Holley/Demon Carb stumble

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This from the Urich and Fisher book.
Link in this post: Carb knowledge help needed

On the primary side it will be easier to determine if initial t-slot - throttle relationship is correct.
The conditions where too much or too little t-slot is exposed are circled.
I crossed off the idling characteristic because I have doubts that will always be true - especially with a four corner. You can add or reduce idle fueling with the mixture screws, or be rich enough for a 'smooth' idle (for a hot cam) but still have the slots out of position for good non-stop delivery as the throttles open.
Write everything down and think about what's probably going on. For example, if the mix screws are non-responsive, then there could be too much fuel being contributed from the slots.
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With 4 corner idle, you've roughly doubled the potential fuel delivery at idle. So don't be surprised if you don't have to open the idle mix screws very much on motor with semi-decent vacuum. The important point is the engine responds to turning them in or out.
 
Tighter converter and taller tires needs more pump shot and richer idle to transition, especially with a single plane intake. Don't be surprised if you need a 50cc shot up front, brown cam #1 hole .035 nozzle. I would also use .035 IFR with .070 IABs.
 
mderoy340 said:
Tighter converter and taller tires needs more pump shot and richer idle to transition, especially with a single plane intake. Don't be surprised if you need a 50cc shot up front, brown cam #1 hole .035 nozzle. I would also use .035 IFR with .070 IABs.
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Agree
 
Ok so there is a lot of info and question.......and Thank You!
PRH, i have been thinking about the same thing.
What rpm is middle of 2nd ?
I can't say for sure as the slick were not hooking on the street and i was paying more attention to keeping it straight then what the tach was say in. Maybe this will help, altho the converter is tight it stretches or stall at 4200 and i shift a 5800 so somewhere in the 5 to 5500 rpm range
LOVE your hair pulling out Icon :rofl:
Measure the turns in on the idle mix screw to open the throttle blades enough to reveal .010, 020, .030 and .040"
Do the same for the secondary throttles.
That's a great idea!!!
Had not thought about the T slots being a different height between the primary and secondary side.
While you're waiting for stuff, go buy the drill sets so you can measure everything.
I spent 3 hours yesterday building me a spreadsheet like you showed me a couple of pages back.
what else do you thing i should add to it?
spread sheet.PNG

Where is the best place to buy the drill sets and more important is sizes???? from...*** to .***
Yes PV block off on secondary as well as new float and jet extensions
Idle transfer slot
"B" is how the throttle blade looks with my drilled butterflies base. maybe not quite that extreme.
Don't be surprised if you need a 50cc shot up front, brown cam #1 hole .035 nozzle.
When i first started to fight this problem i thought about a 50cc but couldn't decide if i wanted it in the primary side or secondary side.
This thing/carb has never had any problem with the primary side, it's when i break the secondaries open and it bogs. where i wank it to the floor or if i roll in to it and then wack it past the start of the secondarys.
With the proform main body the bog has mostly gone a way and traded for the popping and banging issue that overjetting(I think) fixed. Put back in the stock proform jetting and it pulled threw high gear.
(remember! i live at 6600 foot elevation)
 
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So i dug out my pin vise.........yeeeahh need a better one. When out to check the "e2" holes on the good metering block.......well they are close to .026 -.027" My .022" fits sloppy and my .031(next size up) won't fit.

Been looking on amazon and they are all metric????
 
Cudafever said:
LOVE your hair pulling out Icon
Click to expand...
You can thank Trailbeast for that!
laugh2-gif.gif

