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

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Currently in the process of tapping and moving the IFRs. I need to go get a drill for the emulsion blanks so I figured I’d ask this question while I was not working.

Do the IFRs need to be flush with the port they’re going into or can the head of the screw stick up slightly? In this case, it’s not sticking up higher than the gasket and it does allow the block to sit flush in the main body.

I still need to remove the old IFRs, go figure my mini flathead doesn’t have a thick enough head so I need to buy one of those too lol.
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jmanhoff said:
Currently in the process of tapping and moving the IFRs. I need to go get a drill for the emulsion blanks so I figured I’d ask this question while I was not working.

Do the IFRs need to be flush with the port they’re going into or can the head of the screw stick up slightly? In this case, it’s not sticking up higher than the gasket and it does allow the block to sit flush in the main body.

I still need to remove the old IFRs, go figure my mini flathead doesn’t have a thick enough head so I need to buy one of those too lol.View attachment 1716366561
View attachment 1716366562
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I apologize for not being clear. That’s my fault.

First of all, if it’s my carb for me personally I almost never use those flanged jets like that.

They are horribly expensive for one thing, and in certain places like you are showing they sit proud.

I buy brass set screws 150 at a time. I haven’t needed any for awhile but I think that’s about 30 dollars worth. Obviously you don’t need that many but you can buy 50 and they are cheaper than those.

I use them for any internal jet or bleed because they can’t be seen. Externally I still use brass set screws to get the tune up finalized, then I drill the flanged brass and install them. That’s for the main and idle bleeds because people can see them.

If some guy is walking by and can’t see the brass in the main air bleed because I used a set screws it can make them…let’s say nervous.

So I apologize for not being clear on that.

They need to be flush at the highest. They can’t be proud.

You absolutely can’t use flanged brass for T slot restricters because the carb isn’t that thick there and they have to be flush or countersunk a bit.

I get my brass from McMaster-Carr. It’s way cheaper that way.

Edit; it looks like you idle feed restricters are at least partially blocking off the other hole next to it. That can’t happen either.
 
Newbomb Turk said:
I apologize for not being clear. That’s my fault.

First of all, if it’s my carb for me personally I almost never use those flanged jets like that.

They are horribly expensive for one thing, and in certain places like you are showing they sit proud.

I buy brass set screws 150 at a time. I haven’t needed any for awhile but I think that’s about 30 dollars worth. Obviously you don’t need that many but you can buy 50 and they are cheaper than those.

I use them for any internal jet or bleed because they can’t be seen. Externally I still use brass set screws to get the tune up finalized, then I drill the flanged brass and install them. That’s for the main and idle bleeds because people can see them.

If some guy is walking by and can’t see the brass in the main air bleed because I used a set screws it can make them…let’s say nervous.

So I apologize for not being clear on that.

They need to be flush at the highest. They can’t be proud.

You absolutely can’t use flanged brass for T slot restricters because the carb isn’t that thick there and they have to be flush or countersunk a bit.

I get my brass from McMaster-Carr. It’s way cheaper that way.

Edit; it looks like you idle feed restricters are at least partially blocking off the other hole next to it. That can’t happen either.
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Yeah I found out about the t slot restrictors as it won’t sit flush, so I’ll just leave them out for now. I did look and all 3 holes are open though.

I’ll see if I can get a slightly bigger bit in the holes for the IFR and see if I can get it to sit under the other hole
 
Actually scratch that, I’m just going to wait until I get some set screws in. I’d have to drill quite a ways down for it to sit under that hole and I don’t want to mangle this block lol. I am going to put the smaller IFRs in the stock location for now, replacing the 32s that were there originally

I do see that I have tapped far enough down to fit a set screw under the hole, so I’ll just have to order some drill bits as well (though they’re stupid expensive)
 
So after a little bit of driving to work, it has a much crisper rev (I didn’t move the pump cam or anything, all I changed was the IFR to a .028, still at the top though).

I guess a mix of cleaning out the pump shot passage and getting a smaller IFR is bringing me closer to what the engine wants.

So in terms of what the IFR does, it limits the amount of FUEL that comes in, and the bleed limits the amount of AIR. The idle mixture screw changes the amount of air that comes through the idle circuit?

Do I have that correct?
 
jmanhoff said:
So after a little bit of driving to work, it has a much crisper rev (I didn’t move the pump cam or anything, all I changed was the IFR to a .028, still at the top though).

I guess a mix of cleaning out the pump shot passage and getting a smaller IFR is bringing me closer to what the engine wants.

So in terms of what the IFR does, it limits the amount of FUEL that comes in, and the bleed limits the amount of AIR. The idle mixture screw changes the amount of air that comes through the idle circuit?

Do I have that correct?
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Right. When you are adjusting the air/fuel mixture screws you are adding or reducing the amount of air/fuel the engine gets.

When you change the idle feed restriction or the idle air bleed (or both) you are changing the air/fuel ratio the engine gets.
 
Newbomb Turk said:
Right. When you are adjusting the air/fuel mixture screws you are adding or reducing the amount of air/fuel the engine gets.

