B&M Converter is bad

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Ok, Im about to throw my hands up! Just so you know Im holding off on trying to time this car until I can get these resolved.

New issues and questions.

1st issue, I found a vacuum leak on the carb body today. Well actually it was around the top plate that bolts down for the floats. Initially I sprayed carb cleaner around the base of the carb and intake manifold and no leaks. Tonight for some reason I decided to check the entire carb. Sure thing, pretty much the entire fuel inlet side and front side of the carb leaks. Im ready to throw this thing out into the trash. I almost dont want to spend the money on a new gasket kit for the carb if its warped or something else.. Not sure if that will take care of it.

2nd issue, the idle bounces a couple hundered rpm as Im trying to time and tune it... Again not sure if its from the vacuum leak.

3rd issue, my timing fluctuates about 3-4* as Im trying to set the initial. Say I was trying to set it at 15* it will change from 12-15 if I start under the 15* mark or 15-18 if I start at the 15* mark. Although once I have it set and rev it up to check mechanical its nice and steady, dead on the mark. Again is this from a vacuum leak?

Now my questions.

1st When you guys have the vacuum gauge hooked up, does it bounce all over or is it a steady reading? Mine will bounce about 2-3 pounds when trying to adjust. Im just trying to figure out if that is from the vacuum leak or is natural.

2nd I need clarification on the idle screws to max vacuum. This is what I have been doing. Turn each screw out until I reach max vacuum. Then I adjust my idle to 800. The vacuum will drop. So I will turn them out again until max vac is reached and readjust my idle. I've done that 3 times and I get almost 3.5 turns out until I no longer get any more max vacuum.

Is that the correct way to do it or only do it once. Get the initial set and locked down, then turn idle screws out until max vac is reached. Then reset idle to 800 and be done with it?

Im taking a break from this car until I can see if I can find another carb to use and try on this car. That may or may not have been part of my issue.
 
Since you've discovered what I'd call a fairly serious leak(s)..........don't worry about the vaccum gauge or setting the idle until you get that fixed. By the way, horsing down on the carb bolts is a sure way to CAUSE a base leak. Hold your ratchet up by the head like a screwdriver with your hand wrapped around the top.

Timing jumping, could be something worn in the dist, drive, or cam gear, or even the block bushing, but if it's not idling smooth, that will cause it too. Again, fix the leak.

Sounds like you have gained some ground so try to keep "un" frustrated.
 
67Dart273 said:
Since you've discovered what I'd call a fairly serious leak(s)..........don't worry about the vaccum gauge or setting the idle until you get that fixed. By the way, horsing down on the carb bolts is a sure way to CAUSE a base leak. Hold your ratchet up by the head like a screwdriver with your hand wrapped around the top.

Timing jumping, could be something worn in the dist, drive, or cam gear, or even the block bushing, but if it's not idling smooth, that will cause it too. Again, fix the leak.

Sounds like you have gained some ground so try to keep "un" frustrated.
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Thanks for the input.
Just so you know, the leak is not at the base of the carb but actually the upper portion of the carb.

I know the block has a new bushing for the distributor, but the distributor itself is original and who knows how old and how much play it has. I will see if I have another for the future.
 
Just a couple quick thoughts until I can digest all the new info............

1) 3" of vacuum fluctuation is quite a bit with a fairly mild cam. But, if your gauge is connected to a port that's over a single intake runner, it can happen. Mainly because it's reading pulsations, unlike if it was on the carb base or plenum.

2) If you were trying to spray the top section of the carb for a vacuum leak, chances are the primary side of the air horn was pulling it in, giving a false reading.

3) That's a lot of bounce in the timing. My first thought would be your mechanical springs are too light and the weights are at the opening point a little too early.

Like I said, i'll think on it some, and watch what some others have to say.
 
I would like to thank those that have contributed to this thread....even though some of the things being covered are basic it does not hurt to see them being discussed....seems like everyone has there own unique ways of doing things and stuff they look for....this thread has been informative to say the least.....Thanks for the refresher course......
 
OldmanRick said:
Just a couple quick thoughts until I can digest all the new info............

