Strange spark plug problem. I can't get #3 threaded in properly.

[biomedtechguy]

UPDATE!! I was checking in with my best friend and Mopar brother who just got a 1970 340 Duster that's set up as a drag car, to see how his first track trip went. I wasn't able to go unfortunately. Anyway he suggested I talk with a mutual friend, local guy, who has a 70 AAR "tribute" Cuda, 340 6bbl.
EUREKA!!
I believe I have a leaking center carb POWER VALVE. I am going to be under the hood between today (maybe, I have work nearby out of state) definitely Saturday, and hopefully I will be finished and won't need Sunday for repairs.

 

[biomedtechguy]

ANYONE who runs the Holley 6bbl carb system should know how much EASIER it is, by leaps and bounds, to use a braided flexible fuel line system like the Promax system I have, especially if you are going to be tuning, troubleshooting or racing your car!!
I only had to back off 3 fuel line connections to remove the front outboard carb and then the fuel bowl and metering block were ready to come off the center carb!!!
I numbered the 3 fittings I had to loosen:

I've decided to bring the fuel bowl and the Promax metering block with the Power Valve in it to the "brick and mortar" speed shop I'm going to in the morning. It will (should) make it easier for me to ask a few questions and for them to discuss.

 

[biomedtechguy]

Replacing the old PV on the left that looks like it was IN A "LOCKER" at "DAVY JONES AUTO PARTS" has GOT TO make my 440 6bbl run better!
I use NO ethanol premium almost every time I fill up.
Maybe I'm going to have to keep the gas tank full of no ethanol premium and use a good "fuel life longevity" focused additive to keep the moisture out of my 6bbl?

 

[khryslerkid]

Replacing the old PV on the left that looks like it was IN A "LOCKER" at "DAVY JONES AUTO PARTS" has GOT TO make my 440 6bbl run better!
I use NO ethanol premium almost every time I fill up.
Maybe I'm going to have to keep the gas tank full of no ethanol premium and use a good "fuel life longevity" focused additive to keep the moisture out of my 6bbl?
View attachment 1470966

I'll use ethanol free for winter storage but 10% during the summer months when it gets driven periodically. Just a few ounces of Stable 360 per fill up seems to keep the corrosion away.

 

[4406bbl]

Replacing the old PV on the left that looks like it was IN A "LOCKER" at "DAVY JONES AUTO PARTS" has GOT TO make my 440 6bbl run better!
I use NO ethanol premium almost every time I fill up.
Maybe I'm going to have to keep the gas tank full of no ethanol premium and use a good "fuel life longevity" focused additive to keep the moisture out of my 6bbl?
View attachment 1470966

Problem is you never know what you are really getting at the pump, have had good luck with straight race gas or additives thru the years, but also always find a way to run the bowls dry by either shutting down the pump or pulling a line before storage. That is impressive damage on that power valve for one season of storage.

 

[4406bbl]

With flex lines I would be pulling them off, pull a bowl screw out, blow them out with air.

 

[biomedtechguy]

Last UPDATE before final assembly.
Yes, I know this morphed from ignition to carbs, but for those forum members who check my progress daily (slackers! you should check more often) lol....I will add:
The center carb PV is really the only part that showed moisture issues. I have removed all 3 carbs fuel bowls, used the red straw w/the carb cleaner to blow out every orifice on the carbs I can find and for an overall spray down once over. I also blew carb cleaner in to the fuel inlet while the floats were down to get solution through the needle+seat assemblies.
I am using a dab of this:

on the heads of the fuel bowl bolts as a little insurance for leak prevention, but the hole head contact area has the dark gray "washer" that is like a hard fiber material.
So I'm going to button it all up and hope that I've solved the problem I've been having for months now.

 

[RJRENTON]

Last UPDATE before final assembly.
Yes, I know this morphed from ignition to carbs, but for those forum members who check my progress daily (slackers! you should check more often) lol....I will add:
The center carb PV is really the only part that showed moisture issues. I have removed all 3 carbs fuel bowls, used the red straw w/the carb cleaner to blow out every orifice on the carbs I can find and for an overall spray down once over. I also blew carb cleaner in to the fuel inlet while the floats were down to get solution through the needle+seat assemblies.
I am using a dab of this:
View attachment 1471375
on the heads of the fuel bowl bolts as a little insurance for leak prevention, but the hole head contact area has the dark gray "washer" that is like a hard fiber material.
So I'm going to button it all up and hope that I've solved the problem I've been having for months now.

BTW..... I'D be remiss in not asking......did you ever solve the spark plug thread issue? I've been away eith a few health issues......cheers
BOB RENTON

 

[biomedtechguy]

BTW..... I'D be remiss in not asking......did you ever solve the spark plug thread issue? I've been away eith a few health issues......cheers
BOB RENTON

I certainly did and I will link and copy in a sequential post following this one.
I feel like I should have known of your health issues, certainly if you alluded to or posted about them, ONLY because I want you to be well!
@RJRENTON I am glad you just replied because I want to gather a few forum members in particular (apologies if I miss anyone) for a technical discussion, a journey of discovery and shared experiences that focuses on:
*The FUEL VAPOR SEPARATOR/FILTER
*CARTER M6903 Mechanical Fuel Pump
*BRAIDED LOWER &/OR UPPER FUEL LINES
*WIX 33033 metal enclosed 20 micron fuel filter
*Promax reusable washable 40 micron fuel filter
I am going to open this topic in the "fuel and air systems" forum section. Here's the link:
6-BBL / 6 Pack & Hemi 3/8" fuel line FUEL VAPOR SEPARATOR/FILTER w/Braided fuel lines. How to incorporate as factory did? Or don't bother?

