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Take this for whatever it's worth;

I've been rebuilding carbs for 40+ years, professionally for 20. I have literally built thousands of Holley carbs, and I haven't installed a power valve blowout protector in a single unit.

The number of come-backs I've had due to a blown power valve?

Zero.
 

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Take this for whatever it's worth;

I've been rebuilding carbs for 40+ years, professionally for 20. I have literally built thousands of Holley carbs, and I haven't installed a power valve blowout protector in a single unit.

The number of come-backs I've had due to a blown power valve?

Zero.
I have a buddy who is one of those guys for whom every silver cloud has a dark lining. He was always lamenting "there goes the power valve" after the slightest spit / stumble of the engine. Seemed like he wanted a reason to take the carbs apart? I seriously doubt he actually had many failures (if any) and I am SURE he did not have any where the number of failures he fretted about.
 

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Seemed like he wanted a reason to take the carbs apart
I invent reasons to take perfectly fine cabs apart all the time because I like to. But the only bad power valves I ever find are just plain old. They dry rot and crack from sitting. I've goofed a tune or two in my time and had some pretty epic backfires and none of them damaged a power valve. The 307 in my Malibu has at least one, probably several, bad intake valves and sneezes HARD and repeatedly through the carb at anything over half throttle. It has an 1850 on it that doesn't have power valve protection and hasn't damaged one yet.

And for Pete's sake- a power valve costs practically nothing and takes a couple minutes to change!
 

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I invent reasons to take perfectly fine cabs apart all the time because I like to. But the only bad power valves I ever find are just plain old. They dry rot and crack from sitting. I've goofed a tune or two in my time and had some pretty epic backfires and none of them damaged a power valve. The 307 in my Malibu has at least one, probably several, bad intake valves and sneezes HARD and repeatedly through the carb at anything over half throttle. It has an 1850 on it that doesn't have power valve protection and hasn't damaged one yet.

And for Pete's sake- a power valve costs practically nothing and takes a couple minutes to change!
Maybe you mised my point. I was agreeing with the premise that there is IMHO too much focus on the perceived ease of damaging those power valves. IMHO even EPIC backfires don't necessarily kill the PV. I didn't care if he changed the valve everyday same as people change their underware or brush their teeth every day. I was just fed up with hearing the lamentations caused by even sub epic level backfires.
 

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Maybe you mised my point. I was agreeing with the premise that there is IMHO too much focus on the perceived ease of damaging those power valves. IMHO even EPIC backfires don't necessarily kill the PV. I didn't care if he changed the valve everyday same as people change their underware or brush their teeth every day. I was just fed up with hearing the lamentations caused by even sub epic level backfires.
No I got what you were saying. I was just saying I take perfectly good carbs apart just for fun, joking that I can relate to your friend, though for very different reasons.

I probably should've started another paragraph for the rest of what I posted after my bad joke so it didn't seem it was directed at you. Seems like our opinion is the same as far as power valves are concerned. Sorry for the confusion.
 

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No I got what you were saying. I was just saying I take perfectly good carbs apart just for fun, joking that I can relate to your friend, though for very different reasons.

I probably should've started another paragraph for the rest of what I posted after my bad joke so it didn't seem it was directed at you. Seems like our opinion is the same as far as power valves are concerned. Sorry for the confusion.
No sweat Tommy. "No harm no foul" as the saying goes.

It is very refreshing to see your last post. Most people today have no knowledge of the purpose of a new paragraph in a composition. Some of the material I read these day shows absolutely no indication of knowledge of composition rules / possession of composition skills. Everyone makes mistakes, everyone has oversights but some folks don't even have a clue about the rules that they are not applying. No sweat here on my end as far as your earlier response to me!

Yes we do agree on the subject of PV failures. I have had my share of epic backfires and I cannot recall ever killing a power valve. That is the reason I took just shook my head and rolled my eyes whenever my firend, "Mr. Doom and Gloom", went off on another tear about killing another PV because of whatever event he concluded had killed his current PV.
 

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Discussion Starter · #28 ·
All the parts are cleaned up so the rebuild can begin this weekend. In fact, I think the old 37-119 Trick Kit I have may have enough parts to do the rebuild. I could take the new one back or just put it on the shelf for future use. I must have bought the kit years ago, probably to get one or two little parts I needed at the time.
 

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If you need any small parts to keep from having to open the new kit please let me know. I buy all the parts individually and in bulk so I have a small speedshop's level of supplies. I'd be happy to send you whatever you're lacking.
 

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I only dress the threaded metering block boss ends of the body for flat, as the screw hole bosses bend easily when some Gorilla uses 57 foot pounds of screw torque to hold a leaky metering block in place after it was bent so far out of shape it won't work.

For the metering blocks, I lay them out with their bent curvature up in the center, and VERY LIGHTLY press them back flat. Way too easy to turn a metering block into instant junk with other methods.