When you change the idle feed restriction or the idle air bleed (or both) you are changing the air/fuel ratio the engine gets.
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Makes sense.

I ordered a 50 pack of set screws from McMaster. Really just going to use those to block off the middle ports for now as I don’t have the drill bits and don’t have the funds for them right now lol, maybe by the end of the weekend I can order them.

I’m assuming in the future if I wanted to tune the emulsion more I would drill out the current holes that are in there and put in set screws and use those as the port hole?
 
jmanhoff said:
Makes sense.

I ordered a 50 pack of set screws from McMaster. Really just going to use those to block off the middle ports for now as I don’t have the drill bits and don’t have the funds for them right now lol, maybe by the end of the weekend I can order them.

I’m assuming in the future if I wanted to tune the emulsion more I would drill out the current holes that are in there and put in set screws and use those as the port hole?
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Yes
 
Newbomb Turk said:
Yes
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Okay, and then in simple terms changing the hole size in the upper emulsion holes (above fuel level) changes the amount of air in the mixture going to the boosters, and the lower holes are changing the amount of fuel going to the boosters?
 
Supposedly the set screws will arrive Tuesday. I also get paid tomorrow so I’ll order the numbered drill bit set once the check clears. My pin gauge comes tomorrow as well so once everything comes in I’ll measure all the holes and add them to a spreadsheet.

On some other forums it seems like a lot of people use 6-32 set screws for PVCRs, does that sound accurate? If so that makes my life easier because I could just use the 50 pack I already bought for those as well in the future.

Then that leaves the T-slot restrictors which goes into the main body right? And to start I should do .078”? I think that’s what was said. I think those are also 10-32 or 10-24 I wouldn’t think the thread pitch matters, only the size but I think my tap kit has both anyway.
 
jmanhoff said:
Supposedly the set screws will arrive Tuesday. I also get paid tomorrow so I’ll order the numbered drill bit set once the check clears. My pin gauge comes tomorrow as well so once everything comes in I’ll measure all the holes and add them to a spreadsheet.

On some other forums it seems like a lot of people use 6-32 set screws for PVCRs, does that sound accurate? If so that makes my life easier because I could just use the 50 pack I already bought for those as well in the future.

Then that leaves the T-slot restrictors which goes into the main body right? And to start I should do .078”? I think that’s what was said. I think those are also 10-32 or 10-24 I wouldn’t think the thread pitch matters, only the size but I think my tap kit has both anyway.
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You can use 6-32 screws for the power valve channel restrictors but I use 8-32 because you never know how much power these carbs may need to make. If you use 6-32 set screws, you are limited on how big you can make the hole in the brass because eventually you drill out the hex and then you can’t install or remove them if you drill them in place.

I use 10-32 for the T slot restricters. You can use 8-32 screws here too but I’m pretty sure that the biggest you can make the hole in an 8-32 screw is about .078ish before you get into the hex.

As long as you think you’ll never need to drill a hole bigger than what the hex will allow you’ll be ok.

It’s easier just to use the biggest set screw that will fit. I use:

6-32 for idle feed restricters and emulsion.

8-32 for PVCR.

10-32 for T slots and air bleeds.
 
Newbomb Turk said:
You can use 6-32 screws for the power valve channel restrictors but I use 8-32 because you never know how much power these carbs may need to make. If you use 6-32 set screws, you are limited on how big you can make the hole in the brass because eventually you drill out the hex and then you can’t install or remove them if you drill them in place.

I use 10-32 for the T slot restricters. You can use 8-32 screws here too but I’m pretty sure that the biggest you can make the hole in an 8-32 screw is about .078ish before you get into the hex.

As long as you think you’ll never need to drill a hole bigger than what the hex will allow you’ll be ok.

It’s easier just to use the biggest set screw that will fit. I use:

6-32 for idle feed restricters and emulsion.

8-32 for PVCR.

10-32 for T slots and air bleeds.
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Makes sense, I’ll probably start with the 6-32 for the PVCR and go from there. I probably can just order 8-32 and 10-32 at the same time because it would be cheaper with shipping
 
jmanhoff said:
Makes sense, I’ll probably start with the 6-32 for the PVCR and go from there. I probably can just order 8-32 and 10-32 at the same time because it would be cheaper with shipping
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Yup. Always cheaper on shipping to order all the stuff at the same time.
 
Would an AFR gauge be a useful tool to buy or should I really just read the plugs? I'd imagine a gauge would be easier to figure out if I'm having a lean or rich bog during transitions or if the PV is opening too early/too late.
 
jmanhoff said:
Would an AFR gauge be a useful tool to buy or should I really just read the plugs? I'd imagine a gauge would be easier to figure out if I'm having a lean or rich bog during transitions or if the PV is opening too early/too late.
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You need to learn to read plugs and use an AFR gauge. Plugs won’t lie to you. An AFR gauge can.

The issue with blipping the throttle and watching the gauges is the AFR changes so fast you can’t see it on a gauge.

It’s much easier to data log it but that’s expensive.

