Drilling carb butterflies

Ok, stock 200 lower end with a FSP prepped 2V head. Dura spark ignition and a 350 cfm Holley, headers. I flat out think the carb is too big for the engine without serious modifications done to it (carb). I can barely get an idle and forget about idle in gear (auto trans.). Will drilling holes in the butterflies (say 3/64ths) help the idle issue? It runs fine when I get it rolling but otherwise....not! :roll:

Need all the specs on your engine. I think 90% of your problem is ignition related & too much cam & or lobe center.
Another thing is what are you using for a torque converter??
A 350 Holley is not to much carb for your engine.
Yes drilling a .062"-.075 hole will let the carb butterflies move to a lower position in the transfer slot.

"...drilling a .062"-.075 hole…"
not the 1st thing 2 do.
Proper (& all the) tuning steps 1st.

Was it just assembled (the whole engine)?, did U just switch carbs (was running OK on another 1st)?
Let's have some more details...

Thanks fellas. This thing has been whooping my behind one way or another for almost 20 years now! I keep changing things which leads to different tunes. Stock cam with FSP rockers, I believe they are 1.6? Its been awhile. Timing has been set anywhere from 10 to 14 advanced, tried both ported and manifold vacuum 11Hg is the best vacuum I can get out of the engine which confuses me. That kind of indicates a larger cam but its not. I know the rockers would have some effect but I didn't think it would be that much. Valve timing is straight up. The car ran fine with the stock head and a Weber but you know how it goes, wanted more out of it. I don't remember how I set the distributor up, it was along time ago but I think I dropped toral advance in favor of more initial. Right now I just want to get it to idle then I'll go back and revisit the distributor. Had a massive vacuum leak which stumped me for awhile it was the gasket between the carb body and throttle plate AND the gasket between the throttle plate and manifold. Holleys gasket wouldn't work with the adapter I have on there. Don't know what else to tell you other than it takes forever for the engine to warm up enough to get an idle and even then after 3-5 minutes it'll die out. I figure its loading up somehow? PV has been a 8.5 and then 6.5 jets are currently 48s, altitude is around 4700ft.
That should make it clear as mud!

Ron

If you still have the Weber, put that on and see if it makes a difference.

yes that vacuum at idle is very low for a stock cam. I think you still might have some vacum leaks to deal with its too bad your not closer to Flagstaff so I could take a look at it for you. Good luck

Bubba you are on my bucket list. You've helped me more than once here as have some of the long term members. The Weber is still available but I do not have an adapter to the OZ manifold and as far as I know they don't make one Maybe I have the valves adjusted too tight? Compression check is in order I guess :roll: Vacuum leaks? Still??? It is a solid vacuum reading, no flutter so maybe that rules out the valves? Keep on trucking I guess

Play with the timing and a vacuum gauge. Should be able get a higher idle vacuum if the cam isn't too big. Then make sure total advance isn't too much.
My Way

Vacuum leaks or a timing chain jumped time??
Harmonic balancer rotated on hub. Verify TDC.

Ronbo":22tt2or9 said:

The Weber is still available but I do not have an adapter to the OZ manifold and as far as I know they don't make one Maybe I have the valves adjusted too tight? Compression check is in order I guess :roll: Vacuum leaks? Still??? It is a solid vacuum reading, Keep on trucking I guess

Click to expand...

in about 1978 the Aussie 2V intakes begin using the Weber carbs, so you might be able to bolt your Weber on with no adapter needed all depending on the intake casting year. If not there should also be adapters made that would allow the use of a Weber if it's not the right bolt pattern. As a side note I was bolting on the Weber kits like crazy that they made for all the Japanese mini trucks back in the mid 1970's and through into the 80's to replace those old worn out (JapanCo? original) carbs that most of them had. If you were real lucky they could be rebuilt one time to get a few more miles out of them the throdle shafts were so loose they wouldn't run right and I got to where I didn't even bother with rebuilding them. Worked nearby to CB performance in those days and they had the carb adapters and the compleate Weber carb kits for lots of those applications. I think it would be fairly easy to make your own adapter plate out of some 1/4 to 3/8 inch Aluminum plate stock also. Good luck

The throttle shafts...I hear ya, just like on the quadra-leaks when people would use heavier and heavier return springs. The weber is new as well as the holley-weber I have. I never tried mounting the weber directly on the manifold but thinking about it, if it doesn't fit it'll be darned close. The harmonic balancer slipping is something I forgot about. It's new (was) so I never bothered checking it. Bottom line is I need that puppy to limp to the alignment shop and then I'll dig back into it. Don't even want to entertain the thought of the timing set jumping a tooth. That is brand new as well. I have two holleys and rebuilding them over and over is getting old. If I've missed something I'm going to keep on missing it.

would be great if you had some pictures of it when you have had it apart might be able to see a problem with gasket seal. You might try some more base advance 12 to 14 or even more just as long as the starter doesn't kick back, how much total advance have you been running? Good luck

Thought I posted a reply to this but it was kind of late. The balancer is straight, timing is 14 btdc w/vacuum advance disconnected(ported vacuum), weber wont fit but is close, plugs are dry but sooty, electrodes are brown (yay dsII). Whatever is causing this is going to be stupid Tonight back to capping off all vacuum connections and working from there. Vacuum, ARRRggghh!