Before I get plastered by everybody for what I am saying, please remember, I worked in the Pro-Stock carb dept of Holley Racing for 5 years, band sawing Dominator's apart, making them into "Split Duals", then helping tune them on race cars.

As far as the leaking PV, a few ways to get them to leak, frm the wrong gasket, to the over tightening in the metering block, but what aI was asking, and got the right answer, was, did the vacuum diaphragm get punctured, was there fuel leaking into the manifold? I have seen a very small tear in a PV diaphragm load the entire bowl volume down to the hole, into the intake manifold, cylinder, and oil pan. NONE of ahy of that is good at all. Glad that wasn't the issue.

The PV save device is simply to make sure the PV diaphragm doesn't have failure issues if the engine backfires. The reverse pressure can easily kill the PV diaphagm.
 

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It is very refreshing to see your last post. Most people today have no knowledge of the purpose of a new paragraph in a composition. Some of the material I read these day shows absolutely no indication of knowledge of composition rules / possession of composition skills. Everyone makes mistakes, everyone has oversights but some folks don't even have a clue about the rules that they are not applying. No sweat here on my end as far as your earlier response to me!
I didn't graduate high school and English was worst subject up until I called it quits but I do try to use proper structure as best I can. It's hard enough to convey personality, humor and really any inflection in written words when you're using the correct spelling, cadence and punctuation, let alone if you don't even try. Writing is an art I'll never master but I understand it's import and apply the principles to the best of my ability.

My biggest hurdle is that I'm usually typing on a phone while trying to monitor stuff at work and my fingers can't type as fast as my brain moves. Which means I type REALLY slow... Then I get distracted... Then I forget what I was on about in the first place... etc.

I'm glad we understand each other! Back to carb stuff!
 

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Discussion Starter · #32 ·
All buttoned up and ready to go back on. I did end up opening the new Trick Kit, there were just a number of parts I needed which I did not have on hand from the old kit.

So now the bowl screw gaskets are hard plastic? I suppose that will make them reusable, but I sure hope they seal okay and don't melt from fuel contact.

I also found that the springs that support the floats are different. Not a big deal, just never noticed before. One has about twice as many coils as the other. They both supply about the same amount of support, just look different. Hope it doesn't matter which one goes where.

And no parts left over! Yay!
 

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I don't prefer the plastic screws, but, they don't tear, nor separate, and they are reusable. I always coat those paper gaskets with anti-seize. BTW, bowl screw torque is 60 INCH POUNDS, (5 foot pounds), NO TIGHTER.

The different design springs help further dampen float operation when the carbs are mounted on off-road, and/or, high vibration environments.
 

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I don't prefer the plastic screws, but, they don't tear, nor separate, and they are reusable. I always coat those paper gaskets with anti-seize. BTW, bowl screw torque is 60 INCH POUNDS, (5 foot pounds), NO TIGHTER.

The different design springs help further dampen float operation when the carbs are mounted on off-road, and/or, high vibration environments.
Dave,
Not trying to hijack this thread but every time I see a post by you i wonder the following. Are you the same Dave Ray that used to be on Graveyard Carz?
 

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dunno, but he used to be Ignitionman here. Still the best.
 

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I take it that is some sort of TV show, like Overhaulin' and other disasters. Nope, not me, but I do know a very small handful of them. I have always been too busy fixing stuff from those sort of people to spend time on shows like that.

Yes, that is the old board name I used to have.

Right now, I am watching highlights from earlier today, Valencia, Espana, FIM Moto E Race 1, no gasoline engines, only electric Grands Prix race bikes. Strange to hear varying whining of electric motors, instead of 4 stroke exhaust notes.
 

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Whatever paper material they're using these days for bowl screw gaskets is garbage--same goes for power valve gaskets. You hold your lip wrong and the damned things shear in half when you tighten them down, and guarandamnteed they're gonn'a leak.

I used to soak both of them with a light oil (typically 3-in-1) and let them soak for a minute before installing them. This allowed the surfaces to slip when tightening them down and improved the odds of the gasket shearing in half to 50/50. :|

It also allowed the gaskets to compress far better than when dry--you'd be amazed at how many carbs I've had on my bench that came in with LOOSE power valves (and bowl screws). I'm sure they were tight when they were built, but the gaskets obviously took a set once the carb went into service and loosened everything up.

I've since switched to the black nylon bowl screw gaskets, and I had custom Teflon power valve gaskets made a while back. ZERO problems since, but you do have to sauce the bowl screw gaskets up before assembling. The material is pretty "sticky" when it's dry, and often the friction will stop the bowl screw from turning before the screw is actually tight and the gaskets are compressed. A little lube alleviates the problem.

BTW, Rich, I answered your PM.
 
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