Hi all
I have a Holley 3310 on a 440 with manual transmision.
I,m triying to adjust it with no many luck for the moment
If i turn the idle mixture screws all the way in,the engine not only does not die, but the revs goes up 300 rpm or so.

I squared the slots on primaries&secondaries to expose 0.030" or so.Also had a very high fuel bowl level but this has been corrected.

Rough idle fluctuating around 500 rpm or so.

What could be trouble?
Thanks in advance.

vac leak/too lean

Initial timing? Lots of times this is the culprit. Engine wants more timing at idle.

I built a smoke machine this summer and did several tests.I know that i have a vac.leak in the right side of the carb,seems from the throttle body gasket and maybe from some shaft.
I need to find another oil wich produces more smoke.

However,What i though is vac.leak makes the idle to go faster.This is very low,unless i open a vacuum port.

I have 12 deegrees initial.
Casually the vacuum can died today,but while has been working the trouble was the same.

However an engine should to idle well without the vac.advance engaged,shouldn,t it?

Correct & it would not be engaged unless you have the timing setup for "manifold" as opposed to "ported" which it does not sound like you are. Do you have another carb handy you could toss on?

I can't believe I'm the first to tell you this: Your symptoms are the classic indication that the power valve diaphragm is ruptured. There is only one on most 3310s and they are not expensive. You'll need a gasket kit for the float bowl and metering block gaskets. Get nonstick ones.

R.

Remove the carb and reset the secondary throttle blades so they are almost closed. A 3310 is a vacuum secondary carb and normal '2 corner' idle. The secondary transfer slots are high up in the bore. If they are showing .030 below the blade - it is way too far open. That would be both a vac leak and a source of fuel.

,030" on the primaries is a starting point. Anything from .020 to .040 should be OK. While the carb is off, write down the turns out on the screw so you'll know how much they are exposed when you are fiddling with it.

If you see fuel dripping out the boosters when you shut it off, the fuel levels in the bowls are still too high.
If not, then excess fuel at idle could be the bowl leaking through a ruptured PV diagrapm into the manifold.

Not sure what you're trying to do with burning oil and smoke but the rubber diaphrams may not have liked that.

Timing. Initial Timing should always be measured with the vacuum line capped or plugged regardless of whether its using ported or manifold. Thats true for stock or modified. 12*BTC at 500 rpm is good starting point for a stock or close to stock engine.

Buy an old copy of Urich and Fisher's Holley Carburetors and Manifolds Lots of good illustrations explanations in there and things will more sense. Almost as good is Urich's little Holley 4150/60 book. Both are available used for cheap.

I thought some of this sounded familiar. Some of this may be a repeat, but that's OK.
https://board.moparts.org/ubbthreads/ubbt...tml#Post2287841

It,s ok.
The engine takes some seconds to die if i use my thumb to cover the primaries bowl vent.
However i have removed it and checked with a mity- back and it closes at the range stamped in the valve.

You have better memory than me..
I did recall a post about the vacuum advance.In the end we finished talking about the carbs...

I bought the Urich,s book in Amazon,one month ago or so.This is new ,4th edition.
The book is nice, but there are things that i don,t find 100% clear in it.
For example, they say that you can open the secondaries blades a bit,to increase the idle speed.In this manner you can keep correct slot exposure in the the primaries.
Also that they not must to be totally closed otherwhise this woukd cause to stick against their bores.
But they not say that 0.030 is too much exposure for the secondaries ,as you have stated.Actually, that is the info that i did need.
I will adjust sec. to almost closed to see if it goes better.The trouble is the engine does not breath enough air to keep the idle speed.
I have to open a vacuum port lika temporary
solution prior to start drilling the blades.

You can crack the secondary blades open a little bit if the engine needs more air at idle. But not nearly as much as you did.

When you have the carb off, you'll see the bottom of the secondary transfer slots is much higher up than with the primaries. You'll also see a small idle ports. They provide small contribution of fuel from the secondaries at idle.

Sorry if the 4th edition has more changes/confusion than I realized.

I forgot that your engine has the voodoo 60303 and lower compression.
Give it more initial timing. Experiment with 14 to 16* BTC. Idle speed 600 to 750 in neutral would be acceptable.

Don,t feel sorry.There is a lot of info out there that can result confusing.
There a lot of posts of people talking about to use the secondaries to set up the idle speed.
Even Holley,that put that small adjusting screw in a hidden place is now selling a piece or a kit wich makes easier or more confortable to "adjust" the secondaries.

