Flatsman
Member
Hey Steve. I meant to send you this. It is a list of all the non ethonal gas stations in the US. I will be burning the non ethonal in the T and the 32. http://pure-gas.org/index.jsp
Dialing in my Holley Carb
- Thread starter sstock
- Start date
Update:
Still working on the carb. As it stands, I have increased the primary jets over stock two sizes,(any more it is too rich on main metering) Secondary jets are at 80 which is twelve sizes over, 50cc accelerator pump diaphram, 45 squirter(31 was stock). Set up the ignition curve so that it is all in by 3000 with 14 degrees static, 34 degrees total, additional timing with vacuum can is pluged into ported vacuum. I would of liked to have ran it consant vacuum, but I couldn't get it to idle down far enough. The car starts on the choke, the first hit, it actually drives well on the choke and is not cold blooded at all(carb, let alone a tunnel). Driving around on the main metering it is very good, wideband A/Fs are around 13to 1 at cruise. Here is the persistant problem though. If I try and crack the throttle into the secondaries below say 3000, the wideband will go lean, I'll get a lean cough and flatspot, then it will eventually catch and go like hell with A/F in the mid 12s under full power. I can get by this by easing into the throttle slowly to full throttle though. If you drop the hammer though, especially at lower rpms it is not going anywhere fast. BTW, I'm running the most aggressive accel pump cam (brown one) so it gets a good pump shot all the way to full throttle(pump shot setup just touching acc arm at idle). I'm wondering if I should go to a 50 squirter. I'm definitely at a point of diminishing returns here with this carb. My buddy, whom I have gear headed with since the 70s thinks I should give up on this carb, it is just simply the wrong setup. He says a single carb tunnel with vacuum secondaries will never get enough fuel in her transitioning from primary to secondaries. Says I need the additional accelerator pump, power valve of the double pumper. I'm tending to agree now. Any ideas?
Steve
Still working on the carb. As it stands, I have increased the primary jets over stock two sizes,(any more it is too rich on main metering) Secondary jets are at 80 which is twelve sizes over, 50cc accelerator pump diaphram, 45 squirter(31 was stock). Set up the ignition curve so that it is all in by 3000 with 14 degrees static, 34 degrees total, additional timing with vacuum can is pluged into ported vacuum. I would of liked to have ran it consant vacuum, but I couldn't get it to idle down far enough. The car starts on the choke, the first hit, it actually drives well on the choke and is not cold blooded at all(carb, let alone a tunnel). Driving around on the main metering it is very good, wideband A/Fs are around 13to 1 at cruise. Here is the persistant problem though. If I try and crack the throttle into the secondaries below say 3000, the wideband will go lean, I'll get a lean cough and flatspot, then it will eventually catch and go like hell with A/F in the mid 12s under full power. I can get by this by easing into the throttle slowly to full throttle though. If you drop the hammer though, especially at lower rpms it is not going anywhere fast. BTW, I'm running the most aggressive accel pump cam (brown one) so it gets a good pump shot all the way to full throttle(pump shot setup just touching acc arm at idle). I'm wondering if I should go to a 50 squirter. I'm definitely at a point of diminishing returns here with this carb. My buddy, whom I have gear headed with since the 70s thinks I should give up on this carb, it is just simply the wrong setup. He says a single carb tunnel with vacuum secondaries will never get enough fuel in her transitioning from primary to secondaries. Says I need the additional accelerator pump, power valve of the double pumper. I'm tending to agree now. Any ideas?
Steve
2old2fast
Active Member
Steve, I'm running 2-450's, mech sec. w/2-31 squirter's, if I floorboard it from ,say 12-1400 rpm I get maybe 1/100th of a second lag then- GO, if I "roll-in" the throttle, no lag, just GO !! Regardless of any & all mod's I've tried, I think it's just the nature of the beast.Maybe the 660 center squirters would be better, but my personal economy dictates that I'll live w/ what I have!!
dave
dave
Screaming Metal
Active Member
Its just as 2O2F says, theres just a hair of hesitation you'll have to put up with, and that will be just off idle.
