Holley fuel bowl thread tap

[arnie_human]

Hello guys

I'm repairing a holley carb at the moment and one of the long fuel bowl bolts has broken off. Can someone tell me which thread tap I need to get a new bolt in? I allready got a UNC 1/4 tap bit thats to big. Here in Holland we only measure in metric. So bit of a hassle to find correct thread tap.

Thanks guys.

Gr Arnoud

 

[Dana67Dart]

I can't guarantee that there is only one float bowl stud / screw size on all Holley carbs so use this info at your own risk.

based on the below website It looks like 12-24 is what you need

ARP Carburetor Float Bowl Bolt Kits 400-0310

DEWALT #16 Drill and 12-24 NC Tap Set-DWA1408 - The Home Depot

unless the hole is a through hole you should look for a "bottom tap" with the flat end

 

[brian6pac]

You will need a repair kit for 12-24, Heli-coil tap and Heli-coil. It might be tight if you already tapped it 14-20?

 

[brian6pac]

Here is a complete kit,

https://www.globalindustrial.com/p/...m_term=4582627026478408&utm_content=Catch All

 

[Dana67Dart]

arnie_human, because you are in surrounded by a sea of metric with an standard car you might be well invested to get a kit like this:

https://www.amazon.com/dp/B003FJW0GK/?tag=joeychgo-20

 

[brian6pac]

I have worked on old British bikes, 50's Triumphs that have BS British standard, BSW British standard Whitworth, BSPP British Standard Pipe Parallel, BSPT British Standard Pipe Tapered What a nightmare, and metric has 3 thread pitches, English has fine & coarse. Then there is trying to teach a newbe about threads, they just look at me like I'm crazy.

 

[Mattax]

Yes 12-24 sounds right. There's a full list of threads used on Holleys somewhere on RFS. I'll add a link in bit.
There's a few other companies now making quality thread repair inserts (besides Helicoil). I think one is out of Australia. In any event, your closest source of Unified thread stuff is probably the UK.

Deep Roots Holley Thread Sizes and Torque Notes

 

[yellow rose]

I have worked on old British bikes, 50's Triumphs that have BS British standard, BSW British standard Whitworth, BSPP British Standard Pipe Parallel, BSPT British Standard Pipe Tapered What a nightmare, and metric has 3 thread pitches, English has fine & coarse. Then there is trying to teach a newbe about threads, they just look at me like I'm crazy.

Yep...all those threads make you say swear words. Lots of them.

 

[diymirage]

how big a hurry are you in Arnie?

i'll be heading that way in July and if you want to, i can bring a kit then

but im sure places like Stadegaard, or Hendriks would carry them, or could order one for you

in fact, als ik jou was zou ik Hendriks gewoon even bellen, 0413 338100