Mattax, i did folow your indicattions (more or less)
I increased the timming to 17*,also removed the carb and adjusted the secondaries blades to almost closed position.I have used a 0.05 mm feeler gauge between the blade and the bore.

After installing the carb again,it has been difficult to start it at the beginnig,even i have fouled three spark plugs.
After replacing and cleaning the plugs,it has started to have a better idle,vacuum and rpms are stadier now,but it continues needing an extra air source for breathing at idle.
It has been neccesary to open the brake booster port(I have manual brakes right now,so i,m using it for the headlights covers).
I have recorded a video if you want to take it a look:
https://youtu.be/gdl8TiNS31M

About the cam,some users say that they are getting 12"at idle from these 60303.I suppouse they will have automatic transmissiions and higher idle speeds..

Turn the idle UP.

That should idle in the 750-850 range with 18 initial timing.

Do not set timing/idle according to any manual as it's not an OEM camshaft.

With a different combination of parts, maybe they do.

That's fine.
You can experiment with a little more, but there may be other things first.


I watched the video. My observations:
a. I didn't see a PCV valve and hose. You should get one. In the meantime, drill a hole in a wood or metal plug that will fit in the PCV hose. The hose attaches to the large vacuum port on the rear of the baseplate. 3/8" Hose. The drill hole should be around .11 to 0.125" diameter. 1/8" is a common size here. Use your closest metric. It will get you going with the fixed air leak needed at idle.

b. Get it running at higher rpm, especially just after start. It will need more rpm and richer mixtures when the engine is cold. Once the engine is warm, then reduce rpm to whatever it will idle at. Then adjust idle mix, timing if needed and then you may be able to reduce idle speed a little more. If so, readjust idle mix again.

c. After doing above, then see if the primary throttle blades are open too much. If so, open the secondary a little more and repeat.


Once you have the hot idle running well, you can experiment with the choke and fast idle to work for better cold starts.
It shouldn't need too much choke, and it should pull further open quickly after start. Much patience is needed for getting a choke nice on a hot rod. In the meantime you can also leave it open and give the engine more rpm until warmed up.

I have a pcv valve.I remove it when the air filter is out,cause the hose holds it in it's place.
Otherwise it is scapping from the grommet and falling between the headers everytime i,m working on the engine.



Not sure,but i think that i understand what you say about the plug reduction into the pcv hose.
I suppouse that this would need to change the air filter conecttion to a manifold vacuum?

Also i read a post wich talks something about to install a petcock on a manifold port.I think that some people were use this method rather than drilling the blades.

Would it work the same?

Thanks again.

I don't see a PCV Valve there or a location for it in either valve cover.
The breather does two things.
1. It supplies positive air flow when the PCV valve is drawing on the crankcase and air in the engine.
2. It vents crankcase air when the PCV valve flow isn't enough.

This is called a closed crankcase ventilation system:


The large manifold port on the rear of the carb is typically used for the hose to the PCV valve. On Chrysler engines, the valve is usually located in the top of a valve cover.

The PCV valve is a variable restriction. It restricts more at higher vacuum. On a stock engine, idle is high vacuum. On your engine, vacuum looks to be around 10" Hg. Hopefully a little higher when you get things tuned in. So for now, I was suggesting you use a fixed restriction.

If you don't want to put another hole in the valve covers yet,

You can use replace the fill cap with one that has a grommet in the top for this purpose.
Look for 'twist in' or 'twist-lock' fill caps or breathers for PCV valve. Ford-Mercury was a common application here. Replacements come from many sources including Stant and Mr Gasket.
I don't know what's available in the EU.

You are right,what i have is a breather,not a pcv.I was confusing them,sorry.
Some things start to making sense.To add a pcv valve could help in several ways.

I don,t search parts for american cars around here,except for spark plugs,oil or that kind of standard parts.
I use to order from r****uto or s**mit,or eb*y,it is easier ,faster,and most times even cheaper.




please give me the part number for the black one. Thanks.

That particular one is made or distributed by Scott Drake.
https://www.summitracing.com/search/brand/scott-drake/department/engines-components/product-line/scott-drake-valve-cover-oil-caps?N=401272%2B4294949512&SortBy=Default&SortOrder=Ascending&autoview=SKU&ar=1

And there are cheaper ones like these:
https://www.summitracing.com/parts/snn-10071
and
https://www.summitracing.com/parts/trd-4999

Since you have to ship, lets make sure we can match a PCV Valve for it.
Most likely something for a Ford 'CJ' Cobra Jet or such. But most important will be that its the correct size for the grommet or hose. I collected some information about sizes but wont be able to look for it until tonight.