I suggest you idle it up just a hair, check your idle mixture at the front corners agian, also check your fuel level. Then Hook up you vacuum gauge, bump your timing down. Get the motor to where it wants to be, listen to the motor idle, get it to where it idles and comes off idle smoothly, she'll tell you where you want to be. If your now pulling enough vacuum, check your power valve now.
I just got thru writing a 45 minute thing here, but windows 7 just decided I didn't need the post any longer. Anyway, you can also help yourself by lowering the Plenum volume. If your plenum is open like most are, get a 1 or 2" carb spacer, drill and tap your carb mounting bolts on thru the top, and affix this spacer from the inside. I also use this as a tuning aid also. most of the time I use a open spacer, but on occasion have used a 4 hole and used a diegrinder and a small wheel to put a spiral into the air stream, helps with atomization.
Just pull the spacer up against the bottom, using longer hardened carb studs, then pull the spacer down with hardened nuts and some loctite. Or, if your like me, a tack with a mig.
Lessening the volume also makes tuning a little easier. But SS, your almost there....I believe if you now get your idle reset, then bump your timing, you'll get her to where she has a very small hiccup at about 1400 rpm, but revs clean and hard, you'll have it.
I suggest you idle it up just a hair, check your idle mixture at the front corners agian, also check your fuel level. Then Hook up you vacuum gauge, bump your timing down. Get the motor to where it wants to be, listen to the motor idle, get it to where it idles and comes off idle smoothly, she'll tell you where you want to be. If your now pulling enough vacuum, check your power valve now.
I just got thru writing a 45 minute thing here, but windows 7 just decided I didn't need the post any longer. Anyway, you can also help yourself by lowering the Plenum volume. If your plenum is open like most are, get a 1 or 2" carb spacer, drill and tap your carb mounting bolts on thru the top, and affix this spacer from the inside. I also use this as a tuning aid also. most of the time I use a open spacer, but on occasion have used a 4 hole and used a diegrinder and a small wheel to put a spiral into the air stream, helps with atomization.
Just pull the spacer up against the bottom, using longer hardened carb studs, then pull the spacer down with hardened nuts and some loctite. Or, if your like me, a tack with a mig.
Lessening the volume also makes tuning a little easier. But SS, your almost there....I believe if you now get your idle reset, then bump your timing, you'll get her to where she has a very small hiccup at about 1400 rpm, but revs clean and hard, you'll have it.
Screaming Metal
Active Member
If you keep having the problems, a 650 dual feed doublepumper will fit the ticket....I've seen folks take hammers to the old carb after they switched to a doublepumper....
Screamin, Sorry bout the windows 7 thing, I'm not liking mine either. Nothing like taking time writing something then poof gone! I follow your process of tuning, but you lost me on the spacer inside the plenum to reduce volume. Do you two piece it to get it inside the upper??
Wild Mango
Member
SStock I admire your perseverance with the tunnel ram. As screamin' says, just too much volume there for the single pumper to cover the inrush when you kick it in the guts. But we all know, what looks cool on that exposed engine is very important, and, lets face it, if that 283 was under a hood, a torker 2 would be a far better choice, but exposed for all to see, absolutely no way, that tunnel ram perched up for all to see wins hands down. No contest!
And, as I opined once before, the lamda sensor in the collector is giving you a sort of average reading of the four cylinders feeding it, mixture distribution in a manifold with a huge plenum never being equal (which is why racers will jet corners asymmetrically)(screamin' will tell you about that, I'm sure)
And, as I opined once before, the lamda sensor in the collector is giving you a sort of average reading of the four cylinders feeding it, mixture distribution in a manifold with a huge plenum never being equal (which is why racers will jet corners asymmetrically)(screamin' will tell you about that, I'm sure)
Screaming Metal
Active Member
Hi Guys, I'm back for a week....SS, take your single 4 top off. Take it to a table. Drill and tap your carb holes all the way thru, Install WAY LONGER STUDS, have them sticking down into the plenum chamber. Then get a 2" carb spacer, and bolt it to the Plenum chamber on the INSIDE, (you will be reducing the volume of the plenum....), put on some nuts with loctite. Usually what I do is get 2-1" phenolic (funky black plastic) spacers, you have to turn it corner to corner to fish it into the plenum.