1) 3" of vacuum fluctuation is quite a bit with a fairly mild cam. But, if your gauge is connected to a port that's over a single intake runner, it can happen. Mainly because it's reading pulsations, unlike if it was on the carb base or plenum.

2) If you were trying to spray the top section of the carb for a vacuum leak, chances are the primary side of the air horn was pulling it in, giving a false reading.

3) That's a lot of bounce in the timing. My first thought would be your mechanical springs are too light and the weights are at the opening point a little too early.

Like I said, i'll think on it some, and watch what some others have to say.
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Rick, Im using the carb manifold port, I made sure that it was not being sucked into the car while spraying it and the other side of the carb did not react and was not higher or lower than the side that made the rpm change, Im also using one light spring and one stock spring.

FYI, I noticed that the rpm fluctuates 1-150 as I was trying to lock down a specific degree. I think this may be because of the vacuum leak. Also when I sprayed the cleaner on the carb it changed the rpm from 800 to 1300 max so it is a big vacuum leak and I think that may be causing the bouncing timing and vacuum but wanted your opinions.
 
inkjunkie said:
I would like to thank those that have contributed to this thread....even though some of the things being covered are basic it does not hurt to see them being discussed....seems like everyone has there own unique ways of doing things and stuff they look for....this thread has been informative to say the least.....Thanks for the refresher course......
Click to expand...


Ink, I could not agree more with you! This for sure has been very informational and I have a very good idea on how to actually time a car now.. I dont think this would have been so long if it wasnt for all my problems!

Hell someone has to have problems right?

Thanks to EVERYONE that has posted something on this thread. Everyones input is welcome!
 
Just to make sure that the leak on the carb you think you found is in FACT a leak on the carb. I would suggest if possible....installing the air cleaner, putting a "straw adapter" (the little red spout attachment normally) on your can of carburetor cleaner so that you can direct the flow more precisely. and then try spritsing the area you think the leak is at.

like someone else had mentioned....being that the "leak" is near the top of the carb.....it may actually be the vacuum of air going down the throat of the carb sucking the vapor in and raising the idle causing you to think that you found a leak when you didnt.

doing the trick I mentioned with the air cleaner on may rule that possibility out.

and if you find it still leaks then COOL.....why cool?....because odds are you have found your problem....or at the very least a contributing issue.
 
Ok gentleman, I have been very busy and was finally able to get the car back together with the new carb, plugs, wires, cap and rotor.

I went with the Holley Street Dominator 670 carb and once fired up and timing adjusted to 10* to start I hooked up the vacuum guage. Its nice and steady now, maybe moves 1 to 1.5 on the vacuum gauge. Big improvement!

I set the carb up at 10* initial, adjusted the idle. Then tweaked the mixture. Took it for a drive and still cant do a brake stand.

Here is what I do know from when I was adjusting everything prior. The mechanical in the dizzy is 20*, after my mods to the cam plate. This gives me 30* total. So I will bump up the initial. Now if I get it all dialed in and Im still having the same problems with the way it drives what do you think the problem could be?
 
Bump it to 15 initial. Reset the carb settings using the vacuum gauge.

What RPM is the total all in?

As long as it doesn't ping at 15 initial, bump it up a degree or two until you find the pining point. Back it down from there and see where it is. As long as it starts when hot, run it there.
 
crackedback said:
Bump it to 15 initial. Reset the carb settings using the vacuum gauge.

What RPM is the total all in?

As long as it doesn't ping at 15 initial, bump it up a degree or two until you find the pining point. Back it down from there and see where it is. As long as it starts when hot, run it there.
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I will give that a try tomorrow and let you know when it is all in.
 
You need two thick steel plates about one foot square and a big press , place the edelbrock carb between the plates , and press it until the snapping noises stop. Best thing for any carb based on a carter design , for the good of humanity.
There is no way that tiny little cam should idle at 1200 , something is off. Vacuum leaks?
 
Ftw said:
You need two thick steel plates about one foot square and a big press , place the edelbrock carb between the plates , and press it until the snapping noises stop. Best thing for any carb based on a carter design , for the good of humanity.
Click to expand...

I say the same about Holleys!!!...Take that!!!
 
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