1987 318 Tuning with Summit Carb
I just checked. No fast idle cam interference. Cable removed, same thing
I popped the carb off and going against the directions, closed the secondary all the way. The directions say to close the screw until the butterflies are closed, then add 1/4 turn. I started the engine, now it needs the speed screw to run. But the idle mix screws can be shut and it will still run off just 1/4 of a turn on the speed screw at 750 RPM.
Looking at this pic, with the screw all the way out I feel like this is way too much transfer slot showing. I just looked at my Eddy, with the idle screw out you can't see the transfer slot in the primary at all. I wonder if this is normal. I can't see any adjustment or way to fix it. Anyone with a Holley, is it normal for Holley's to show some transfer slot when the speed screw is out??
As the beer flows through my system, I'm starting to think it's running off the transfer slot and not the idle circuit.
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Ok, let’s clear up some **** before you go down a rabbit hole you don’t want to.
Unless you have way more T slot showing than what you showed, quit worrying about T slot exposure.
Just stop. If not, you’ll go bat **** crazy trying to do something that isn’t THAT critical.
How much is too much? When they aren’t working that is too much T slot exposure.
If it takes a .060 or .080 wide window who cares?
Does it idle? Good!
Do the idle mixture screws work? Yes. Then who cares?
What if it idles but the screws don’t work?
Well, you can jack a bunch of initial timing into it, but I’m not a fan of that but I use IF I have no other options.
So it idles but the screws don’t work. Then you drill a 3/32 hole in each butterfly and see if you can shut the throttle down and get the screws to work.
If they work then you’re golden. If not make the holes .125 and check it again. If it idles and the mixture screws work you’re good. If not, repeat the steps in very small increments. Once you get to .125 any increase in hole size should be about .010 at a time.
If you get greedy and try to cut a corner and make another 1/16 after the 1/8 inch holes (so going right to 3/16 from 1/8 is a BIG move.
And what happens if the holes are too big? Then you can shut the throttle and the idle speed would stil be too high.
Then you need to buy a new set of throttle blades and start over.
Take your time and don’t cut corners.
If you really want to do the super zoot drilling, line the holes in the throttle blades with the curb idle discharge port. And keep the hole close to the edge of the blade but stay far enough back so you can increase the size to At least 3/16 and still keep the hole far enough from the edge of the throttle blade.
Some guys hate drilling holes. So what? It’s an acceptable practice solution to a small problem. Do it if you have to.
And so I’m clear, a .020-.040 T slot exposure is great, but if it won’t idle correctly and you have to open the throttle and make the exposure .080 who cares?
It won’t idle any better if you screw around and get the T slot to have less exposure. It won’t make 1 hp more.
I see guys going bonkers fight T slot showing. It’s insanity.
Of course, you’ll have guys tell you my way is cutting corners and their **** idles blah blah blah, blah blah, blah blah blah.
Don’t die on the “if the T slot is exposed more than square the world will end” hill.
You could put those efforts into tuning that makes power.