 

[biomedtechguy]

..did you ever solve the spark plug thread issue?

You actually replied right after I posted the last (long) post describing the completion of the spark plug changing SAGA..
Strange spark plug problem. I can't get #3 threaded in properly.

 

[biomedtechguy]

With flex lines I would be pulling them off, pull a bowl screw out, blow them out with air.

I think the meaning of this quoted post has finally become clear in my mind!
Not that it would have changed my plans for how to go about or complete that repair, as I was already beyond the halfway point, I will certainly give this technique a shot in the future!
I believe the consensus is that the old, crusty PV HAD to be replaced, I certainly think so, and I believe there's value in "having a look-see" inside ALL 3 carbs since several years have passed since the last time I had my 6BBL called to muster for an inspection!
BUT
My schedule is usually tight on time, but flexible
AND
I seem to always get the "bad surprises" right around Cruisin the Coast, or the DAY before a "track day" like a number of years ago, when I used to have a 3 finger Borg & Beck style clutch, and one of the fingers BROKE on the 15 minute drive back from what was supposed to be the "last thing" I had to do to get the Roadrunner ready for my Day Of Conquest (in my mind) with my car club at the local drag strip.
SO a quick and easy technique like this is a great idea. @4406bbl I want to be sure I understand. You're suggesting taking my fuel flex lines off of the carb fuel bowl inlet fitting and removing the fuel bowl site plug, then blow compressed air in through the fuel line inlet, allowing it to escape via the site plug hole? Please let me know, and I hope others will chime in.

 

[4406bbl]

I think the meaning of this quoted post has finally become clear in my mind!
Not that it would have changed my plans for how to go about or complete that repair, as I was already beyond the halfway point, I will certainly give this technique a shot in the future!
I believe the consensus is that the old, crusty PV HAD to be replaced, I certainly think so, and I believe there's value in "having a look-see" inside ALL 3 carbs since several years have passed since the last time I had my 6BBL called to muster for an inspection!
BUT
My schedule is usually tight on time, but flexible
AND
I seem to always get the "bad surprises" right around Cruisin the Coast, or the DAY before a "track day" like a number of years ago, when I used to have a 3 finger Borg & Beck style clutch, and one of the fingers BROKE on the 15 minute drive back from what was supposed to be the "last thing" I had to do to get the Roadrunner ready for my Day Of Conquest (in my mind) with my car club at the local drag strip.
SO a quick and easy technique like this is a great idea. @4406bbl I want to be sure I understand. You're suggesting taking my fuel flex lines off of the carb fuel bowl inlet fitting and removing the fuel bowl site plug, then blow compressed air in through the fuel line inlet, allowing it to escape via the site plug hole? Please let me know, and I hope others will chime in.

No simply remove a lower fuel bowl screw, drain then blow a little air down the vent tubes, that way there is very little fuel left in the bowls to get nasty. Pull the line off the fuel pump inlet and run it until it dies for starters. This is even easy with steel lines as the front carb comes right off.

 

[biomedtechguy]

No simply remove a lower fuel bowl screw, drain then blow a little air down the vent tubes, that way there is very little fuel left in the bowls to get nasty. Pull the line off the fuel pump inlet and run it until it dies for starters. This is even easy with steel lines as the front carb comes right off.

Thanks for the detailed explanation.
At this point I am going to be running the engine more often, partly to keep it "exercised" and with the weather, friends going to our local drag strip more often, local car shows & car club monthly cruises so I plan on using a fuel treatment that is formulated to address moisture in the tank specifically for this "service event" along with filling up the tank with 100% no ethanol premium as normal, I just hadn't been filling the tank, and that invited water and possibly other "empty space funk" to develop.

 

[biomedtechguy]

PROBLEM SOLVED!!​

Today I had to address the teeny fuel leak from the front carb that looked like it could be coming from the fuel fitting that threads into the bowl, which uses a hair-thin gasket ring to seal and has been a known seal to be careful to verify. I used a little of that same Form-A-Gasket #1 that I had used to insure a seal at the fuel bowl bolt heads. Fired it up and opened the electronic cutouts so I could hear every pulse of the ignition.
Ran great, especially at part throttle and squeezing the throttle down a bit...
most importantly steady state throttle is SMOOTH, no more jerky feel or sounds in the driveline!
I do have to fine tune the idle but thanks to the Promax angled idle mixture screws on the rear carb plate, I can access all 6 screws while it's running.
One last note: I am convinced the old, crusty POWER VALVE is the reason for the problem I've had, and one of the things that stood out is: Turning the idle mixture screws on either outboard carb or the center carb metering block made very little difference in the idle speed or quality. The "6bbl trick" to tune the outboard carbs' idle screws by blocking either air bleed hole and watching the RPMs rise or fall also had little effect if any. Normally I would suspect a vacuum leak, but I guess the power valve problem was affecting the fuel delivery at idle too!

 

[biomedtechguy]

I still have to do a fine tune on the 6 idle mixture screws, but the main problem was during steady or part throttle driving.
Here's a video from after I put the 3 carbs back together: