Author Topic: high flow petcock?  (Read 640 times)

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Offline Don R

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high flow petcock?
« on: October 30, 2023, 03:42:30 pm »
 I remember a petcock thread but can't find it anywhere.
 I bought a mid 70's 750K Honda that had a brass pipe x flare adapter screwed onto the tank nipple with a large flare type brass gas cock and 1/4" copper sticking out.
 At any rate, that alerted me to the possibility of using a female flare or pipe thread to get to a better flowing petcock. The project in question will be a larger cc sohc with a turbo. I've been warned that the zenith/bendix carb bowl is notorious for going dry.
 Pingel's web site is pretty vague as far as what fits our stuff. Has anyone found a decent performance petcock that fits any of our tanks? I'll need a 5/16" fuel line going to an electric pump. 
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Offline BenelliSEI

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Re: high flow petcock?
« Reply #1 on: October 30, 2023, 05:58:37 pm »
Don….. from memory; 1975/76 tanks have a fairly large nipple brazed to the tank. It’s got a hole big enough to slip in the screen filter. The petcock is held on with a large gland nut and rubber seal. Might be easiest to use that nut/ sealing washer to hold a piece of flared pipe (or even turn some pipe to resemble the petcock)? Then just add and “in line” shut off?

Offline scottly

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Re: high flow petcock?
« Reply #2 on: October 30, 2023, 08:50:48 pm »
If I recall correctly, Frank used to make adapters that screwed onto the tank nipple, with a copper crush washer, and a tapered pipe thread that a Pingle threaded into.
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Offline Don R

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Re: high flow petcock?
« Reply #3 on: October 31, 2023, 07:37:09 pm »
  Exactly what I was thinking thanks for the leads about finding that info.
  I boiled that F gas tank with cleaning vinegar to pre-derust before a finish flush using my expensive evaporust. It turned out the rust is what was keeping the gas in it. L0L.
  I also have a k tank with that same size nipple, I'm thinking it's really close to 3/8" pipe which is also close to AN-6 female flare.

  I'll try a 3/8" pipe inlet petcock with a 3/8" pipe coupling screwed directly to the tank.  The 3/8" NPT fitting that's on it now seals well enough to keep the vinegar in it.
 
« Last Edit: October 31, 2023, 07:43:18 pm by Don R »
No matter how many times you paint over a shadow, it's still there.
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 You don't need a weatherman to know which way the wind blows.

Offline MRieck

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Re: high flow petcock?
« Reply #4 on: November 01, 2023, 04:47:59 pm »
If I recall correctly, Frank used to make adapters that screwed onto the tank nipple, with a copper crush washer, and a tapered pipe thread that a Pingle threaded into.
Did the same thing....drilled and tapped a piece of aluminum rod and cut some flats into it to be able to tighten it up.
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Offline Tracksnblades1

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Re: high flow petcock?
« Reply #5 on: November 01, 2023, 05:01:14 pm »
  Exactly what I was thinking thanks for the leads about finding that info.
  I boiled that F gas tank with cleaning vinegar to pre-derust before a finish flush using my expensive evaporust. It turned out the rust is what was keeping the gas in it. L0L.
  I also have a k tank with that same size nipple, I'm thinking it's really close to 3/8" pipe which is also close to AN-6 female flare.

  I'll try a 3/8" pipe inlet petcock with a 3/8" pipe coupling screwed directly to the tank.  The 3/8" NPT fitting that's on it now seals well enough to keep the vinegar in it.

Don,

Chapin Cylinder Head Inc, used gasoline to check for leaks after weld repairing cracks in cast iron cylinder heads and blocks last time I had one repaired. Said gasoline will find a crack cold that won’t show up with water even under pressure cold…not sure about vinegar…
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Offline Don R

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Re: high flow petcock?
« Reply #6 on: November 01, 2023, 06:52:29 pm »
 I'm pretty sure I can make it hold gas, but I do know what you mean.
 I'm seeing some interesting Harley petcocks with 3/8" threads.
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline Old Scrambler

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Re: high flow petcock?
« Reply #7 on: November 02, 2023, 05:51:00 pm »
Guzzler units from Pingle are pricy................I use Fastenall units on the cheap but never fail :D ;D
Dennis in Wisconsin
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Offline BenelliSEI

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Re: high flow petcock?
« Reply #8 on: November 03, 2023, 10:34:58 am »
  Exactly what I was thinking thanks for the leads about finding that info.
  I boiled that F gas tank with cleaning vinegar to pre-derust before a finish flush using my expensive evaporust. It turned out the rust is what was keeping the gas in it. L0L.
  I also have a k tank with that same size nipple, I'm thinking it's really close to 3/8" pipe which is also close to AN-6 female flare.

  I'll try a 3/8" pipe inlet petcock with a 3/8" pipe coupling screwed directly to the tank.  The 3/8" NPT fitting that's on it now seals well enough to keep the vinegar in it.

Don,

Chapin Cylinder Head Inc, used gasoline to check for leaks after weld repairing cracks in cast iron cylinder heads and blocks last time I had one repaired. Said gasoline will find a crack cold that won’t show up with water even under pressure cold…not sure about vinegar…

Very true….. I also use Varsol. It will creep into anything.