Are my float levels too high? - Carb flooding

[rollo1504]

Hey Guys!

As some of you might already have read in another topic I have rebuilt by Holley 4160 4BBL vac sec carb some time ago.

Since I have it installed back onto the intake manifold the motor runs quite good but I can see that there is quite much fuel in the valley pan which gives me not a really good feeling...

So my question is before I start unmounting too much things If the float levels of my carb are set too high....

I have to say that during the rebuild process I have adjusted the float levels as the holley manual for my carb told me to do so.... (put float bowls upside down and check if they are parallel aligned etc)

Or did I some other thing wrong...?

Thanks for any input.

Roland

[XH29N0G]

That does not seem right at all.  It also looks like a fire hazard. 

My guess is that the float level being too high would send fuel out the boosters and down into the carb barrels filling the manifold with fuel. 

I would look for a bad connection or a leaky gasket on the float bowls or the metering blocks or the accelerator pump.

[rollo1504]

YES, it IS a fire hazard, thats why I am questioning and afraid of continuing driving...... .

Mmmmhhh. I was working really slowly and doublechecked everything twice concerning the gaskets but I will check that again....

I also assume that the float level is too high.....

....

To be continued...

Thanks Roland

[XH29N0G]

I would also check the tube that connects the two fuel bowls.  Is the capped hose in the top right of the picture, a vacuum hose?

[sccachallenger]

look at the accelerator pump diaphragm housing while you work the throttle linkage.
A pinhole in the diaphragm will drip fuel every time the throttle is moved.
If the engine runs well, and is not hard to start when hot,(like it's flooded)the float level is probably OK.
As always, let us know what you find.

[rollo1504]

I would also check the tube that connects the two fuel bowls.  Is the capped hose in the top right of the picture, a vacuum hose?

Yes, this is a vacuum hose to my vacuum gauge....Everything fine there

[rollo1504]

..... mmmmhhh another thing I have to mention is that I also have replaced the powervalve....

Is there a possibility that this thing is broken and because of this it is permanently open and too much fuel floods in?

Just thinking....

Thanks Roland

[XH29N0G]

I think the power valve would just send gas into the boosters because there is still a gasket on the metering block to hold the gas in the bowls and keep it from leaking out. 

I would search around for leaks at all possible connections that lead to the outside.  With that much gas, it has to be coming out somewhere.  If it is not leaking out when the engine is running, then maybe it is something that happens with the fuel pump is working.  The suggestion by sccachallenger is a good one because it involves a test that is not a simple leak, but something that happens when the throttle is depressed.  I would check around with a paper towel to see if any leaks could be located, then try the same while manipulating the throttle, and then with the engine running.  My guess is that you will find a leak with the carburetor or with one of the connections to the carburetor or hoses.  don't forget the tube that connects the two bowls.

[rollo1504]

Ok.... Concerning the left red square in the pic.... It looks like that fuel is slighty coming out of the linkage which opens the secondaries ....

... and the other thing at the moment I am guessing around is HOW is fuel coming to the valley pan (seee right red square in pic)? Might this indicate also a leak between heads and intake manifold? Just asking as I think if the fuel would go down outside the carb over the intake into the valley pan there would be much more messed up with fuel on the intake as fuel must get over the intake to the valley pan...

Sorry for my bad english I hope you guys understand what I mean though...

Thanks Roland

[rollo1504]

I have also checked some pix in the internet of the underside from the intake manifold....

In my opinion all these breadcrumbs lead to the point that there is something wrong with the Throttle Body of the carb or its gasket....

We'll see

[XH29N0G]

If you think you have a spot where fuel appears to be coming out, I would focus there and on any joint or gasket near that point.  I suppose it could be near the throttle body, but maybe where something is connected with the floats.

No worries about the English.  (1) I am almost certain my responses would be impossible if I wrote in your language (which I assume I do not know) or even in other languages that I think I know how to speak. 

[rollo1504]

Update:

Fired engine up yesterday....

Cold Start: Engine cranked pretty good and ran almost instantly.... Let it runf for a while to get hot and checked carb outside if fuel drops out somewhere -> NO FUEL DROPS out
Hot Start: Engine fires up immediately

Then things started to get interesting

As I COMPLETELY screwed in both idle mixture screws the engine DID NOT DIE!

So I think following things are happening....

- Possibility A: The newly installed powervalve is defective and is permanently open which causes the engine not to die after closing the mixture screws
- Possibility B: The power valve blow protection has a small ball inside so far as I can remember... Mmmhhh. At the moment I do NOT know if I have checked it if the small ball is inside the blow protection or not
- Possibility C: As I also took both fuel bowls apart I might have done something wrong during reassembling it but to be honest I do not really believe that....
- Possibility D: As I can see much fuel in the valley pan after driving around for a short while and have pushed it several times I also think that the secondaries are opening way too far so the engine does not burn all incoming fuel which leads to this fuel leak in the valley pan....

Sounds like I have a plan or at least I found some possibilities to check....

By the way I do not think that it is a gasket issue....

Thoughts?

To be continued....

Thanks Roland

[XH29N0G]

I don't have further thoughts, hopefully someone else does.  I will let you know if I get any ideas.

[charger Downunder]

You may need to replace the needle and seat it may be damaged at the end and leaking fuel in when it should be closed.

[rollo1504]

You may need to replace the needle and seat it may be damaged at the end and leaking fuel in when it should be closed.

During rebuild process the needles have been replaced....

But I will come back as soon as I have an update about the situation as I still have not checked it yet...

Thank you all for your thoughts and help

Roland

[rollo1504]

Update:

- Possibility A: The newly installed powervalve is defective and is permanently open which causes the engine not to die after closing the mixture screws
- Possibility B: The power valve blow protection has a small ball inside so far as I can remember... Mmmhhh. At the moment I do NOT know if I have checked it if the small ball is inside the blow protection or not
- Possibility C: As I also took both fuel bowls apart I might have done something wrong during reassembling it but to be honest I do not really believe that....
- Possibility D: As I can see much fuel in the valley pan after driving around for a short while and have pushed it several times I also think that the secondaries are opening way too far so the engine does not burn all incoming fuel which leads to this fuel leak in the valley pan....