Its hard to find dimensions on-line. The Ford Cobra Jet used a threaded PCV valve so that's not a match.

A review for the Stant 10071 states it comes with two grommets. If so, then its more likely for a common PCV valve will fit.

Ok don,t worry.They are not expensive parts,so i can order a couple of pcv valves and use the most aproppiate.The stant cap you posted looks good to start.What i don,t know is why all these breathers-pcv caps do throw vapors to the atmosphere instead to have a connection tube for the air filter.

If the PCV doesn't fix it for you, I would suggest checking everything that would make it run rich. Make sure the air bleeds are not blocked (they are the 4 very small passages on the front, just under the choke plate). I think the idle air bleeds are the outer 2. Make sure the floats don't have any gas in them, and are adjusted right. Make sure you have the correct gasket between the carb body and the metering block. Not a likely cause, but make sure it doesn't have some crazy sized jets in the front, (should be around a 76) because that could make it idle a little rich. I would definitely put another PV in it too, just to completely rule that out.

OK.
You can try one for a Chrysler v-8 and if you want to experiment,
ACDelco CV736c has is reported to be good for engines with lower manifold vac, and has 3/8" connection (suction side). I don't have the other diameter.

As to why so many open breathers? That might be a sociology question as much as a technical one.

On a good running engine, the most of the vapors will to through the PCV valve and the breather is just air in. Before 1960 or so, cars here used draft tubes to evacuate the crankcase. The low pressure under the moving car sucked the vapors out. Probably the same in Europe.
To address the greater blow at high rpm, wide open throttle, some racers use vacuum pumps or evacuation tubes in the exhaust.

One problem with PCV valves is with engines that have poor manifold vacuum at idle. There has to be enough vacuum at idle for the valve to be in the most restrictive position. I *think* if your engine can get 11 - 12"Hg at idle, it should be OK with a stock PCV Valve. This why some people experiment with different valves like that CV736. I had plans to test the flow of PCV valves but that's been sidetracked.

IMO, Isolate the intake tract from everything else, booster, PCV, all of it. Plug that stuff at the intake. Cars run without those emission/accessories all the time. It's not those items causing the bad idle situation.

Figure out why the engine won't run without a gaping vacuum leak.

That camshaft should not require any type of "drilling" anything on the carb to run properly.

Hello,i blew all the cicuits with air pressure when i removed the carb a couple of days ago and i didn,t find a blocked passage.I removed the primaries metering plate to check the PV valve.
Fuel bowls level ok,in the botton of the window,drip a bit of fuel if i shake
the car.
I put a new body gasket that i had stored from a Holley trick kit i bought several years ago.All the holes match.I just had to make another hole for a center pin,cause the body has two and the gasket only had for one.
I found that the throttle body has threads
for eight bolts and i only had six.
I started to imagine horrible things about where the two screws could have gone until i read in the Urich,s book that even having 8 threads,only the earlier models came with 8 screws.
However the two center bolts were in the wrong threads.I put them where it should to go(Taking the book pictures as a guide)and tightened them a bit using an impact screw driver.That solved the vac.leak i had between the plate and the body at the front of the carb.The right side continues leaking a bit(Tested with that smoke machine that Mattax likes )

Both main Jets are 70s.
I know you can change air bleeds in the latest carbs.That is a good improvement.

Interisting. i have seen that Moroso sells a system wich threads a tube in the header close to the out for this purpouse.

Also ,i have done a new test today.
I have stolen the pcv valve from my Jeep 5.2 magnum wich has a 3/8 nipple and i have connected to the 3/8 port in the rear of the carb.






The idle is erratic and low rpms when the pcv valve is connected.Rightnow ,this thing needs an open 6-7mm
(Sorry for the metric,1/4"?) hole for a decent idling .
When that port is open it idles around 750-800 and seems to throw less smoke and fuel smell.However the engine was still cold and i haven,t had the time for warming it up.

Regards,

That,s what i think.This cam is more mild than wild.
The trouble has to be in the carb.I think that it creates a rich condition and needs that air for compensating it or something.
In the end a fixed leak is a temporary solution..

Turn the idle UP using the adjustment screw on the carb. 800 rpm in park/neutral.

Where are the idle mixture screws set? Most of the time if you leave them at 1 1/2 turns out, it's going to be rich.

Is fuel dripping in from the boosters?

