More Power Valve Questions

[SofaKing]

My stock 21 stud engine is incredibly hard to start and runs very rough when it does, will not idle and accelerates poorly. Plugs are sooty black,strong gas smell in cab. I can find no fault in ignition system. I have a holley carb, #91-99. I put a daytona carb kit in it. The Daytona power valve is stamped 5.5 and will drain the float bowl when it is not running or carb is on the bench. Books indicate valve is statically open and pulled closed by vacuum.

I have a hard time believing the float bowl is supposed to drain everytime the car is turned -off. Since the truck has never run before and does not now I also cannot take vacuum readings to select the proper power valve. Lastly, different sources state the "stock" power valve ranges from a 5.5 to a 7.5 and that being off by .5 is detrimental. The carb originally had a #3 stamped on its power valve when I replaced it. I am at 4500' now, truck spent previous life in S. Utah at a slightly lower altitude I believe.

So my questions are:
1. Is the power valve supposed to pass fuel when no vacuum is available?
2. What size is standard from factory?
3. How does one make selection if engine doesn't run/idle?
4. How do you test/ measure the valve operation on the bench?

Thanks

[Mart]

1 No. It should seal. To be more exact, while the valve is technically open, (Vacuum draws it shut) there are no fuel passages that will leak through.
2, 7.5 I think
3, a 7.5 should be ok, the problem is elsewhere. (Actually altitude may play a part) 5.5 should work, I guess.
4, You can't test the operation, but you can check for leaks.

I'd be looking at the power valve seat, the radius and the gasket. Lots and lots of previous posts here on 94s running rich. You can get rich running for many other reasons, but as you have a static fuel drain problem, check those items I mentioned above, plus is the valve itself leaking through the diaphragm? the underside face of the diaphragm should not be wet.

Mart.

[Terry,OH]

Daytona makes a fairly good rebuilding kit for the 94. Check all that Mart has suggested. The altitude your at should make very little difference. With the leakage of fuel from the float bowl into the running engine you will experience the hard starts (in essence the engine is flooded) rough idle (TOOO much fuel) inability to adjust idle mixture correctly.

[Charlie ny]

SofaKing,
Here is my take on your situation.......there are no better kits than Daytona
Parts kits. The one issue however is the power valve. The PV functions well and
holds up to corn gas with no issues. The rub is there is no real gasket face on the PV.
As a matter of practice I machine these PV's to create a proper gasket surface
which is square with the threads, flat and exactly the right diameter to trap the
gasket of my design and manufacture. The gasket is integral with the PV.
I will admit to selling a lot of these babies to whom ever wants them.
Charlie ny

[Ronnie]

This will test a valve for pass or fail.

R

[tubman]

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I really don't know how to put this without being laughed at or getting funny looks, but I just suck on 'em and see if they work (same principle as above). Also, whenever I rebuild a carb, I fill the float bowl with gas and let it sit on the bench overnight. If the float bowl is down significantly the next day, I know I'm not done.

[JT FORD]

Good idea Tubman, I do the same thing.

[Mart]

I suck on em too. Have detected some bad ones that way.

[SofaKing]

Originally Posted by Charlie ny

SofaKing,
Here is my take on your situation.......there are no better kits than Daytona
Parts kits. The one issue however is the power valve. The PV functions well and
holds up to corn gas with no issues. The rub is there is no real gasket face on the PV.
As a matter of practice I machine these PV's to create a proper gasket surface
which is square with the threads, flat and exactly the right diameter to trap the
gasket of my design and manufacture. The gasket is integral with the PV.
I will admit to selling a lot of these babies to whom ever wants them.
Charlie ny

Charlie, I called Vintage Speed 772-778-0809 yesterday and today and no one answered or returned message. I assume that is your business based on past threads. I'd like to buy one and a spare please before I push my soon to be flaming truck into one of the many open pit mines that dot the landscape here.

To Mart, Tubman and the rest who suck on them, it occurred to me but I was enjoying a nice homebrew and didn't want to ruin the taste.

[tubman]

Do a little research on Vintage Speed and Charlie-NY and you will see they are very different.

You have to get the taste out of your mouth some way; I can't think of a better reason for another homebrew.

[SofaKing]

Originally Posted by tubman

Do a little research on Vintage Speed and Charlie-NY and you will see they are very different.

You have to get the taste out of your mouth some way; I can't think of a better reason for another homebrew.

Thanks for the info, I hope no one was offended. I sent Charlie-NY a PM.

I am at that happy time in life when no reason at all is sufficient for another beer.

[jack orchard]

The advantage of using a vacuum gauge:
1) you can see when the valve begins to open
2) you can see when the valve is fully open

[Mart]

Vacuum sucks.

[FireEngineMike]

Send your carb to Charlieny. He just rebuilt my Stromberg 97 and it started today as soon as I pushed the button. Never did that before.

[Charlie ny]

Greg,
As Tubman says I have nothing at all to do with VS, I will say no more.
I will check my PM's.
Charlie ny

[AnthonyG]

As FireEngineMike did so did I on my tri carb 94s. Send the carb to Charlie let him do his thing. You'll be happy you did!!
Thx again Charlie!

[bluardun]

Mr. Sofaking, I have been experiencing similar problems with my "94" Carb. I have found that Holley makes power valves for their modern carburetors that are being sold in the rebuild kits for our vintage carburetors. The difference is very slight, but allows the carb. to "leak down". Notice very carefully at the area where the threaded shaft meets the mushroom that houses the diaphragm. The power valves for the vintage carbs this transition is a sharp 90% angle. And used a lead gasket. The modern replacement has a slight radius from the threaded shaft to the area the gasket would seal. Plus the new kits supply a red fiber gasket that difficult to center on the threaded shaft and make a good seal. Take a very close good look.
enjoy your hobby.

[chap52]

If you have contacted CharleyNY you will get it worked out. Don't worry about getting all the bugs worked out...I guarantee there will be new ones down the road. Enjoy the adventure.

[Charlie ny]

SK,
Your PV 'kit' is on the way.
Charlie ny

[outlaw]

Moroso makes a checker for testing power valves. Pn #62295. I don't remember the cost, & I havn't used mine yet. You screw the power valve into it & put the cap with the nipple on it, the plug your vacuum tester on it. Pump it up & see at what vacume level it will pull before it closes. Bill