Did not have time to take the carb apart but can say that there was a fuel leak in the valley pan because there was toooooo much fuel incoming from the carb which could not be burned by the motor. As I said the mixture screws are completely screwed in I wanted to know how car behaves when I try to make a short drive.....

Car ran almost fine and after the return there were NO fuel lakes anymore around the intake manifold and in the valley pan....

So I suppose that the new power valve is broken and is permanently open and additionally with the mixture screws set to 1,5 turnarounds loosen the motor was running far way too rich....

As engine fires up immediately even if HOT then the fuel levels in the float bowls should be fine...

So the only logical conclusion is the powervalve..... But that are my thoughts and I am NOT a mechanic.....



Will be back soon.

Roland

[XH29N0G]

I am glad that the leak has worked itself out. 

I believe if the power valve is ruptured then you might leak fuel into the other circuits, but if it is not ruptured, I think it should feed fuel to the same place the main Jets do (the boosters) and this should not affect idle.

Check the transfer slots to make sure they are not set improperly.  This can also determine whether the idle mixture screws work.

[68 RT]

If your screw in your mixture screws all the way and the car does not stall one thing to check is your idle speed screw, it is probably in to far causing the throttle blades to be open too far.

[sccachallenger]

If your screw in your mixture screws all the way and the car does not stall one thing to check is your idle speed screw, it is probably in to far causing the throttle blades to be open too far.

Agreed! open the secondaries a little(takes a tiny screwdriver)this should let you close the primary side a little and may restore the idle screw function.
It may take a couple of tries to get this right, but worth it!

[rollo1504]

I have set up the secondaries like many guys told it in the web to the famous "Square" by adjusting the small screw underneath the throttle body plate.....

Mmmmmh... was this wrong...

OK OK I think I understand now more whats going on and HOW a carb is working or its parts....

Last time I played around with the curb idle screw I could see that I was not able to stall the motor with it even if completely loosen.... -> I guess then that my throttle blades are open to far in the "ZERO" position? right?

Thanks

[sccachallenger]

you may be at the other extreme!
Hold the carb over a strong light.
it'll give you an idea how open the throttle plates are.
if you see more that a small crescent of light from around the secondary plates they may be open too far.
Make a very slight adjustment to close them slightly.
This assumes that the stop is against the screw when throttle is closed, If not you may have to adjust(bend) the closing link to allow them to close fully.
Make sure the closing link isn't holding the secondaries open,even slightly.

[XH29N0G]

The transition slot with a Holley carburetor flipped upside down should be a square shape.  If it is this shape, then it works as designed.  There are also transition slots on the primaries.

It is probably also significant that your car does not die with the idle speed screw completely backed off so that the primaries are closed.  What is the idle speed (RPM) when the idle speed screw is backed out.  Also make sure the throttle cable or something else isn't holding it open a little. 

[rollo1504]

... Today it was the time to take the carb apart again....

Could find 2 things:

- Power Valve was installed with 2 gaskets... Do not know how I could have overseen that.....
- Secondaries were open to far (Did the test with the bright light idea) :-)

In the next couple of days I will have the time to put all back together and check the RPM if curb idle screw is completely loose...

More to come...

Thank you all for your suggestions/ideas

Roland

[XH29N0G]

While you have it apart, it is worth making sure all passage ways are clear.

I found it informative to track down the passageways with information like that at the bottom of this web page: http://members.tccoa.com/392bird/tuning.htm

I hope to hear about a successful fix soon

[rollo1504]

Hello Guys!

Well I think I have good news....

After replacing the "new" power valve with another new power valve and install it with one instead of two gaskets :-) the engine dies if idle mixture screw are screwed in...
Further the secondaries were open too far... Adjusted them with the bright light hint. Now the car dies if the curb idle screw is screwed out to far as well.....

There are no vakuum or fuel leaks caused by a worn out/damaged gasket or something like that....

So engine runs pretty good in idle and responds very fast if pushed (as far as I would understand it)....
Replaced also the vacuum diaphragm of the secondaries and tested it if they open with a paperclip... yes, this seems also to work....

the very last problem I have is now that I think the engine leans out if WOT for some seconds and engine stumbles then just a little bit....
What do you think guys I can do to fix this? Currently a 6.5 power valve is installed..... Could it have something to do with the secondaries opening too early or too late? Or will I have to look for bigger jets?
Have to mention that my carb actually only has primary jets and NO secondary jets.

Thanks

Roland

PS: During some more testings I figures out that the intake manifold is just a little bit leaky at the heatcrossover to the cylinderheads. Have bought this famous Black RTV Silicone tube to fix this....

[sccachallenger]

Congratulations!
You can disconnect the secondaries to make sure that the primary side isn't too lean.
The secondaries can be tuned by swapping to lighter or heavier springs, see if that helps.
No jets on the secondaries! there may be an aftermarket conversion metering block with replaceable jets, if Holley doesn't offer one.
Holley might still sell metering plates with different sized holes, for tuning purposes.
Experienced tuners with number drills will sometimes drill the passages larger.
Not sure I'd recommend  that for you, try everything else first!
Glad to hear progress is being made.

[rollo1504]

Hey,

Ok I can disconnect the secondaries but how do I recognize then if the primary side is too lean?  I mean if the sec are disconnected then I will always be too lean at WOT or not?

A shipment will arrive in the next 2 weeks with a huge amount of holley stuff

... new carb
... set of jets
... set of nozzles
... new sec vac diaphragm
... set of pump cams
... new fuel lines
... new fuel pump

... I am in contact with Mr. Firecore (Ron) to get a new distributor and spark plugs

and many other things...

Can't wait as I then really can try things out :-)

Regards

Roland

[sccachallenger]

if it pulls cleanly through the rpm range, you can rule them out as being the problem.
Then concentrate on the secondaries.
Please,please,please, only change one thing or new part at a time, you want to be sure what hurt or helped.

[rollo1504]

if it pulls cleanly through the rpm range, you can rule them out as being the problem.
Then concentrate on the secondaries.
Please,please,please, only change one thing or new part at a time, you want to be sure what hurt or helped.

Promised.... I will only change one thing at a time... :-)

I am the type of hobby mechanic who always wants to know whats going on so I will take the time for it....

