I am working on the center Carburetor of a six pack setup. I am tired of replacing check valves if this engine coughs once. So I found and installed the Holley branded "Power Valve Check Valve Kit" and here are my observations.

Here is how the Check Valve Ball install went. First I followed the directions to the letter and double checked everything. In a word the install went smoothly and will work. But here are my observations of this kit and the install. The original hole for the vacuum to get to the power valve in the carb base is .155 of an inch. The drill is a #16 drill at .177". The little orifice/seat that I installed was .190" in diameter. Here is the kicker for me. All this went well but the check ball that was installed was .140" in diameter. The only thing keeping this in place and from going through the engine is a very tiny, very light wound spring. I'm sure Holley gave this some thought and I'm sure worse case scenario is that 440 could pass that ball right through it without any damage but this would be my only concern with this kit. The orifice is a .013" press fit and it's not going anywhere.

I am asking here what others think of this. As I said this is a Holley kit that went into a Holley carburetor base as directed. I'm sure this will do it's intended job but does anyone share my concern of that check ball and the tiny spring?

Thanks for taking your time to comment on this.

Lisa

 

what i read years ago. was that the hole that the check ball seats on is small enough that the ball cant fall theou. then take a Phillips screwdriver and dent the edges of the hole to let the vac go pull around the ball. when pressure comes up the ball is pushed up blocking the pressure from going to the vac valve. no spring. and the ball can NOT get sucked into the engine.

 

Thank you Moe7404 for your input. But at this point in the game the carburetors are on and the entire fuel system from the tank to the cars has been renewed. Going to put five gallons of clear premium fuel in it and start it today.

The ball is held under tension at the base of the seat by the spring. The spring would have to disintegrate or rust out to let that ball out in reality and then the ball would go through the engine with what ever was left of the spring. As mentioned the ball is .015" smaller then the factory hole in the base. The ball WILL go through that hole. If the carburetor comes off again in the future I would try your idea of using a center punch and try to move the metal of that hole closed to keep that ball and spring captive at all costs. But at this point I am going to trust in Holley to know what they were doing.

Thanks for your feedback.

Lisa

 

to combat rust start using Marvel Mystery Oil in the fuel. 4 oz for 10 gal gas. you will find it will start better. and amount of oil is low enough the it wont drop the octane. and / or check this out. http://www.ampcolubes.com/

 

Here is an update on my progress with this six pak repair. Yesterday I put five gallons of fresh "clear" premium fuel in the car and started it up for the first time. To my chagrin the car ran a little better and was not pouring out black smoke but it was still fat and had trouble idling; just like a bad power valve! So I remove the center carburetor again and also place a call to Holley's tech support for some advice. I had to wait for a return call from them and in the mean time I'm checking out the power valve system. All looks well but when I suck on this new valve that is in the metering body it moves but just doesn't want to seem to hold a vacuum when I put my tongue against it. So I take the "old" valve that I removed and put it back in and did the same thing and this one there was no doubt that it was holding the vacuum. About this time the Holley tech called me back and we discussed the Holley check valve kit that I put in. It was installed correctly and was free and should work. But it was clear this Tech had no magic bullet for me and even questioned why I would be working on this old school stuff when FI was clearly the way to go. I was obviously talking to someone that was born after this six pak was already an old system. So I got off the phone and decided to take a punch and remove the Check ball system from the carburetor. The bottom line was that Holley and Chrysler for what ever reason put in a .155" passage for the vacuum signal to pass though to get to the power valve and with this kit I restricted that down to about .050". So I reassemble the carb and install it. I start the car this time and it runs perfectly; snappy throttle response and a nice idle. So for what ever reason I would have to say that the "Power Valve Saver" - the check ball kit may have been my problem. Yes I did install it correctly and it would test properly but what other conclusion can I come to. The new factory sealed power valve could have been bad or had issues too that the restricted vacuum just couldn't pull the valve closed and hold it closed at idle. But for now the bottom line is the car is running like new again and I gained more experience working on these Holley's.

One other little issue I had after I got it running I discovered that the fuel pump diaphragm was leaking now and the sitting with the alcohol fuel took it's toll there too. So I ordered a new pump and will get that one and then I'm finished and will make a point now to drive these vehicles more regularly and keep them going. Sitting is a huge problem and now I have the time to avoid that issue too. Being "clear" alcohol free premium fuel is available where I live that will be all I put in my show cars from now on.

With regards to Marvel Mystery Oil, well I have added that to the crankcase of everything I own for years. But I have never put it in the fuel. I have read about that and with this recent spat of fuel related issues I will start that routine too. Can't hurt. But I also think that keeping the vehicles more available to run is important.

One other quick fact that may help others, when I was talking to the Holley Tech he mentioned that in their newer carburetors the passage for the Vacuum signal to get to the power valve is quite small and thus the design of the kit that I installed. The ball that was in the kit was .140" in diameter so their factory passage is probably in the neighborhood or .125" or smaller to keep that ball from going through the engine. Remember the factory hole in the throttle body of my six pak carb was .155". But the vacuum restrictor plate that the ball seated against had about a .050 hole in it. I know it all doesn't make a lot of sense but I wanted to share the information incase others had issues.

I appreciate all your help and comments and thanks for taking you time to put them down here. They have been very helpful.

Lisa

 

I'm Wondering if the difference is in the metering block itself at this point?
At any rate... Glad you got them squared away... Now you just need to get them out on the road and get the tires pounded out round again.....

 

In looking at the main carb body the cavity that is in it for the power valve is huge. It's a big casting relief to keep the carb light but it's still pretty big. I don't know how big it is in a newer carb. As I mentioned I put the old power valve back in and took the restrictor of the back fire valve out. All I can say is it works like new. Once I get all the issues sorted out on this vehicle I may go back in and just play with this carburetor and with the engine running perfect, take the carb off and install that check valve back in and try it again. THEN if the engine is still running perfect take the carb off again and swap out the power valve again and check that too. But what ever the combination is it's running like new right now and I am moving on to solving the other issues with this car now. I can always come back and experiment in the future and of course I would report here what I find.

Lisa

 

mslisaj

The only time I have ever had backfire issues was when I created a lean issue with the center carb.

When I adjusted my accelerator pump to activate at launch rpms on the converter, I had an inherent lean condition in street driving operations. I never ever had a power valve blow with many, many backfires (lucky??).

I believe if you get the accelerator pump adjusted as per spec, you will not have any backfire issues. I also found it is good to drill out or install a larger accelerator pump nozzle to get that extra fuel into the airstream quicker which will relieve any inherent off idle/cruise lean conditions.

 

Well Drag Pak I think you have it nailed. The reality is this car has done a lot of sitting over it's life together; which now i have the time on my hands to correct that. But truly the only time this backfires is when I'm trying to start dry carburetors and I'm pumping the throttle to get and keep it going. Then it will pop back. Now I have been very lucky too as I have not blow a valve every time this things lets go and pops back. It never back fires when I have it running and on the street but then again I am not nailing the throttle either. A long long time ago when I acquired these two six pak set ups I overhauled all the carbs and there was a whole series of mods to do on them; drill out this orifice, use that spring and so on. The accelerator pump squirter got the treatment too as I remember. But this is a great running system. I have put all the bugs in it by and through the lack of use. Plus now I have the money to buy the parts for these carbs that they really need like fuel bowls. So today I will put the new fuel pump on and take this for a ride. Then I vow to keep it running regularly.

Anyway, thanks for your help and suggestions.

Lisa