Author Topic: Six Pack issues and rebuilding (Read 150019 times)

tommyg29 · « **Reply #285 on:** November 18, 2014 - 04:54:20 PM »

Quote from: Chryco Psycho on October 14, 2014 - 07:20:21 AM

The 600 or 1600 idle is one of 2 things , 1600 rpm is running off the boosters , 600 is on the idle circuit so you need more air flow without uncovering the idle transfer slots so you have to drill holes in the throttle plates so it ill idle between the 2.
It could also be in the mechanical advance , if the springs are too light it can change the timing at idle causing the speed to flare up

It must be the idle circuit. Prior owner had small copper wires down into the openings and I removed them over a year ago.
When I place new wires of similar small gauge (or put my fingers over them) the idle raises a lot.
I think I will remove the main and check the transition slots again but Im pretty sure they were more or less square. Then Ill drill the 3/32 holes and see what it does with and without the copper wire trick (which looks rigged)
edit
After removing the main, the throttle shaft spring is not closing the blades all the way. Is there a replacement shaft spring, or can I just twist it another revolution? But... even when I force the blades closed they have lots of light showing through around the edges when the idle slot shows square. Also, I noticed the shaft spring is enough to shut the blades when the throttle plate is off the carb, but when the base is mounted, and it has to also push on other levers, it isnt enough tension to close the blades by itself. Im sure when mounted on the manifold though the addition of the main throttle return spring helps it to fully close.
Btw, the idle screw had been turned in too far, exposing almost the entire slot, so at least I fixed that.
Im going to put it back on without drilling holes yet and see if my minor tinkering has helped any.

cuda346pk · « **Reply #286 on:** November 18, 2014 - 10:31:13 PM »

I had to file edges of my throttle plates to get them to seal good in each carb. Also be careful tightening down the carbs. They warp easy and then the plates will bind.

AARuFAST · « **Reply #287 on:** November 18, 2014 - 10:51:01 PM »

My

Tommy

start motor Spray with ether or carb cleaner around the manifold, manifold bolts, carb plates. bolts.
My manifold bolts holding the bracket coil
were sucking air. If no increase in idle next steps.

This will cause vacuum problems.>
You mentioned in the first posting the brake booster was full of gas.
You have done everything I would have and have done with my AAR 6 pak.

Since the booster was full of gas, did you check the vacum on the brake booster.
Did you check the valve on the booster to see if it is operating with the engine vacuum

1. is the brake pedal hard to press when car is running? Do you need to pump the brakes?
2. disconnect the brake booster hose and plug it.
3. run the motor and see if the idle changes. Switch the hose back and forth on the booster.
4. if the idle changes and it runs smooth. the brake booster is damaged from filling with fuel. If the brake pedal is hard you damaged the booster when it filled with gas. This affects the vacuum over all ..
6. I would need to read more if you have electric fuel pump, can you turn it off and run the motor
until the fuel emptys from the carbs?
Start it to get the fuel bowls up. Turn electric fuel pump off and run the motor until bowls empty to see if it runs ok.
be sure the accelerator pump is set correct.

Good luck.

Chryco Psycho · « **Reply #288 on:** November 19, 2014 - 12:02:29 AM »

Are the throttle plates properly centered , if the screws have been loosened the plates could be off center causing the throttle to not fully close, this may not help anyway as you will limit air past the t plates even more adding to the need to drill holes .
Inserting wire in the bleeds limits air flow & causes lower vacuum to draw in more fuel , imagine a straw with a hole in the top [air bleed] , bottom [transfer slot] & a hole in the side where you apply vacuum to draw fuel into the idle circuit from the fuel bowl but this is above the fuel level in the bowl . As you close the hole at the top of the straw the vacuum at the bottom has more effect on pulling fuel into the idle circuit . Drilling holes allows in more air without exposing the transfer slot & will help with engines with lower vacuum at idle as will restricting the air bleeds at the top . , it is easy to see if the brake booster is a problem , just plug the port to the booster & see if the engine runs better .

tommyg29 · « **Reply #289 on:** November 22, 2014 - 02:51:58 PM »