Post a couple of close up pictures of a couple of plugs.
 
Newbomb Turk said:
Just pull them out as they are.
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Sounds good, I’ll try to this afternoon when I get back from class.

I do have pictures from awhile ago with the same carb setup minus the smaller IFR of that would be helpful at all.

Also, is there any plug wires that don’t fall apart when you pull them off plugs? I used the plug wires that came with my distributor and I was able to pull each wire off a plug one time before the conductor broke off the connector. Ordered a new set off of amazon and same issue.

Should I just splurge on an expensive DIY set that way I don’t have stupid long plug wires and have them also not just break? I’ve tried using like hose clamp pliers and grabbing right where the connector sits on the plug and twisting and pulling and no luck it still breaks.
 
Just noticed the bit set I bought only goes down to a .040 bit which sucks because it means I have to buy yet another drill bit to make the IFRs and MABs but I guess for IABs and T-slots I can use these

EDIT: I ordered a #61-80 bit set that will let me make smaller holes, but it arrives Friday. For now I think I’ll keep the IFRs at the top of the well, granted with the weather forecasted I don’t think I’ll really have any time to mess with stuff until Friday anyway.
 
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Alright guys, progress has finally been made lol.

Granted my hands are frozen and typing is hard, here goes. I have blocked off the middle emulsion ports on both metering blocks, as well as moved the IFRs down. Drilled out .028 and they are below that other hole. I’ll have a picture below everything.

I measured the emulsion holes and they’re just about .028”

The bleeds are true to stamping, IABs are .070”, MABs are .028”.

I have also drilled and tapped the t slot ports on both sides of the main body and put in a .078” hole to start.

Last thing I did was put in the blue pump cam. I already had everything inside and apart so I figured I’d just slap it in. It’s currently on hold 1.

It’s currently almost in the negatives with the wind chill so I don’t plan to mess with the engine running today, but I have work tomorrow so I can update again then. I think I’m going to bring the timing back to 14 or so as I’m at about 16 right now and get very very slight pinging at heavy throttle going up this specific hill in 3rd gear. It’s a super steep hill by my apartment and if I’m in 3rd going about 30 I’m at around 2500rpm or so, and the engine labors so I think it’s a good ping test spot lol. I did go back to 87 octane which could be related, but I think I’m going to try to tune this motor for 87.

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jmanhoff said:
Alright guys, progress has finally been made lol.

Granted my hands are frozen and typing is hard, here goes. I have blocked off the middle emulsion ports on both metering blocks, as well as moved the IFRs down. Drilled out .028 and they are below that other hole. I’ll have a picture below everything.

I measured the emulsion holes and they’re just about .028”

The bleeds are true to stamping, IABs are .070”, MABs are .028”.

I have also drilled and tapped the t slot ports on both sides of the main body and put in a .078” hole to start.

Last thing I did was put in the blue pump cam. I already had everything inside and apart so I figured I’d just slap it in. It’s currently on hold 1.

It’s currently almost in the negatives with the wind chill so I don’t plan to mess with the engine running today, but I have work tomorrow so I can update again then. I think I’m going to bring the timing back to 14 or so as I’m at about 16 right now and get very very slight pinging at heavy throttle going up this specific hill in 3rd gear. It’s a super steep hill by my apartment and if I’m in 3rd going about 30 I’m at around 2500rpm or so, and the engine labors so I think it’s a good ping test spot lol. I did go back to 87 octane which could be related, but I think I’m going to try to tune this motor for 87.
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Remember when I said “get the carb squared away and then work on the curve”? Moving the timing around at idle is the wrong way to tune it out of detonation. But that’s a tomorrow problem. Set it where it won’t detonate EVER for right now and leave it alone. Then continue with the carb.
 
TT5.9mag said:
Remember when I said “get the carb squared away and then work on the curve”? Moving the timing around at idle is the wrong way to tune it out of detonation. But that’s a tomorrow problem. Set it where it won’t detonate EVER for right now and leave it alone. Then continue with the carb.
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Yeah I should’ve clarified that’s what I meant, I need to stop changing octanes and timing but right now I’m going to go back to 87, I got away with more timing with 93 obviously, but I need to reset the foundation.
 
Oh I also forgot to mention, guess I’ll add this to my spreadsheet as well. Surprisingly, the primary metering block is tapped and has PCVRs, which are currently 0.048”.
 
Short driving update: after turning out the idle screws to about 7/8 of a turn it feels very smooth off idle, and mashing the throttle is instant throw into the seat torque so the blue cam was definitely on point. Timing is back down to 13-14 degrees at 800, my idle is sticking once again but I think it could just be the cable.
 
jmanhoff said:
Short driving update: after turning out the idle screws to about 7/8 of a turn it feels very smooth off idle, and mashing the throttle is instant throw into the seat torque so the blue cam was definitely on point. Timing is back down to 13-14 degrees at 800, my idle is sticking once again but I think it could just be the cable.
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OUTSTANDING!!!! I love progress. Keep chipping away at it and you’ll have EFI drivability and carbureted horsepower.
 
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