I'd suggest you sell me that head and I can test if it messes up my smooth running 200

Seriously, I wish I had a 2V Oz head but dont, so this suggestion is based on vacuum leaks I've heard others talk about. Some people seem to have had a real hard time getting those intake gaskets to seal well, especially in the lower middle ports area. I've heard of people running double or triple gaskets with spray-on gasket adhesive to make it seal right. Have you checked that?

Scott

Shoot, I've been trying to post a reply for two days so this is a test.

Ok, now that we have that straight... :roll: Scott good suggestion. I already thought of that though. Replaced the gasket and I have never used any kind of sealant on an intake. Does not mean it wont work, my thick skull refuses to use it. Here is where I'm at now. I got the thing down the road, one way on manifold vacuum the other on ported. No changes other that a lower idle. Still wont idle in gear AND it has a massive hole when you try and accelerate. I'm back to timing or fuel. WSA mentioned the timing and I haven't checked the rate of advance yet. Don't remember if it was this one or the Bronco I was messing with. Either way it wouldn't have effect on idle right? That would be initial timing right? Now back to fuel, floats are set proper air screws are around 1.5-1.75 out and it smells lean when the choke opens. until the choke opens I have to blip the throttle and it'll run 30-40 seconds before dying out. I'm talking smooth idle until it sounds like its running out of gas again and then I hit the gas and then 30-40 seconds of smooth idle intill history repeats itself or the engine warms up. So much for an electric choke which is another problem I'll address later. The cap keeps cracking apart Don't know if its heat or what, not a show stopper right now it still works.

That was one wild ride (15 miles one way) to get the car aligned. Well worth the money, it hadn't been aligned in 18 years, that's two front end rebuilds and several modifications later, much better now Well back to banging my head. I know its hard to do this in front of the computer but I am getting closer. I'm hoping one of you folks unlocks my brain freeze here.

How did this last Compression test turn out? From some of your other descriptions it dose sound like you have most of your tune up settings just about right the only thing that I can think of besides the possibility of the Vacuum leaks. Is that maybe some of your the carb settings could use some tweaking (see below for some tune up specs I use to get them running).

Over the years I found this is best order and quickest way to dial in a basic running tuneup and some of the specs to use to get them into the ball park! Updated Now that I know most of your combo of parts

1. Set your Spark Plug Gaps for DSII (.044 to .045) and then install the plugs.

2. Next set your Base Timing with Vacuum to Distribitor disconnected and 12 to 16 degrees BTDC. i.e. Taking into consideration the Air Temps and Elevation, etc. in your area I personally like to use a Ported Vacuum Sorce if possible for any street type car IMOP this gives better drivability and economy. Manifold Vacuum will also work though it takes a little different level of tuning.

3. Now you will need to verify the carbs float level setting is correct for a Holley you can remove the fuel bowl plug to check it (if you have a glass type plug then there is no need to remove) the wet fuel level should be just at the bottom of the hole with the engine idling.

4. Holley 350 CFM 2V carb the Power Valve to install is yet to be determined. Example would be 5.5 Hg if your Idle Vacuum reading stays at 11Hg with the parking brake set and the Auto trans in drive.

5. Next set your carb mixture to the lean best idle, the starting setting after a carb rebuild is usually 1 1/2 turns out. With a tach hooked up and engine warmed up to normal operating temp. Turn the mixture screw or screws each in until idle speed drops slightly then turn screw out until you reach highest idle RPM then turn the screw back in 1/4 turn (Leaning it) this is your lean best idle setting.

6. Last set the Curb Idle RPM (500 to 600 in Drive with parking brake set). This setting is for a mostly stock engine combo, you may need to raise it some depending on your location etc. IE with car in gear punching it and taking off there shouldn't be any stumbling.

7. If the carb still has all the working choke parts then it now needs to be set also. Auto or Elec. choke is set about 2 index marks past center Index Mark to the Rich side. And with the fast idle screw set on the fast idle cam index Mark (>) you will want to adjust screw so it's from 1200 to 1500 RPM or just a high enough RPM so that the car will drive without stalling. When warmed up choke should release the fast idle cam and choke blade should be fully open. Recheck this setup after the engine is cold again to see if it resets the Fast Idle cam and the choke blade closes.

For the best results I usually repeat steps 5, & 6 just to verify that the carb settings are right. You know the tune is good if the car starts when warmed up without touching the gas pedal! This should give you a good basic tune to adjust from and fine tune it since every engine can like a slightly different tune. You can then try molding the tune (do only one thing at a time though) until you find the sweet spot that your engine likes. Remember if you change base timing then you will also need to reset the carbs Idle Mixture and reset the Curb Idle again. If you decide to use some sealer on your intake gaskets you can try something like the Permatex Non Hardening type, I don't use any of the Silicone types around fuel. By the way I would also swap my good 1981 200 Mustang head for that 2V setup and even do all the install and tune, :rolflmao:. Just kidding you Rambo I think your real close now to getting it right and like you said it's going to be something simple. Good luck in your tuning!

Bubba, your a hoot! I'll go over that laundry list you left pretty much its all straight but you never know. Weren't you interested in a header I had at one time? The Borla one?

On a side note, choke vent on a electric choke, it draws vacuum right? I know it says not to block it but.....

I'm already cracking covers so maybe it is blocked when it shouldn't be? I'll add that to the check list!

Yes I think I did ask you about that Borla header once. You are correct that heat stove (Tube) for the Choke is a controlled Vacuum leak to draw warm air into the Choke body. How do you have your stove pipe hooked up, and the electrical power source, and voltage, that it's hooked up to now? It sure sounds like its getting too hot for some reason if it's cracking the cover. Good luck