Still hunting...the idle, that is.
Video (click on first picture) shows it hunting from 1500 rpm or so to stumble speed and back and forth.
Brake booster is not a problem.
Thanks for all the replies, especially CP. I know you have told me at least twice in this thread to use 61-62 primary jet, but heres my setup:
Jets- 66 primary, 80 secondaries
6.5PV (I think)
31 squirter
Approx. 6.5 psi fuel pressure
290 cam in position 1
MSD timing 16/36 (more or less)
Cam: Crane hydraulic 302
Getting about 10 inches vacuum at 1000 rpm and 20-21 at cruising speed
Vacuum drops to 5-6 inches at anything in the 700-800 rpm range
From the pictures you can see I just drilled out the primary blades with a 3/32 bit and made sure the transition slot is at a reasonable position. It does seem to be running slightly better since then, but consistent problems remain.
Btw, what is that other small horizontal slot (near the transition slot) in the one barrel for?
I have come a long way. It isnt smoking anymore, and Im getting close thanks to many hours of fiddling with every adjustment screw but I will be happy with a STEADY idle at 1000 if I can manage it.
Oh, and if I can figure why after about 10 minutes of running/idling it just quits out of nowhere. It happened once in an intersection and wouldnt restart for about 5 minutes

but it does it consistently, even just sitting in my driveway.
And still, hard starting. With the choke removed, it takes a while to warm it up, and I dont even think to try and expect it to idle half way normal if it isnt warmed up at least 5 minutes.

In summary, 3 main problems:
- hunts at warmed up idle
- quits after 10 minutes running
- hard starting

AARuFAST · « **Reply #290 on:** November 22, 2014 - 08:25:58 PM »

POWER VALVES:
The number stamped on a power valve, such as 65, indicates the manifold vacuum below which the power valve is operational. In this case, all manifold vacuums below 6.5� Hg, the power valve is operating. Generally a 65 power valve is sufficient for most high performance applications that have a manifold vacuum of 12� Hg or higher. However, some problems can result with radically cammed engines equipped with automatic transmissions. These vehicles often �idle� at 2000 rpm, approx. 6.0� Hg. At this point the main nozzles are starting to feed and richen the mixture (supplied by the power valve) and the engine will probably �load up�. To correct this problem, install a 45 or 35 power valve. If the engine has a manifold vacuum of 12� Hg or less, a good way to determine power valve size is take the manifold vacuum at idle and divide that number by two. The answer is the power valve size. This will provide idling and proper fuel flow under wide open throttle conditions when manifold vacuums seldom rise above 1� Hg.

tommyg29 · « **Reply #291 on:** November 23, 2014 - 01:38:46 AM »

I thought with a 6.5pv I would be good with pressure of 8 inches or more at idle.
Would the wrong size cause my problems of hunting, hard starts and quitting?

Chryco Psycho · « **Reply #292 on:** November 23, 2014 - 08:18:17 AM »

You say you only have 5-6 " of vacuum around 700-800 rpm so I would have no higher than a 3.5 " power valve in there . also is that in gear if it is automatic if not it will drop more in gear ?
You really are at the low end with vacuum & need a lot of tweaking to get it to idle well , the power valve would definatly be causing the hunting at idle . You will need smaller bleeds on the idle circuit so the low vacuum will draw in enough fuel & with the 6 pack the bleeds are fixed so you could restrict them with solder or epoxy & drill them out much smaller or restrict them with wire trapped by the squirter .

tommyg29 · « **Reply #293 on:** November 23, 2014 - 10:37:25 AM »

Thanks.
I will go ahead and order a 3.5 power valve.
And I forgot to mention I have put copper wire down the idle bleeds. That definitely helped bring up the speed.

And PS, I have a 4 speed

Spent last night troubleshooting an ignition problem. It was cranking fine, but no spark. Charged the battery up a little bit and it worked.
I read the MSD is very sensitive to the volts while cranking. Worries me since thats never happened before

HP_Cuda · « **Reply #294 on:** November 23, 2014 - 01:05:47 PM »

Yeah the MSD ignition box wants to see nice voltage from 11-12V but I hear it will work down to 7V. Of course I have never gone there.

Originally when this problem started I thought you said that you had like 12" vacuum at idle and now it's like 8"? If that is the case, two things may have happened - you changed your cam or you have a nice vacuum leak. I'm leaning towards the leak because you say the motor is hunting when trying to idle and the is a sure sign.

