question on stripped out bolt holes

[Triple Pickle]

Not universally so, especially on non-"race bowl" carbs. I believe the OP stated it is a 4175 spreadbore?

He did? I know not all of them are, but I think the majority of them are adjusted with the bowl on. TV

Both of those are extremely bad ideas.


I don't know what new Holly carbs are made of... All the old ones are a zinc rich diecast, sometimes called "pot metal". They may be doing a cast aluminum, but I doubt it.

If you stripped 3 out of 4, you are doing something wrong. Either you are cross threading (getting the screw started crooked) or overtightening the bolts. If there is resistance to turning in the screw, you are doing something wrong. Bowl screws are just to be snugged firmly, not cranked on. Too tight and you start causing all sorts of issues with warping the main body or the bowl.

Not universally so, especially on non-"race bowl" carbs.

Not universally so, especially on non-"race bowl" carbs. I believe the OP stated it is a 4175 spreadbore?

He did? Ok. Good luck! What’s the worse that could happen anyway?

 

[Big_John]

He did? I know not all of them are, but I think the majority of them are adjusted with the bowl on. TV

I think those carbs don't have a sight plug or an external adjustment. I could be wrong though.... I haven't touched a Holley carb in many years.

 

[Gerald Morris]

i bought a ten dollar set of chinese metric taps and dies at a flea market to use as thread chasers at home. i have real taps and dies for all the more common metric sizes but i'm too cheap to buy a complete good set for the house. so far i have used them as intended with good results. i'm an old hand of course and experience counts.

Yes, I too have some Chinese taps and dies, for pipe. Even Swedish steel can snap in unskilled hands. Still, for my engine block, heads, or other mission critical bits of iron, I use old U.S., Canadian, U.K., West German or Scandinavian taps and dies. One can find old tool sets from estates, flea markets and of course, eBay, often for very reasonable prices. Building trade professional tools are very good, as are machinist tools. Its more hit and miss aside from those kind.

 

[rags]

One can find old tool sets from estates, flea markets and of course, eBay, often for very reasonable prices. Building trade professional tools are very good, as are machinist tools. Its more hit and miss aside from those kind.

absolutely. most of my stuff is second hand. as for tradesmans tools, guys all want battery stuff now so good commercial grade corded tools can be gotten for pennies on the dollar. my 12k rotary drive on was a repo. $2800 and they installed it. there really is no reason that people can't have good tools, they just have to be vigilant and bag deals as they come along.

 

[rags]

A Heli-Coiled hole is stronger than a tapped hole and much more durable.

that's a fact. it really is the best solution here. as for heliicoil tapping aluminum directly, well it takes a steady hand. with aluminum, i'd rather have more material to work with than less. once it's drilled the material's gone. depends a lot on the situation. if it's an ear and there's a danger of cracking the ear, it's getting drilled and very carefully.

 

[Gerald Morris]

Not a good idea in this case.

The screws for the float bowl on a Holley not only hold the float bowl on, they have to seal to the float bowl itself. Small washer type gaskets are under the head. You make it oversize and now you have to get the screw head to seal, you'll have to drill a larger hole and counterbore the float bowl for a larger sealing washer. The screw will need a flat sealing surface and then there's the gasket.

You're so right here! I repent the advice, if an easier, viable way can be found. I'd probably just get another carb.

 

[spstan]

Heli-coil.

Triple; my machinist friend also swears by helicoil. I watched this fellow on YouTube (Project Farm) and he compared the different thread restorers (metal insert versus epoxy). He showed the helicoil held at above 1000lbs of torque and that the Locite form a thread held up to 130 lbs of torque. I'm thinking that helicoil is overkill and that the Loctite may be sufficient for a small carb job. Besides if the Loctite doesn't work I can always step up to the helicoil. Paul