OR, if you just want to see how much it'll help you, you can get a couple of pieces of alum. and epoxy them inside the plenum. What your after is to reduce the internal area.
We use this as a tuning aid sometimes....me and a few others....
This will aid in tuning for a non-doublepumper. I used this trick on a .03 over 283 with a solid lifter cam of medium lift and duration. however, the owner only had 3 carbs, all essentially junk. A 600 vac. secondary single feed. a 650 dual feed vac. secondary, and a 850 doublepumper. I chose the 650 because we needed to run it a little rich to be able to tune it....
I had to cannabalize a few parts off all the others, made 1 decent carb out of the lot....
I put a 1 1/2 alum. block between the runners, right below the carb. This was on a older TRY-1.
Idles good, just a hesitation right off idle, pulls really strong thru mids and hi,....took me longer to find the correct spring to put in the vac. can on the rear.
I just got thru writting about a 30 minute reply and windows7 just deleted it. Ya know, they need to fix one windows system before they are allowed to release a new one....
Well SS, if all else fails, if you have a friend, well, maybe your buddy has a 650 or possibly a 600 doublepumper, he'll trade you. The 600 will work fine. the 650 will be a touch on the big side, but workable.
OR, if you just want to see how much it'll help you, you can get a couple of pieces of alum. and epoxy them inside the plenum. What your after is to reduce the internal area.
We use this as a tuning aid sometimes....me and a few others....
This will aid in tuning for a non-doublepumper. I used this trick on a .03 over 283 with a solid lifter cam of medium lift and duration. however, the owner only had 3 carbs, all essentially junk. A 600 vac. secondary single feed. a 650 dual feed vac. secondary, and a 850 doublepumper. I chose the 650 because we needed to run it a little rich to be able to tune it....
I had to cannabalize a few parts off all the others, made 1 decent carb out of the lot....
I put a 1 1/2 alum. block between the runners, right below the carb. This was on a older TRY-1.
Idles good, just a hesitation right off idle, pulls really strong thru mids and hi,....took me longer to find the correct spring to put in the vac. can on the rear.
I just got thru writting about a 30 minute reply and windows7 just deleted it. Ya know, they need to fix one windows system before they are allowed to release a new one....
Well SS, if all else fails, if you have a friend, well, maybe your buddy has a 650 or possibly a 600 doublepumper, he'll trade you. The 600 will work fine. the 650 will be a touch on the big side, but workable.
Screaming Metal
Active Member
As Wild M. said, sometimes we have 3 diff. size jets in the carbs....its what they like. To make max. power, you gotta have enough enough fuel to make the power, hot enough to burn it efficiently, and keep some residual warmth in the motor, while a cool dense intake charge.
Colder plugs, leaner mixtures are good, to a point.
If you build a super efficient motor, put all the right parts for the purpose intended....you will have a very powerful motor, Horsepower is a byproduct of efficiency.
Colder plugs, leaner mixtures are good, to a point.
If you build a super efficient motor, put all the right parts for the purpose intended....you will have a very powerful motor, Horsepower is a byproduct of efficiency.
Thanks guys for the help. Even though I worked long on this and tried a lot of different changes, I'm throwing in the towel on this 570 Avenger vac secondary. It is a good carb, starts well on the choke, most excellent drivability but I cant get the lean hiccup out on the secondaries-even with all the jet changes and squirters. I ended up with a 50cc pump and .050 squirter and brown cam(the biggest you can run on a 4150) and it still had a hiccup. I could live with it if I wanted, it ended up being a nuisance more than anything. But if it aint right it aint right in my mind. So that said the avenger is going on a buddies dual plane model A, it will serve finely there. Has anyone have any info on Quick Fuel's 600 HR series double pumper? It comes with a electric choke and screw in air bleeds. I'm told all the holley tuning parts work, priced really reasonable.
Thanks for the offer Fred, but that is pretty much what I'm taking off. The problem is it needs the additional accelerator pump of a double pumper because I'm just a single carb tunnel. Thanks again.
