BritishV8 Forum

Curtis, you really don't want to use a bolt for an air cleaner, too much wear on the threads in the carb body, better to use some sort of stud and a nut on top and leave the threads in the carb stationary. In addition that air cleaner needs a fairly large nut on top to give it a finished look, I'm sure the original fastener was a rather large Buick emblem of some sort. The nut that Jim machined for it was so neat, octagonal in shape, just the perfect touch. A shame it was lost.

Allthread is what, about grade 3 I think? Then there is the fact that it broke below the nut locking it to the air horn, which basically means the leverage from the air cleaner wobbling around is what broke it. This sort of failure is not unheard of. I do seem to remember having seen a sort of stud with an enlarged hex portion on the plain shank above the threads, and such a stud would be ideal but we don't have one, and the lengths of the ends would be fairly critical. I have a thought, if Carl gets the end out and can measure that for me I think I might be able to turn down a spare ARP head stud and cut some flats to tighten it. Then I'd just need the measurement to the air cleaner for the top part. Doing that I could even enlarge the shank a little where it goes through the air horn before it hits the threads. That would really make it a lot stronger. Then probably go for 5/16" on the top section.

Jim

Hey Jim,

"all thread" or "ready rod" as we Canucks call it comes in various grades up to grade 8.
They also offer connecting nuts that are aprox an inch long and through threaded internally.
A 1/4 to 5/16 adapter nut might solve the problem rather easily.
The ARP head bolt idea is probably the ideal fix but the ready rod fix can be done "in the field".
What about some sort of strap or strut down to the manifold to take some of the stress off of the stud?

Okay, pay up!

I had Carl would be the first one to break it!   :-)   (jk)

JIm:  Was there a locknut at the top of the carb to hold the stud in?  (Or no room?)   This at least would mean the shank will snap one nuts height above the carb next time!  :-)

There are some hi-tech inserts these days (*Time-Sert* comes to mind) that you could install IN the carb body to keep it from getting wallowed out.  

Then I'm with Bill-- Grade 8 and lop the head off.    

I was snapping double-ended studs on my rear sway bar with regularity-- each time I'd drill it out, install a cut Grd 8 bolt instead.   Knock wood-- no problems, two years running.   (All four ends now Grd 8, though the shank I've tapped into is still the original material.)  

RE:  Tool Kit.   We looked into that while it was here, but didn't get the car finished enough to outfit it for the road.   The plan was a travelling tool kit in a case (there is a decent Automotive one at Lowes of all places--- $70).  Then a Dr's bag for the "specialty" tools, and then a webbing/pouch thing to hold the specific chemicals that the car needs.   Also a small try of assorted hardware, maybe.  

This way the touring drivers wouldn't have to worry about transporting their own tools (Cell phone would suffice!) and the kit would slowly evolve over time into whatever was necessary.  

We also were going to start a "Log Book" with comments, events, etc.    Looks like we have an entry!   (Though, technically, all of Dan's driving should have been in there, too-- the events it went to, the mileage, the oil consumption, etc.   You never know when an off-hand observation-- "I hear a little rattling under the hood"-- by one driver will lead to FACT by another:  'Okay, found that rattle-- the air cleaner nut must have been loose, 'cuz now it's GONE!"  

(You get the idea....   Basically, you don't want to have to read through <this> whole Forum to find comments and build notes on the car.  It needs to be WITH THE CAR for he who is currently driving it!   :-)  )

$.02

M

[qoute]There are some hi-tech inserts these days (*Time-Sert* comes to mind) that you could install IN the carb body to keep it from getting wallowed out. [/quote]

Too late. It's already wallowed out.

I removed what's left of the stud last night. I was surprised how much it would wiggle while still all the way down in the carb.  I unscrewed about 1/2" of threads, then the last 1 1/2" of all thread pulled straight up & out without the need to turn it.



BTW, I didn't break it, it broke itself!  I have been exceptionally careful with the tranny so I wouldn't be the one to break it.

Carl, I need dimensions. You say 1-1/2" inserted then 1/2" of threads, is this accurate enough for me to make the replacement that way? Do you have dial calipers? What is the diameter of the hole in the top of the air horn? For instance, will a 9/32" drill bit go in 1-1/2" deep? If so I can make a stepped stud with a hex that will not break. Then I need the distance from the air horn to the nut seat on the air cleaner and I think I can manage the rest. I have a piece I can make a new nut from. The sooner I have accurate dimensions the sooner I can make the new parts.

