Starting to understand why building engines may be best left to the professional

[Drew Pojedinec]

Looks good.
Sometimes the red plastic choke part can get hung up with the choke too.  Some are more annoying to get set right than others.

Tiny metal flakes are normal to find in the filter on a new build?

[Yellow Truck]

I have the choke rotated so it is out of the equation for now, hence my surprise that it was still a factor. Thought I'd get it running properly, then mess with the choke. Pain in the ass that you have to take the carb off to adjust much of this stuff. Wouldn't mind except for getting gas all over the place.

Regarding the flakes - they were few and tiny, but what do I know. It is my first engine. Given that I tend to seek adult supervision for critical bits, and I have a fiend who is a mechanic for Caterpillar. He has built a few engines, generally the top end leaving the short block to a machine shop. His current project is a 521 he built in a '68 F100. Makes mine look like an econobox, in fact, makes my C13 in my motor home look reasonable.

Certainly he is not a builder, but he has installed a lot of new or newly rebuilt engines, mostly diesels, and run them for an hour then pulled oil filter and inspected it (that is why he has the oil filter opener - a CAT part), he was not concerned and felt that the little bits we saw were normal left overs from the machining that you can't get when you clean it.

I have no prior experience to rely on. I will be cutting open the filter I took off today - it has about 40 minutes on it. I'll post a picture.

[Tobbemek]

You are spot on with throttle position pri and sec,the secondary should just be open so much that its not sticking in the bore.
Mark your curb idle screw so you know exactly where the position on square transition slots are with out taking the carby of to check.fore it so uyo always can com back to it easily when you are tuning back and fort  with idle mix crews and idle settings and static timing.
If you need more "idle opening"of the pri throttle plates over "square position" the right thing to do is drill holes in pri plates, it all depends
on engine size, intake typ, cam, PCV,static timing settings and so on.
445" size engine might need drill holes in pri plates in 0.080 " size to start with.
Total advance timing if latest edition fast burn combustion chambers BBM heads, should not need more than 33" i beleve.

[My427stang]

I would not drill your plates unless absolutely required, and rarely do I see a need for that unless severely undercarbed

In theory, if your no choke settings looked like the "hung up choke" settings. I'd close the primaries (I like the idea of marking the screw, very clever)  Then open the secondaries until you have a good warm idle with choke linkage verified out of the way, set idle a/f and tweak if required. 

Then secondary transition slot is much less fussy and with an 830 cfm carb, there should be no reason that the engine needs to go deep into them to get where you need to be

However, your picture of the primaries with the choke holding it up is irrelevant.  Once warm, the two pics you have are good.   You seem to be where you need to be and have room to raise idle if you have to using the primaries.  Just remember if running vacuum advance, you cannot set initial timing with the plates held open by the choke, you have to have it in it's hot idle configuration (choke out of the way)

[Yellow Truck]

I agree about marking the screw, was thinking about that last night. The tricky bit is adjusting the secondaries if I want a bit more air. I will spend a bit of time messing with the choke to make sure it is OUT of play for now. It was keeping the primaries open regardless of the idle screw position.

I did have it in a shop briefly last year and they may have played with the choke. For now I don't want it in my path. Then I'll put the carb back and start it and play with the timing and idle mixture a little. I don't have O2 bungs in it at the moment, my exhaust shop forgot them last year, but I'll have them put in this week coming and I can get a better idea of what it is doing.

I will also cut open that filter I just took off and give it a look. Then I need to deal with the oiling and lifter preload.

[Drew Pojedinec]

I've worked on many many engines and have always been able to avoid drilling the throttle plates.
Seems like that is just a bandaid for improper settings.  (using initial timing to raise idle speed and close plates)

Secondaries on your quickfuel are easily adjusted while the carb is installed with a 3/32 allen wrench.  It takes a lil practice to do it while it's running and the engine is shaking.


Don't be surprised if yours Wideband isn't an exact thing with your cam/engine setup.
Use it for a reference point, don't get hung up on a particular number.

[machoneman]

I've worked on many many engines and have always been able to avoid drilling the throttle plates.
Seems like that is just a bandaid for improper settings.  (using initial timing to raise idle speed and close plates)

I agree in principle Drew that most (95% +) don't need drilled plates. But on a really hot-cammed engine, it does work.