Classic Smilies
Apparently someone in charge didn't appreciate our suggestions and had no sense of humor.
At least they did not delete the thread. :)
Cudafever said:
Had not thought about the T slots being a different height between the primary and secondary side.
Click to expand...
On some vacuum secondary carbs the secondary slots are way high up. Two corner double pumpers I haven't looked at enough to say 'most' but they do vary.
Four corner I don't know. Logically it seems like they ought to be pretty similar to primaries, but maybe not the same.
Cudafever said:
what else do you thing i should add to it?
Click to expand...
Depends how you are using it. Since I use each column for note changes, on the carb I'm tuning I have a line for turns in on the throttle screw and a cheat sheet for converting that to transfer slot revealed. Last year I started adding a couple rows for notes about wires. That's because I often use wires to reduce the air bleed sizes. Thats a quick way to reduce the openings when working with press in air bleeds.
Cudafever said:
Where is the best place to buy the drill sets and more important is sizes???? from...*** to .***
Click to expand...
I don't know the "best" place. I was lazy and just ordered from McMaster Carr a 61-80 bit set (along with a couple of pin vises).
This set: McMaster-Carr
Hobby shops probably have them if one is close to you. I wanted a full set of indexed drills for the garage, so for the larger numbers I already had box of number, letter and fractional drills. Probably got that from Enco.
Not too long ago I picked up an set of open wire style spark plug gap gages. Those go from around .020 to over .040. Not sure how common that style is - first time I have had access to that type.
Cudafever said:
Yes PV block off on secondary as well as new float and jet extensions
Click to expand...
I use the hexagonal screw in extensions. But some of the guys working with higher horsepower applications have said that sometimes those don't work as well as press on tube type extensions. Just something to tuck away in the back of you mind.
 
Got my 3310 carb yesterday, looks unmolested but haven't had a chance to really look at it or take it apart to remove the metering block.(the reason I bought the carb in the first place)
So i now have two primary metering blocks.
Also got my base plate, so i'm ready!!!.........If i can ever get enough time away from work to play with them.
I hope Saturday night. finger crossed.
 
The metering block that has the jet extensions and is clean is the first metering block i got.
The one i got from buying a hole carb is the one with gasket that i'm still removing(hate the old school holley gaskets!!!)
there is some difference between the two.
tell me what you think while i go scrap the rest of the gasket off this metering block.
3310 metering block differances.-1.PNG

3310 metering block differances.-2.PNG

3310 metering block differances.PNG
 
On the left looks like to be an unmolested primary block.
It has port for timing vacuum, low position IFRs, power valve.

On the right, not sure what it was originally.
Angle channel looks like it was enlarged (alcohol use ?)
No provision for ported vacuum, and never was.
Power valve but restriction holes are very large - again possibly alky.
upload_2019-8-10_20-47-24.png

IFR might be in the cross channel at the top (white arrow).
It also might be pressed in the idle upwell, under the cap.
 
so the larger PVCR is not an issue if it becomes the back metering block. It will have a Power Valve Plug in it anyways.
But....................
 
Cudafever said:
so the larger PVCR is not an issue if it becomes the back metering block. It will have a Power Valve Plug in it anyways.
But....................
Click to expand...


If it's a secondary metering block it's not an issue. If you want to use it as a primary...then it's an issue. You should probably drill both plates out for threaded channel restricters.

I know next year I'm going to go back to true 1:1 throttle linkage and run a power valve in both ends. I think when you run enough RPM and gear it's a better way to do it.
 
so i still have the problem of the brass restrictor in the bottom on one and in the top on the other. how is this going to affect the install?
 
^^^ Agree. The one you got off the carb looks fine, but the other looks like its been worked over for alcohol. It might work as the secondary block with the power valve blocked, but if it were me I'd look for another unmodified block.
 
Pick up another 3310 off ebay, screw them back together with the blocks you pulled off and sell them.
 
I think it would have been worth 80 buck to NOT have to Scrap all this old gasket of the good one.:D
Know they sucked but forgot how bad.....that is if you don't want to destroy all the seal beads
 
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skrews said:
Pick up another 3310 off ebay, screw them back together with the blocks you pulled off and sell them.
Click to expand...
nah couldn't do that. they will just end up with all the other holley spare parts..........Who knows i may want to run alcohol some day.
 
skrews said:
Soak it with carb/brake clean they're not too bad.
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i used ATF to soften them up but there just a pain in the A@#$#$@^@^^. It's done just need a bunch of carb spray threw the passages now.
 
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