While I certainly agree that might look cool, how does that affect performance in a positive way? And why would I want to pay more for a part that's hidden under a float bowl? Not bein smart......just asking.
Jetted holley now it bogs
- Thread starter Hansen
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While I certainly agree that might look cool, how does that affect performance in a positive way? And why would I want to pay more for a part that's hidden under a float bowl? Not bein smart......just asking.
thesiren74
Well-Known Member
They can sell quicker but no difference in performance, the raw one is probably a few bucks cheaper that's all I'm saying tiger.
And that's right up my alley. LOL
thesiren74
Well-Known Member
Mine too lol
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Did you make any other changes?
The thing with the white plugs is, on what circuit were you running while the plugs turned white? Your primary side has Four circuits and each one is tuned differently. They are;
Idle/ transfers/ mains/ and power.
The early players are the transfer slots. Your stock 360, in a pick-up, with say 3.23s and 235/75-15 tires, is gonna cruise at around 35= 2000rpm in 1.45 second gear. This is slow enough and with very little throttle-opening, that the carb is very likely to still be on the transfers. If it's a lil lean at this time, and by all your descriptions it is, then jetting the mains will not help. In fact, as long as the mains are larger than what the engine needs, you could cruise with no mainjets at all. Or MJs that are way too small.
There is no good way to tune the transfers except by messing with the bleeds or changing the wet fuel level in the bowl . But the good news is you almost never have to. The thing is, whatever your Idle mixture screws are set to, that fuel gets added to the low-speed circuit at all times regardless of rpm or load. Sooo if yur sharp, you have figured out that you can use that Idle-fuel to augment the transfers.
Badaboom!
Step-1
Ok now comes the important part. We have to know what a tip-in hesitation is, and what causes it.
Ok well, Tip-in implies that the throttle is going from idle to just off idle, and it ain't moving very fast. At this time, the accelerator pump may not / probably will not, react fast enough so the engine is practically guaranteed to sag. The way we overcome this is by keeping the transfers up to speed and ready to pounce when you tickle the throttle. And the way you do that is with Transfer slot exposure under the primary throttles.
If the throttles are too far closed, air will sneak down from above the blades to below, thru the transfer slot sorta drying them up. You will know when this is happening because the mixture screws will be cranked way open just to idle, and you get a tip-in hesitation from modest to nearly stalling. The cure for this is More exposure under the throttles to keep the Transfers flowing.
If the throttles are too far open, the mixture screws will be nearly closed in compensation for the excessive fuel being supplied by the transfers. You will not have a tip-in sag. You may have an exhaust that drips sooty water and stinks like raw gas. But the tip-in response is likely to be mushy, sorta like in slow-motion.
When the exposure is just right, the mixture screws will be in the zone and close to .75T out, No stall/No sag and truck jumps when you tickle the throttle.
And the way you get the Idle-Speed is with Idle-Timing. Whatever it takes or doesn't take. The tip-in response takes precedence. Now the secret is that the more timing you give it, the faster the idle goes. BUT once you get the Transfer-slot exposure set right, DO NOT twiddle those screws any more!
Instead, set the idle speed with Idle-Timing. Set it Slow enough that it doesn't bang when going into gear, and Fast enough that once in gear, the engine is willing to jump, but not so high that it pulls all the time. I target a setting that results in an rpm drop of about 50 to 100 rpm, when going into gear.
So now that you what needs to be done, here's how I do it.
Firstly; I have to assume a few things because if your engine is sick or tired, it can happen that my method will not work, and I hate to see you spend hours dicking with the carb and nothing works cuz you have one stinking burned intake valve.
So , I will assume;
Your elevation is 1000ft or less,
Your compression is even with adequately high numbers for your elevation,
Your minimum coolant temperature is 180 or more,
Your gas is fresh and NOT contaminated,
your float level is correct, and is stable,
you searched for and found NO vacuum leaks, Including
not sucking air from the Crankcase
your valves are working correctly,
your PCV is plumbed correctly, and working correctly,
Your Vcan is plumbed to the sparkport,
your mechanical advance system is working correctly,
your Idle-Timing is less than 12* , and
your exhaust is NOT restricted.
ok so;
Step-2
Rev the engine up to ~2000 and put the throttle up on the nearest fast-idle step. Make sure the choke is wide-open. Now, screw the mixture screws in/out until the rpm peaks; this should happen between .5 and 1.5 , on a Holley-type carb. Then add 1/8th turn more fuel for the idle requirement. Then kick the fast-idle off.
If the mixture screws did not land in the zone of .5 to 1.5, something is wrong! They should actually land closer to 3/4 turn with a Holley-type carb.
So if this happens to you;
first, check your timing at 2000, including the Vcan timing. Then disconnect the Vcan, and check the timing again, at same 2000rpm. The Vcan should be bringing in at least 12 to 16 degrees. More is better. So, I would be looking for 20 degrees from the distributor at 2000rpm, and a minimum of say 14* from the Vcan, for a total of ~34* at 2000 rpm with no-load. If you do not have at least this much, increase your idle-timing to make up the difference, WRITE THE TIMING DOWN! then rerun the Step-1 test.More about this later.
If the mixture screws now fall into the zone, go to step5.
If the mixture screws are more than 1.5, go to step 4
If the mixture screws are less than .5, go to step 3
Step5
in the zone and less than 1.0 is where you wanna be. Now we have to MAKE the idle fuel right by adjusting the Transfer-slot exposure underneath the blades, at some arbitrarily chosen rpm, for a smooth idle, and NOT changing the mixture screws. So step-one is choosing an rpm. Lets ball-park 650 in Neutral. DO NOT TOUCH the mixture screws. So reset the idlespeed to 650 with the speed-screw then, put it into gear. If it stalls; take out 4 degrees of timing,reset the speed back to 650, and try again. If it still stalls, take out 2 degrees of Idle-timing, reset the speed to 650 and try again. Keep going this way until the Idle-timing might hit 6*. If it still stalls at 6* .... something is wrong, go to step-10. But if it doesn't stall read the Idle-timing and WRITE IT DOWN; hopefully it is between 6 and 12. What we have been doing by increasing the speed screw each time is giving the idling-engine ever more fuel on the transfers, to augment the mixture screws, which were previously set for best at 2000rpm. It's kindof working in reverse. But what we are doing is trying to find the optimal Idle timing and Transfer slot exposure, both simultaneously! So this is how I do it. So at this time we are just ball-parking the low-speed circuit.
Ok so by now, the Idle-timing is between 6 and 12, but we do not yet know if the mixture is ideal nor if we can run a lil more idle-timing.
So. Shut the engine off, and find out exactly where the mixture screws are set to, WRITE IT DOWN, then put them back. Start the engine, Now adjust the MIXTURE screws for best quality idle; NOT highest speed! And specially NOT highest intake vacuum. Just best quality. Trust your senses. If this takes more than 1.5 turns, then we need MORE transfer fuel, so crank up the idle speed, and back off the Mixture screws. And if the idle speed goes higher than 700 then retard the timing again. Repeat until the engine likes 1.0 turn on the mixtures and the idle speed is between 600 and 700; and it doesn't stall going into gear.
NEVERMIND what the timing is!
Now we are really close. We just have to go look for the tip-in sag.....
Steps 3 to 5,and 10 not listed until we need them,
Whops I see I contradicted myself a time or two, but not enough to matter, I don't think.
Ok done for today.
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AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
- Joined
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no just time. and a passion to help. Just one finger does it all; the other hand is engaged in setting the Caps, and keeps the keyboard from wandering too far, under the one-finger onslaught. lol.
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