And concerning the bunch of spare/tuning parts which will arrive soon...... I live in AUSTRIA and ordering just one part also takes so much time and costs to come over to my home in Europe and because of this I have prepared myself through getting much information and then ordered a bunch of parts.....

Roland

[rollo1504]

if it pulls cleanly through the rpm range, you can rule them out as being the problem.
Then concentrate on the secondaries.
Please,please,please, only change one thing or new part at a time, you want to be sure what hurt or helped.

Shall I test it like just push the pedal halfway down? Or must it be tested with WOT?

Just questioning because if it is needed to be tested at WOT with secondaries disconnected and it pulls cleanly through the rpm range why would the secondaries be needed then? :-)

Thanks

[XH29N0G]

Can you describe again the behavior that makes you think it is lean at WOT?

I get the impression from what you wrote that if you depress the throttle, there is a hesitation.  I just don't know if it is a hesitation that happens right after the throttle is depressed or if it accelerates for a few seconds and then hesitates (which is what I thought the first time I looked at your description). 

Or are you suggesting that it is lean for some other reason? 

I always have to remind myself that I can tinker with carburetors for ever, but if I keep looking at how they perform with an ever more critical eye, I will always find someplace where they are not perfect.  Sometimes the limit that is reached is inherent in the design.

[rollo1504]

Hey,

It does NOT hesitate if throttle is depressed.... Thats fine...

I hesitates after around 2 seconds at WOT.... I suppose it is because there are no jets in the secondaries?.....

So after reading through many other topics I think my problem is the "missing" jets in the secondaries, or the secondaries are opening too early or too late, or the power valve .....

Everything else is pretty good at the moment....

Regards

[XH29N0G]

Double check to make sure you do not have a metering plate.  Something like that shown at http://www.jegs.com/p/Holley/Holley-Secondary-Metering-Plates/761696/10002/-1

The 2 second delay (starting off fine, then after 2 seconds hesitating, and then picking back up again) is not something I have experience with.  Hopefully someone else will recognize this behavior.  It seems a little late for the pump shot to make a difference.  I wonder if it has something to do with the secondaries opening - like the initial push is with the primaries opening and the pump shot covering them, and then later the vacuum allows the secondaries to open a little too fast to cover the transition to the main circuit.  

I suppose bigger jets could cover up something like this but if it were me, I would want to hear from someone who knows the answer.  

My suggestion is to start a new thread that asks if people have seen this type of behavior and know the answer.  I think you have some good answers here, but it is possible that people have stopped scanning this thread - so a new one on that specific topic may bring a more specific answer.

[rollo1504]

The 2 second delay (starting off fine, then after 2 seconds hesitating, and then picking back up again) is not something I have experience with.  

Hey!

As far as I can remember I DID NOT SAY "... and then picking back up again".

Starting off fine, then after 2 seconds engine begins to stumble and continues stumbling as long as pedal is at WOT.

Sorry if I said something different....

Regards

Roland

[XH29N0G]

Most likely I misread or misunderstood.  Apologies.

The important thing is to make sure they know what the symptoms are.  I am responding because I am trying help, but my responses have reached the point of speculation But someone else here might have the answer that will provide a solution to what you are seeing.

So stumble and continue to stumble (it isn't knocking is it?).  If it truly is lean, then I would be careful because I believe that can lead to much bigger problems.

[rollo1504]

Don't worry...

I really appreciate your help and suggestions/thoughts :-)

Hahahaha that would be the next question if it is stumbling or knocking.... Are there somewhere youtube videos or something similar which explains me what really knocking is?

I have found several youtube videos but I cannot really determine HOW knocking sounds.....

Nevermind.... Right now I am in contact with Ron to get a new distributor, firecore coils and wires. Further new NGK sparks will be installed and hopefully Ron will guide me to set the correct timing curve for my application....

Thanks though dude

[sccachallenger]

I would  suggest wide open to at least 5000rpms to test.
It should not accelerate as rapidly on just the primaries, but shouldn't miss or stumble.
With the secondaries working, you'll get there faster and your problem may return.
You should also check your fuel pressure, a big block at WOT will probably need more fuel than many stock pumps can provide.
Many stock fuel systems are fine for normal driving but can't supply enough volume at WOT for a full 1/4 mile.
Glad you're checking one thing at a time!

[69wannabe]

Really can't go wrong with the firecore ignition set up. I have never been a fan of the holley 600 carb's. I have had a couple of good one's and several bad one's but you may want to check fuel pressure, sounds like you may have a weak fuel pump or maybe the pump pushrod is worn. Are you running a 383 engine?? I'm assuming you are with a 600 holley. I ran a 670 holley street avenger on my 383 and with some minor jetting it ran pretty good!! Never liked the 600's when they went to the sealed fuel bowl so you had to pull the bowl to set the float level, most of the center hung float bowls had the external adjusting needle and seat's. Reading the spark plugs once you get it up and running good will tell you if you need more or less fuel. Getting one tuned in is a process but it's not rocket science......

[rollo1504]

Thank you all for your inputs....

I will check all that step by step...

The stock fuel pump was replaced by a new stock fuel pump BUT the pushrod was NOT checked during replacing the pump.

I really wanna renew the whole fuel line "system"

Actually a new tank is already installed. Have 3/8 fuel sending unit already at home but not installed yet. Fuel lines will also be upgraded to 3/8 as well as the edelrock fuel pump recommended by Ron which provides constant 6 PSI and where no fuel pressure regulator is not needed. Also the fuel line pump to carb will be upgraded to 3/8 and a fuel pressure gauge near carb will be installed.

Firecore parts like distributor, coil and spark plugs are provided by Ron and already on the way to Austria.

Meanwhile another package with lots of "tuning" parts from Holley will arrive to be able to test with different jets, nozzles etc.
Finally a holley street avenger 770 cfm 4bbl vac sec will be installed.

