throttle blades, if you only need a slight change, now is when you can go back and crack the secondary open slightly. Remember I told you early on to close them down and tune the primary? Hopefully you did that, and now you can add some air with em. After you do go back through the idle mixture screw tuning process. BTW your idle mixture screws should be between 3/4 turn out and 1-1/2 turn out from lightly bottomed. That’s the “preferred” range.
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Good call.
 
TT5.9mag said:
Instead of introducing more idle bypass air by drilling the primary throttle blades, if you only need a slight change, now is when you can go back and crack the secondary open slightly. Remember I told you early on to close them down and tune the primary? Hopefully you did that, and now you can add some air with em. After you do go back through the idle mixture screw tuning process. BTW your idle mixture screws should be between 3/4 turn out and 1-1/2 turn out from lightly bottomed. That’s the “preferred” range.
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Okay I was actually sort of pointing at asking this question. I understand the concept of changing IFRs and IABs to get the right “mixture” but didn’t know what the ideal number of turns was.

When I pull the carb off tomorrow I’m going to “reset” it, so square t slot, I’m going to verify the number of turns for the curb idle until it’s at the right exposure, and then going to probably start the primary mixtures at 1 turn and secondaries all the way in.
 
jmanhoff said:
Okay I was actually sort of pointing at asking this question. I understand the concept of changing IFRs and IABs to get the right “mixture” but didn’t know what the ideal number of turns was.

When I pull the carb off tomorrow I’m going to “reset” it, so square t slot, I’m going to verify the number of turns for the curb idle until it’s at the right exposure, and then going to probably start the primary mixtures at 1 turn and secondaries all the way in.
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Start with all 4 idle mixture screws at 1 turn.
 
TT5.9mag said:
Start with all 4 idle mixture screws at 1 turn.
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What should I do about getting the secondary side “closed” then and just using the primaries?

Also, if I’m going to commit to running 93 octane all the time, should I power time it so I have the most timing it likes before continuing to tune the carb? I would imagine that would give me the best power/mpg
 
I like to put the secondary idle speed screw in upside down, the screw driver slot facing up. Sometimes, on some carbs, this means tapping the hole all the way through from the bottom. I put a dab of silicone on the threads, which allows it to be adjusted, but won't vibrate loose. It is much easier to adjust from the top.
 
Put an allen set screw in the secondary adjuster.

Once you get it sort of right, if required, use a piece of notebook paper to open the secondaries slightly, fold it over if not enough. Each paper piece roughly .035 thick,is about 3/4 of a turn on a 24 pitch adjuster, 1 full turn on a 32 pitch.
 
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jmanhoff said:
Okay I was actually sort of pointing at asking this question. I understand the concept of changing IFRs and IABs to get the right “mixture” but didn’t know what the ideal number of turns was.

When I pull the carb off tomorrow I’m going to “reset” it, so square t slot, I’m going to verify the number of turns for the curb idle until it’s at the right exposure, and then going to probably start the primary mixtures at 1 turn and secondaries all the way in.
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Go back in this thread (search may save time. LOL) and find the posts about setting the transfer slot as well as the one(s) that link to timing for a magnum 360.

I don't know what is 'right' for that carb. Nor do I beleive anyone here knows. What we do know is there is a range in which the idle throttle position will have a working relationship that provides off-idle AFR to where it can be trimmed with the idle screws, and then if needed some IAB or IAB/IFR adjustment.
If the t-slot is too wide or too long, it can be shortened up as Aquartlow posted on the racingfuelsystems forum (version that is now tapatalk). It also may need tightening up using a t-slot restriction.

This is all an iterative process. If you have a leaner than ideal fuel mix, then it will likely do better by lighting it off sooner. Change the fuel mix at a given condition and the timing required to develop the most pressure and force will change. Get the timing curves in the window that was established by Chrysler and Mopar Performance and there will be less iterations until the gains are no longer noticable.
 
crackedback said:
Put an allen set screw in the secondary adjuster.

Once you get it sort of right, if required, use a piece of notebook paper to open the secondaries slightly, fold it over if not enough. Each paper piece roughly .035 thick,is about 3/4 of a turn on a 24 pitch adjuster, 1 full turn on a 32 pitch.
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I think you missed a zero for your paper thickness. Common note paper is about .0035" -.0040" thick. I use it all the time to touch off on the work piece in the mill and when the tool catches it, you know you are .004" off zero.
 
gzig5 said:
I think you missed a zero for your paper thickness. Common note paper is about .0035" -.0040" thick. I use it all the time to touch off on the work piece in the mill and when the tool catches it, you know you are .004" off zero.
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Yep. Thanks for the correction. I remembered how I did it before and looked it up and it spit out .035... mm LOL that pesky metric system.

Whatever the method, it's easier to prop them open than fighting with that screw head in the baseplate. Once you got it, make adjust the screw to spec.
 