Wild Mango
Member
Talking about this one with a few like mindeds over friday night beers today. Way back when, running a big plenum manifold so the little 330's could wind out to 9000+ in the traps with a single 4bbl like a Holley 650, some builders used to extend the throttle bores down into the manifold space with tubing. This had the effect of placing the pump shots and power valve rich mix close to the intake runners so it wasn't diluted by the air volume in the plenum. I recall some manufacturers called them reversion plates, but they weren't for that, they were, as I said, to get that nourishing rich fuel charge into the runners so that little mouse could generate some air flow and start making useful HP. Once the show was on the road, air flow took care of things and the unchanged volume of the plenum damped out intake pulses the way it was meant to. The introduction of full IR rams made this approach unecessary.
Screamin' will know what I'm on about.
Thats kinda like Screamin is saying with bolting a phenolic inside the upper plenum. Reducing plenum volume and dropping the charge in lower where the manifold is a tad warmer. This I'm looking into. I'm making a wood templet of a phenolic and see what it takes to stuff it in there.
Wild Mango
Member
Yep, thats the idea. The intent with extending the throttle bores with tube was perhaps to preserve the plenum volume so that still worked as intended. I just found a picture in (the recently late and always revered) Bill Jenkins' book "The Chevrolet Racing Engine", in the intake chapter of the manual. The Jenkins solution was with two fours, but with a single four you would possibly bring the extension tubes down to over the divider of each port pair. Be quite easy to make with a phenolic spacer, epoxy glue and tubing of suitable diameter (1 5/8"). Be fun to experiment with, thats for sure.
OK, for those interested in this tuning saga, I've been poking away at it slowly with encouraging results, to date I have perfect startup cold on choke and warm engine. A/fs for idle are 13 to 13.5 to one understandable rich but the idle is stable both in neutral and gear and will idkle all day long, I really like the 4 corner screws. I jetted down the primary to 62s and the transitions from idle to main metering is really nice and no surge and the wideband reads mid 13s which I'm ok with. I've tried shooters from 40to 55 all of which will work 55 is the best with the blue cam. But still have a cough when the secondaries open under vacuum under 3000 rpm with the 55. I decided to tie wire the secondaries shut, hooked up the wide band and went out to see how this power valve is working--there lies the problem. The engine goes lean before the secondaries open, fact is A/F of 16to 1 was seen at full throttle then the cough hit. Hmm, not enough fuel going by the PV channel. I feel like Ive found the jule of the nile now. So, called holley to see if the offer a metering block with an adjustable PV channel restriction--nope says the tech, so either I drill it or try a Quick fuel metering block. Any ideas?
Thanks
Steve
Thanks
Steve
I think you just need the power valve to open sooner. Most power valves now have the square windows for fuel flow, make sure this is the type you are using. I have a single 4 barrel, 600 cfm, vacuum secondaries on my 302 stock Ford with a tunnel ram. Running stock jets, power valve and secondary springs, no issues. I think you are taking too big of a swing at your adjustments. Carb manufacturers put jets and metering systems that work with the air flow for the size carb. A/F meters are great tools, but trying to get a perfect reading with a carb, all the time is just a labor of obsession. The seat of the pants will tell how to get it steetable and then check it with the O2 sensor. The primary shooters help correct sudden openings on the primary side. Thinking you can correct the secondary flat spot with it is not right. The secondary spring is used to control the opening at a time the engine can use the additional air and fuel without bogging. After you put in a higher primary power valve, take the next stiffer spring out of the secondary spring assortment kit you bought and install it. I do not think your engine is so radical you will need to do ANY drilling.
Thanks Railroad for your input, I believe you are tight with the wb being a tool and all, it does come down to the sotp. You mention your combo with the 600, I would be willing to bet this avenger carb has a puny pv restriction channel, I'll know when I pull the primary metering block off. These avengers were Holley's answer to some of the more universal carbs they offer being so rich out of the box and have been very well known to be lean on most all instances, I may be speculating wrong here though. I have thee black spring in the seconday vacuum , so they dont offer a stiffer one Im told. Im banking on the flat spot being still in the primary, would explain why the secondary jets are 10 sizes over just to get a 12.5to1 af. stock were 68 and I put some 80s in there
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