The issue IS NOT anything related to the PCV or booster. Isolate the intake and solve the carb/timing issue and worry about the other stuff later.

The car has manual gearbox,are not 800 rpm are a bit high?
If i use the idle screw i loss the transfer slots adjustment.Don,t understand the Holley design,why that screw is so accessible.
The mixture idles are 1&1/2 or 1&1/4 (i don,t remember how i set them last time)turns out.
Tomorrow i will check if i see fuel dripping from the boosters.
Also it has manual brakes,the only thing connected to manifold are the headlights covers.The vacuum advance does not work so i have plugged the port.

Thanks

Manual trans run it at 800 rpm. It's fine. This is NOT a factory cam with 200* of duration, it's in the mid high 220's and needs more RPM to run right. Additionally, run it lower and the splash to oil the cam is minimized at idle which is BAD!

Turn the mix screws to about 3/4-1 turn out.

Lose transfer slot? If the mix screws don't do anything, it's likely dropping fuel in from somewhere else (ruptured PV diaphram) or dripping boosters is likely. At least you don't have the in gear issue that an auto trans would have. If need be open the secondaries slightly. Use a .015 feeler gauge or some paper layered up between the set screw and arm on pass side to hold it open as a test.

The inside of the carb looks black which usually means it's really rich with inadequate initial timing. Now that the timing is about right, the rich side needs to be solved.

Not much to add here. Hard to imagine this is going to come from me, but don't wory so much about the instruments and measurements. Just spend the time fiddling until it starts running good. See what I posted on the 18th - pretty similar to what Crackedback wrote. Open up the throttles for more rpm. As it warms up and you start to tune it in, you can lower it.

The engine is cold. Either hold the throttle open on the fast idle step, or just screw the idle stop in until its warm. Stock '69 440 fast idle speed was 1700 rpm! I'm too lazy to pull my '67 book off the shelf, but I'm sure even pre-smog, it was at least 1400 rpm. After a minute or two you can reduce it 3 or 400 rpm to something around 1000. Then when its warmer, a little less. Once your closer 800-900, then fiddle with idle mix and see what does.

7 mm hole is out line. Half that diameter - which is roughly 1/4 of the area is all that a PCV valve would be. So it doesn't seem like you have a vacuum leak at all.

Oh,they do.Very strange things but they do The pcv diaphragm is ok and i haven,t seen the boosters dripping at idle.
I have done several tests today ,engine at 170 celsius and every time a diffent thing occurs here,very confusing.
Let me repeat the tests again,to see if i,m
able to get a better conclusion.I will record another video to show you how this is going on.

Meanwhile a bit offtopic,but i need to order some parts,a vacuum canister for example.The broke unit i got is the part 3656766.I have seen it on the web listed as a part for small block dist.There is another part number for BB i think.
Do you know if this part is correct for this distributor (MP electronic ign)or maybe a previous owner made it to fit ?

Thanks

170* C!?? What is ? Coolant? Oil?
Coolant should be 180* F, or roughly 90*C when the engine is warmed up.
Oil temperatures in the sump will be similar when just idling.

Well I'm tired after a day playing in a parking lot. So maybe more in the morning. Don't worry about the vacuum advance for now. What's wrong with it anyway?

170*Farenheit ,coolant.
The vac advance stopped working few days ago.Just wander if this unit is correct for the BB dist.I have found that all the MP dists have the same body and only the shaft lenght changes,and due these canister are adjustable ,i suppouse that i can mount the same part number.

Reply wen you can or you want,of course.No hurry.

Broken? Difficult item to break. Did you put a vacuum pump on it? Could it be the ported vacuum is blocked by the substitute gasket? No rush to test. Work on getting the engine running nice at idle. It will be itererative. Which is another way of saying the process is repeated several times as you closer.

When you order more bowl and block gaskets, order a 10 pack. Its much cheaper.

Yes, i did:

https://youtu.be/WvjHgs5YX8c


I continue studying the carb,just to become familiar with the circuits.

Just one question:Wich holley carburetors had auxiliary idle air bleeds?
Had that circuit The 4160 factory installed on latest 60s Chryslers ?
I did notice that the gasket does not have a hole for the ports marked with the yellow circle:




I have a set of spare gaskets and neither have them.
On the orher hand ,there is a picture in the Urich&Fisher book wich shows a correct gasket for the 4160 that came in the 68-up Chryslers, and it has the hole for those ports.

The additional idle air bleeds came on carbs as part of a package to meet then new exhaust emmissions requirements. Many had an adjustable air bleed and sealed idle fuel mixture screws.

