2x2’s again- power valve questions

[Bruce_MO]

I have been following the recent thread about 2x2’s on an 8BA with interest. My ‘53 Ranch Wagon has a EAB motor with Offy heads and Offy intake with two 94’s. Also has a Mallory distributor. It has always run rich and had any manner of flat spots when accelerating. I have tried several jet/PV combinations thru the years. Per Charlie-NY, my latest set-up is I’ve blanked off the PV’s and am running jets of a size he recommended but I can recall. It runs “fair” after about 10 minutes to get thoroughly warmed up, but runs really badly until then. So I’m going back to one of the options described in the original thread… 49 jets and either 5.5 or 4.5 PV’s. Below is a photo of the assortment of PV’s I’ve used. One thing is strange… the 5.5 and 4.5 PV’s on the top and middle row are very stiff and seem to “snap” open and closed. There is no continuous motion i.e., start to open at the initial vacuum value, and then gradually open to 100%. They would just pop open and dump fuel. The other PV’s at the bottom of the photo labeled Daytona have a smooth and continuous opening action, and they seem to be much easier to open than the other PV’s. The pressure to initiate opening is far less.
So… what’s the proper opening action of a PV? Closed, then snap open? Or gradually open? Anybody have a recommendation for the best choice and a p/n? And I will recheck everything for vac leaks and fuel leaks. Thanks

[petehoovie]

Originally Posted by Bruce_MO

I have been following the recent thread about 2x2’s on an 8BA with interest. My ‘53 Ranch Wagon has a EAB motor with Offy heads and Offy intake with two 94’s. Also has a Mallory distributor. It has always run rich and had any manner of flat spots when accelerating. I have tried several jet/PV combinations thru the years. Per Charlie-NY, my latest set-up is I’ve blanked off the PV’s and am running jets of a size he recommended but I can recall. It runs “fair” after about 10 minutes to get thoroughly warmed up, but runs really badly until then. So I’m going back to one of the options described in the original thread… 49 jets and either 5.5 or 4.5 PV’s. Below is a photo of the assortment of PV’s I’ve used. One thing is strange… the 5.5 and 4.5 PV’s on the top and middle row are very stiff and seem to “snap” open and closed. There is no continuous motion i.e., start to open at the initial vacuum value, and then gradually open to 100%. They would just pop open and dump fuel. The other PV’s at the bottom of the photo labeled Daytona have a smooth and continuous opening action, and they seem to be much easier to open than the other PV’s. The pressure to initiate opening is far less.
So… what’s the proper opening action of a PV? Closed, then snap open? Or gradually open? Anybody have a recommendation for the best choice and a p/n? And I will recheck everything for vac leaks and fuel leaks. Thanks

[Ziggster]

From the pic, it seems the top two (5.5) still have the radius at the base of the stem. If so, the gasket will not seat properly, and it will leak fuel past the gasket and into the intake. The second row (4.5) seems to have that radius machined off which is what you need for the gasket to seal. The last two from Daytona parts also seem to have that radius present, but cannot say for sure on any of them as the pics are a bit blurry.

[Ziggster]

Pics from Post #76 in my thread about a 2 x 2 carb setup that shows the the radius/non-radius on the base of the stem.

https://www.fordbarn.com/forum/showt...=Radius&page=4

[petehoovie]

Originally Posted by Ziggster

Pics from Post #76 in my thread about a 2 x 2 carb setup that shows the the radius/non-radius on the base of the stem.

https://www.fordbarn.com/forum/showt...=Radius&page=4

[Sid]

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I'm sure you have seen my posts. As mentioned be sure the seating surface on the power valve is smooth. No slightly raised portion on it. My 2 cents worth here. I played with my carbs. this last weekend. I have either a 5.5 or 6.5 pv in the rear carb. I put a 2.5 in the front carb. .050 jets in rear and .049 in front as that was the smallest I had. I initially ran the carbs direct and it worked well. Then I started thinking that is a whole lot of fuel when driving around town with a small c.i. engine so I set it up progressive. Front carb pulls in at between 1/3 and 1/2 throttle. It is working very well. My though process is why dump excess fuel into motor while low speed driving. Think about your other V8 cars. The secondaries or 4 barrel don't kick in until you have some rpm. I took mine out for a short try out Sunday night and pulled the plugs the next morning and they were a nice cocoa color after idling for about 5 minutes. Also keep in mind your elevation. I'm 2300 feet. My 40 Ford is running 2 Stromberg 97 with 43 mains and 65 pv direct linkage and it is happy. Whatever I would not run the same power valve in both carbs. That is one hell of a lot of fuel once the vacuum drops. I would also consider running slightly smaller jets in one carb. like .047-.049's. I' played with several tri powers and 2x4's but not so much with flatheads. Some here may not agree with me but what I said worked for me.

[Terry,OH]

I also have noticed some of the PV snap into position and some move smoothly. I feel either is good as long as they return to the "closed" position on their own. I believe Charlie Schwindler has a test device he made to check operation and for leaks in their diaphragm.