What kind of cam are you running on this motor?

tommyg29 · « **Reply #295 on:** November 23, 2014 - 02:41:47 PM »

I must be loosing volts somewhere to the ignition box, because the starter was cranking over strong.
Anyways, I ordered a 3.5 PV, and some 62 jets and new idle screws and metering block gaskets just in case, since Im going back in (for about the 10th time).
But....the car is running MUCH better today. Started right up (almost) and idled and ran fairly well.

Idling in my driveway in the beautiful 72 degree weather this afternoon:

tommyg29 · « **Reply #296 on:** November 27, 2014 - 12:29:15 PM »

Happy Thanksgiving!
My Holley stuff from Summit arrived yesterday so this morning put my primary back together with 35 PV, 64 jets and replaced one of the idle screws.
I noticed none of my idle screws were identical. The points on them were different, and even slightly different lengths. Crappy production quality?
I decided to use the two middle screws as they were most similar and had decent points on them. The one on the left had no point. New ones are on the right.

Not sure if these screw changes made much difference but after putting things together it seems to be running better, and idling with a small hunt between 850 and 950 rpm or so.
Vacuum is fairly steady about 10 inches at 900 rpm (give or take same as before) but vacuum drops quickly and gets very erratic once rpm drops to 800 or below.
Took some fiddling but my screws are out a little more than before, from about 5/8 turn to about 1-1/8 turns out. Seems to run decent there, but still doesnt want to start right up again after its been running a while. Have to let it sit a good 5 minutes before it will start.
Also checked timing and it seems to be about 14/32. Its a MSD6AL system so Ive never fiddled with it.
I'm getting closer.

HP_Cuda · « **Reply #297 on:** November 27, 2014 - 02:18:02 PM »

Check your voltage from the red wire to your MSD6AL.

Btw, what is your voltage at the coil?

tommyg29 · « **Reply #298 on:** November 27, 2014 - 02:29:23 PM »

Quote from: HP_Cuda on November 27, 2014 - 02:18:02 PM

Check your voltage from the red wire to your MSD6AL.

Btw, what is your voltage at the coil?

I will check, but...I think my alternator isnt putting out. Im having to charge up the battery and it seems voltage at the alternator at idle is about 11.75. Battery will charge with my tender up to about 13.5 volts, but with a bad alternator it doesnt last long.
How do I check coil voltage?

HP_Cuda · « **Reply #299 on:** November 27, 2014 - 02:53:33 PM »

When mine is idling my voltage at the battery shows about 13.15V or thereabouts.

To measure any under hood voltage I make it easy on myself and put the negative probe from my multimeter and wedge it into my negative terminal. Then I can take the positive and check the positive side of the coil. You can then check voltages at your ballast resistor and check output from your alternator as well. Be careful not to short the probe to anything as you will get one heck of a eye opener near the alternator.

Sounds like you will need to swap out your alternator, which I recently had to do - at this time most folks say to swap out the voltage regulator at the same time but I will give you a warning. The guy who swapped out my alternator and voltage regulator at the shop didn't securely ground the regulator and hence I had an overcharging condition. To securely ground the regulator make sure it's making good contact with the firewall and make sure it's nice and snug.

Once you have these voltages let us know.

Author Topic: Six Pack issues and rebuilding (Read 150019 times)

tommyg29

Re: Six Pack issues and rebuilding

cuda346pk

Re: Six Pack issues and rebuilding

AARuFAST

Re: Six Pack issues and rebuilding

Chryco Psycho

Re: Six Pack issues and rebuilding

tommyg29

Re: Six Pack issues and rebuilding

AARuFAST

Re: Six Pack issues and rebuilding

tommyg29

Re: Six Pack issues and rebuilding

Chryco Psycho

Re: Six Pack issues and rebuilding

tommyg29

Re: Six Pack issues and rebuilding

HP_Cuda

Re: Six Pack issues and rebuilding

tommyg29

Re: Six Pack issues and rebuilding

tommyg29

Re: Six Pack issues and rebuilding

HP_Cuda

Re: Six Pack issues and rebuilding

tommyg29

Re: Six Pack issues and rebuilding

HP_Cuda

Re: Six Pack issues and rebuilding