As soon as all parts have arrived I will continue as follows:

- Install new fuel sending unit 3/8"
- Install new fuel lines 3/8" from tank to pump
- Install new mechanical fuel pump with "internal 6 psi regulator" AND check pushrod if worn out and replace if necessary <<< --- Is there a special trick to get the pushrod out from the engine???
- Install new fuel lines 3/8" from pump to carb
- Install fuel pressure gauge near carb
-->> Testing
- Install new distributor and coil from Ron
- Set timing
-->> Testing
- Begin step by step testing by changing spring, jets, nozzles

Pretty sure I will find it out. Will just take some time... :-)

Maybe with some luck I will find out HOW knocking sounds to determine if engine knocks or not.... :-)

Thanks guys

Roland

[rollo1504]

Really can't go wrong with the firecore ignition set up. I have never been a fan of the holley 600 carb's. I have had a couple of good one's and several bad one's but you may want to check fuel pressure, sounds like you may have a weak fuel pump or maybe the pump pushrod is worn. Are you running a 383 engine?? I'm assuming you are with a 600 holley. I ran a 670 holley street avenger on my 383 and with some minor jetting it ran pretty good!! Never liked the 600's when they went to the sealed fuel bowl so you had to pull the bowl to set the float level, most of the center hung float bowls had the external adjusting needle and seat's. Reading the spark plugs once you get it up and running good will tell you if you need more or less fuel. Getting one tuned in is a process but it's not rocket science......

I am running a stock 400 big block engine...

Regards

[XH29N0G]

I changed the fuel pump and fuel pump rod on my 1970 383 and it was not difficult. I had to remove the fuel pump and drop out a plug from the block that has a hex fitting.  I copied this image from the web that shows it.

Before doing that, I would check the pressure with a gauge.  I had to buy a gauge and plumb it in to the line with a T fitting.  I only had to test at idle to see I had a problem.  Some people have taped it with a tube to the windshield (don't bring it into the cabin) to see while running to see it under load.  

If you have fuel pressure, I would see what happens with your other tests and changes.  If you like swapping things, go ahead, but if those aren't the parts that are broke, then maybe you don't want to fix them.  

For the 770, I would post a question on here and also ask to carburetor company what would be a good starting jet setting to use.  I had a 670 on my 383 and it came very lean and backfired through the carburetor.  I do not know if that is typical, but I wish I had asked.

As far as being able to identify knocking, it is a little difficult and I did not find listening to youtube videos super helpful.  they were helpful a little.  What you will notice is a change in the tone of the engine and what sounds like metallic rattling.  You do not want it.  I missed what the compression was on your engine.  Compression can make a difference.  My guess is that once you get the firecore set up right and with the help of people like Ron and others here you will be in good shape ignition-wise and probably not have too many issues with knock.  I think they can also advise on a starting set up for the carburetor.



     

[rollo1504]

I changed the fuel pump and fuel pump rod on my 1970 383 and it was not difficult. I had to remove the fuel pump and drop out a plug from the block that has a hex fitting.  I copied this image from the web that shows it.

Before doing that, I would check the pressure with a gauge.  I had to buy a gauge and plumb it in to the line with a T fitting.  I only had to test at idle to see I had a problem.  Some people have taped it with a tube to the windshield (don't bring it into the cabin) to see while running to see it under load.  

If you have fuel pressure, I would see what happens with your other tests and changes.  If you like swapping things, go ahead, but if those aren't the parts that are broke, then maybe you don't want to fix them.  

For the 770, I would post a question on here and also ask to carburetor company what would be a good starting jet setting to use.  I had a 670 on my 383 and it came very lean and backfired through the carburetor.  I do not know if that is typical, but I wish I had asked.

As far as being able to identify knocking, it is a little difficult and I did not find listening to youtube videos super helpful.  they were helpful a little.  What you will notice is a change in the tone of the engine and what sounds like metallic rattling.  You do not want it.  I missed what the compression was on your engine.  Compression can make a difference.  My guess is that once you get the firecore set up right and with the help of people like Ron and others here you will be in good shape ignition-wise and probably not have too many issues with knock.  I think they can also advise on a starting set up for the carburetor.



     

Not sure if the 400 engine has this plug with a hex fitting but will check that out...
I already heard about taping a gauge to the windshield idea. I have the gauge and the hose, just the T-fitting is missing but will get one of those and check it out if fuel pressure drops below 6 psi if under load...

Thanks for the hint concerning questioning carb company concerning good starting jet setting....

Mmmh... Concerning "knocking".... Does the engine knocking come up when timing is set too advanced and ignition is too early and works "against" pistons as they still haven't reached TDC? During setting the timing the very first time I recognized some detonations... Is detonation the same as knocking? If YES, then I know how "knocking" sounds...

[XH29N0G]

Yes detonation and knocking (a little like a diesel) can be interchanged (or at least I do and also preignition and pinging).  There is another thing (run on when the engine is turned off) that can also happen but that is different.  Yes it happens when the timing is too far advanced, too hot spark plugs, or when the fuel is too lean.  My understanding is that it has to do with heat in the combustion chamber causing the fuel to ignite too early.  I think we mean the same thing.  If I have messed up the terminology, someone will correct it.

[rollo1504]

I know what too early ignition means but didn't yet how knocking sounds....

Nevermind.... if the new dist is here I will adjust the mechanical, advanced and total timing correctly for my application with support by Ron...

As many other guys here in this forum reported Ron as great guy with great knowledge I am pretty sure concerning setting the correct timing curve for my application he will also provide some help to me and I will set it as it should...

Will be back as soon as I have news for you...

Thanks for all the support

Roland

[69wannabe]

I changed the fuel pump and fuel pump rod on my 1970 383 and it was not difficult. I had to remove the fuel pump and drop out a plug from the block that has a hex fitting.  I copied this image from the web that shows it.

Before doing that, I would check the pressure with a gauge.  I had to buy a gauge and plumb it in to the line with a T fitting.  I only had to test at idle to see I had a problem.  Some people have taped it with a tube to the windshield (don't bring it into the cabin) to see while running to see it under load.  

If you have fuel pressure, I would see what happens with your other tests and changes.  If you like swapping things, go ahead, but if those aren't the parts that are broke, then maybe you don't want to fix them.  

For the 770, I would post a question on here and also ask to carburetor company what would be a good starting jet setting to use.  I had a 670 on my 383 and it came very lean and backfired through the carburetor.  I do not know if that is typical, but I wish I had asked.