[Yellow Truck]

I have read about drilling the plates, but generally the advise is to not do it. I'm no expert, but I don't think my cam runs into the category of "really hot cam". I will mark the screw, that is a good suggestion, and if I need more air than I think the primary should be giving, I'll open the secondary a fraction.

When we first got it started we opened the primary too much just to keep it lit, and noticed that the mixture screws had zero effect. Even turning the all the way in the idle stayed the same. I'm more cautious now about that idle adjustment screw.

[Tobbemek]

Hi everybody i have been a member to this forum fore a while trying to read up my knowing on FE´s have plans for a 68 coup 427 so build
this was my presentation.I am a Swedish old fart so you have to  excuse my spelling now and den.
My suggestions to yellow truck that he maybe has to drill the pri plates was meant as a last resorse to avoid open pri ore sec plates up to far on Tsl
there is absolutely no disadvantage to drill the plates to gain a proper idle if you have to, except the hassel to do it.
Think of the idlemix screws as a valve to open ore close metered fuel to the engine sucked in by intake vac and Tsl to bring the rpm up still depending of int vac fore delivery before air stream  starts to bring on yore boosters.
To much Tsl opening on idle will therefor swing your idle AF/R way of tuning ability with the vacuum swings between idle of idle and light cruise
witsh all are depending on int vac fore fuel delivery. ok lets say you bring your initial timing way up to get maximum int vac at idle, lots of timing requaier a leaner AF/R to burn properly and if you have a stall conv and the tranny loads up a little you get a significant more idle rpm drop
bacuse high timing lean AF/R idle has lesser power to stand against loads  and when idle rpm drops so duss int vac and very often even a little of centrifugal timing it is very important to set your dizzy up to avoid to earlie centrifigal advance lets say a couple of 100 rpm above idle
between idle of idle and idle in gear with auto trans there should not bee any timing differences to avoid disturb-ens of your carb   calibration
You can absolutley tinker with pri and sec throttle plates opening to gain proper idle ass long you are shore of how far up Tsl you are and take in to consideration of what it brings your calibration. There shore is a reason for all cars to have a functional choke a proper sett up carb shall run like crapp for a few minutes even in desent temp with out a choke. most people just dont realises  how lean there carbs can be set up and still get you all the power you want on demand but have a clean cruising engine
I just tuned a 440 hp GTX with rpm int a 286"fl hyd  HE cam std longblock with headers 750 annular carb . I drilled taped the carb just like in Drews picture to get a desired calibration and this was set up with a wide band AF/R meter ended up with 0.031 IFR, 0.073 IAB ,0.070 Tslr
0.098 holes in pri plates,drilled and tapped for a mec choke as well.  sweet spot on timing was 16 initial welded up slots in dizzy to bring timing to 36 total and a wire to restrict dizzy vac to 10" vac advance and vacuum on dizzy adjusted to com in on 10 HG and and off cause goose  away at 10 HG just before real engine load and powervalve opening at 8,5 HG
All this parts was certainly not chosen by me just helping a kid that did a wonderfully restoration of a musclecar, and tuning what it had.
This was what suited dis particularly engin trans conv rear end gearing and every car is different you just have to ask the combo that you have what it likes. 

 

[Yellow Truck]

Tobbemek,

Thanks for the note - I was able to make out most of it, but what the heck is Tsl?

[Drew Pojedinec]

tsl= transfer slot.

On larger carbs you sometimes need to drill/tap and make a restriction for them.

[Yellow Truck]

tsl= transfer slot.

On larger carbs you sometimes need to drill/tap and make a restriction for them.

Thanks Drew, didn't expect translation services as part of the bargain.

[Drew Pojedinec]

Paul,
I noticed in the other thread they you said you are running a Holley Blue.

What do you have it regulated to?
(I get best results with the center hung float Holley's to be about 6-7psi and the side hung to be 4.5-5.5psi)

[Yellow Truck]

The fuel pressure is regulated to 7 psi. I had to replace the regulator that came with it as it kept creeping up to 10-12. The new regulator has been pretty consistent.

[Falcon67]

On your transfer slots, I start out with the back looking square and the front about .030 exposed.  Run it and if I have to idle up very much, I'll open the back about 1/8 turn on the adjustment and back down the front.  Also, most times on 4 corner idle the screws are maybe 1/4~3/8 turn out - rarely more than 1/2 turn.

I never drill the plates. The dragster motor has near .700 lift and a lot of duration, idles good at 1200.  No holes.