Jim

Re: Lowe's tools.  Kobalt tools are made by Snap-On

I'll try to get those measurements Sunday.

Busy trying to fix the fuel leak today.  We 'bout had a melt down. Y'all said it was running way too rich, but I smelled raw gas.  Fuel was spurting out of the top of the fuel pressure regulator towards the header turndown.  Has the fuel pressure been tested?

Tools....great idea.  Maybe we should start with a spare tire, a jack, & a lug wrench.  Or, at least, a can of fix-a-flat.  

Carl,
The part for the speedo came yesterday evening, UPS ground.  I will mail it to you at Imperial Drive, OK?

That's fine.  Surely US Mail in a padded envelope would be cheaper than UPS.

Carl, et al:

The Time Sert starts with an oversize drill that you tap for an oversize, threaded OD that itself holds the correct ID.   So as long as the hole isn't wallowed out more than this drill size, it would still work.   :-)

RE:  fuel pressure.   I don't ever remember getting far enough to check, but maybe Tim remembers differently?  I did vacuum and timing checks, but that was it.  

RE:  Kobalt tools and Snap-On.   I find that VERY hard to believe, Dan!   Given Snap-On's reputation and pricing, IF they made it-- they'd put their name on it!  (And charge 5x more!)   Now, it might be same base company or supplier that Snap-On uses for it's "other" tools (Blue Point, etc.)  

A set of Kobalt sockets is around $25.  That same Snap-On set would be $198.   I find it hard to reconcile that gap!    :-)   (That being said, I think Kobalt stuff is fine for a "hopefully-limited-usage", bang around the trunk, tool kit.)

Cheers!   Hitting 79 degrees here on Wednesday!   Hopefully Carl gets the same nice driving weather...

M

I highly doubt we need to do anything to repair the carb. The air horn is not a threaded part. The threads are in the body below it, and a half inch of thread engagement for a quarter inch bolt is about right for zinc. The allthread broke off BELOW the jam nut, meaning that a combination of too much tensile force and rocking the jam nut against the air horn overstressed and work fatigued it and the cracks that developed at the thread root eventually propagated far enough to let it snap off. To me the curious thing is that the big nut didn't stay attached to the air cleaner body but I guess the jam nut was small enough to go through the hole with the threaded rod. Even if it had for awhile, as the point sticking up the farthest it would have been the most scarred up by the road so we'd still be at the very least trying to clean it up. But between Dan and Carl I'm getting lots of good practice making 8 sided nuts ;-)

I'm with Bill though, I think we need to get a proper fastener back on it. running around with a bolt in the thing is a good way to wallow out the threads for real.

Jim

My store manager read through this Roadmaster thread and was truly impressed with the car as it exists today, considering what we started with in 2008.

He's a Corvette enthusiast from years ago.

OK brother Racoons, here we go again. New stud and Big Nut for the air cleaner. A little different this time but hopefully it'll work OK.

Jim







The stud is made from heat treated 4140 alloy and the shank is .020" oversized. Should be plenty stout.

Amazing!

I would have loved to watch you make that.

Nice work, Jim.

May I make a suggestion? Run a nut up on the threaded portion that goes into the carb. After the shaft is threaded into the carb body, run the nut down tight against the carb. That way, if it should ever break again, most likely it will break above the nut, making it easier to back out the stub.

BTDT.

We tried that and it broke below the nut. This stud is designed so that the shoulder tightens down on top of the air horn (where the jam nut would normally be) and the oversized (.270") shank above the threads will be a close fit, making the assembly much stronger than the allthread we used before. I don't think this one will break. The heat treated chrome moly is very strong. We are also looking at alternate ways to secure the air cleaner and take some of the stress off the stud.

btw, any of you guys notice anything unusual about that stud?

Jim

Quote...any of you guys notice anything unusual about that stud?

Probably a cannabalized part from a BBB. (camshaft maybe?)

That would be a rather lumpy cam.  

Looks great, Jim...you are and extremely talented individual.

Thanks guys. But if you look closely at the stud, there's something you're missing. Clue? Top photo should give it away.

Jim

Distributor shaft?

Ha!

Okay, this is where I usually draw the line. I'm cannibalizing parts from my 'was running'  MG. Need a source for fuel pressure regulator diaphragm and spring.

We have $253.73 in the BADASS  account.
Just to let everyone know.

Steve

Quoteany of you guys notice anything unusual about that stud?

Must have something to do with the hexagonal section that's smaller than the major diameter, eh?