As far as being able to identify knocking, it is a little difficult and I did not find listening to youtube videos super helpful.  they were helpful a little.  What you will notice is a change in the tone of the engine and what sounds like metallic rattling.  You do not want it.  I missed what the compression was on your engine.  Compression can make a difference.  My guess is that once you get the firecore set up right and with the help of people like Ron and others here you will be in good shape ignition-wise and probably not have too many issues with knock.  I think they can also advise on a starting set up for the carburetor.



     

Yep, the 670 street avenger was lean on my 383 too, I think I jetted it up 4 jet sizes in the front and 2 jet sizes in the back and stayed with the 6.5 power valve. After jetting it up it ran out pretty good, a 770 maybe rich on a stock 400 but once you got the initial timing pulled up around 16 or 18 it should run it good from there. I have seen alot of holley 750's on 383's that ran out good so that 770 maybe a good choice for it. I didn't know how to set the distributor up on my 383 way back then so my initial was only about 12 or 14 BTDC. Thanks to the guy's on here I know how to set my distributor up now and limit my total advance so I can run some good initial timing. You are on the right track with the firecore ignition and the holley carb and fuel pump pre set at 6psi. That is pretty much the set up I have and so far it works good.....

[rollo1504]

Thanks for your reply!

And which diameter does your fuel line have? 5/16 or 3/8?

Roland

[69wannabe]

Thanks for your reply!

And which diameter does your fuel line have? 5/16 or 3/8?

Roland

I am running 3/8 from the tank to the pump and 3/8 from the pump to the carb. Before I went with the stroker kit in my 440 I ran the 5/16 line from the tank to the pump and the 3/8 from the pump to the carb with no problems......

[rollo1504]

Hey guys!

Disconnected the secondaries and engine beautifully pulls up the rpm's without any stumbling...

So I think the secondaries are opening too early or too late..... Still have not received my spring set to test yet....

But I really suppose that engine stumbles as there are no jets in the secondaries........

Shipment with set of jets, springs, a metering block for the secondaries will arrive in 2 weeks... Then I will have the possibility to test all sort of things out...
But after the test from yesterday I can say that the primary side is OK I think because engine does not hesitate stand off and pulls nicely up the rpms  near WOT but then stumbles....

So total timing and a 2nd metering block will improve the situation... We will see...

Will keep you up to date guys...

Thanks for all your help

Roland

[rollo1504]

Hey Folks!

It's been a long time since my last post but had a lot of work to do around my house but now the oddysee can continue....

Whats the actual status:

- Received Firecore Parts from Ron and installed them (Coil, Spark Plug Wires, NGK Sparks, Distributor)
> Engine is now idling very smooth

- Installed the vac sec quick change spring kit and installed a stronger spring
> Now engine pulls through the RPM ranges without stumbling and actually it makes a lot of fun driving her

- What problems still persist:
a) If engine is shut off after driving around and I let the car in park after some minutes I still can see that fuel is dropping out from the secondary throttle shaft on both sides of the shaft - One drop every 3 minutes which stopps after 15 minutes..... Still do not know whats going on.... Any suggestions ?

b) If I play with the pedal and push it from off idle to WOT it hesitates for a very very small time -> Jets to small or accerlator pump? Not sure. If I drive off with 50-70% pedal down it does NOT hesitate...

Thanks for any comments....

Regards from Austria

[XH29N0G]

Glad to hear progress has been made.

- What problems still persist:
a) If engine is shut off after driving around and I let the car in park after some minutes I still can see that fuel is drop :rotz:ping out from the secondary throttle shaft on both sides of the shaft - One drop every 3 minutes which stopps after 15 minutes..... Still do not know whats going on.... Any suggestions ?

b) If I play with the pedal and push it from off idle to WOT it hesitates for a very very small time -> Jets to small or accerlator pump? Not sure. If I drive off with 50-70% pedal down it does NOT hesitate...

Thanks for any comments....

Regards from Austria

Concerning point (a) see if others have any ideas.  My understanding is that the throttle shafts are not directly connected to any particular gas filled reservoir in the metering blocks that could leak to them.  Is there gas leaking onto the blades of the throttle shaft, or from the gasket between metering blocks or fuel bowl and the main body?

Concerning point (b) If it is the Jets, then it will be lean at WOT and high RPM.  Have you checked the plugs to see if they give symptoms of being lean?  Usually, once the jets are set, hesitation with the pedal push to WOT is the accelerator pump system (make sure it squirts as soon as it is touched)  If that is the case, change the accelerator pump cams (what color is on there now).  I would think something like an orange cam is a good place to start.  You can also work on the squirters (nozzles) on the accelerator pump, but I would start with the cam.  What Nozzle is on the carburetor?

[sccachallenger]

For a, does the pump lever move as soon as the throttle is opened?
sometimes there's a little slack that can be adjusted out by that bolt with the spring on it, lengthen to take out slack.
For b, your secondary float level may be too high.
Other possibilities are leaky needle and seat, and/or o-rings on needle if you have external adjustment.
Finally, what was ambient when this happens?
Excess heat can raise the fuel level, more noticeable after shut down on hot days.
Adding a heat shield under the carb, and blocking the exhaust crossover in the intake manifold will help.
Glad you're back behind the wheel!

[rollo1504]

Hey,

The pump lever move as soon as the throttle is opended but I will try to lengthen that bolt -> Have read between the bolt and lever should be 0,015" of space when lever is at WOT...
Will check the needle and seat at secondary float bowl again (have been already renewed) ... No o-rings as this carb does not have external adjustment

Ambient was a normal sunny day with around 66°F. Further a valley pan with blocked heat crossover is already installed but will also check this out closer as I will redo the sealing of the valleypan very soon.

Aluminum spacer with 0,5" is also already in use.

I really don't believe that it is a fuel boiling problem or a heat problem.

A good idea might be a problem at the gaskets between metering blocks....will also check this...

Actually a yellow cam with screw in hole Nr. 2 is used but I have a sortiment of all other colours as well.... Will try the orange cam.

Size of actually used nozzles is 31.....

Also want to mention that I live around 2500 ft above sealevel....