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So I ended up not doing anything on the carb on Monday as I got side tracked by working on my girlfriend’s pilot. I 100% do not recommend changing the cats on a 2007 pilot this has to be one of the worst experiences of my life lol.

Anyway, it’s probably a little late to ask this question but for measuring push rods, what’s a good amount of preload for them?

I have a tapping sound that very much sounds like valve noise (I’ve had 2 mechanics tell me the same). It slowly comes out on a cold start, it’s audible at idle and below 2000rpm or so, over that it goes away. Stethoscope on the head is where the sound is the loudest. So it’s either lifters or pushrods, I checked and retorqued the rockers to rule those out.

I did order 6.831” melling pushrods when I built the motor, one of the stock replacement sizes, but I think they may be too short but I’m not sure, hence the question.

I have an adjustable pushrod tool and a caliper, so when I measure them, you put the rod in, torque the rocker, and then extend it until it contacts the rocker, then measure and add preload? I think 0.030” is a pretty normal amount for these engines right?
 
So surprise surprise, my $25 Amazon fuel pump crapped out, at least it seems like it did. I heard it running but no fuel at the carb, I shook the feed line and then it started feeding again but the pump doesn’t sound good. I plan to buy a Carter 4594 as I read on another thread that they’re good.

Is there any barb fitting fuel socks I can add onto my fuel line? I currently have a hose run from the outlet of the EFI pump assembly to the inline pump, but there’s just a hose dangling inside of the cradle so I’d imagine it’s sucking stuff up even after the “pre-filter” the assembly has.

EDIT: literally right after this I googled barb fuel filter and found one, no idea why I wasn’t able to find one before lol. Annoyingly however, my pump is dead dead now it seems like, so have to order a new pump.
 
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Alright guys, back on the road. Got the new pump installed, runs, actually feeds fuel, and got the truck running again. Annoyingly the only place that I could mount the pump currently that is below the tank and not in the way of anything was on the outside of the frame (c-channel, due to the size of the pump it doesn’t fit inside the c).

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This is before any wire and hose management was done. Definitely need to build a rock guard of some sort to protect the pump.

Strangely, one of the mounting studs was stripped out. I’m not entirely sure how as I started them all by hand and then went to tighten them until snug with a small wrench, probably just soft metal. Anyway, I’m not entirely sure what exactly these bolt/stud things are called so I don’t know how to go for looking for a replacement. I googled “carter p4594 mounting hardware replacement” to no avail, so I was wondering if anyone on here knew.

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Here’s a zoom in on the stud I need. Has threads on both sides, one side goes into the body of the pump and seals the top, then has a hex, shoulders then more threads on top.
 
This is probably a stupid question, but are jet extensions really designed only for the secondary bowl and only for hard acceleration? I’m asking because the other day at work I was sitting in someone’s driveway which was really steep and the truck was nose down, obviously meaning the primary bowl had the fuel all the way in the front, uncovering the jets. While I was trying to reverse out of the driveway, it was sputtering and it was very hard to keep idling, I had to basically run it off of the accelerator pump until I got back to flat ground where it went back to normal.

Would extensions help this issue or would it help this issue but if say I was on a steep hill nose up I would then have the same issue?

I also plan to pull the carb off to reset it tomorrow. I have a new cable and bracket to install so might as well pop off the carb and take a look at everything while I’m in there
 
jmanhoff said:
This is probably a stupid question, but are jet extensions really designed only for the secondary bowl and only for hard acceleration? I’m asking because the other day at work I was sitting in someone’s driveway which was really steep and the truck was nose down, obviously meaning the primary bowl had the fuel all the way in the front, uncovering the jets. While I was trying to reverse out of the driveway, it was sputtering and it was very hard to keep idling, I had to basically run it off of the accelerator pump until I got back to flat ground where it went back to normal.

Would extensions help this issue or would it help this issue but if say I was on a steep hill nose up I would then have the same issue?

I also plan to pull the carb off to reset it tomorrow. I have a new cable and bracket to install so might as well pop off the carb and take a look at everything while I’m in there
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That’s a rare exception and you almost never drive downhill like that.

Jet extensions are for the rear during acceleration.
 
Yea jet extensions on the front would uncover the jets during acceleration exactly the time you DONT want to do that.
 
TT5.9mag said:
Yea jet extensions on the front would uncover the jets during acceleration exactly the time you DONT want to do that.
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okay I was just curious if they made like 2 inlets, front and back of the bowl, instead of just the one but I guess it would make more sense for just one lol
 
Holley makes an offroad carburetor that has a different metering block that allows for a 40° ascent, and 30°decending.
I never tried it, nor know anyone who has.
The edelbrock's and the holley version of the autolight (summit brand) both have their jets down low and do well off road
 
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