The passage for the timed vacuum port is at the bottom.

If the canister isn't holding vacuum, the diaphram must be damaged. Replacement of the diaphram is possible but not usually worth the cost unless its an unusual cannister. (about 75 USD).

You mentioned its a Mopar performance distributor. It will either have been made by Chrysler or Mallory. The main difference is the advance mechanism. The vacuum advances are probably the same. Any vacuum advance for a Chrysler built B/RB magnetic pickup distributor should physically fit and work. The differences will be the internal spring, and the notch which limits the maximum degrees, and the preload adjustment on the spring.

Beware of that.
I just have received the new part that i had ordered.It was listed as a direct replacement part for my canister ,but it is not.
As you can see,they are symmetric,it means the lever and the bracket are inverted.
Here are a couple of pictures,just in case it can helps to someone else:

https://ibb.co/eO2sG9
https://ibb.co/bS6Kw9

Check the needle and seat. The rubber could be deteriorated and not sealing. Very easy to take out and change. Take it out , look at the rubber. If it looks questionable and you don't remember if it ever was changed. Put a new assembly in.

From what I see,one is BB,the other SB.

You are probably right.
That is what i asked a few posts ago.
Rockauto has it listed as replacement part for tne part 3656766 wich is what i have ,and it is not.

VC 187 seems to be the part for the BB(if somebody else needs to order a canister)

I,m going to see if at least they don,t charge to me the shipping of the correct one.

The one on the right in photo 1 is for small block, and maybe slant 6.

My notes have VC-190 as small block, with 11 distributor degrees and starts to add advance around 9" manifold vacuum.

The small block Mopar Performance vacuum advances that I own have 8.5 distributor degrees. My guess is the big block versions were close to that range.

Mancini sells a couple versions for B/RB with electronics or single pooint including VC187.

Any progress on tuning?

Continue to fight

I'll update the thread with the new tests these days.
Rightnow i,m just checking all the circuits again and i don,t find nothing wrong.

However,what is the purpouse of the channel and holes with the red arrows in the picture?


They are connected to the primaries curb idle circuit but seem to be blind in the secondaries side.
I have circuit diagrams for the metering and the front side of the primary body but i don,t find one for the trottle an main body base.
Thanks

Where you able to take a peek at the needle and seat. Make sure the rubber is intact and still soft.

Not used on the list 3310s. It is for carburetors that had rear idle ports fed from the primary idle.

I think you need to fiddle with the adjustments, even though its going to burn 5 gals of petrol doing so. getting running at fast idle speeds, using timing and throttle etc so its smooth. Then start working everything slowly back down to a lower rpm, 9000 - 1000. Then lower if you can.

Its really important the timing curve doesn't start advancing to soon with that cam.
If its 20* at 1000 rpm, 17* at 900 rpm, then it could 16* at 800 and 15* at 700. That would be a reason why it won't run as well at 700 or 800 if for this particular engine combo it needs 17* at idle.

Excuse me for the delay in replying.
This was driving my nuts, so i did prefer to take a break while i was receiving the parts i was waiting for.
Now i got the Stant 10071 cap and the AC delco CV736 pcv valve.The Stant cap comes with two grommets and one of them fits perfect with this valve.The bad point it doesnt seem to be a breather but just a cap for the pcv installation.
I also have installed the correct vacuum advance canister .




I suppouse this will be with the vacuum advance plugged in?
Connecting to manifold vac.i,m around 36* at idle.Also helps to increase the rpm a bit.
Another thing to consider about timming is how many volts does need a MP ignition system to produce a healthy spark for a good combustion.
The stock alternator with the mechanical stock regulator starts charging over the 800 rpm and i would say that it does not arrive to 14 volts.

There should be a breather on one valve cover and a PCV valve on the other. The pcv valve connects to the carburetor base. The 'breather cap is for a 'closed system' with a hose to the air cleaner base. Or you can use an open breather like in this illustration:
http://www.imperialclub.org/Repair/Lit/Master/154/Page15.htm
No vacuum advance!!! My statement quoted above is about mechanical advance starting at an rpm lower than idle rpm.

First establish timing without vacuum advance.
This is true for factory stock as well as modified engines like yours.

Igniting the mixture earlier using vacuum advance is for conditions when the mixture density is low and the flame develops slowly. Idle mixtures need to be moderately rich to be efficient maker of power. 12:1 AFR cold, 12.5 to 13.7 AFR warm depending on the compression, overlap, etc.

The ignition will work fine with even 11-12 Volts.