Yesterday removed the old spark plugs and the positive thing is that all of them are looking exactly the same but the negative thing that all are completely black.... So I would assume that the mixture is way too rich but on the other hand I have to say that its NOTreally puffing that much black smoke out of the exhausts .... Will keep investing on this as well....

I know that I am almost there comparing where I was at the beginning as everything was set up completely wrong....

But as I many times said I am not a mechanic but I am after it to increase my knowledge about this great piece of american history.

Thank you mopar guys

Cheers Roland

[XH29N0G]

I am a little confused by the yellow cam comment.  I have a large yellow cam with my set, but it fits on a larger diameter throttle shaft and is for a 50 cc dominator pump. My guess is that your yellow cam is not this one.  Using hole #2 is supposed to delay the shot a little.  It might be that you should be using hole #1.  There is some information on the youtube video by Holley https://www.youtube.com/watch?v=eiRIfcrc2yA on pump cams that I found useful.

After rereading some of the previous posts, I have some questions and want to make sure I understand your set up.

You have a 400 ci engine and it has a stumble when you step on it. My discussion assumes it is a lean stumble (not getting enough gas) rather than being too much gas (rich bog).

Are you still using the 4160?  I am guessing from what you have written that it is the 4160 rather than the Street Avenger you mentioned in an earlier post.  I assume the jets are what it came with.  Do you know which ones are in it?

For what it is worth, I found with a 670 street avenger that I needed to increase jet sizes as described in an earlier post.  While this was for WOT A/F and that also made a difference with what cam and squirters I needed to use.  I had a manual 383 with 3.23 gears and found that the orange cam hole 1 with 035 to 032 squirters worked well for me. 

[rollo1504]

Hey,

I am still using the 4160 as I want to "set it up correctly" before I swap to the avenger... Lets say its a kind of training of myself...playing around with the old one before installing the new one...

Thanks for the video link.... I also found a great vid concerning adjusting the accelerator pump.... will check this things out again...

The "old" 4160 which is still in use has a 31 noozle and 64 jets installed....

Concerning the pump cam colour and setting I will also check again to be 100% sure how it is set actually....

For further testing I am already prepared as I have received a tuning kit which contains nozzles, pump cams and a sortiment of jets....

Regards

[XH29N0G]

OK,  See what you can do with the cams and nozzles. I bet you can get pretty close.  If it seems like you are needing to really push things then the problem may be somewhere else.

If it comes to working with the Jets you will need to have a way to gauge the A/F at WOT and up at high RPM.  This can be done by reading plugs (I am not good at that) and it can be done with an A/F gauge.  Someone may know what jets are good for your engine and carburetor, but that isn't me.

[sccachallenger]

Sounds like you're doing all the right things to keep the carb cooler.
I would think if it was a gasket causing the dripping fuel, it would also drip while the engine is running, not just after shutdown.
lowering the float a small amount may be all you need.
I think you understand that changing the pump cam will probably mean re-adjusting the spring on the lever.
And make sure you're not overtaxing anything at wide open throttle, with the new cam/lever position.
And changing to a larger nozzle size is pretty easy, and may help your problem.
I don't understand why the plugs are black, is the vacuum advance hooked up?
Are they the correct heat range spark plugs?
Does the choke open all the way when warmed up?
Are you running a thermostat in the engine?

[XH29N0G]

I missed that about the plugs.  All of those are good points.  I also believe it is possible for excessive idling to lead to carbon deposits on plugs which is black (oily black is wet looking).  The time I had it was a combination of idling and heat range.  For reading plugs, I am told you want to test them after running it up through to WOT. 

[rollo1504]

Hey Folks!

- Installed new orange pump cam and put screw in to 1 as it was installed a ?yellow? cam and screw was set to 2.
- Adjusted pump cam to lever distance to 0,015" as it was around 0,030"

- Installed fuel pressure gauge -> Shows permanently 7,5-8 psi when engine is in idle or at WOT ... ... ... car was not driven... Motor was in Park

- Experimenting with noozles -> Status = pending
- Experimenting with jets -> Status = pending

- Took a picture of the OLD plugs (please see enclosed pix) -> ATTENTION: These plugs have been installed eversince I got the car 3 years ago.
Installed new NGK plugs recommended by RON -> Visual check of new plugs -> PENDING

- Manual Choke installed -> Choke does open all way when engine is warmed up and there is no binding at all
- Installed new thermostat and thermostat was working fine but will check temperatures again next time

- Have also seen dripping fuel from secondary shaft when engine was running !!! I have read somewhere that there should be some teflon bushings inside. May they be damaged? Do they also normally prevent dripping fuel?....

>>> When engine is warmed up and pedal is pushed it revs up pretty fine BUT I could find out when pedal is pressed AND hold around 30% after 2-3 seconds engine stumbles just a little bit and sometimes it detonates out of the exhausts -> It does NOT backfire. If then pedal is pushed more or to WOT everything sounds nice. No backfire nor detonation at exhausts<<<

If I drive it it pulls pretty nice through all RPM ranges.... As said If pedal held for a couple of seconds at 30% it begins to stumble for a short period... If pedal is pressed more then it continues revving up without any problem.

Thanks guys! You are great!

Roland

[BSB67]

- What problems still persist:
a) If engine is shut off after driving around and I let the car in park after some minutes I still can see that fuel is dropping out from the secondary throttle shaft on both sides of the shaft - One drop every 3 minutes which stopps after 15 minutes..... Still do not know whats going on.... Any suggestions ?

b) If I play with the pedal and push it from off idle to WOT it hesitates for a very very small time -> Jets to small or accerlator pump? Not sure. If I drive off with 50-70% pedal down it does NOT hesitate...

a)
- Are any of the boosters dripping during idle or after you shut it down?
- Rear floats too high
- Rear N/S leaking
- Shaft bushing and maybe shaft could be replaced but it is probably not that bad IMO.  The issue is not really the gas leaking, but the vacuum leak that it is likely causing.

b)
- Is the bog you describe in park/neutral our under power going down the road? 
- Have you visually checked to see if the squirters are actually functioning properly?
- float on primary side too low
- Power valve opening too late.
- Squirter too small
- some spec of dirt someplace it should not be in the carb
- timing
- idle mixture too lean (possible, but less likely)
- vacuum leak (unlikely based on your description)
- IFR too small (unlikely)

[sccachallenger]

I think the only way fuel can drip from the secondary throttle shaft is as was stated, the boosters on that side are dripping.
Take a strong light and look into the secondary side, you shouldn't see any fuel dripping at idle!
Which we believe can only be caused by the reasons given.
Now, If you have a way of lowering that fuel pressure, I'd certainly try to get it below 6 lbs at idle.
But ONLY after verifying that float, needle and seat, and float level are "perfect"

[rollo1504]

Hey,

@BSB67: Sorry but what does Rear "N/S" leaking mean?
- Concerning the floats I need some time as you know it is a closed system
- Is the bog you describe in park/neutral our under power going down the road?
> I would not call it a bog, I would call it stumbling and YES it is also when engine is in Park/Neutral.... How it behaves under load I still need to test...
- Have you visually checked to see if the squirters are actually functioning properly?
> As far as I can see it I would say they are working as they should but I will make a video and put it to youtube that you guys can see it....

@sccachallenger:
You mean the venturi boosters? No was not able to see it but will also check it again..
Fuel pressure: Actually a new stock mechanical fuel pump is in use.... And the newly installed gauge tells me 7,5-8 psi BUT i have another testing gauge... I will hang this one in as well to ensure that both gauges are telling the same story.... Do you guys know about stock mechanical fuel pumps which provide more than 6,5 psi? I do have a fuel pressure regulator from Holley but not installed yet.... If the other gauge is also telling around 8 psi then I will install the regulator....

New questions:
Today I just had a little bit of time to have a closer look to my NEW Holley Street Avenger carburetor.... and the very first thing what I could see was that the T-Slot at the secondaries is completely covered and not adjusted to look like a square.... So my question is now: Is this correct? Just asking as I might think to have read somewhere that it is very important to set the secondary throttleblades so that the T-Slot is looking like a square but on this completely new carb the T-Slot is completely covered.... So is that right? Is the "square"-adjustment only important for the primaries or ALSO for the secondaries?

If motor is warmed up, it idles very smoothly with new dist from Ron and if set IN GEAR - my vacuum gauge tells me 16,-17 ... Is this a good value?

Next question which came right now to my mind is to check if the throttle plate which is mounted to my old carb is really a correct throttle plate for this application..... Will check that as well.... Just to be sure...

Did not have more time for testing today but will continue tomorrow.....

Thanks so far

Roland

PS: Will try to make a good video to give you guys an overview about the actual situation....

[BSB67]

Again - Check for dribble from the boosters. This takes 30 seconds

Check the float levels.  It is the next thing to do.  It'll take 15 min.

You cannot tune the carb by winging the throttle in park/neutral.  The only way to diagnose and tune off idle is by driving it.  Don't try to tune it that way.

N/S = needle and seat.

You need to check the basics I listed.

[rollo1504]

Hey Folks!

First the "good" news:

- I was driving around near my house for about 20 minutes and tried several things
a) Steady drive with around 35-40 MPH -> Drives perfectly
b) Start off idle to WOT -> Succeeded in doing a small burnout. The only thing which I could notice (BUT ONLY ONCE) -> was a single detonation at the carb but could not reproduce it...
c) Checked dripping fuel at secondary throttle shaft with several stopps on the road -> NO DRIPPING!

- Installed a fuel pressure regulator as without it there is a pressure around 7,5-8 psi
a) Drove around WITH regulator installed at 6,5psi - Drives fine
b) Drove around WITHOUT regulator at 7,5-8 psi - Drives fine and behaves equally as WITH fuel pressure regulator.....

- Checked if secondary boosters are dripping fuel when warmed up engine is in park and idles AFTER coming back from pushing her down the road:
> NO THEY ARE NOT!

- What else did I find:
> I could find out that fuel drips when engine is shut off AND I could also see that ALL 4 srews which hold the intake manifold to the heads are SWEATING....So another culprit in my opinion is that I really need to renew the sealing of the intake manifold.... Will do it as soon as possible.

Open points:
- Checking the float levels -> Question please: HOW to check this if primary and secondary bowls are completely closed. I do not have the possibilty to see the float level. Neither are is a screw to remove to see the level nor sight windows.

And NOW the BAD NEWS:

My old 4160 carb is BROKEN  
As I was removing the squirter to check again which size it has I could see a small peace of the thread where the screw which holds the squirter in place broke off......

I had a closer look at the thread and could see that it was completely worn out and damaged as well by one of the f...... preowners........

So I cant use the carb anymore and I will have to continue with the new carb....
Buying a new mainbody does not make sense for me.....

So I will remove the intakte an redo the sealing as RON kindly explained me how to do it....


Will be back soon....

Thanks for all your inputs...

Cheers Roland

[sccachallenger]

Sorry to hear about the damaged threads, I've not had this problem, previous user may have overtightened due to missing/damaged gaskets leaking.
Do some searching, there may be a repair procedure.
I may have missed this, but we're assuming your vacuum advance is hooked up and functioning properly? This is very important for fuel economy and cleaner spark plugs.
Your spark plugs look dry to me which is good, but way too black!
if it's working properly, try a leaner main jet
Hope someone comes up with a repair procedure for the nozzle screw, they don't need to be very tight if both gaskets are in good shape.
I might try using a little epoxy on the threads to hold it in for now.

[rollo1504]

Naaaah...

Won't waste time right now on repairing it...

Will continue with the new carb but before I will take the opportunity and will remove the intake and valley pan and redo the whole sealing first ...

Vacuum advance is hooked up and works as far as I understand it...

Have checked the noozle screw on my new carb, and yes you are right, they really are not very tight...

Regards

[rollo1504]

As I said it was time to take the intake off....

And what could I say?? 

Have a look on your own....

Will post again pictures as soon as it is cleaned....

Roland

[rollo1504]

Guys!

Can someone please tell me the amount of torque I need to bolt on the valley pan....

Is the torque needed for the intake manifold screws the same as the torque needed to bolt on the endstraps of the valley pan?

Can't find them actually....

New valley pan arrives tomorrow and I do not want to waste time looking for the torque specifications then...

Thanks!

Cheers Roland

[sccachallenger]

fasteners are very small, don't over tighten!
I think 15 foot lbs. should be plenty!
Truthfully I doubt I ever checked, just went by "feel" and used a little sealant on the block.
40 is way too much, you'll stretch or break them.

[rollo1504]

Ok. Thanks! Will consider that....

Will be back soon with some results....!

Roland

[BSB67]

35 I think.

1) did you check for leaks from the previous set up?
2) be sure to check that the intake and head meet up properly.

Intake gaskets don't just start leaking.  If it was actually leaking, it's likely an alignment issue that won't fix itself by replacing the pan.

[rollo1504]

Hey,

1) Could find out that the teflon "bushings" inside of the sec throttle shaft were completely worn out/damaged... Do not ask me how this can happen... Maybe some poor guy installed them wrong or with wrong tools... Don't know...Further comparing to the first float bowl it seemed that the sec float level was correct but the needle was not well installed during rebuild which could have caused the issues I had but will not find it out anymore because I can't use this carb with the broken main body anymore...

2. The amount of RTV for the sealing of the intake manifold was way too less and obviously the bolts were torqued way too much which obviously destroyed the sealing. Further around the heat cross over there was no RTV used at all as well as NO gaskets have been used at least...

3. One of the screws which tighten down the strips of the valley pan broke off obviously during last bolt on process... This also lead to malfunctioning of sealing the valley pan 100%...


That was (I think so) the root cause of fuel "dripping" and being inside the valley pan which I asked for what it is in the very first picture of this thread...

Ron (firefighter) was very kind and told me exactly how to install the new valley pan and how/where to use the RTV in a correct way to get a good sealing without any leak not using the paper gaskets...

I will do it as Ron described it....

Will post more pictures later after the cleaning and installation process so that you (experts) :-) can see what I am doing....

Thanks for all you greatness and suggestions.... Would really have been lost without you guys..

More to come soon...

Regards

Roland

PS: Sorry for my bad english again and the mistakes I made during writing this post but hopefully you understand what I want to tell you.... :-)

[sccachallenger]

Glad your float level was "correct", you can still try a lower setting as a tuning tool.
This is what we were trying to tell you.
Also, many people will hold a carburetor or fuel bowl assemby upside down and blow into the fuel inlet, lifting the float will let the air escape, should stop when you let go.
This may reveal a loose or worn needle and seat.
Worth doing on a brand new carb. as a test.

[rollo1504]

Damn!

Cleaned, everything today, re-sealed pan and intake... snugged down the whole thing... Final bolt on will be done tomorrow....

BUT

as I was completely connected to the "Matrix" during work, totally focused not making anything wrong... I completely forgot to take some pictures for you guys....

SORRY!

What have I done so far:

- Removed intake manifold, old valley pan, old sealing and cleaned everything as good as possible and took care of preventing dust and dirt going somewhere into the head ports, camshaft etc....
- Put RTV around cylinder head ports as well as along the bottom end of the head casting from end to end underneath the intake ports
- Put a bead on the ends of the block with an extra dab in all 4 corners
- Put valley pan in place, installed end straps end bolts and just snugged the bolts down enough to keep valley pan in place
- Put RTV around the intake port openings
- Set intake manifold in place, installed bolts and just snugged them up enough to hold intake in place

- RTV is now curing overnight and well be finally tightened down tomorrow....


Thats how Ron described it to me to do so....

Regards

[rollo1504]

Well guys I am back with really good news!

Tightened everything down with personal feel and I think it is working!

Installed new carb and adjusted idle mixture, idle speed, fuel levels... As I am living 2400 feet above sea level I decreased main jets one size.
Engine idles very smoothly (vacuum gauge shows steady 17 in PARK) and drives great overall. No backfire/detonation under full load.

If start off WOT it pulls nicely.... maybe it just hesitates just a little bit but then pulls straight through all RPM ranges smoothly.

Was her driving around for about 20 minutes and checked then intake manifold and valley pan concerning fuel leaks - NOT EXISTANT ANYMORE !
So I think I did the sealing right....

What "problem" or "misbehavior" I recognized 2 times after letting off pedal when it WOT was that engine stalled. I went from idle cruise to WOT and after a put my foot quickly off the pedal so the RPM dropped and 2 times then the engine stalled.... Tried to reproduce the error but was not succeeding in it. I think if I remove foot from pedal after WOT very quickly the engine comes close to stall. If I put off my foot not that quick engine feels like NOT coming close to stall....

Can you tell me concerning this behavior where to look at?

Did NOT touch the squirters, power valve, pump cam and pump lever so far - Its still all factory set....

Will "tune" it later furthermore.... But for now I am good to go ... Am I?

Will try to make a video for you guys to hear/see how it idles and sounds like....

But for now have a look at the enclosed pictures...

Thanks!

Roland

PS: Sorry forgot another thing to ask... If I put her IN GEAR the vacuum pressure drops from 17 to 12 or 13.... Is that a normal value? Should the vacuum when in gear not be around 10? Just asking...

[cdr]

for one thing ,get that fuel line OFF the upper radiator hose 

[rollo1504]

Will do it! I know that it is very important to keep fuel lines away from heat sources!

It was just for a short testing... Will reroute the fuel lines anyway very soon... but thank you for the concern.

Roland

[BSB67]

Looks good.  Nice job.

[firefighter3931]

Great work Roland....the project turned out very well. You're getting a handle on this Mopar thing 

The slight hesitation going wide open is normal for a vacuum secondary carb....nothing to worry about. I would recommend setting the idle at 750-800 in gear (drive) which should help with the stalling out issue. 

Vaccum readings are fine....the idle vacuum might increase with an increase in idle speed 

Nice improvement on the looks and performance 



Ron

[rollo1504]

Hey!

Ok Ron...!

Thank you all for helping me!

This service is priceless to me... 

Will come back for sure later with other normal and dumb questions....

Next steps:

- Fine tuning via reading and hopefully understanding spark plugs
- Uprade fuel lines to 3/8"
- Install mech fuel pump edelbrock 1723
- Install 3/8" fuel sending unit
- Install front and rear shocks

Will see what problem will come up next....

Thaaaaank you guys!

Regards from AUSTRIA